From c74994eb14c4d1e34f5f5e7ff630c2c7f5f19ad2 Mon Sep 17 00:00:00 2001
From: akshayaurora <akshayaurora@gmail.com>
Date: Sat, 10 Dec 2016 04:08:27 +0530
Subject: [PATCH 1/2] fix pkgresources recipe

---
 recipes/pkgresources/__init__.py                 | 2 +-
 recipes/pkgresources/{ => pkgr}/pkg_resources.py | 0
 2 files changed, 1 insertion(+), 1 deletion(-)
 rename recipes/pkgresources/{ => pkgr}/pkg_resources.py (100%)

diff --git a/recipes/pkgresources/__init__.py b/recipes/pkgresources/__init__.py
index a46869f..8924556 100644
--- a/recipes/pkgresources/__init__.py
+++ b/recipes/pkgresources/__init__.py
@@ -7,7 +7,7 @@ import os
 class pkg_resources(Recipe):
     depends = ["hostpython", "python"]
     archs = ['i386']
-    url = ""
+    url = "pkgr"
 
     def prebuild_arch(self, arch):
         sh.cp("pkg_resources.py", join(self.ctx.dist_dir, "root", "python", "lib", "python2.7", "site-packages", "pkg_resources.py"))
diff --git a/recipes/pkgresources/pkg_resources.py b/recipes/pkgresources/pkgr/pkg_resources.py
similarity index 100%
rename from recipes/pkgresources/pkg_resources.py
rename to recipes/pkgresources/pkgr/pkg_resources.py

From 8655bf279b8edb47d3920ffca2095880b4420053 Mon Sep 17 00:00:00 2001
From: akshayaurora <akshayaurora@gmail.com>
Date: Mon, 26 Dec 2016 21:07:38 +0530
Subject: [PATCH 2/2] Update PIL and Libffi recipes to latest versions

---
 recipes/host_setuptools/__init__.py           |   27 +-
 recipes/hostlibffi/__init__.py                |    3 +-
 recipes/pil/__init__.py                       |   10 +-
 recipes/pil/pil_setup.patch                   |  128 +-
 recipes/pkgresources/__init__.py              |    7 +-
 .../pkgr/{pkg_resources.py => __init__.py}    | 1448 +++--
 recipes/pkgresources/pkgr/_vendor/__init__.py |    0
 recipes/pkgresources/pkgr/_vendor/appdirs.py  |  552 ++
 .../pkgr/_vendor/packaging/__about__.py       |   21 +
 .../pkgr/_vendor/packaging/__init__.py        |   14 +
 .../pkgr/_vendor/packaging/_compat.py         |   30 +
 .../pkgr/_vendor/packaging/_structures.py     |   68 +
 .../pkgr/_vendor/packaging/markers.py         |  301 +
 .../pkgr/_vendor/packaging/requirements.py    |  127 +
 .../pkgr/_vendor/packaging/specifiers.py      |  774 +++
 .../pkgr/_vendor/packaging/utils.py           |   14 +
 .../pkgr/_vendor/packaging/version.py         |  393 ++
 .../pkgresources/pkgr/_vendor/pyparsing.py    | 5696 +++++++++++++++++
 recipes/pkgresources/pkgr/_vendor/six.py      |  868 +++
 recipes/pkgresources/pkgr/extern/__init__.py  |   73 +
 20 files changed, 9849 insertions(+), 705 deletions(-)
 rename recipes/pkgresources/pkgr/{pkg_resources.py => __init__.py} (75%)
 create mode 100644 recipes/pkgresources/pkgr/_vendor/__init__.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/appdirs.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/__about__.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/__init__.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/_compat.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/_structures.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/markers.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/requirements.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/specifiers.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/utils.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/packaging/version.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/pyparsing.py
 create mode 100644 recipes/pkgresources/pkgr/_vendor/six.py
 create mode 100644 recipes/pkgresources/pkgr/extern/__init__.py

diff --git a/recipes/host_setuptools/__init__.py b/recipes/host_setuptools/__init__.py
index 5ee6056..53f6a7f 100644
--- a/recipes/host_setuptools/__init__.py
+++ b/recipes/host_setuptools/__init__.py
@@ -11,10 +11,27 @@ class HostSetuptools(Recipe):
     archs = ["x86_64"]
     url = "setuptools"
 
+    def get_stt_env(self, arch):
+        build_env = arch.get_env()
+        build_env["IOSROOT"] = self.ctx.root_dir
+        build_env["IOSSDKROOT"] = arch.sysroot
+        build_env["LDSHARED"] = join(self.ctx.root_dir, "tools", "liblink")
+        build_env["ARM_LD"] = build_env["LD"]
+        build_env["ARCH"] = arch.arch
+        build_env["C_INCLUDE_PATH"] = join(arch.sysroot, "usr", "include")
+        build_env["LIBRARY_PATH"] = join(arch.sysroot, "usr", "lib")
+        build_env["CFLAGS"] = " ".join([
+            "-I{}".format(join(self.ctx.dist_dir, "include", arch.arch, "freetype")) +
+            " -I{}".format(join(self.ctx.dist_dir, "include", arch.arch, "libjpeg")) +
+            " -arch {}".format(arch.arch)
+            ])
+        return build_env
+
+
     def prebuild_arch(self, arch):
         hostpython = sh.Command(self.ctx.hostpython)
         sh.curl("-O",  "https://bootstrap.pypa.io/ez_setup.py")
-        shprint(hostpython, "./ez_setup.py")
+        shprint(hostpython, "./ez_setup.py", _env=self.get_stt_env(arch))
         # Extract setuptools egg and remove .pth files. Otherwise subsequent
         # python package installations using setuptools will raise exceptions.
         # Setuptools version 28.3.0
@@ -26,9 +43,9 @@ class HostSetuptools(Recipe):
             setuptools_egg_path = f.read().strip('./').strip('\n')
             unzip = sh.Command('unzip')
             shprint(unzip, setuptools_egg_path)
-        os.remove(setuptools_egg_path)
-        os.remove('setuptools.pth')
-        os.remove('easy-install.pth')
-        shutil.rmtree('EGG-INFO')
+        #os.remove(setuptools_egg_path)
+        #os.remove('setuptools.pth')
+        #os.remove('easy-install.pth')
+        #shutil.rmtree('EGG-INFO')
 
 recipe = HostSetuptools()
diff --git a/recipes/hostlibffi/__init__.py b/recipes/hostlibffi/__init__.py
index 7d64efa..a0a0ada 100644
--- a/recipes/hostlibffi/__init__.py
+++ b/recipes/hostlibffi/__init__.py
@@ -4,7 +4,8 @@ import sh
 
 class LibffiRecipe(Recipe):
     version = "3.2.1"
-    url = "ftp://sourceware.org/pub/libffi/libffi-{version}.tar.gz"
+    #url = "ftp://sourceware.org/pub/libffi/libffi-{version}.tar.gz"
+    url = "https://www.mirrorservice.org/sites/sourceware.org/pub/libffi/libffi-{version}.tar.gz"
     library = "build/Release-{arch.sdk}/libffi.a"
     include_per_arch = True
     include_dir = "build_{arch.sdk}-{arch.arch}/include"
diff --git a/recipes/pil/__init__.py b/recipes/pil/__init__.py
index f2e159c..f4bee01 100644
--- a/recipes/pil/__init__.py
+++ b/recipes/pil/__init__.py
@@ -6,9 +6,9 @@ import fnmatch
 
 
 class PillowRecipe(Recipe):
-    version = "2.8.2"
-    url = "https://pypi.python.org/packages/source/P/Pillow/Pillow-{version}.tar.gz"
-    #url = "https://github.com/python-pillow/Pillow/archive/{version}.tar.gz"
+    version = "3.4.2"
+    #url = "https://pypi.python.org/packages/source/P/Pillow/Pillow-{version}.tar.gz"
+    url = "https://github.com/python-pillow/Pillow/archive/{version}.tar.gz"
     library = "libpil.a"
     depends = ["hostpython", "host_setuptools", "pkgresources", "freetype", "libjpeg", "python", "ios"]
     pbx_libraries = ["libz", "libbz2"]
@@ -49,7 +49,9 @@ class PillowRecipe(Recipe):
         build_env = self.get_pil_env(arch)
         dest_dir = join(self.ctx.dist_dir, "root", "python")
         build_env['PYTHONPATH'] = join(dest_dir, 'lib', 'python2.7', 'site-packages')
-        shprint(hostpython, "-m", "easy_install",
+        es = self.ctx.dist_dir + '/hostpython/bin/easy_install'
+        easy_install = sh.Command(es)
+        shprint(easy_install, 
                 "--prefix", dest_dir, "-Z", "./",
                 _env=build_env)
 
diff --git a/recipes/pil/pil_setup.patch b/recipes/pil/pil_setup.patch
index 7b54193..571d6b5 100644
--- a/recipes/pil/pil_setup.patch
+++ b/recipes/pil/pil_setup.patch
@@ -1,60 +1,94 @@
---- Pillow-2.7.0/setup.py	2014-12-31 20:42:56.000000000 +0530
-+++ Pillow-2.7.0/setup.py	2015-02-26 19:38:59.000000000 +0530
-@@ -20,7 +20,6 @@
- 
+--- Pillow-3.4.2/setup.py 2016-12-19 19:10:30.000000000 +0530
++++ Pillow-2.4.2/setup.py 2016-12-19 23:07:15.000000000 +0530
+@@ -6,7 +6,9 @@
+ # Final rating: 10/10
+ # Your cheese is so fresh most people think it's a cream: Mascarpone
+ # ------------------------------
++
+ from __future__ import print_function
++BUILD_IOS = True
+ import glob
+ import os
+ import platform as plat
+@@ -21,7 +23,8 @@
+
  # monkey patch import hook. Even though flake8 says it's not used, it is.
  # comment this out to disable multi threaded builds.
 -import mp_compile
- 
- _IMAGING = (
-     "decode", "encode", "map", "display", "outline", "path")
-@@ -83,7 +82,7 @@
++if not BUILD_IOS:
++    import mp_compile
+
+ _IMAGING = ("decode", "encode", "map", "display", "outline", "path")
+
+@@ -103,11 +106,13 @@
      return open(file, 'rb').read()
- 
- try:
+
+
+-try:
 -    import _tkinter
-+    _tkinter = None
- except (ImportError, OSError):
-     # pypy emits an oserror
-     _tkinter = None
-@@ -186,7 +185,7 @@
-                 for d in os.environ[k].split(os.path.pathsep):
+-except (ImportError, OSError):
+-    # pypy emits an oserror
+-    _tkinter = None
++_tkinter = None
++if not BUILD_IOS:
++    try:
++        import _tkinter
++    except (ImportError, OSError):
++        # pypy emits an oserror
++        pass
+
+ NAME = 'Pillow'
+ PILLOW_VERSION = '3.4.2'
+@@ -216,7 +221,7 @@
                      _add_directory(library_dirs, d)
- 
--        prefix = sysconfig.get_config_var("prefix")
-+        prefix = False
-         if prefix:
+
+         prefix = sysconfig.get_config_var("prefix")
+-        if prefix:
++        if not BUILD_IOS and prefix:
              _add_directory(library_dirs, os.path.join(prefix, "lib"))
              _add_directory(include_dirs, os.path.join(prefix, "include"))
-@@ -199,7 +198,9 @@
-             _add_directory(library_dirs, os.path.join(
-                 "/usr/lib", "python%s" % sys.version[:3], "config"))
- 
+
+@@ -232,7 +237,7 @@
+                            os.path.join("/usr/lib", "python%s" %
+                                         sys.version[:3], "config"))
+
 -        elif sys.platform == "darwin":
-+        elif True:
-+            pass
-+        if False:
++        elif not BUILD_IOS and sys.platform == "darwin":
              # attempt to make sure we pick freetype2 over other versions
              _add_directory(include_dirs, "/sw/include/freetype2")
              _add_directory(include_dirs, "/sw/lib/freetype2/include")
-@@ -346,11 +347,7 @@
-                 _add_directory(include_dirs, tcl_dir)
- 
+@@ -346,7 +351,7 @@
+         # FIXME: check /opt/stuff directories here?
+
          # standard locations
--        _add_directory(library_dirs, "/usr/local/lib")
--        _add_directory(include_dirs, "/usr/local/include")
- 
--        _add_directory(library_dirs, "/usr/lib")
--        _add_directory(include_dirs, "/usr/include")
- 
-         # on Windows, look for the OpenJPEG libraries in the location that
-         # the official installer puts them
-@@ -575,7 +572,7 @@
-             exts.append(Extension(
-                 "PIL._webp", ["_webp.c"], libraries=libs, define_macros=defs))
- 
--        if sys.platform == "darwin":
-+        if False:
-             # locate Tcl/Tk frameworks
-             frameworks = []
-             framework_roots = [
+-        if not self.disable_platform_guessing:
++        if not BUILD_IOS and not self.disable_platform_guessing:
+             _add_directory(library_dirs, "/usr/local/lib")
+             _add_directory(include_dirs, "/usr/local/include")
+
+@@ -389,7 +394,9 @@
+
+         if feature.want('zlib'):
+             _dbg('Looking for zlib')
+-            if _find_include_file(self, "zlib.h"):
++            if BUILD_IOS:
++                feature.zlib = 'z'
++            elif _find_include_file(self, "zlib.h"):
+                 if _find_library_file(self, "z"):
+                     feature.zlib = "z"
+                 elif (sys.platform == "win32" and
+@@ -592,10 +599,10 @@
+                                   define_macros=defs))
+
+         tk_libs = ['psapi'] if sys.platform == 'win32' else []
+-        exts.append(Extension("PIL._imagingtk",
+-                              ["_imagingtk.c", "Tk/tkImaging.c"],
+-                              include_dirs=['Tk'],
+-                              libraries=tk_libs))
++#        exts.append(Extension("PIL._imagingtk",
++#                              ["_imagingtk.c", "Tk/tkImaging.c"],
++#                              include_dirs=['Tk'],
++#                              libraries=tk_libs))
+
+         exts.append(Extension("PIL._imagingmath", ["_imagingmath.c"]))
+         exts.append(Extension("PIL._imagingmorph", ["_imagingmorph.c"]))
diff --git a/recipes/pkgresources/__init__.py b/recipes/pkgresources/__init__.py
index 8924556..cc723b5 100644
--- a/recipes/pkgresources/__init__.py
+++ b/recipes/pkgresources/__init__.py
@@ -10,7 +10,12 @@ class pkg_resources(Recipe):
     url = "pkgr"
 
     def prebuild_arch(self, arch):
-        sh.cp("pkg_resources.py", join(self.ctx.dist_dir, "root", "python", "lib", "python2.7", "site-packages", "pkg_resources.py"))
+        pkgdir = join(self.ctx.dist_dir, "root", "python", "lib", "python2.7", "site-packages", "pkg_resources")
+        if not os.path.exists(pkgdir):
+            sh.mkdir(pkgdir)
+        sh.cp("-a", "./", pkgdir)
+        #sh.pip('install', '-t', join(self.ctx.dist_dir, "root", "python", "lib", "python2.7", "site-packages"))
+
 
 recipe = pkg_resources()
 
diff --git a/recipes/pkgresources/pkgr/pkg_resources.py b/recipes/pkgresources/pkgr/__init__.py
similarity index 75%
rename from recipes/pkgresources/pkgr/pkg_resources.py
rename to recipes/pkgresources/pkgr/__init__.py
index 511068a..9250328 100644
--- a/recipes/pkgresources/pkgr/pkg_resources.py
+++ b/recipes/pkgresources/pkgr/__init__.py
@@ -1,3 +1,4 @@
+# coding: utf-8
 """
 Package resource API
 --------------------
@@ -14,41 +15,38 @@ The package resource API is designed to work with normal filesystem packages,
 method.
 """
 
+from __future__ import absolute_import
+
 import sys
 import os
 import io
 import time
 import re
-import imp
+import types
 import zipfile
 import zipimport
 import warnings
 import stat
 import functools
 import pkgutil
-import token
-import symbol
 import operator
 import platform
 import collections
 import plistlib
 import email.parser
 import tempfile
+import textwrap
+import itertools
 from pkgutil import get_importer
 
-PY3 = sys.version_info > (3,)
-PY2 = not PY3
+try:
+    import _imp
+except ImportError:
+    # Python 3.2 compatibility
+    import imp as _imp
 
-if PY3:
-    from urllib.parse import urlparse, urlunparse
-
-if PY2:
-    from urlparse import urlparse, urlunparse
-
-if PY3:
-    string_types = str,
-else:
-    string_types = str, eval('unicode')
+from pkg_resources.extern import six
+from pkg_resources.extern.six.moves import urllib, map, filter
 
 # capture these to bypass sandboxing
 from os import utime
@@ -62,50 +60,190 @@ except ImportError:
 from os import open as os_open
 from os.path import isdir, split
 
-# Avoid try/except due to potential problems with delayed import mechanisms.
-if sys.version_info >= (3, 3) and sys.implementation.name == "cpython":
-    import importlib._bootstrap as importlib_bootstrap
-else:
-    importlib_bootstrap = None
-
 try:
-    import parser
+    import importlib.machinery as importlib_machinery
+    # access attribute to force import under delayed import mechanisms.
+    importlib_machinery.__name__
 except ImportError:
+    importlib_machinery = None
+
+from pkg_resources.extern import appdirs
+from pkg_resources.extern import packaging
+__import__('pkg_resources.extern.packaging.version')
+__import__('pkg_resources.extern.packaging.specifiers')
+__import__('pkg_resources.extern.packaging.requirements')
+__import__('pkg_resources.extern.packaging.markers')
+
+if (3, 0) < sys.version_info < (3, 3):
+    raise RuntimeError("Python 3.3 or later is required")
+
+# declare some globals that will be defined later to
+# satisfy the linters.
+require = None
+working_set = None
+
+
+class PEP440Warning(RuntimeWarning):
+    """
+    Used when there is an issue with a version or specifier not complying with
+    PEP 440.
+    """
+
+
+class _SetuptoolsVersionMixin(object):
+    def __hash__(self):
+        return super(_SetuptoolsVersionMixin, self).__hash__()
+
+    def __lt__(self, other):
+        if isinstance(other, tuple):
+            return tuple(self) < other
+        else:
+            return super(_SetuptoolsVersionMixin, self).__lt__(other)
+
+    def __le__(self, other):
+        if isinstance(other, tuple):
+            return tuple(self) <= other
+        else:
+            return super(_SetuptoolsVersionMixin, self).__le__(other)
+
+    def __eq__(self, other):
+        if isinstance(other, tuple):
+            return tuple(self) == other
+        else:
+            return super(_SetuptoolsVersionMixin, self).__eq__(other)
+
+    def __ge__(self, other):
+        if isinstance(other, tuple):
+            return tuple(self) >= other
+        else:
+            return super(_SetuptoolsVersionMixin, self).__ge__(other)
+
+    def __gt__(self, other):
+        if isinstance(other, tuple):
+            return tuple(self) > other
+        else:
+            return super(_SetuptoolsVersionMixin, self).__gt__(other)
+
+    def __ne__(self, other):
+        if isinstance(other, tuple):
+            return tuple(self) != other
+        else:
+            return super(_SetuptoolsVersionMixin, self).__ne__(other)
+
+    def __getitem__(self, key):
+        return tuple(self)[key]
+
+    def __iter__(self):
+        component_re = re.compile(r'(\d+ | [a-z]+ | \.| -)', re.VERBOSE)
+        replace = {
+            'pre': 'c',
+            'preview': 'c',
+            '-': 'final-',
+            'rc': 'c',
+            'dev': '@',
+        }.get
+
+        def _parse_version_parts(s):
+            for part in component_re.split(s):
+                part = replace(part, part)
+                if not part or part == '.':
+                    continue
+                if part[:1] in '0123456789':
+                    # pad for numeric comparison
+                    yield part.zfill(8)
+                else:
+                    yield '*' + part
+
+            # ensure that alpha/beta/candidate are before final
+            yield '*final'
+
+        def old_parse_version(s):
+            parts = []
+            for part in _parse_version_parts(s.lower()):
+                if part.startswith('*'):
+                    # remove '-' before a prerelease tag
+                    if part < '*final':
+                        while parts and parts[-1] == '*final-':
+                            parts.pop()
+                    # remove trailing zeros from each series of numeric parts
+                    while parts and parts[-1] == '00000000':
+                        parts.pop()
+                parts.append(part)
+            return tuple(parts)
+
+        # Warn for use of this function
+        warnings.warn(
+            "You have iterated over the result of "
+            "pkg_resources.parse_version. This is a legacy behavior which is "
+            "inconsistent with the new version class introduced in setuptools "
+            "8.0. In most cases, conversion to a tuple is unnecessary. For "
+            "comparison of versions, sort the Version instances directly. If "
+            "you have another use case requiring the tuple, please file a "
+            "bug with the setuptools project describing that need.",
+            RuntimeWarning,
+            stacklevel=1,
+        )
+
+        for part in old_parse_version(str(self)):
+            yield part
+
+
+class SetuptoolsVersion(_SetuptoolsVersionMixin, packaging.version.Version):
     pass
 
 
+class SetuptoolsLegacyVersion(_SetuptoolsVersionMixin,
+                              packaging.version.LegacyVersion):
+    pass
+
+
+def parse_version(v):
+    try:
+        return SetuptoolsVersion(v)
+    except packaging.version.InvalidVersion:
+        return SetuptoolsLegacyVersion(v)
+
+
 _state_vars = {}
 
+
 def _declare_state(vartype, **kw):
     globals().update(kw)
     _state_vars.update(dict.fromkeys(kw, vartype))
 
+
 def __getstate__():
     state = {}
     g = globals()
     for k, v in _state_vars.items():
-        state[k] = g['_sget_'+v](g[k])
+        state[k] = g['_sget_' + v](g[k])
     return state
 
+
 def __setstate__(state):
     g = globals()
     for k, v in state.items():
-        g['_sset_'+_state_vars[k]](k, g[k], v)
+        g['_sset_' + _state_vars[k]](k, g[k], v)
     return state
 
+
 def _sget_dict(val):
     return val.copy()
 
+
 def _sset_dict(key, ob, state):
     ob.clear()
     ob.update(state)
 
+
 def _sget_object(val):
     return val.__getstate__()
 
+
 def _sset_object(key, ob, state):
     ob.__setstate__(state)
 
+
 _sget_none = _sset_none = lambda *args: None
 
 
@@ -132,9 +270,10 @@ def get_supported_platform():
             pass
     return plat
 
+
 __all__ = [
     # Basic resource access and distribution/entry point discovery
-    'require', 'run_script', 'get_provider',  'get_distribution',
+    'require', 'run_script', 'get_provider', 'get_distribution',
     'load_entry_point', 'get_entry_map', 'get_entry_info',
     'iter_entry_points',
     'resource_string', 'resource_stream', 'resource_filename',
@@ -153,6 +292,9 @@ __all__ = [
     'ResolutionError', 'VersionConflict', 'DistributionNotFound',
     'UnknownExtra', 'ExtractionError',
 
+    # Warnings
+    'PEP440Warning',
+
     # Parsing functions and string utilities
     'parse_requirements', 'parse_version', 'safe_name', 'safe_version',
     'get_platform', 'compatible_platforms', 'yield_lines', 'split_sections',
@@ -175,19 +317,90 @@ __all__ = [
     'run_main', 'AvailableDistributions',
 ]
 
+
 class ResolutionError(Exception):
     """Abstract base for dependency resolution errors"""
+
     def __repr__(self):
-        return self.__class__.__name__+repr(self.args)
+        return self.__class__.__name__ + repr(self.args)
+
 
 class VersionConflict(ResolutionError):
-    """An already-installed version conflicts with the requested version"""
+    """
+    An already-installed version conflicts with the requested version.
+
+    Should be initialized with the installed Distribution and the requested
+    Requirement.
+    """
+
+    _template = "{self.dist} is installed but {self.req} is required"
+
+    @property
+    def dist(self):
+        return self.args[0]
+
+    @property
+    def req(self):
+        return self.args[1]
+
+    def report(self):
+        return self._template.format(**locals())
+
+    def with_context(self, required_by):
+        """
+        If required_by is non-empty, return a version of self that is a
+        ContextualVersionConflict.
+        """
+        if not required_by:
+            return self
+        args = self.args + (required_by,)
+        return ContextualVersionConflict(*args)
+
+
+class ContextualVersionConflict(VersionConflict):
+    """
+    A VersionConflict that accepts a third parameter, the set of the
+    requirements that required the installed Distribution.
+    """
+
+    _template = VersionConflict._template + ' by {self.required_by}'
+
+    @property
+    def required_by(self):
+        return self.args[2]
+
 
 class DistributionNotFound(ResolutionError):
     """A requested distribution was not found"""
 
+    _template = ("The '{self.req}' distribution was not found "
+                 "and is required by {self.requirers_str}")
+
+    @property
+    def req(self):
+        return self.args[0]
+
+    @property
+    def requirers(self):
+        return self.args[1]
+
+    @property
+    def requirers_str(self):
+        if not self.requirers:
+            return 'the application'
+        return ', '.join(self.requirers)
+
+    def report(self):
+        return self._template.format(**locals())
+
+    def __str__(self):
+        return self.report()
+
+
 class UnknownExtra(ResolutionError):
     """Distribution doesn't have an "extra feature" of the given name"""
+
+
 _provider_factories = {}
 
 PY_MAJOR = sys.version[:3]
@@ -197,6 +410,7 @@ SOURCE_DIST = 1
 CHECKOUT_DIST = 0
 DEVELOP_DIST = -1
 
+
 def register_loader_type(loader_type, provider_factory):
     """Register `provider_factory` to make providers for `loader_type`
 
@@ -206,6 +420,7 @@ def register_loader_type(loader_type, provider_factory):
     """
     _provider_factories[loader_type] = provider_factory
 
+
 def get_provider(moduleOrReq):
     """Return an IResourceProvider for the named module or requirement"""
     if isinstance(moduleOrReq, Requirement):
@@ -218,6 +433,7 @@ def get_provider(moduleOrReq):
     loader = getattr(module, '__loader__', None)
     return _find_adapter(_provider_factories, loader)(module)
 
+
 def _macosx_vers(_cache=[]):
     if not _cache:
         version = platform.mac_ver()[0]
@@ -233,9 +449,11 @@ def _macosx_vers(_cache=[]):
         _cache.append(version.split('.'))
     return _cache[0]
 
+
 def _macosx_arch(machine):
     return {'PowerPC': 'ppc', 'Power_Macintosh': 'ppc'}.get(machine, machine)
 
+
 def get_build_platform():
     """Return this platform's string for platform-specific distributions
 
@@ -261,6 +479,7 @@ def get_build_platform():
             pass
     return plat
 
+
 macosVersionString = re.compile(r"macosx-(\d+)\.(\d+)-(.*)")
 darwinVersionString = re.compile(r"darwin-(\d+)\.(\d+)\.(\d+)-(.*)")
 # XXX backward compat
@@ -274,7 +493,7 @@ def compatible_platforms(provided, required):
 
     XXX Needs compatibility checks for Linux and other unixy OSes.
     """
-    if provided is None or required is None or provided==required:
+    if provided is None or required is None or provided == required:
         # easy case
         return True
 
@@ -321,12 +540,14 @@ def run_script(dist_spec, script_name):
     ns['__name__'] = name
     require(dist_spec)[0].run_script(script_name, ns)
 
+
 # backward compatibility
 run_main = run_script
 
+
 def get_distribution(dist):
     """Return a current distribution object for a Requirement or string"""
-    if isinstance(dist, string_types):
+    if isinstance(dist, six.string_types):
         dist = Requirement.parse(dist)
     if isinstance(dist, Requirement):
         dist = get_provider(dist)
@@ -334,21 +555,23 @@ def get_distribution(dist):
         raise TypeError("Expected string, Requirement, or Distribution", dist)
     return dist
 
+
 def load_entry_point(dist, group, name):
     """Return `name` entry point of `group` for `dist` or raise ImportError"""
     return get_distribution(dist).load_entry_point(group, name)
 
+
 def get_entry_map(dist, group=None):
     """Return the entry point map for `group`, or the full entry map"""
     return get_distribution(dist).get_entry_map(group)
 
+
 def get_entry_info(dist, group, name):
     """Return the EntryPoint object for `group`+`name`, or ``None``"""
     return get_distribution(dist).get_entry_info(group, name)
 
 
 class IMetadataProvider:
-
     def has_metadata(name):
         """Does the package's distribution contain the named metadata?"""
 
@@ -490,8 +713,7 @@ class WorkingSet(object):
         if dist is not None and dist not in req:
             # XXX add more info
             raise VersionConflict(dist, req)
-        else:
-            return dist
+        return dist
 
     def iter_entry_points(self, group, name=None):
         """Yield entry point objects from `group` matching `name`
@@ -530,7 +752,7 @@ class WorkingSet(object):
 
             for key in self.entry_keys[item]:
                 if key not in seen:
-                    seen[key]=1
+                    seen[key] = 1
                     yield self.by_key[key]
 
     def add(self, dist, entry=None, insert=True, replace=False):
@@ -546,12 +768,12 @@ class WorkingSet(object):
         will be called.
         """
         if insert:
-            dist.insert_on(self.entries, entry)
+            dist.insert_on(self.entries, entry, replace=replace)
 
         if entry is None:
             entry = dist.location
-        keys = self.entry_keys.setdefault(entry,[])
-        keys2 = self.entry_keys.setdefault(dist.location,[])
+        keys = self.entry_keys.setdefault(entry, [])
+        keys2 = self.entry_keys.setdefault(dist.location, [])
         if not replace and dist.key in self.by_key:
             # ignore hidden distros
             return
@@ -590,6 +812,8 @@ class WorkingSet(object):
         best = {}
         to_activate = []
 
+        req_extras = _ReqExtras()
+
         # Mapping of requirement to set of distributions that required it;
         # useful for reporting info about conflicts.
         required_by = collections.defaultdict(set)
@@ -600,6 +824,10 @@ class WorkingSet(object):
             if req in processed:
                 # Ignore cyclic or redundant dependencies
                 continue
+
+            if not req_extras.markers_pass(req):
+                continue
+
             dist = best.get(req.key)
             if dist is None:
                 # Find the best distribution and add it to the map
@@ -617,19 +845,13 @@ class WorkingSet(object):
                             ws = WorkingSet([])
                     dist = best[req.key] = env.best_match(req, ws, installer)
                     if dist is None:
-                        #msg = ("The '%s' distribution was not found on this "
-                        #       "system, and is required by this application.")
-                        #raise DistributionNotFound(msg % req)
-
-                        # unfortunately, zc.buildout uses a str(err)
-                        # to get the name of the distribution here..
-                        raise DistributionNotFound(req)
+                        requirers = required_by.get(req, None)
+                        raise DistributionNotFound(req, requirers)
                 to_activate.append(dist)
             if dist not in req:
                 # Oops, the "best" so far conflicts with a dependency
-                tmpl = "%s is installed but %s is required by %s"
-                args = dist, req, list(required_by.get(req, []))
-                raise VersionConflict(tmpl % args)
+                dependent_req = required_by[req]
+                raise VersionConflict(dist, req).with_context(dependent_req)
 
             # push the new requirements onto the stack
             new_requirements = dist.requires(req.extras)[::-1]
@@ -638,6 +860,7 @@ class WorkingSet(object):
             # Register the new requirements needed by req
             for new_requirement in new_requirements:
                 required_by[new_requirement].add(req.project_name)
+                req_extras[new_requirement] = req.extras
 
             processed[req] = True
 
@@ -706,8 +929,7 @@ class WorkingSet(object):
                 try:
                     resolvees = shadow_set.resolve(req, env, installer)
 
-                except ResolutionError:
-                    v = sys.exc_info()[1]
+                except ResolutionError as v:
                     # save error info
                     error_info[dist] = v
                     if fallback:
@@ -745,11 +967,17 @@ class WorkingSet(object):
 
         return needed
 
-    def subscribe(self, callback):
-        """Invoke `callback` for all distributions (including existing ones)"""
+    def subscribe(self, callback, existing=True):
+        """Invoke `callback` for all distributions
+
+        If `existing=True` (default),
+        call on all existing ones, as well.
+        """
         if callback in self.callbacks:
             return
         self.callbacks.append(callback)
+        if not existing:
+            return
         for dist in self:
             callback(dist)
 
@@ -771,6 +999,26 @@ class WorkingSet(object):
         self.callbacks = callbacks[:]
 
 
+class _ReqExtras(dict):
+    """
+    Map each requirement to the extras that demanded it.
+    """
+
+    def markers_pass(self, req):
+        """
+        Evaluate markers for req against each extra that
+        demanded it.
+
+        Return False if the req has a marker and fails
+        evaluation. Otherwise, return True.
+        """
+        extra_evals = (
+            req.marker.evaluate({'extra': extra})
+            for extra in self.get(req, ()) + (None,)
+        )
+        return not req.marker or any(extra_evals)
+
+
 class Environment(object):
     """Searchable snapshot of distributions on a search path"""
 
@@ -805,7 +1053,7 @@ class Environment(object):
         is returned.
         """
         return (self.python is None or dist.py_version is None
-            or dist.py_version==self.python) \
+            or dist.py_version == self.python) \
             and compatible_platforms(dist.platform, self.platform)
 
     def remove(self, dist):
@@ -974,22 +1222,23 @@ class ResourceManager:
         old_exc = sys.exc_info()[1]
         cache_path = self.extraction_path or get_default_cache()
 
-        err = ExtractionError("""Can't extract file(s) to egg cache
+        tmpl = textwrap.dedent("""
+            Can't extract file(s) to egg cache
 
-The following error occurred while trying to extract file(s) to the Python egg
-cache:
+            The following error occurred while trying to extract file(s) to the Python egg
+            cache:
 
-  %s
+              {old_exc}
 
-The Python egg cache directory is currently set to:
+            The Python egg cache directory is currently set to:
 
-  %s
+              {cache_path}
 
-Perhaps your account does not have write access to this directory?  You can
-change the cache directory by setting the PYTHON_EGG_CACHE environment
-variable to point to an accessible directory.
-""" % (old_exc, cache_path)
-        )
+            Perhaps your account does not have write access to this directory?  You can
+            change the cache directory by setting the PYTHON_EGG_CACHE environment
+            variable to point to an accessible directory.
+            """).lstrip()
+        err = ExtractionError(tmpl.format(**locals()))
         err.manager = self
         err.cache_path = cache_path
         err.original_error = old_exc
@@ -1009,7 +1258,7 @@ variable to point to an accessible directory.
         extract, as it tracks the generated names for possible cleanup later.
         """
         extract_path = self.extraction_path or get_default_cache()
-        target_path = os.path.join(extract_path, archive_name+'-tmp', *names)
+        target_path = os.path.join(extract_path, archive_name + '-tmp', *names)
         try:
             _bypass_ensure_directory(target_path)
         except:
@@ -1103,49 +1352,18 @@ variable to point to an accessible directory.
         """
         # XXX
 
+
 def get_default_cache():
-    """Determine the default cache location
-
-    This returns the ``PYTHON_EGG_CACHE`` environment variable, if set.
-    Otherwise, on Windows, it returns a "Python-Eggs" subdirectory of the
-    "Application Data" directory.  On all other systems, it's "~/.python-eggs".
     """
-    try:
-        return os.environ['PYTHON_EGG_CACHE']
-    except KeyError:
-        pass
+    Return the ``PYTHON_EGG_CACHE`` environment variable
+    or a platform-relevant user cache dir for an app
+    named "Python-Eggs".
+    """
+    return (
+        os.environ.get('PYTHON_EGG_CACHE')
+        or appdirs.user_cache_dir(appname='Python-Eggs')
+    )
 
-    if os.name!='nt':
-        return os.path.expanduser('~/.python-eggs')
-
-    # XXX this may be locale-specific!
-    app_data = 'Application Data'
-    app_homes = [
-        # best option, should be locale-safe
-        (('APPDATA',), None),
-        (('USERPROFILE',), app_data),
-        (('HOMEDRIVE','HOMEPATH'), app_data),
-        (('HOMEPATH',), app_data),
-        (('HOME',), None),
-        # 95/98/ME
-        (('WINDIR',), app_data),
-    ]
-
-    for keys, subdir in app_homes:
-        dirname = ''
-        for key in keys:
-            if key in os.environ:
-                dirname = os.path.join(dirname, os.environ[key])
-            else:
-                break
-        else:
-            if subdir:
-                dirname = os.path.join(dirname, subdir)
-            return os.path.join(dirname, 'Python-Eggs')
-    else:
-        raise RuntimeError(
-            "Please set the PYTHON_EGG_CACHE enviroment variable"
-        )
 
 def safe_name(name):
     """Convert an arbitrary string to a standard distribution name
@@ -1156,13 +1374,15 @@ def safe_name(name):
 
 
 def safe_version(version):
-    """Convert an arbitrary string to a standard version string
-
-    Spaces become dots, and all other non-alphanumeric characters become
-    dashes, with runs of multiple dashes condensed to a single dash.
     """
-    version = version.replace(' ','.')
-    return re.sub('[^A-Za-z0-9.]+', '-', version)
+    Convert an arbitrary string to a standard version string
+    """
+    try:
+        # normalize the version
+        return str(packaging.version.Version(version))
+    except packaging.version.InvalidVersion:
+        version = version.replace(' ', '.')
+        return re.sub('[^A-Za-z0-9.]+', '-', version)
 
 
 def safe_extra(extra):
@@ -1171,7 +1391,7 @@ def safe_extra(extra):
     Any runs of non-alphanumeric characters are replaced with a single '_',
     and the result is always lowercased.
     """
-    return re.sub('[^A-Za-z0-9.]+', '_', extra).lower()
+    return re.sub('[^A-Za-z0-9.-]+', '_', extra).lower()
 
 
 def to_filename(name):
@@ -1179,194 +1399,37 @@ def to_filename(name):
 
     Any '-' characters are currently replaced with '_'.
     """
-    return name.replace('-','_')
+    return name.replace('-', '_')
 
 
-class MarkerEvaluation(object):
-    values = {
-        'os_name': lambda: os.name,
-        'sys_platform': lambda: sys.platform,
-        'python_full_version': platform.python_version,
-        'python_version': lambda: platform.python_version()[:3],
-        'platform_version': platform.version,
-        'platform_machine': platform.machine,
-        'python_implementation': platform.python_implementation,
-    }
+def invalid_marker(text):
+    """
+    Validate text as a PEP 508 environment marker; return an exception
+    if invalid or False otherwise.
+    """
+    try:
+        evaluate_marker(text)
+    except SyntaxError as e:
+        e.filename = None
+        e.lineno = None
+        return e
+    return False
 
-    @classmethod
-    def is_invalid_marker(cls, text):
-        """
-        Validate text as a PEP 426 environment marker; return an exception
-        if invalid or False otherwise.
-        """
-        try:
-            cls.evaluate_marker(text)
-        except SyntaxError:
-            return cls.normalize_exception(sys.exc_info()[1])
-        return False
 
-    @staticmethod
-    def normalize_exception(exc):
-        """
-        Given a SyntaxError from a marker evaluation, normalize the error
-        message:
-         - Remove indications of filename and line number.
-         - Replace platform-specific error messages with standard error
-           messages.
-        """
-        subs = {
-            'unexpected EOF while parsing': 'invalid syntax',
-            'parenthesis is never closed': 'invalid syntax',
-        }
-        exc.filename = None
-        exc.lineno = None
-        exc.msg = subs.get(exc.msg, exc.msg)
-        return exc
+def evaluate_marker(text, extra=None):
+    """
+    Evaluate a PEP 508 environment marker.
+    Return a boolean indicating the marker result in this environment.
+    Raise SyntaxError if marker is invalid.
 
-    @classmethod
-    def and_test(cls, nodelist):
-        # MUST NOT short-circuit evaluation, or invalid syntax can be skipped!
-        items = [
-            cls.interpret(nodelist[i])
-            for i in range(1, len(nodelist), 2)
-        ]
-        return functools.reduce(operator.and_, items)
+    This implementation uses the 'pyparsing' module.
+    """
+    try:
+        marker = packaging.markers.Marker(text)
+        return marker.evaluate()
+    except packaging.markers.InvalidMarker as e:
+        raise SyntaxError(e)
 
-    @classmethod
-    def test(cls, nodelist):
-        # MUST NOT short-circuit evaluation, or invalid syntax can be skipped!
-        items = [
-            cls.interpret(nodelist[i])
-            for i in range(1, len(nodelist), 2)
-        ]
-        return functools.reduce(operator.or_, items)
-
-    @classmethod
-    def atom(cls, nodelist):
-        t = nodelist[1][0]
-        if t == token.LPAR:
-            if nodelist[2][0] == token.RPAR:
-                raise SyntaxError("Empty parentheses")
-            return cls.interpret(nodelist[2])
-        msg = "Language feature not supported in environment markers"
-        raise SyntaxError(msg)
-
-    @classmethod
-    def comparison(cls, nodelist):
-        if len(nodelist) > 4:
-            msg = "Chained comparison not allowed in environment markers"
-            raise SyntaxError(msg)
-        comp = nodelist[2][1]
-        cop = comp[1]
-        if comp[0] == token.NAME:
-            if len(nodelist[2]) == 3:
-                if cop == 'not':
-                    cop = 'not in'
-                else:
-                    cop = 'is not'
-        try:
-            cop = cls.get_op(cop)
-        except KeyError:
-            msg = repr(cop) + " operator not allowed in environment markers"
-            raise SyntaxError(msg)
-        return cop(cls.evaluate(nodelist[1]), cls.evaluate(nodelist[3]))
-
-    @classmethod
-    def get_op(cls, op):
-        ops = {
-            symbol.test: cls.test,
-            symbol.and_test: cls.and_test,
-            symbol.atom: cls.atom,
-            symbol.comparison: cls.comparison,
-            'not in': lambda x, y: x not in y,
-            'in': lambda x, y: x in y,
-            '==': operator.eq,
-            '!=': operator.ne,
-        }
-        if hasattr(symbol, 'or_test'):
-            ops[symbol.or_test] = cls.test
-        return ops[op]
-
-    @classmethod
-    def evaluate_marker(cls, text, extra=None):
-        """
-        Evaluate a PEP 426 environment marker on CPython 2.4+.
-        Return a boolean indicating the marker result in this environment.
-        Raise SyntaxError if marker is invalid.
-
-        This implementation uses the 'parser' module, which is not implemented
-        on
-        Jython and has been superseded by the 'ast' module in Python 2.6 and
-        later.
-        """
-        return cls.interpret(parser.expr(text).totuple(1)[1])
-
-    @classmethod
-    def _markerlib_evaluate(cls, text):
-        """
-        Evaluate a PEP 426 environment marker using markerlib.
-        Return a boolean indicating the marker result in this environment.
-        Raise SyntaxError if marker is invalid.
-        """
-        import _markerlib
-        # markerlib implements Metadata 1.2 (PEP 345) environment markers.
-        # Translate the variables to Metadata 2.0 (PEP 426).
-        env = _markerlib.default_environment()
-        for key in env.keys():
-            new_key = key.replace('.', '_')
-            env[new_key] = env.pop(key)
-        try:
-            result = _markerlib.interpret(text, env)
-        except NameError:
-            e = sys.exc_info()[1]
-            raise SyntaxError(e.args[0])
-        return result
-
-    if 'parser' not in globals():
-        # Fall back to less-complete _markerlib implementation if 'parser' module
-        # is not available.
-        evaluate_marker = _markerlib_evaluate
-
-    @classmethod
-    def interpret(cls, nodelist):
-        while len(nodelist)==2: nodelist = nodelist[1]
-        try:
-            op = cls.get_op(nodelist[0])
-        except KeyError:
-            raise SyntaxError("Comparison or logical expression expected")
-        return op(nodelist)
-
-    @classmethod
-    def evaluate(cls, nodelist):
-        while len(nodelist)==2: nodelist = nodelist[1]
-        kind = nodelist[0]
-        name = nodelist[1]
-        if kind==token.NAME:
-            try:
-                op = cls.values[name]
-            except KeyError:
-                raise SyntaxError("Unknown name %r" % name)
-            return op()
-        if kind==token.STRING:
-            s = nodelist[1]
-            if not cls._safe_string(s):
-                raise SyntaxError(
-                    "Only plain strings allowed in environment markers")
-            return s[1:-1]
-        msg = "Language feature not supported in environment markers"
-        raise SyntaxError(msg)
-
-    @staticmethod
-    def _safe_string(cand):
-        return (
-            cand[:1] in "'\"" and
-            not cand.startswith('"""') and
-            not cand.startswith("'''") and
-            '\\' not in cand
-        )
-
-invalid_marker = MarkerEvaluation.is_invalid_marker
-evaluate_marker = MarkerEvaluation.evaluate_marker
 
 class NullProvider:
     """Try to implement resources and metadata for arbitrary PEP 302 loaders"""
@@ -1394,16 +1457,11 @@ class NullProvider:
     def has_metadata(self, name):
         return self.egg_info and self._has(self._fn(self.egg_info, name))
 
-    if sys.version_info <= (3,):
-        def get_metadata(self, name):
-            if not self.egg_info:
-                return ""
-            return self._get(self._fn(self.egg_info, name))
-    else:
-        def get_metadata(self, name):
-            if not self.egg_info:
-                return ""
-            return self._get(self._fn(self.egg_info, name)).decode("utf-8")
+    def get_metadata(self, name):
+        if not self.egg_info:
+            return ""
+        value = self._get(self._fn(self.egg_info, name))
+        return value.decode('utf-8') if six.PY3 else value
 
     def get_metadata_lines(self, name):
         return yield_lines(self.get_metadata(name))
@@ -1423,7 +1481,7 @@ class NullProvider:
         return []
 
     def run_script(self, script_name, namespace):
-        script = 'scripts/'+script_name
+        script = 'scripts/' + script_name
         if not self.has_metadata(script):
             raise ResolutionError("No script named %r" % script_name)
         script_text = self.get_metadata(script).replace('\r\n', '\n')
@@ -1439,7 +1497,7 @@ class NullProvider:
             cache[script_filename] = (
                 len(script_text), 0, script_text.split('\n'), script_filename
             )
-            script_code = compile(script_text, script_filename,'exec')
+            script_code = compile(script_text, script_filename, 'exec')
             exec(script_code, namespace, namespace)
 
     def _has(self, path):
@@ -1469,6 +1527,7 @@ class NullProvider:
             "Can't perform this operation for loaders without 'get_data()'"
         )
 
+
 register_loader_type(object, NullProvider)
 
 
@@ -1484,8 +1543,8 @@ class EggProvider(NullProvider):
         # of multiple eggs; that's why we use module_path instead of .archive
         path = self.module_path
         old = None
-        while path!=old:
-            if path.lower().endswith('.egg'):
+        while path != old:
+            if _is_unpacked_egg(path):
                 self.egg_name = os.path.basename(path)
                 self.egg_info = os.path.join(path, 'EGG-INFO')
                 self.egg_root = path
@@ -1493,6 +1552,7 @@ class EggProvider(NullProvider):
             old = path
             path, base = os.path.split(path)
 
+
 class DefaultProvider(EggProvider):
     """Provides access to package resources in the filesystem"""
 
@@ -1512,10 +1572,14 @@ class DefaultProvider(EggProvider):
         with open(path, 'rb') as stream:
             return stream.read()
 
-register_loader_type(type(None), DefaultProvider)
+    @classmethod
+    def _register(cls):
+        loader_cls = getattr(importlib_machinery, 'SourceFileLoader',
+            type(None))
+        register_loader_type(loader_cls, cls)
 
-if importlib_bootstrap is not None:
-    register_loader_type(importlib_bootstrap.SourceFileLoader, DefaultProvider)
+
+DefaultProvider._register()
 
 
 class EmptyProvider(NullProvider):
@@ -1529,6 +1593,7 @@ class EmptyProvider(NullProvider):
     def __init__(self):
         pass
 
+
 empty_provider = EmptyProvider()
 
 
@@ -1607,7 +1672,7 @@ class ZipProvider(EggProvider):
 
     def __init__(self, module):
         EggProvider.__init__(self, module)
-        self.zip_pre = self.loader.archive+os.sep
+        self.zip_pre = self.loader.archive + os.sep
 
     def _zipinfo_name(self, fspath):
         # Convert a virtual filename (full path to file) into a zipfile subpath
@@ -1621,9 +1686,9 @@ class ZipProvider(EggProvider):
     def _parts(self, zip_path):
         # Convert a zipfile subpath into an egg-relative path part list.
         # pseudo-fs path
-        fspath = self.zip_pre+zip_path
-        if fspath.startswith(self.egg_root+os.sep):
-            return fspath[len(self.egg_root)+1:].split(os.sep)
+        fspath = self.zip_pre + zip_path
+        if fspath.startswith(self.egg_root + os.sep):
+            return fspath[len(self.egg_root) + 1:].split(os.sep)
         raise AssertionError(
             "%s is not a subpath of %s" % (fspath, self.egg_root)
         )
@@ -1694,7 +1759,7 @@ class ZipProvider(EggProvider):
                         #  so proceed.
                         return real_path
                     # Windows, del old file and retry
-                    elif os.name=='nt':
+                    elif os.name == 'nt':
                         unlink(real_path)
                         rename(tmpnam, real_path)
                         return real_path
@@ -1714,7 +1779,7 @@ class ZipProvider(EggProvider):
         if not os.path.isfile(file_path):
             return False
         stat = os.stat(file_path)
-        if stat.st_size!=size or stat.st_mtime!=timestamp:
+        if stat.st_size != size or stat.st_mtime != timestamp:
             return False
         # check that the contents match
         zip_contents = self.loader.get_data(zip_path)
@@ -1764,6 +1829,7 @@ class ZipProvider(EggProvider):
     def _resource_to_zip(self, resource_name):
         return self._zipinfo_name(self._fn(self.module_path, resource_name))
 
+
 register_loader_type(zipimport.zipimporter, ZipProvider)
 
 
@@ -1783,14 +1849,24 @@ class FileMetadata(EmptyProvider):
         self.path = path
 
     def has_metadata(self, name):
-        return name=='PKG-INFO'
+        return name == 'PKG-INFO' and os.path.isfile(self.path)
 
     def get_metadata(self, name):
-        if name=='PKG-INFO':
-            with open(self.path,'rU') as f:
-                metadata = f.read()
-            return metadata
-        raise KeyError("No metadata except PKG-INFO is available")
+        if name != 'PKG-INFO':
+            raise KeyError("No metadata except PKG-INFO is available")
+
+        with io.open(self.path, encoding='utf-8', errors="replace") as f:
+            metadata = f.read()
+        self._warn_on_replacement(metadata)
+        return metadata
+
+    def _warn_on_replacement(self, metadata):
+        # Python 2.6 and 3.2 compat for: replacement_char = '�'
+        replacement_char = b'\xef\xbf\xbd'.decode('utf-8')
+        if replacement_char in metadata:
+            tmpl = "{self.path} could not be properly decoded in UTF-8"
+            msg = tmpl.format(**locals())
+            warnings.warn(msg)
 
     def get_metadata_lines(self, name):
         return yield_lines(self.get_metadata(name))
@@ -1827,7 +1903,7 @@ class EggMetadata(ZipProvider):
     def __init__(self, importer):
         """Create a metadata provider from a zipimporter"""
 
-        self.zip_pre = importer.archive+os.sep
+        self.zip_pre = importer.archive + os.sep
         self.loader = importer
         if importer.prefix:
             self.module_path = os.path.join(importer.archive, importer.prefix)
@@ -1835,7 +1911,9 @@ class EggMetadata(ZipProvider):
             self.module_path = importer.archive
         self._setup_prefix()
 
-_declare_state('dict', _distribution_finders = {})
+
+_declare_state('dict', _distribution_finders={})
+
 
 def register_finder(importer_type, distribution_finder):
     """Register `distribution_finder` to find distributions in sys.path items
@@ -1853,6 +1931,7 @@ def find_distributions(path_item, only=False):
     finder = _find_adapter(_distribution_finders, importer)
     return finder(importer, path_item, only)
 
+
 def find_eggs_in_zip(importer, path_item, only=False):
     """
     Find eggs in zip files; possibly multiple nested eggs.
@@ -1868,44 +1947,78 @@ def find_eggs_in_zip(importer, path_item, only=False):
         # don't yield nested distros
         return
     for subitem in metadata.resource_listdir('/'):
-        if subitem.endswith('.egg'):
+        if _is_unpacked_egg(subitem):
             subpath = os.path.join(path_item, subitem)
             for dist in find_eggs_in_zip(zipimport.zipimporter(subpath), subpath):
                 yield dist
 
+
 register_finder(zipimport.zipimporter, find_eggs_in_zip)
 
+
 def find_nothing(importer, path_item, only=False):
     return ()
+
+
 register_finder(object, find_nothing)
 
+
+def _by_version_descending(names):
+    """
+    Given a list of filenames, return them in descending order
+    by version number.
+
+    >>> names = 'bar', 'foo', 'Python-2.7.10.egg', 'Python-2.7.2.egg'
+    >>> _by_version_descending(names)
+    ['Python-2.7.10.egg', 'Python-2.7.2.egg', 'foo', 'bar']
+    >>> names = 'Setuptools-1.2.3b1.egg', 'Setuptools-1.2.3.egg'
+    >>> _by_version_descending(names)
+    ['Setuptools-1.2.3.egg', 'Setuptools-1.2.3b1.egg']
+    >>> names = 'Setuptools-1.2.3b1.egg', 'Setuptools-1.2.3.post1.egg'
+    >>> _by_version_descending(names)
+    ['Setuptools-1.2.3.post1.egg', 'Setuptools-1.2.3b1.egg']
+    """
+    def _by_version(name):
+        """
+        Parse each component of the filename
+        """
+        name, ext = os.path.splitext(name)
+        parts = itertools.chain(name.split('-'), [ext])
+        return [packaging.version.parse(part) for part in parts]
+
+    return sorted(names, key=_by_version, reverse=True)
+
+
 def find_on_path(importer, path_item, only=False):
     """Yield distributions accessible on a sys.path directory"""
     path_item = _normalize_cached(path_item)
 
     if os.path.isdir(path_item) and os.access(path_item, os.R_OK):
-        if path_item.lower().endswith('.egg'):
-            # unpacked egg
+        if _is_unpacked_egg(path_item):
             yield Distribution.from_filename(
                 path_item, metadata=PathMetadata(
-                    path_item, os.path.join(path_item,'EGG-INFO')
+                    path_item, os.path.join(path_item, 'EGG-INFO')
                 )
             )
         else:
             # scan for .egg and .egg-info in directory
-            for entry in os.listdir(path_item):
+            path_item_entries = _by_version_descending(os.listdir(path_item))
+            for entry in path_item_entries:
                 lower = entry.lower()
                 if lower.endswith('.egg-info') or lower.endswith('.dist-info'):
                     fullpath = os.path.join(path_item, entry)
                     if os.path.isdir(fullpath):
                         # egg-info directory, allow getting metadata
+                        if len(os.listdir(fullpath)) == 0:
+                            # Empty egg directory, skip.
+                            continue
                         metadata = PathMetadata(path_item, fullpath)
                     else:
                         metadata = FileMetadata(fullpath)
                     yield Distribution.from_location(
                         path_item, entry, metadata, precedence=DEVELOP_DIST
                     )
-                elif not only and lower.endswith('.egg'):
+                elif not only and _is_unpacked_egg(entry):
                     dists = find_distributions(os.path.join(path_item, entry))
                     for dist in dists:
                         yield dist
@@ -1920,10 +2033,12 @@ def find_on_path(importer, path_item, only=False):
                         for item in dists:
                             yield item
                         break
+
+
 register_finder(pkgutil.ImpImporter, find_on_path)
 
-if importlib_bootstrap is not None:
-    register_finder(importlib_bootstrap.FileFinder, find_on_path)
+if hasattr(importlib_machinery, 'FileFinder'):
+    register_finder(importlib_machinery.FileFinder, find_on_path)
 
 _declare_state('dict', _namespace_handlers={})
 _declare_state('dict', _namespace_packages={})
@@ -1946,6 +2061,7 @@ def register_namespace_handler(importer_type, namespace_handler):
     """
     _namespace_handlers[importer_type] = namespace_handler
 
+
 def _handle_ns(packageName, path_item):
     """Ensure that named package includes a subpath of path_item (if needed)"""
 
@@ -1957,10 +2073,10 @@ def _handle_ns(packageName, path_item):
         return None
     module = sys.modules.get(packageName)
     if module is None:
-        module = sys.modules[packageName] = imp.new_module(packageName)
+        module = sys.modules[packageName] = types.ModuleType(packageName)
         module.__path__ = []
         _set_parent_ns(packageName)
-    elif not hasattr(module,'__path__'):
+    elif not hasattr(module, '__path__'):
         raise TypeError("Not a package:", packageName)
     handler = _find_adapter(_namespace_handlers, importer)
     subpath = handler(importer, path_item, packageName, module)
@@ -1968,15 +2084,43 @@ def _handle_ns(packageName, path_item):
         path = module.__path__
         path.append(subpath)
         loader.load_module(packageName)
-        for path_item in path:
-            if path_item not in module.__path__:
-                module.__path__.append(path_item)
+        _rebuild_mod_path(path, packageName, module)
     return subpath
 
+
+def _rebuild_mod_path(orig_path, package_name, module):
+    """
+    Rebuild module.__path__ ensuring that all entries are ordered
+    corresponding to their sys.path order
+    """
+    sys_path = [_normalize_cached(p) for p in sys.path]
+
+    def safe_sys_path_index(entry):
+        """
+        Workaround for #520 and #513.
+        """
+        try:
+            return sys_path.index(entry)
+        except ValueError:
+            return float('inf')
+
+    def position_in_sys_path(path):
+        """
+        Return the ordinal of the path based on its position in sys.path
+        """
+        path_parts = path.split(os.sep)
+        module_parts = package_name.count('.') + 1
+        parts = path_parts[:-module_parts]
+        return safe_sys_path_index(_normalize_cached(os.sep.join(parts)))
+
+    orig_path.sort(key=position_in_sys_path)
+    module.__path__[:] = [_normalize_cached(p) for p in orig_path]
+
+
 def declare_namespace(packageName):
     """Declare that package 'packageName' is a namespace package"""
 
-    imp.acquire_lock()
+    _imp.acquire_lock()
     try:
         if packageName in _namespace_packages:
             return
@@ -1994,8 +2138,8 @@ def declare_namespace(packageName):
 
         # Track what packages are namespaces, so when new path items are added,
         # they can be updated
-        _namespace_packages.setdefault(parent,[]).append(packageName)
-        _namespace_packages.setdefault(packageName,[])
+        _namespace_packages.setdefault(parent, []).append(packageName)
+        _namespace_packages.setdefault(packageName, [])
 
         for path_item in path:
             # Ensure all the parent's path items are reflected in the child,
@@ -2003,18 +2147,20 @@ def declare_namespace(packageName):
             _handle_ns(packageName, path_item)
 
     finally:
-        imp.release_lock()
+        _imp.release_lock()
+
 
 def fixup_namespace_packages(path_item, parent=None):
     """Ensure that previously-declared namespace packages include path_item"""
-    imp.acquire_lock()
+    _imp.acquire_lock()
     try:
-        for package in _namespace_packages.get(parent,()):
+        for package in _namespace_packages.get(parent, ()):
             subpath = _handle_ns(package, path_item)
             if subpath:
                 fixup_namespace_packages(subpath, package)
     finally:
-        imp.release_lock()
+        _imp.release_lock()
+
 
 def file_ns_handler(importer, path_item, packageName, module):
     """Compute an ns-package subpath for a filesystem or zipfile importer"""
@@ -2022,22 +2168,24 @@ def file_ns_handler(importer, path_item, packageName, module):
     subpath = os.path.join(path_item, packageName.split('.')[-1])
     normalized = _normalize_cached(subpath)
     for item in module.__path__:
-        if _normalize_cached(item)==normalized:
+        if _normalize_cached(item) == normalized:
             break
     else:
         # Only return the path if it's not already there
         return subpath
 
+
 register_namespace_handler(pkgutil.ImpImporter, file_ns_handler)
 register_namespace_handler(zipimport.zipimporter, file_ns_handler)
 
-if importlib_bootstrap is not None:
-    register_namespace_handler(importlib_bootstrap.FileFinder, file_ns_handler)
+if hasattr(importlib_machinery, 'FileFinder'):
+    register_namespace_handler(importlib_machinery.FileFinder, file_ns_handler)
 
 
 def null_ns_handler(importer, path_item, packageName, module):
     return None
 
+
 register_namespace_handler(object, null_ns_handler)
 
 
@@ -2045,6 +2193,7 @@ def normalize_path(filename):
     """Normalize a file/dir name for comparison purposes"""
     return os.path.normcase(os.path.realpath(filename))
 
+
 def _normalize_cached(filename, _cache={}):
     try:
         return _cache[filename]
@@ -2052,6 +2201,16 @@ def _normalize_cached(filename, _cache={}):
         _cache[filename] = result = normalize_path(filename)
         return result
 
+
+def _is_unpacked_egg(path):
+    """
+    Determine if given path appears to be an unpacked egg.
+    """
+    return (
+        path.lower().endswith('.egg')
+    )
+
+
 def _set_parent_ns(packageName):
     parts = packageName.split('.')
     name = parts.pop()
@@ -2062,7 +2221,7 @@ def _set_parent_ns(packageName):
 
 def yield_lines(strs):
     """Yield non-empty/non-comment lines of a string or sequence"""
-    if isinstance(strs, string_types):
+    if isinstance(strs, six.string_types):
         for s in strs.splitlines():
             s = s.strip()
             # skip blank lines/comments
@@ -2073,86 +2232,21 @@ def yield_lines(strs):
             for s in yield_lines(ss):
                 yield s
 
-# whitespace and comment
-LINE_END = re.compile(r"\s*(#.*)?$").match
-# line continuation
-CONTINUE = re.compile(r"\s*\\\s*(#.*)?$").match
-# Distribution or extra
-DISTRO = re.compile(r"\s*((\w|[-.])+)").match
-# ver. info
-VERSION = re.compile(r"\s*(<=?|>=?|==|!=)\s*((\w|[-.])+)").match
-# comma between items
-COMMA = re.compile(r"\s*,").match
-OBRACKET = re.compile(r"\s*\[").match
-CBRACKET = re.compile(r"\s*\]").match
+
 MODULE = re.compile(r"\w+(\.\w+)*$").match
 EGG_NAME = re.compile(
-    r"(?P<name>[^-]+)"
-    r"( -(?P<ver>[^-]+) (-py(?P<pyver>[^-]+) (-(?P<plat>.+))? )? )?",
-    re.VERBOSE | re.IGNORECASE
+    r"""
+    (?P<name>[^-]+) (
+        -(?P<ver>[^-]+) (
+            -py(?P<pyver>[^-]+) (
+                -(?P<plat>.+)
+            )?
+        )?
+    )?
+    """,
+    re.VERBOSE | re.IGNORECASE,
 ).match
 
-component_re = re.compile(r'(\d+ | [a-z]+ | \.| -)', re.VERBOSE)
-replace = {'pre':'c', 'preview':'c','-':'final-','rc':'c','dev':'@'}.get
-
-def _parse_version_parts(s):
-    for part in component_re.split(s):
-        part = replace(part, part)
-        if not part or part=='.':
-            continue
-        if part[:1] in '0123456789':
-            # pad for numeric comparison
-            yield part.zfill(8)
-        else:
-            yield '*'+part
-
-    # ensure that alpha/beta/candidate are before final
-    yield '*final'
-
-def parse_version(s):
-    """Convert a version string to a chronologically-sortable key
-
-    This is a rough cross between distutils' StrictVersion and LooseVersion;
-    if you give it versions that would work with StrictVersion, then it behaves
-    the same; otherwise it acts like a slightly-smarter LooseVersion. It is
-    *possible* to create pathological version coding schemes that will fool
-    this parser, but they should be very rare in practice.
-
-    The returned value will be a tuple of strings.  Numeric portions of the
-    version are padded to 8 digits so they will compare numerically, but
-    without relying on how numbers compare relative to strings.  Dots are
-    dropped, but dashes are retained.  Trailing zeros between alpha segments
-    or dashes are suppressed, so that e.g. "2.4.0" is considered the same as
-    "2.4". Alphanumeric parts are lower-cased.
-
-    The algorithm assumes that strings like "-" and any alpha string that
-    alphabetically follows "final"  represents a "patch level".  So, "2.4-1"
-    is assumed to be a branch or patch of "2.4", and therefore "2.4.1" is
-    considered newer than "2.4-1", which in turn is newer than "2.4".
-
-    Strings like "a", "b", "c", "alpha", "beta", "candidate" and so on (that
-    come before "final" alphabetically) are assumed to be pre-release versions,
-    so that the version "2.4" is considered newer than "2.4a1".
-
-    Finally, to handle miscellaneous cases, the strings "pre", "preview", and
-    "rc" are treated as if they were "c", i.e. as though they were release
-    candidates, and therefore are not as new as a version string that does not
-    contain them, and "dev" is replaced with an '@' so that it sorts lower than
-    than any other pre-release tag.
-    """
-    parts = []
-    for part in _parse_version_parts(s.lower()):
-        if part.startswith('*'):
-            # remove '-' before a prerelease tag
-            if part < '*final':
-                while parts and parts[-1] == '*final-':
-                    parts.pop()
-            # remove trailing zeros from each series of numeric parts
-            while parts and parts[-1]=='00000000':
-                parts.pop()
-        parts.append(part)
-    return tuple(parts)
-
 
 class EntryPoint(object):
     """Object representing an advertised importable object"""
@@ -2177,17 +2271,30 @@ class EntryPoint(object):
     def __repr__(self):
         return "EntryPoint.parse(%r)" % str(self)
 
-    def load(self, require=True, env=None, installer=None):
+    def load(self, require=True, *args, **kwargs):
+        """
+        Require packages for this EntryPoint, then resolve it.
+        """
+        if not require or args or kwargs:
+            warnings.warn(
+                "Parameters to load are deprecated.  Call .resolve and "
+                ".require separately.",
+                DeprecationWarning,
+                stacklevel=2,
+            )
         if require:
-            self.require(env, installer)
-        entry = __import__(self.module_name, globals(), globals(),
-            ['__name__'])
-        for attr in self.attrs:
-            try:
-                entry = getattr(entry, attr)
-            except AttributeError:
-                raise ImportError("%r has no %r attribute" % (entry, attr))
-        return entry
+            self.require(*args, **kwargs)
+        return self.resolve()
+
+    def resolve(self):
+        """
+        Resolve the entry point from its module and attrs.
+        """
+        module = __import__(self.module_name, fromlist=['__name__'], level=0)
+        try:
+            return functools.reduce(getattr, self.attrs, module)
+        except AttributeError as exc:
+            raise ImportError(str(exc))
 
     def require(self, env=None, installer=None):
         if self.extras and not self.dist:
@@ -2196,6 +2303,15 @@ class EntryPoint(object):
         items = working_set.resolve(reqs, env, installer)
         list(map(working_set.add, items))
 
+    pattern = re.compile(
+        r'\s*'
+        r'(?P<name>.+?)\s*'
+        r'=\s*'
+        r'(?P<module>[\w.]+)\s*'
+        r'(:\s*(?P<attr>[\w.]+))?\s*'
+        r'(?P<extras>\[.*\])?\s*$'
+    )
+
     @classmethod
     def parse(cls, src, dist=None):
         """Parse a single entry point from string `src`
@@ -2207,25 +2323,23 @@ class EntryPoint(object):
         The entry name and module name are required, but the ``:attrs`` and
         ``[extras]`` parts are optional
         """
-        try:
-            attrs = extras = ()
-            name, value = src.split('=', 1)
-            if '[' in value:
-                value, extras = value.split('[', 1)
-                req = Requirement.parse("x[" + extras)
-                if req.specs:
-                    raise ValueError
-                extras = req.extras
-            if ':' in value:
-                value, attrs = value.split(':', 1)
-                if not MODULE(attrs.rstrip()):
-                    raise ValueError
-                attrs = attrs.rstrip().split('.')
-        except ValueError:
+        m = cls.pattern.match(src)
+        if not m:
             msg = "EntryPoint must be in 'name=module:attrs [extras]' format"
             raise ValueError(msg, src)
-        else:
-            return cls(name.strip(), value.strip(), attrs, extras, dist)
+        res = m.groupdict()
+        extras = cls._parse_extras(res['extras'])
+        attrs = res['attr'].split('.') if res['attr'] else ()
+        return cls(res['name'], res['module'], attrs, extras, dist)
+
+    @classmethod
+    def _parse_extras(cls, extras_spec):
+        if not extras_spec:
+            return ()
+        req = Requirement.parse('x' + extras_spec)
+        if req.specs:
+            raise ValueError()
+        return req.extras
 
     @classmethod
     def parse_group(cls, group, lines, dist=None):
@@ -2237,7 +2351,7 @@ class EntryPoint(object):
             ep = cls.parse(line, dist)
             if ep.name in this:
                 raise ValueError("Duplicate entry point", group, ep.name)
-            this[ep.name]=ep
+            this[ep.name] = ep
         return this
 
     @classmethod
@@ -2263,12 +2377,24 @@ class EntryPoint(object):
 def _remove_md5_fragment(location):
     if not location:
         return ''
-    parsed = urlparse(location)
+    parsed = urllib.parse.urlparse(location)
     if parsed[-1].startswith('md5='):
-        return urlunparse(parsed[:-1] + ('',))
+        return urllib.parse.urlunparse(parsed[:-1] + ('',))
     return location
 
 
+def _version_from_file(lines):
+    """
+    Given an iterable of lines from a Metadata file, return
+    the value of the Version field, if present, or None otherwise.
+    """
+    is_version_line = lambda line: line.lower().startswith('version:')
+    version_lines = filter(is_version_line, lines)
+    line = next(iter(version_lines), '')
+    _, _, value = line.partition(':')
+    return safe_version(value.strip()) or None
+
+
 class Distribution(object):
     """Wrap an actual or potential sys.path entry w/metadata"""
     PKG_INFO = 'PKG-INFO'
@@ -2286,31 +2412,34 @@ class Distribution(object):
         self._provider = metadata or empty_provider
 
     @classmethod
-    def from_location(cls, location, basename, metadata=None,**kw):
-        project_name, version, py_version, platform = [None]*4
+    def from_location(cls, location, basename, metadata=None, **kw):
+        project_name, version, py_version, platform = [None] * 4
         basename, ext = os.path.splitext(basename)
         if ext.lower() in _distributionImpl:
-            # .dist-info gets much metadata differently
+            cls = _distributionImpl[ext.lower()]
+
             match = EGG_NAME(basename)
             if match:
                 project_name, version, py_version, platform = match.group(
-                    'name','ver','pyver','plat'
+                    'name', 'ver', 'pyver', 'plat'
                 )
-            cls = _distributionImpl[ext.lower()]
         return cls(
             location, metadata, project_name=project_name, version=version,
             py_version=py_version, platform=platform, **kw
-        )
+        )._reload_version()
+
+    def _reload_version(self):
+        return self
 
     @property
     def hashcmp(self):
         return (
-            getattr(self, 'parsed_version', ()),
+            self.parsed_version,
             self.precedence,
             self.key,
             _remove_md5_fragment(self.location),
-            self.py_version,
-            self.platform,
+            self.py_version or '',
+            self.platform or '',
         )
 
     def __hash__(self):
@@ -2351,24 +2480,47 @@ class Distribution(object):
 
     @property
     def parsed_version(self):
-        try:
-            return self._parsed_version
-        except AttributeError:
-            self._parsed_version = pv = parse_version(self.version)
-            return pv
+        if not hasattr(self, "_parsed_version"):
+            self._parsed_version = parse_version(self.version)
+
+        return self._parsed_version
+
+    def _warn_legacy_version(self):
+        LV = packaging.version.LegacyVersion
+        is_legacy = isinstance(self._parsed_version, LV)
+        if not is_legacy:
+            return
+
+        # While an empty version is technically a legacy version and
+        # is not a valid PEP 440 version, it's also unlikely to
+        # actually come from someone and instead it is more likely that
+        # it comes from setuptools attempting to parse a filename and
+        # including it in the list. So for that we'll gate this warning
+        # on if the version is anything at all or not.
+        if not self.version:
+            return
+
+        tmpl = textwrap.dedent("""
+            '{project_name} ({version})' is being parsed as a legacy,
+            non PEP 440,
+            version. You may find odd behavior and sort order.
+            In particular it will be sorted as less than 0.0. It
+            is recommended to migrate to PEP 440 compatible
+            versions.
+            """).strip().replace('\n', ' ')
+
+        warnings.warn(tmpl.format(**vars(self)), PEP440Warning)
 
     @property
     def version(self):
         try:
             return self._version
         except AttributeError:
-            for line in self._get_metadata(self.PKG_INFO):
-                if line.lower().startswith('version:'):
-                    self._version = safe_version(line.split(':',1)[1].strip())
-                    return self._version
-            else:
+            version = _version_from_file(self._get_metadata(self.PKG_INFO))
+            if version is None:
                 tmpl = "Missing 'Version:' header and/or %s file"
                 raise ValueError(tmpl % self.PKG_INFO, self)
+            return version
 
     @property
     def _dep_map(self):
@@ -2383,11 +2535,11 @@ class Distribution(object):
                             extra, marker = extra.split(':', 1)
                             if invalid_marker(marker):
                                 # XXX warn
-                                reqs=[]
+                                reqs = []
                             elif not evaluate_marker(marker):
-                                reqs=[]
+                                reqs = []
                         extra = safe_extra(extra) or None
-                    dm.setdefault(extra,[]).extend(parse_requirements(reqs))
+                    dm.setdefault(extra, []).extend(parse_requirements(reqs))
             return dm
 
     def requires(self, extras=()):
@@ -2409,11 +2561,11 @@ class Distribution(object):
             for line in self.get_metadata_lines(name):
                 yield line
 
-    def activate(self, path=None):
+    def activate(self, path=None, replace=False):
         """Ensure distribution is importable on `path` (default=sys.path)"""
         if path is None:
             path = sys.path
-        self.insert_on(path)
+        self.insert_on(path, replace=replace)
         if path is sys.path:
             fixup_namespace_packages(self.location)
             for pkg in self._get_metadata('namespace_packages.txt'):
@@ -2460,7 +2612,12 @@ class Distribution(object):
 
     def as_requirement(self):
         """Return a ``Requirement`` that matches this distribution exactly"""
-        return Requirement.parse('%s==%s' % (self.project_name, self.version))
+        if isinstance(self.parsed_version, packaging.version.Version):
+            spec = "%s==%s" % (self.project_name, self.parsed_version)
+        else:
+            spec = "%s===%s" % (self.project_name, self.parsed_version)
+
+        return Requirement.parse(spec)
 
     def load_entry_point(self, group, name):
         """Return the `name` entry point of `group` or raise ImportError"""
@@ -2478,15 +2635,32 @@ class Distribution(object):
                 self._get_metadata('entry_points.txt'), self
             )
         if group is not None:
-            return ep_map.get(group,{})
+            return ep_map.get(group, {})
         return ep_map
 
     def get_entry_info(self, group, name):
         """Return the EntryPoint object for `group`+`name`, or ``None``"""
         return self.get_entry_map(group).get(name)
 
-    def insert_on(self, path, loc = None):
-        """Insert self.location in path before its nearest parent directory"""
+    def insert_on(self, path, loc=None, replace=False):
+        """Ensure self.location is on path
+
+        If replace=False (default):
+            - If location is already in path anywhere, do nothing.
+            - Else:
+              - If it's an egg and its parent directory is on path,
+                insert just ahead of the parent.
+              - Else: add to the end of path.
+        If replace=True:
+            - If location is already on path anywhere (not eggs)
+              or higher priority than its parent (eggs)
+              do nothing.
+            - Else:
+              - If it's an egg and its parent directory is on path,
+                insert just ahead of the parent,
+                removing any lower-priority entries.
+              - Else: add it to the front of path.
+        """
 
         loc = loc or self.location
         if not loc:
@@ -2494,13 +2668,20 @@ class Distribution(object):
 
         nloc = _normalize_cached(loc)
         bdir = os.path.dirname(nloc)
-        npath= [(p and _normalize_cached(p) or p) for p in path]
+        npath = [(p and _normalize_cached(p) or p) for p in path]
 
         for p, item in enumerate(npath):
             if item == nloc:
-                break
+                if replace:
+                    break
+                else:
+                    # don't modify path (even removing duplicates) if found and not replace
+                    return
             elif item == bdir and self.precedence == EGG_DIST:
                 # if it's an .egg, give it precedence over its directory
+                # UNLESS it's already been added to sys.path and replace=False
+                if (not replace) and nloc in npath[p:]:
+                    return
                 if path is sys.path:
                     self.check_version_conflict()
                 path.insert(p, loc)
@@ -2509,13 +2690,16 @@ class Distribution(object):
         else:
             if path is sys.path:
                 self.check_version_conflict()
-            path.append(loc)
+            if replace:
+                path.insert(0, loc)
+            else:
+                path.append(loc)
             return
 
         # p is the spot where we found or inserted loc; now remove duplicates
         while True:
             try:
-                np = npath.index(nloc, p+1)
+                np = npath.index(nloc, p + 1)
             except ValueError:
                 break
             else:
@@ -2555,7 +2739,7 @@ class Distribution(object):
             return False
         return True
 
-    def clone(self,**kw):
+    def clone(self, **kw):
         """Copy this distribution, substituting in any changed keyword args"""
         names = 'project_name version py_version platform location precedence'
         for attr in names.split():
@@ -2568,6 +2752,25 @@ class Distribution(object):
         return [dep for dep in self._dep_map if dep]
 
 
+class EggInfoDistribution(Distribution):
+    def _reload_version(self):
+        """
+        Packages installed by distutils (e.g. numpy or scipy),
+        which uses an old safe_version, and so
+        their version numbers can get mangled when
+        converted to filenames (e.g., 1.11.0.dev0+2329eae to
+        1.11.0.dev0_2329eae). These distributions will not be
+        parsed properly
+        downstream by Distribution and safe_version, so
+        take an extra step and try to get the version number from
+        the metadata file itself instead of the filename.
+        """
+        md_version = _version_from_file(self._get_metadata(self.PKG_INFO))
+        if md_version:
+            self._version = md_version
+        return self
+
+
 class DistInfoDistribution(Distribution):
     """Wrap an actual or potential sys.path entry w/metadata, .dist-info style"""
     PKG_INFO = 'METADATA'
@@ -2591,54 +2794,38 @@ class DistInfoDistribution(Distribution):
             self.__dep_map = self._compute_dependencies()
             return self.__dep_map
 
-    def _preparse_requirement(self, requires_dist):
-        """Convert 'Foobar (1); baz' to ('Foobar ==1', 'baz')
-        Split environment marker, add == prefix to version specifiers as
-        necessary, and remove parenthesis.
-        """
-        parts = requires_dist.split(';', 1) + ['']
-        distvers = parts[0].strip()
-        mark = parts[1].strip()
-        distvers = re.sub(self.EQEQ, r"\1==\2\3", distvers)
-        distvers = distvers.replace('(', '').replace(')', '')
-        return (distvers, mark)
-
     def _compute_dependencies(self):
         """Recompute this distribution's dependencies."""
-        from _markerlib import compile as compile_marker
         dm = self.__dep_map = {None: []}
 
         reqs = []
         # Including any condition expressions
         for req in self._parsed_pkg_info.get_all('Requires-Dist') or []:
-            distvers, mark = self._preparse_requirement(req)
-            parsed = next(parse_requirements(distvers))
-            parsed.marker_fn = compile_marker(mark)
-            reqs.append(parsed)
+            reqs.extend(parse_requirements(req))
 
         def reqs_for_extra(extra):
             for req in reqs:
-                if req.marker_fn(override={'extra':extra}):
+                if not req.marker or req.marker.evaluate({'extra': extra}):
                     yield req
 
         common = frozenset(reqs_for_extra(None))
         dm[None].extend(common)
 
         for extra in self._parsed_pkg_info.get_all('Provides-Extra') or []:
-            extra = safe_extra(extra.strip())
-            dm[extra] = list(frozenset(reqs_for_extra(extra)) - common)
+            s_extra = safe_extra(extra.strip())
+            dm[s_extra] = list(frozenset(reqs_for_extra(extra)) - common)
 
         return dm
 
 
 _distributionImpl = {
     '.egg': Distribution,
-    '.egg-info': Distribution,
+    '.egg-info': EggInfoDistribution,
     '.dist-info': DistInfoDistribution,
     }
 
 
-def issue_warning(*args,**kw):
+def issue_warning(*args, **kw):
     level = 1
     g = globals()
     try:
@@ -2651,6 +2838,11 @@ def issue_warning(*args,**kw):
     warnings.warn(stacklevel=level + 1, *args, **kw)
 
 
+class RequirementParseError(ValueError):
+    def __str__(self):
+        return ' '.join(self.args)
+
+
 def parse_requirements(strs):
     """Yield ``Requirement`` objects for each specification in `strs`
 
@@ -2659,122 +2851,58 @@ def parse_requirements(strs):
     # create a steppable iterator, so we can handle \-continuations
     lines = iter(yield_lines(strs))
 
-    def scan_list(ITEM, TERMINATOR, line, p, groups, item_name):
-
-        items = []
-
-        while not TERMINATOR(line, p):
-            if CONTINUE(line, p):
-                try:
-                    line = next(lines)
-                    p = 0
-                except StopIteration:
-                    raise ValueError(
-                        "\\ must not appear on the last nonblank line"
-                    )
-
-            match = ITEM(line, p)
-            if not match:
-                msg = "Expected " + item_name + " in"
-                raise ValueError(msg, line, "at", line[p:])
-
-            items.append(match.group(*groups))
-            p = match.end()
-
-            match = COMMA(line, p)
-            if match:
-                # skip the comma
-                p = match.end()
-            elif not TERMINATOR(line, p):
-                msg = "Expected ',' or end-of-list in"
-                raise ValueError(msg, line, "at", line[p:])
-
-        match = TERMINATOR(line, p)
-        # skip the terminator, if any
-        if match:
-            p = match.end()
-        return line, p, items
-
     for line in lines:
-        match = DISTRO(line)
-        if not match:
-            raise ValueError("Missing distribution spec", line)
-        project_name = match.group(1)
-        p = match.end()
-        extras = []
-
-        match = OBRACKET(line, p)
-        if match:
-            p = match.end()
-            line, p, extras = scan_list(
-                DISTRO, CBRACKET, line, p, (1,), "'extra' name"
-            )
-
-        line, p, specs = scan_list(VERSION, LINE_END, line, p, (1, 2),
-            "version spec")
-        specs = [(op, safe_version(val)) for op, val in specs]
-        yield Requirement(project_name, specs, extras)
+        # Drop comments -- a hash without a space may be in a URL.
+        if ' #' in line:
+            line = line[:line.find(' #')]
+        # If there is a line continuation, drop it, and append the next line.
+        if line.endswith('\\'):
+            line = line[:-2].strip()
+            line += next(lines)
+        yield Requirement(line)
 
 
-class Requirement:
-    def __init__(self, project_name, specs, extras):
+class Requirement(packaging.requirements.Requirement):
+    def __init__(self, requirement_string):
         """DO NOT CALL THIS UNDOCUMENTED METHOD; use Requirement.parse()!"""
-        self.unsafe_name, project_name = project_name, safe_name(project_name)
+        try:
+            super(Requirement, self).__init__(requirement_string)
+        except packaging.requirements.InvalidRequirement as e:
+            raise RequirementParseError(str(e))
+        self.unsafe_name = self.name
+        project_name = safe_name(self.name)
         self.project_name, self.key = project_name, project_name.lower()
-        index = [
-            (parse_version(v), state_machine[op], op, v)
-            for op, v in specs
-        ]
-        index.sort()
-        self.specs = [(op, ver) for parsed, trans, op, ver in index]
-        self.index, self.extras = index, tuple(map(safe_extra, extras))
+        self.specs = [
+            (spec.operator, spec.version) for spec in self.specifier]
+        self.extras = tuple(map(safe_extra, self.extras))
         self.hashCmp = (
             self.key,
-            tuple((op, parsed) for parsed, trans, op, ver in index),
+            self.specifier,
             frozenset(self.extras),
+            str(self.marker) if self.marker else None,
         )
         self.__hash = hash(self.hashCmp)
 
-    def __str__(self):
-        specs = ','.join([''.join(s) for s in self.specs])
-        extras = ','.join(self.extras)
-        if extras:
-            extras = '[%s]' % extras
-        return '%s%s%s' % (self.project_name, extras, specs)
-
     def __eq__(self, other):
         return (
             isinstance(other, Requirement) and
             self.hashCmp == other.hashCmp
         )
 
+    def __ne__(self, other):
+        return not self == other
+
     def __contains__(self, item):
         if isinstance(item, Distribution):
             if item.key != self.key:
                 return False
-            # only get if we need it
-            if self.index:
-                item = item.parsed_version
-        elif isinstance(item, string_types):
-            item = parse_version(item)
-        last = None
-        # -1, 0, 1
-        compare = lambda a, b: (a > b) - (a < b)
-        for parsed, trans, op, ver in self.index:
-            # Indexing: 0, 1, -1
-            action = trans[compare(item, parsed)]
-            if action == 'F':
-                return False
-            elif action == 'T':
-                return True
-            elif action == '+':
-                last = True
-            elif action == '-' or last is None:
-                last = False
-        # no rules encountered
-        if last is None:
-            last = True
-        return last
+
+            item = item.version
+
+        # Allow prereleases always in order to match the previous behavior of
+        # this method. In the future this should be smarter and follow PEP 440
+        # more accurately.
+        return self.specifier.contains(item, prereleases=True)
 
     def __hash__(self):
         return self.__hash
@@ -2783,31 +2911,21 @@ class Requirement:
 
     @staticmethod
     def parse(s):
-        reqs = list(parse_requirements(s))
-        if reqs:
-            if len(reqs) == 1:
-                return reqs[0]
-            raise ValueError("Expected only one requirement", s)
-        raise ValueError("No requirements found", s)
-
-state_machine = {
-    #       =><
-    '<': '--T',
-    '<=': 'T-T',
-    '>': 'F+F',
-    '>=': 'T+F',
-    '==': 'T..',
-    '!=': 'F++',
-}
+        req, = parse_requirements(s)
+        return req
 
 
 def _get_mro(cls):
     """Get an mro for a type or classic class"""
     if not isinstance(cls, type):
-        class cls(cls, object): pass
+
+        class cls(cls, object):
+            pass
+
         return cls.__mro__[1:]
     return cls.__mro__
 
+
 def _find_adapter(registry, ob):
     """Return an adapter factory for `ob` from `registry`"""
     for t in _get_mro(getattr(ob, '__class__', type(ob))):
@@ -2822,14 +2940,14 @@ def ensure_directory(path):
         os.makedirs(dirname)
 
 
-def _bypass_ensure_directory(path, mode=0o777):
+def _bypass_ensure_directory(path):
     """Sandbox-bypassing version of ensure_directory()"""
     if not WRITE_SUPPORT:
         raise IOError('"os.mkdir" not supported on this platform.')
     dirname, filename = split(path)
     if dirname and filename and not isdir(dirname):
         _bypass_ensure_directory(dirname)
-        mkdir(dirname, mode)
+        mkdir(dirname, 0o755)
 
 
 def split_sections(s):
@@ -2857,39 +2975,75 @@ def split_sections(s):
     # wrap up last segment
     yield section, content
 
-def _mkstemp(*args,**kw):
+
+def _mkstemp(*args, **kw):
     old_open = os.open
     try:
         # temporarily bypass sandboxing
         os.open = os_open
-        return tempfile.mkstemp(*args,**kw)
+        return tempfile.mkstemp(*args, **kw)
     finally:
         # and then put it back
         os.open = old_open
 
 
-# Set up global resource manager (deliberately not state-saved)
-_manager = ResourceManager()
-def _initialize(g):
-    for name in dir(_manager):
-        if not name.startswith('_'):
-            g[name] = getattr(_manager, name)
-_initialize(globals())
+# Silence the PEP440Warning by default, so that end users don't get hit by it
+# randomly just because they use pkg_resources. We want to append the rule
+# because we want earlier uses of filterwarnings to take precedence over this
+# one.
+warnings.filterwarnings("ignore", category=PEP440Warning, append=True)
 
-# Prepare the master working set and make the ``require()`` API available
-working_set = WorkingSet._build_master()
-_declare_state('object', working_set=working_set)
 
-require = working_set.require
-iter_entry_points = working_set.iter_entry_points
-add_activation_listener = working_set.subscribe
-run_script = working_set.run_script
-# backward compatibility
-run_main = run_script
-# Activate all distributions already on sys.path, and ensure that
-# all distributions added to the working set in the future (e.g. by
-# calling ``require()``) will get activated as well.
-add_activation_listener(lambda dist: dist.activate())
-working_set.entries=[]
-# match order
-list(map(working_set.add_entry, sys.path))
+# from jaraco.functools 1.3
+def _call_aside(f, *args, **kwargs):
+    f(*args, **kwargs)
+    return f
+
+
+@_call_aside
+def _initialize(g=globals()):
+    "Set up global resource manager (deliberately not state-saved)"
+    manager = ResourceManager()
+    g['_manager'] = manager
+    g.update(
+        (name, getattr(manager, name))
+        for name in dir(manager)
+        if not name.startswith('_')
+    )
+
+
+@_call_aside
+def _initialize_master_working_set():
+    """
+    Prepare the master working set and make the ``require()``
+    API available.
+
+    This function has explicit effects on the global state
+    of pkg_resources. It is intended to be invoked once at
+    the initialization of this module.
+
+    Invocation by other packages is unsupported and done
+    at their own risk.
+    """
+    working_set = WorkingSet._build_master()
+    _declare_state('object', working_set=working_set)
+
+    require = working_set.require
+    iter_entry_points = working_set.iter_entry_points
+    add_activation_listener = working_set.subscribe
+    run_script = working_set.run_script
+    # backward compatibility
+    run_main = run_script
+    # Activate all distributions already on sys.path with replace=False and
+    # ensure that all distributions added to the working set in the future
+    # (e.g. by calling ``require()``) will get activated as well,
+    # with higher priority (replace=True).
+    tuple(
+        dist.activate(replace=False)
+        for dist in working_set
+    )
+    add_activation_listener(lambda dist: dist.activate(replace=True), existing=False)
+    working_set.entries = []
+    # match order
+    list(map(working_set.add_entry, sys.path))
+    globals().update(locals())
diff --git a/recipes/pkgresources/pkgr/_vendor/__init__.py b/recipes/pkgresources/pkgr/_vendor/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/recipes/pkgresources/pkgr/_vendor/appdirs.py b/recipes/pkgresources/pkgr/_vendor/appdirs.py
new file mode 100644
index 0000000..f4dba09
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/appdirs.py
@@ -0,0 +1,552 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright (c) 2005-2010 ActiveState Software Inc.
+# Copyright (c) 2013 Eddy Petrișor
+
+"""Utilities for determining application-specific dirs.
+
+See <http://github.com/ActiveState/appdirs> for details and usage.
+"""
+# Dev Notes:
+# - MSDN on where to store app data files:
+#   http://support.microsoft.com/default.aspx?scid=kb;en-us;310294#XSLTH3194121123120121120120
+# - Mac OS X: http://developer.apple.com/documentation/MacOSX/Conceptual/BPFileSystem/index.html
+# - XDG spec for Un*x: http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
+
+__version_info__ = (1, 4, 0)
+__version__ = '.'.join(map(str, __version_info__))
+
+
+import sys
+import os
+
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    unicode = str
+
+if sys.platform.startswith('java'):
+    import platform
+    os_name = platform.java_ver()[3][0]
+    if os_name.startswith('Windows'): # "Windows XP", "Windows 7", etc.
+        system = 'win32'
+    elif os_name.startswith('Mac'): # "Mac OS X", etc.
+        system = 'darwin'
+    else: # "Linux", "SunOS", "FreeBSD", etc.
+        # Setting this to "linux2" is not ideal, but only Windows or Mac
+        # are actually checked for and the rest of the module expects
+        # *sys.platform* style strings.
+        system = 'linux2'
+else:
+    system = sys.platform
+
+
+
+def user_data_dir(appname=None, appauthor=None, version=None, roaming=False):
+    r"""Return full path to the user-specific data dir for this application.
+
+        "appname" is the name of application.
+            If None, just the system directory is returned.
+        "appauthor" (only used on Windows) is the name of the
+            appauthor or distributing body for this application. Typically
+            it is the owning company name. This falls back to appname. You may
+            pass False to disable it.
+        "version" is an optional version path element to append to the
+            path. You might want to use this if you want multiple versions
+            of your app to be able to run independently. If used, this
+            would typically be "<major>.<minor>".
+            Only applied when appname is present.
+        "roaming" (boolean, default False) can be set True to use the Windows
+            roaming appdata directory. That means that for users on a Windows
+            network setup for roaming profiles, this user data will be
+            sync'd on login. See
+            <http://technet.microsoft.com/en-us/library/cc766489(WS.10).aspx>
+            for a discussion of issues.
+
+    Typical user data directories are:
+        Mac OS X:               ~/Library/Application Support/<AppName>
+        Unix:                   ~/.local/share/<AppName>    # or in $XDG_DATA_HOME, if defined
+        Win XP (not roaming):   C:\Documents and Settings\<username>\Application Data\<AppAuthor>\<AppName>
+        Win XP (roaming):       C:\Documents and Settings\<username>\Local Settings\Application Data\<AppAuthor>\<AppName>
+        Win 7  (not roaming):   C:\Users\<username>\AppData\Local\<AppAuthor>\<AppName>
+        Win 7  (roaming):       C:\Users\<username>\AppData\Roaming\<AppAuthor>\<AppName>
+
+    For Unix, we follow the XDG spec and support $XDG_DATA_HOME.
+    That means, by default "~/.local/share/<AppName>".
+    """
+    if system == "win32":
+        if appauthor is None:
+            appauthor = appname
+        const = roaming and "CSIDL_APPDATA" or "CSIDL_LOCAL_APPDATA"
+        path = os.path.normpath(_get_win_folder(const))
+        if appname:
+            if appauthor is not False:
+                path = os.path.join(path, appauthor, appname)
+            else:
+                path = os.path.join(path, appname)
+    elif system == 'darwin':
+        path = os.path.expanduser('~/Library/Application Support/')
+        if appname:
+            path = os.path.join(path, appname)
+    else:
+        path = os.getenv('XDG_DATA_HOME', os.path.expanduser("~/.local/share"))
+        if appname:
+            path = os.path.join(path, appname)
+    if appname and version:
+        path = os.path.join(path, version)
+    return path
+
+
+def site_data_dir(appname=None, appauthor=None, version=None, multipath=False):
+    """Return full path to the user-shared data dir for this application.
+
+        "appname" is the name of application.
+            If None, just the system directory is returned.
+        "appauthor" (only used on Windows) is the name of the
+            appauthor or distributing body for this application. Typically
+            it is the owning company name. This falls back to appname. You may
+            pass False to disable it.
+        "version" is an optional version path element to append to the
+            path. You might want to use this if you want multiple versions
+            of your app to be able to run independently. If used, this
+            would typically be "<major>.<minor>".
+            Only applied when appname is present.
+        "multipath" is an optional parameter only applicable to *nix
+            which indicates that the entire list of data dirs should be
+            returned. By default, the first item from XDG_DATA_DIRS is
+            returned, or '/usr/local/share/<AppName>',
+            if XDG_DATA_DIRS is not set
+
+    Typical user data directories are:
+        Mac OS X:   /Library/Application Support/<AppName>
+        Unix:       /usr/local/share/<AppName> or /usr/share/<AppName>
+        Win XP:     C:\Documents and Settings\All Users\Application Data\<AppAuthor>\<AppName>
+        Vista:      (Fail! "C:\ProgramData" is a hidden *system* directory on Vista.)
+        Win 7:      C:\ProgramData\<AppAuthor>\<AppName>   # Hidden, but writeable on Win 7.
+
+    For Unix, this is using the $XDG_DATA_DIRS[0] default.
+
+    WARNING: Do not use this on Windows. See the Vista-Fail note above for why.
+    """
+    if system == "win32":
+        if appauthor is None:
+            appauthor = appname
+        path = os.path.normpath(_get_win_folder("CSIDL_COMMON_APPDATA"))
+        if appname:
+            if appauthor is not False:
+                path = os.path.join(path, appauthor, appname)
+            else:
+                path = os.path.join(path, appname)
+    elif system == 'darwin':
+        path = os.path.expanduser('/Library/Application Support')
+        if appname:
+            path = os.path.join(path, appname)
+    else:
+        # XDG default for $XDG_DATA_DIRS
+        # only first, if multipath is False
+        path = os.getenv('XDG_DATA_DIRS',
+                         os.pathsep.join(['/usr/local/share', '/usr/share']))
+        pathlist = [os.path.expanduser(x.rstrip(os.sep)) for x in path.split(os.pathsep)]
+        if appname:
+            if version:
+                appname = os.path.join(appname, version)
+            pathlist = [os.sep.join([x, appname]) for x in pathlist]
+
+        if multipath:
+            path = os.pathsep.join(pathlist)
+        else:
+            path = pathlist[0]
+        return path
+
+    if appname and version:
+        path = os.path.join(path, version)
+    return path
+
+
+def user_config_dir(appname=None, appauthor=None, version=None, roaming=False):
+    r"""Return full path to the user-specific config dir for this application.
+
+        "appname" is the name of application.
+            If None, just the system directory is returned.
+        "appauthor" (only used on Windows) is the name of the
+            appauthor or distributing body for this application. Typically
+            it is the owning company name. This falls back to appname. You may
+            pass False to disable it.
+        "version" is an optional version path element to append to the
+            path. You might want to use this if you want multiple versions
+            of your app to be able to run independently. If used, this
+            would typically be "<major>.<minor>".
+            Only applied when appname is present.
+        "roaming" (boolean, default False) can be set True to use the Windows
+            roaming appdata directory. That means that for users on a Windows
+            network setup for roaming profiles, this user data will be
+            sync'd on login. See
+            <http://technet.microsoft.com/en-us/library/cc766489(WS.10).aspx>
+            for a discussion of issues.
+
+    Typical user data directories are:
+        Mac OS X:               same as user_data_dir
+        Unix:                   ~/.config/<AppName>     # or in $XDG_CONFIG_HOME, if defined
+        Win *:                  same as user_data_dir
+
+    For Unix, we follow the XDG spec and support $XDG_CONFIG_HOME.
+    That means, by deafult "~/.config/<AppName>".
+    """
+    if system in ["win32", "darwin"]:
+        path = user_data_dir(appname, appauthor, None, roaming)
+    else:
+        path = os.getenv('XDG_CONFIG_HOME', os.path.expanduser("~/.config"))
+        if appname:
+            path = os.path.join(path, appname)
+    if appname and version:
+        path = os.path.join(path, version)
+    return path
+
+
+def site_config_dir(appname=None, appauthor=None, version=None, multipath=False):
+    """Return full path to the user-shared data dir for this application.
+
+        "appname" is the name of application.
+            If None, just the system directory is returned.
+        "appauthor" (only used on Windows) is the name of the
+            appauthor or distributing body for this application. Typically
+            it is the owning company name. This falls back to appname. You may
+            pass False to disable it.
+        "version" is an optional version path element to append to the
+            path. You might want to use this if you want multiple versions
+            of your app to be able to run independently. If used, this
+            would typically be "<major>.<minor>".
+            Only applied when appname is present.
+        "multipath" is an optional parameter only applicable to *nix
+            which indicates that the entire list of config dirs should be
+            returned. By default, the first item from XDG_CONFIG_DIRS is
+            returned, or '/etc/xdg/<AppName>', if XDG_CONFIG_DIRS is not set
+
+    Typical user data directories are:
+        Mac OS X:   same as site_data_dir
+        Unix:       /etc/xdg/<AppName> or $XDG_CONFIG_DIRS[i]/<AppName> for each value in
+                    $XDG_CONFIG_DIRS
+        Win *:      same as site_data_dir
+        Vista:      (Fail! "C:\ProgramData" is a hidden *system* directory on Vista.)
+
+    For Unix, this is using the $XDG_CONFIG_DIRS[0] default, if multipath=False
+
+    WARNING: Do not use this on Windows. See the Vista-Fail note above for why.
+    """
+    if system in ["win32", "darwin"]:
+        path = site_data_dir(appname, appauthor)
+        if appname and version:
+            path = os.path.join(path, version)
+    else:
+        # XDG default for $XDG_CONFIG_DIRS
+        # only first, if multipath is False
+        path = os.getenv('XDG_CONFIG_DIRS', '/etc/xdg')
+        pathlist = [os.path.expanduser(x.rstrip(os.sep)) for x in path.split(os.pathsep)]
+        if appname:
+            if version:
+                appname = os.path.join(appname, version)
+            pathlist = [os.sep.join([x, appname]) for x in pathlist]
+
+        if multipath:
+            path = os.pathsep.join(pathlist)
+        else:
+            path = pathlist[0]
+    return path
+
+
+def user_cache_dir(appname=None, appauthor=None, version=None, opinion=True):
+    r"""Return full path to the user-specific cache dir for this application.
+
+        "appname" is the name of application.
+            If None, just the system directory is returned.
+        "appauthor" (only used on Windows) is the name of the
+            appauthor or distributing body for this application. Typically
+            it is the owning company name. This falls back to appname. You may
+            pass False to disable it.
+        "version" is an optional version path element to append to the
+            path. You might want to use this if you want multiple versions
+            of your app to be able to run independently. If used, this
+            would typically be "<major>.<minor>".
+            Only applied when appname is present.
+        "opinion" (boolean) can be False to disable the appending of
+            "Cache" to the base app data dir for Windows. See
+            discussion below.
+
+    Typical user cache directories are:
+        Mac OS X:   ~/Library/Caches/<AppName>
+        Unix:       ~/.cache/<AppName> (XDG default)
+        Win XP:     C:\Documents and Settings\<username>\Local Settings\Application Data\<AppAuthor>\<AppName>\Cache
+        Vista:      C:\Users\<username>\AppData\Local\<AppAuthor>\<AppName>\Cache
+
+    On Windows the only suggestion in the MSDN docs is that local settings go in
+    the `CSIDL_LOCAL_APPDATA` directory. This is identical to the non-roaming
+    app data dir (the default returned by `user_data_dir` above). Apps typically
+    put cache data somewhere *under* the given dir here. Some examples:
+        ...\Mozilla\Firefox\Profiles\<ProfileName>\Cache
+        ...\Acme\SuperApp\Cache\1.0
+    OPINION: This function appends "Cache" to the `CSIDL_LOCAL_APPDATA` value.
+    This can be disabled with the `opinion=False` option.
+    """
+    if system == "win32":
+        if appauthor is None:
+            appauthor = appname
+        path = os.path.normpath(_get_win_folder("CSIDL_LOCAL_APPDATA"))
+        if appname:
+            if appauthor is not False:
+                path = os.path.join(path, appauthor, appname)
+            else:
+                path = os.path.join(path, appname)
+            if opinion:
+                path = os.path.join(path, "Cache")
+    elif system == 'darwin':
+        path = os.path.expanduser('~/Library/Caches')
+        if appname:
+            path = os.path.join(path, appname)
+    else:
+        path = os.getenv('XDG_CACHE_HOME', os.path.expanduser('~/.cache'))
+        if appname:
+            path = os.path.join(path, appname)
+    if appname and version:
+        path = os.path.join(path, version)
+    return path
+
+
+def user_log_dir(appname=None, appauthor=None, version=None, opinion=True):
+    r"""Return full path to the user-specific log dir for this application.
+
+        "appname" is the name of application.
+            If None, just the system directory is returned.
+        "appauthor" (only used on Windows) is the name of the
+            appauthor or distributing body for this application. Typically
+            it is the owning company name. This falls back to appname. You may
+            pass False to disable it.
+        "version" is an optional version path element to append to the
+            path. You might want to use this if you want multiple versions
+            of your app to be able to run independently. If used, this
+            would typically be "<major>.<minor>".
+            Only applied when appname is present.
+        "opinion" (boolean) can be False to disable the appending of
+            "Logs" to the base app data dir for Windows, and "log" to the
+            base cache dir for Unix. See discussion below.
+
+    Typical user cache directories are:
+        Mac OS X:   ~/Library/Logs/<AppName>
+        Unix:       ~/.cache/<AppName>/log  # or under $XDG_CACHE_HOME if defined
+        Win XP:     C:\Documents and Settings\<username>\Local Settings\Application Data\<AppAuthor>\<AppName>\Logs
+        Vista:      C:\Users\<username>\AppData\Local\<AppAuthor>\<AppName>\Logs
+
+    On Windows the only suggestion in the MSDN docs is that local settings
+    go in the `CSIDL_LOCAL_APPDATA` directory. (Note: I'm interested in
+    examples of what some windows apps use for a logs dir.)
+
+    OPINION: This function appends "Logs" to the `CSIDL_LOCAL_APPDATA`
+    value for Windows and appends "log" to the user cache dir for Unix.
+    This can be disabled with the `opinion=False` option.
+    """
+    if system == "darwin":
+        path = os.path.join(
+            os.path.expanduser('~/Library/Logs'),
+            appname)
+    elif system == "win32":
+        path = user_data_dir(appname, appauthor, version)
+        version = False
+        if opinion:
+            path = os.path.join(path, "Logs")
+    else:
+        path = user_cache_dir(appname, appauthor, version)
+        version = False
+        if opinion:
+            path = os.path.join(path, "log")
+    if appname and version:
+        path = os.path.join(path, version)
+    return path
+
+
+class AppDirs(object):
+    """Convenience wrapper for getting application dirs."""
+    def __init__(self, appname, appauthor=None, version=None, roaming=False,
+                 multipath=False):
+        self.appname = appname
+        self.appauthor = appauthor
+        self.version = version
+        self.roaming = roaming
+        self.multipath = multipath
+
+    @property
+    def user_data_dir(self):
+        return user_data_dir(self.appname, self.appauthor,
+                             version=self.version, roaming=self.roaming)
+
+    @property
+    def site_data_dir(self):
+        return site_data_dir(self.appname, self.appauthor,
+                             version=self.version, multipath=self.multipath)
+
+    @property
+    def user_config_dir(self):
+        return user_config_dir(self.appname, self.appauthor,
+                               version=self.version, roaming=self.roaming)
+
+    @property
+    def site_config_dir(self):
+        return site_config_dir(self.appname, self.appauthor,
+                             version=self.version, multipath=self.multipath)
+
+    @property
+    def user_cache_dir(self):
+        return user_cache_dir(self.appname, self.appauthor,
+                              version=self.version)
+
+    @property
+    def user_log_dir(self):
+        return user_log_dir(self.appname, self.appauthor,
+                            version=self.version)
+
+
+#---- internal support stuff
+
+def _get_win_folder_from_registry(csidl_name):
+    """This is a fallback technique at best. I'm not sure if using the
+    registry for this guarantees us the correct answer for all CSIDL_*
+    names.
+    """
+    import _winreg
+
+    shell_folder_name = {
+        "CSIDL_APPDATA": "AppData",
+        "CSIDL_COMMON_APPDATA": "Common AppData",
+        "CSIDL_LOCAL_APPDATA": "Local AppData",
+    }[csidl_name]
+
+    key = _winreg.OpenKey(
+        _winreg.HKEY_CURRENT_USER,
+        r"Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders"
+    )
+    dir, type = _winreg.QueryValueEx(key, shell_folder_name)
+    return dir
+
+
+def _get_win_folder_with_pywin32(csidl_name):
+    from win32com.shell import shellcon, shell
+    dir = shell.SHGetFolderPath(0, getattr(shellcon, csidl_name), 0, 0)
+    # Try to make this a unicode path because SHGetFolderPath does
+    # not return unicode strings when there is unicode data in the
+    # path.
+    try:
+        dir = unicode(dir)
+
+        # Downgrade to short path name if have highbit chars. See
+        # <http://bugs.activestate.com/show_bug.cgi?id=85099>.
+        has_high_char = False
+        for c in dir:
+            if ord(c) > 255:
+                has_high_char = True
+                break
+        if has_high_char:
+            try:
+                import win32api
+                dir = win32api.GetShortPathName(dir)
+            except ImportError:
+                pass
+    except UnicodeError:
+        pass
+    return dir
+
+
+def _get_win_folder_with_ctypes(csidl_name):
+    import ctypes
+
+    csidl_const = {
+        "CSIDL_APPDATA": 26,
+        "CSIDL_COMMON_APPDATA": 35,
+        "CSIDL_LOCAL_APPDATA": 28,
+    }[csidl_name]
+
+    buf = ctypes.create_unicode_buffer(1024)
+    ctypes.windll.shell32.SHGetFolderPathW(None, csidl_const, None, 0, buf)
+
+    # Downgrade to short path name if have highbit chars. See
+    # <http://bugs.activestate.com/show_bug.cgi?id=85099>.
+    has_high_char = False
+    for c in buf:
+        if ord(c) > 255:
+            has_high_char = True
+            break
+    if has_high_char:
+        buf2 = ctypes.create_unicode_buffer(1024)
+        if ctypes.windll.kernel32.GetShortPathNameW(buf.value, buf2, 1024):
+            buf = buf2
+
+    return buf.value
+
+def _get_win_folder_with_jna(csidl_name):
+    import array
+    from com.sun import jna
+    from com.sun.jna.platform import win32
+
+    buf_size = win32.WinDef.MAX_PATH * 2
+    buf = array.zeros('c', buf_size)
+    shell = win32.Shell32.INSTANCE
+    shell.SHGetFolderPath(None, getattr(win32.ShlObj, csidl_name), None, win32.ShlObj.SHGFP_TYPE_CURRENT, buf)
+    dir = jna.Native.toString(buf.tostring()).rstrip("\0")
+
+    # Downgrade to short path name if have highbit chars. See
+    # <http://bugs.activestate.com/show_bug.cgi?id=85099>.
+    has_high_char = False
+    for c in dir:
+        if ord(c) > 255:
+            has_high_char = True
+            break
+    if has_high_char:
+        buf = array.zeros('c', buf_size)
+        kernel = win32.Kernel32.INSTANCE
+        if kernal.GetShortPathName(dir, buf, buf_size):
+            dir = jna.Native.toString(buf.tostring()).rstrip("\0")
+
+    return dir
+
+if system == "win32":
+    try:
+        import win32com.shell
+        _get_win_folder = _get_win_folder_with_pywin32
+    except ImportError:
+        try:
+            from ctypes import windll
+            _get_win_folder = _get_win_folder_with_ctypes
+        except ImportError:
+            try:
+                import com.sun.jna
+                _get_win_folder = _get_win_folder_with_jna
+            except ImportError:
+                _get_win_folder = _get_win_folder_from_registry
+
+
+#---- self test code
+
+if __name__ == "__main__":
+    appname = "MyApp"
+    appauthor = "MyCompany"
+
+    props = ("user_data_dir", "site_data_dir",
+             "user_config_dir", "site_config_dir",
+             "user_cache_dir", "user_log_dir")
+
+    print("-- app dirs (with optional 'version')")
+    dirs = AppDirs(appname, appauthor, version="1.0")
+    for prop in props:
+        print("%s: %s" % (prop, getattr(dirs, prop)))
+
+    print("\n-- app dirs (without optional 'version')")
+    dirs = AppDirs(appname, appauthor)
+    for prop in props:
+        print("%s: %s" % (prop, getattr(dirs, prop)))
+
+    print("\n-- app dirs (without optional 'appauthor')")
+    dirs = AppDirs(appname)
+    for prop in props:
+        print("%s: %s" % (prop, getattr(dirs, prop)))
+
+    print("\n-- app dirs (with disabled 'appauthor')")
+    dirs = AppDirs(appname, appauthor=False)
+    for prop in props:
+        print("%s: %s" % (prop, getattr(dirs, prop)))
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/__about__.py b/recipes/pkgresources/pkgr/_vendor/packaging/__about__.py
new file mode 100644
index 0000000..95d330e
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/__about__.py
@@ -0,0 +1,21 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+__all__ = [
+    "__title__", "__summary__", "__uri__", "__version__", "__author__",
+    "__email__", "__license__", "__copyright__",
+]
+
+__title__ = "packaging"
+__summary__ = "Core utilities for Python packages"
+__uri__ = "https://github.com/pypa/packaging"
+
+__version__ = "16.8"
+
+__author__ = "Donald Stufft and individual contributors"
+__email__ = "donald@stufft.io"
+
+__license__ = "BSD or Apache License, Version 2.0"
+__copyright__ = "Copyright 2014-2016 %s" % __author__
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/__init__.py b/recipes/pkgresources/pkgr/_vendor/packaging/__init__.py
new file mode 100644
index 0000000..5ee6220
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/__init__.py
@@ -0,0 +1,14 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+from .__about__ import (
+    __author__, __copyright__, __email__, __license__, __summary__, __title__,
+    __uri__, __version__
+)
+
+__all__ = [
+    "__title__", "__summary__", "__uri__", "__version__", "__author__",
+    "__email__", "__license__", "__copyright__",
+]
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/_compat.py b/recipes/pkgresources/pkgr/_vendor/packaging/_compat.py
new file mode 100644
index 0000000..210bb80
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/_compat.py
@@ -0,0 +1,30 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import sys
+
+
+PY2 = sys.version_info[0] == 2
+PY3 = sys.version_info[0] == 3
+
+# flake8: noqa
+
+if PY3:
+    string_types = str,
+else:
+    string_types = basestring,
+
+
+def with_metaclass(meta, *bases):
+    """
+    Create a base class with a metaclass.
+    """
+    # This requires a bit of explanation: the basic idea is to make a dummy
+    # metaclass for one level of class instantiation that replaces itself with
+    # the actual metaclass.
+    class metaclass(meta):
+        def __new__(cls, name, this_bases, d):
+            return meta(name, bases, d)
+    return type.__new__(metaclass, 'temporary_class', (), {})
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/_structures.py b/recipes/pkgresources/pkgr/_vendor/packaging/_structures.py
new file mode 100644
index 0000000..ccc2786
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/_structures.py
@@ -0,0 +1,68 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+
+class Infinity(object):
+
+    def __repr__(self):
+        return "Infinity"
+
+    def __hash__(self):
+        return hash(repr(self))
+
+    def __lt__(self, other):
+        return False
+
+    def __le__(self, other):
+        return False
+
+    def __eq__(self, other):
+        return isinstance(other, self.__class__)
+
+    def __ne__(self, other):
+        return not isinstance(other, self.__class__)
+
+    def __gt__(self, other):
+        return True
+
+    def __ge__(self, other):
+        return True
+
+    def __neg__(self):
+        return NegativeInfinity
+
+Infinity = Infinity()
+
+
+class NegativeInfinity(object):
+
+    def __repr__(self):
+        return "-Infinity"
+
+    def __hash__(self):
+        return hash(repr(self))
+
+    def __lt__(self, other):
+        return True
+
+    def __le__(self, other):
+        return True
+
+    def __eq__(self, other):
+        return isinstance(other, self.__class__)
+
+    def __ne__(self, other):
+        return not isinstance(other, self.__class__)
+
+    def __gt__(self, other):
+        return False
+
+    def __ge__(self, other):
+        return False
+
+    def __neg__(self):
+        return Infinity
+
+NegativeInfinity = NegativeInfinity()
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/markers.py b/recipes/pkgresources/pkgr/_vendor/packaging/markers.py
new file mode 100644
index 0000000..892e578
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/markers.py
@@ -0,0 +1,301 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import operator
+import os
+import platform
+import sys
+
+from pkg_resources.extern.pyparsing import ParseException, ParseResults, stringStart, stringEnd
+from pkg_resources.extern.pyparsing import ZeroOrMore, Group, Forward, QuotedString
+from pkg_resources.extern.pyparsing import Literal as L  # noqa
+
+from ._compat import string_types
+from .specifiers import Specifier, InvalidSpecifier
+
+
+__all__ = [
+    "InvalidMarker", "UndefinedComparison", "UndefinedEnvironmentName",
+    "Marker", "default_environment",
+]
+
+
+class InvalidMarker(ValueError):
+    """
+    An invalid marker was found, users should refer to PEP 508.
+    """
+
+
+class UndefinedComparison(ValueError):
+    """
+    An invalid operation was attempted on a value that doesn't support it.
+    """
+
+
+class UndefinedEnvironmentName(ValueError):
+    """
+    A name was attempted to be used that does not exist inside of the
+    environment.
+    """
+
+
+class Node(object):
+
+    def __init__(self, value):
+        self.value = value
+
+    def __str__(self):
+        return str(self.value)
+
+    def __repr__(self):
+        return "<{0}({1!r})>".format(self.__class__.__name__, str(self))
+
+    def serialize(self):
+        raise NotImplementedError
+
+
+class Variable(Node):
+
+    def serialize(self):
+        return str(self)
+
+
+class Value(Node):
+
+    def serialize(self):
+        return '"{0}"'.format(self)
+
+
+class Op(Node):
+
+    def serialize(self):
+        return str(self)
+
+
+VARIABLE = (
+    L("implementation_version") |
+    L("platform_python_implementation") |
+    L("implementation_name") |
+    L("python_full_version") |
+    L("platform_release") |
+    L("platform_version") |
+    L("platform_machine") |
+    L("platform_system") |
+    L("python_version") |
+    L("sys_platform") |
+    L("os_name") |
+    L("os.name") |  # PEP-345
+    L("sys.platform") |  # PEP-345
+    L("platform.version") |  # PEP-345
+    L("platform.machine") |  # PEP-345
+    L("platform.python_implementation") |  # PEP-345
+    L("python_implementation") |  # undocumented setuptools legacy
+    L("extra")
+)
+ALIASES = {
+    'os.name': 'os_name',
+    'sys.platform': 'sys_platform',
+    'platform.version': 'platform_version',
+    'platform.machine': 'platform_machine',
+    'platform.python_implementation': 'platform_python_implementation',
+    'python_implementation': 'platform_python_implementation'
+}
+VARIABLE.setParseAction(lambda s, l, t: Variable(ALIASES.get(t[0], t[0])))
+
+VERSION_CMP = (
+    L("===") |
+    L("==") |
+    L(">=") |
+    L("<=") |
+    L("!=") |
+    L("~=") |
+    L(">") |
+    L("<")
+)
+
+MARKER_OP = VERSION_CMP | L("not in") | L("in")
+MARKER_OP.setParseAction(lambda s, l, t: Op(t[0]))
+
+MARKER_VALUE = QuotedString("'") | QuotedString('"')
+MARKER_VALUE.setParseAction(lambda s, l, t: Value(t[0]))
+
+BOOLOP = L("and") | L("or")
+
+MARKER_VAR = VARIABLE | MARKER_VALUE
+
+MARKER_ITEM = Group(MARKER_VAR + MARKER_OP + MARKER_VAR)
+MARKER_ITEM.setParseAction(lambda s, l, t: tuple(t[0]))
+
+LPAREN = L("(").suppress()
+RPAREN = L(")").suppress()
+
+MARKER_EXPR = Forward()
+MARKER_ATOM = MARKER_ITEM | Group(LPAREN + MARKER_EXPR + RPAREN)
+MARKER_EXPR << MARKER_ATOM + ZeroOrMore(BOOLOP + MARKER_EXPR)
+
+MARKER = stringStart + MARKER_EXPR + stringEnd
+
+
+def _coerce_parse_result(results):
+    if isinstance(results, ParseResults):
+        return [_coerce_parse_result(i) for i in results]
+    else:
+        return results
+
+
+def _format_marker(marker, first=True):
+    assert isinstance(marker, (list, tuple, string_types))
+
+    # Sometimes we have a structure like [[...]] which is a single item list
+    # where the single item is itself it's own list. In that case we want skip
+    # the rest of this function so that we don't get extraneous () on the
+    # outside.
+    if (isinstance(marker, list) and len(marker) == 1 and
+            isinstance(marker[0], (list, tuple))):
+        return _format_marker(marker[0])
+
+    if isinstance(marker, list):
+        inner = (_format_marker(m, first=False) for m in marker)
+        if first:
+            return " ".join(inner)
+        else:
+            return "(" + " ".join(inner) + ")"
+    elif isinstance(marker, tuple):
+        return " ".join([m.serialize() for m in marker])
+    else:
+        return marker
+
+
+_operators = {
+    "in": lambda lhs, rhs: lhs in rhs,
+    "not in": lambda lhs, rhs: lhs not in rhs,
+    "<": operator.lt,
+    "<=": operator.le,
+    "==": operator.eq,
+    "!=": operator.ne,
+    ">=": operator.ge,
+    ">": operator.gt,
+}
+
+
+def _eval_op(lhs, op, rhs):
+    try:
+        spec = Specifier("".join([op.serialize(), rhs]))
+    except InvalidSpecifier:
+        pass
+    else:
+        return spec.contains(lhs)
+
+    oper = _operators.get(op.serialize())
+    if oper is None:
+        raise UndefinedComparison(
+            "Undefined {0!r} on {1!r} and {2!r}.".format(op, lhs, rhs)
+        )
+
+    return oper(lhs, rhs)
+
+
+_undefined = object()
+
+
+def _get_env(environment, name):
+    value = environment.get(name, _undefined)
+
+    if value is _undefined:
+        raise UndefinedEnvironmentName(
+            "{0!r} does not exist in evaluation environment.".format(name)
+        )
+
+    return value
+
+
+def _evaluate_markers(markers, environment):
+    groups = [[]]
+
+    for marker in markers:
+        assert isinstance(marker, (list, tuple, string_types))
+
+        if isinstance(marker, list):
+            groups[-1].append(_evaluate_markers(marker, environment))
+        elif isinstance(marker, tuple):
+            lhs, op, rhs = marker
+
+            if isinstance(lhs, Variable):
+                lhs_value = _get_env(environment, lhs.value)
+                rhs_value = rhs.value
+            else:
+                lhs_value = lhs.value
+                rhs_value = _get_env(environment, rhs.value)
+
+            groups[-1].append(_eval_op(lhs_value, op, rhs_value))
+        else:
+            assert marker in ["and", "or"]
+            if marker == "or":
+                groups.append([])
+
+    return any(all(item) for item in groups)
+
+
+def format_full_version(info):
+    version = '{0.major}.{0.minor}.{0.micro}'.format(info)
+    kind = info.releaselevel
+    if kind != 'final':
+        version += kind[0] + str(info.serial)
+    return version
+
+
+def default_environment():
+    if hasattr(sys, 'implementation'):
+        iver = format_full_version(sys.implementation.version)
+        implementation_name = sys.implementation.name
+    else:
+        iver = '0'
+        implementation_name = ''
+
+    return {
+        "implementation_name": implementation_name,
+        "implementation_version": iver,
+        "os_name": os.name,
+        "platform_machine": platform.machine(),
+        "platform_release": platform.release(),
+        "platform_system": platform.system(),
+        "platform_version": platform.version(),
+        "python_full_version": platform.python_version(),
+        "platform_python_implementation": platform.python_implementation(),
+        "python_version": platform.python_version()[:3],
+        "sys_platform": sys.platform,
+    }
+
+
+class Marker(object):
+
+    def __init__(self, marker):
+        try:
+            self._markers = _coerce_parse_result(MARKER.parseString(marker))
+        except ParseException as e:
+            err_str = "Invalid marker: {0!r}, parse error at {1!r}".format(
+                marker, marker[e.loc:e.loc + 8])
+            raise InvalidMarker(err_str)
+
+    def __str__(self):
+        return _format_marker(self._markers)
+
+    def __repr__(self):
+        return "<Marker({0!r})>".format(str(self))
+
+    def evaluate(self, environment=None):
+        """Evaluate a marker.
+
+        Return the boolean from evaluating the given marker against the
+        environment. environment is an optional argument to override all or
+        part of the determined environment.
+
+        The environment is determined from the current Python process.
+        """
+        current_environment = default_environment()
+        if environment is not None:
+            current_environment.update(environment)
+
+        return _evaluate_markers(self._markers, current_environment)
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/requirements.py b/recipes/pkgresources/pkgr/_vendor/packaging/requirements.py
new file mode 100644
index 0000000..0c8c4a3
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/requirements.py
@@ -0,0 +1,127 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import string
+import re
+
+from pkg_resources.extern.pyparsing import stringStart, stringEnd, originalTextFor, ParseException
+from pkg_resources.extern.pyparsing import ZeroOrMore, Word, Optional, Regex, Combine
+from pkg_resources.extern.pyparsing import Literal as L  # noqa
+from pkg_resources.extern.six.moves.urllib import parse as urlparse
+
+from .markers import MARKER_EXPR, Marker
+from .specifiers import LegacySpecifier, Specifier, SpecifierSet
+
+
+class InvalidRequirement(ValueError):
+    """
+    An invalid requirement was found, users should refer to PEP 508.
+    """
+
+
+ALPHANUM = Word(string.ascii_letters + string.digits)
+
+LBRACKET = L("[").suppress()
+RBRACKET = L("]").suppress()
+LPAREN = L("(").suppress()
+RPAREN = L(")").suppress()
+COMMA = L(",").suppress()
+SEMICOLON = L(";").suppress()
+AT = L("@").suppress()
+
+PUNCTUATION = Word("-_.")
+IDENTIFIER_END = ALPHANUM | (ZeroOrMore(PUNCTUATION) + ALPHANUM)
+IDENTIFIER = Combine(ALPHANUM + ZeroOrMore(IDENTIFIER_END))
+
+NAME = IDENTIFIER("name")
+EXTRA = IDENTIFIER
+
+URI = Regex(r'[^ ]+')("url")
+URL = (AT + URI)
+
+EXTRAS_LIST = EXTRA + ZeroOrMore(COMMA + EXTRA)
+EXTRAS = (LBRACKET + Optional(EXTRAS_LIST) + RBRACKET)("extras")
+
+VERSION_PEP440 = Regex(Specifier._regex_str, re.VERBOSE | re.IGNORECASE)
+VERSION_LEGACY = Regex(LegacySpecifier._regex_str, re.VERBOSE | re.IGNORECASE)
+
+VERSION_ONE = VERSION_PEP440 ^ VERSION_LEGACY
+VERSION_MANY = Combine(VERSION_ONE + ZeroOrMore(COMMA + VERSION_ONE),
+                       joinString=",", adjacent=False)("_raw_spec")
+_VERSION_SPEC = Optional(((LPAREN + VERSION_MANY + RPAREN) | VERSION_MANY))
+_VERSION_SPEC.setParseAction(lambda s, l, t: t._raw_spec or '')
+
+VERSION_SPEC = originalTextFor(_VERSION_SPEC)("specifier")
+VERSION_SPEC.setParseAction(lambda s, l, t: t[1])
+
+MARKER_EXPR = originalTextFor(MARKER_EXPR())("marker")
+MARKER_EXPR.setParseAction(
+    lambda s, l, t: Marker(s[t._original_start:t._original_end])
+)
+MARKER_SEPERATOR = SEMICOLON
+MARKER = MARKER_SEPERATOR + MARKER_EXPR
+
+VERSION_AND_MARKER = VERSION_SPEC + Optional(MARKER)
+URL_AND_MARKER = URL + Optional(MARKER)
+
+NAMED_REQUIREMENT = \
+    NAME + Optional(EXTRAS) + (URL_AND_MARKER | VERSION_AND_MARKER)
+
+REQUIREMENT = stringStart + NAMED_REQUIREMENT + stringEnd
+
+
+class Requirement(object):
+    """Parse a requirement.
+
+    Parse a given requirement string into its parts, such as name, specifier,
+    URL, and extras. Raises InvalidRequirement on a badly-formed requirement
+    string.
+    """
+
+    # TODO: Can we test whether something is contained within a requirement?
+    #       If so how do we do that? Do we need to test against the _name_ of
+    #       the thing as well as the version? What about the markers?
+    # TODO: Can we normalize the name and extra name?
+
+    def __init__(self, requirement_string):
+        try:
+            req = REQUIREMENT.parseString(requirement_string)
+        except ParseException as e:
+            raise InvalidRequirement(
+                "Invalid requirement, parse error at \"{0!r}\"".format(
+                    requirement_string[e.loc:e.loc + 8]))
+
+        self.name = req.name
+        if req.url:
+            parsed_url = urlparse.urlparse(req.url)
+            if not (parsed_url.scheme and parsed_url.netloc) or (
+                    not parsed_url.scheme and not parsed_url.netloc):
+                raise InvalidRequirement("Invalid URL given")
+            self.url = req.url
+        else:
+            self.url = None
+        self.extras = set(req.extras.asList() if req.extras else [])
+        self.specifier = SpecifierSet(req.specifier)
+        self.marker = req.marker if req.marker else None
+
+    def __str__(self):
+        parts = [self.name]
+
+        if self.extras:
+            parts.append("[{0}]".format(",".join(sorted(self.extras))))
+
+        if self.specifier:
+            parts.append(str(self.specifier))
+
+        if self.url:
+            parts.append("@ {0}".format(self.url))
+
+        if self.marker:
+            parts.append("; {0}".format(self.marker))
+
+        return "".join(parts)
+
+    def __repr__(self):
+        return "<Requirement({0!r})>".format(str(self))
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/specifiers.py b/recipes/pkgresources/pkgr/_vendor/packaging/specifiers.py
new file mode 100644
index 0000000..7f5a76c
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/specifiers.py
@@ -0,0 +1,774 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import abc
+import functools
+import itertools
+import re
+
+from ._compat import string_types, with_metaclass
+from .version import Version, LegacyVersion, parse
+
+
+class InvalidSpecifier(ValueError):
+    """
+    An invalid specifier was found, users should refer to PEP 440.
+    """
+
+
+class BaseSpecifier(with_metaclass(abc.ABCMeta, object)):
+
+    @abc.abstractmethod
+    def __str__(self):
+        """
+        Returns the str representation of this Specifier like object. This
+        should be representative of the Specifier itself.
+        """
+
+    @abc.abstractmethod
+    def __hash__(self):
+        """
+        Returns a hash value for this Specifier like object.
+        """
+
+    @abc.abstractmethod
+    def __eq__(self, other):
+        """
+        Returns a boolean representing whether or not the two Specifier like
+        objects are equal.
+        """
+
+    @abc.abstractmethod
+    def __ne__(self, other):
+        """
+        Returns a boolean representing whether or not the two Specifier like
+        objects are not equal.
+        """
+
+    @abc.abstractproperty
+    def prereleases(self):
+        """
+        Returns whether or not pre-releases as a whole are allowed by this
+        specifier.
+        """
+
+    @prereleases.setter
+    def prereleases(self, value):
+        """
+        Sets whether or not pre-releases as a whole are allowed by this
+        specifier.
+        """
+
+    @abc.abstractmethod
+    def contains(self, item, prereleases=None):
+        """
+        Determines if the given item is contained within this specifier.
+        """
+
+    @abc.abstractmethod
+    def filter(self, iterable, prereleases=None):
+        """
+        Takes an iterable of items and filters them so that only items which
+        are contained within this specifier are allowed in it.
+        """
+
+
+class _IndividualSpecifier(BaseSpecifier):
+
+    _operators = {}
+
+    def __init__(self, spec="", prereleases=None):
+        match = self._regex.search(spec)
+        if not match:
+            raise InvalidSpecifier("Invalid specifier: '{0}'".format(spec))
+
+        self._spec = (
+            match.group("operator").strip(),
+            match.group("version").strip(),
+        )
+
+        # Store whether or not this Specifier should accept prereleases
+        self._prereleases = prereleases
+
+    def __repr__(self):
+        pre = (
+            ", prereleases={0!r}".format(self.prereleases)
+            if self._prereleases is not None
+            else ""
+        )
+
+        return "<{0}({1!r}{2})>".format(
+            self.__class__.__name__,
+            str(self),
+            pre,
+        )
+
+    def __str__(self):
+        return "{0}{1}".format(*self._spec)
+
+    def __hash__(self):
+        return hash(self._spec)
+
+    def __eq__(self, other):
+        if isinstance(other, string_types):
+            try:
+                other = self.__class__(other)
+            except InvalidSpecifier:
+                return NotImplemented
+        elif not isinstance(other, self.__class__):
+            return NotImplemented
+
+        return self._spec == other._spec
+
+    def __ne__(self, other):
+        if isinstance(other, string_types):
+            try:
+                other = self.__class__(other)
+            except InvalidSpecifier:
+                return NotImplemented
+        elif not isinstance(other, self.__class__):
+            return NotImplemented
+
+        return self._spec != other._spec
+
+    def _get_operator(self, op):
+        return getattr(self, "_compare_{0}".format(self._operators[op]))
+
+    def _coerce_version(self, version):
+        if not isinstance(version, (LegacyVersion, Version)):
+            version = parse(version)
+        return version
+
+    @property
+    def operator(self):
+        return self._spec[0]
+
+    @property
+    def version(self):
+        return self._spec[1]
+
+    @property
+    def prereleases(self):
+        return self._prereleases
+
+    @prereleases.setter
+    def prereleases(self, value):
+        self._prereleases = value
+
+    def __contains__(self, item):
+        return self.contains(item)
+
+    def contains(self, item, prereleases=None):
+        # Determine if prereleases are to be allowed or not.
+        if prereleases is None:
+            prereleases = self.prereleases
+
+        # Normalize item to a Version or LegacyVersion, this allows us to have
+        # a shortcut for ``"2.0" in Specifier(">=2")
+        item = self._coerce_version(item)
+
+        # Determine if we should be supporting prereleases in this specifier
+        # or not, if we do not support prereleases than we can short circuit
+        # logic if this version is a prereleases.
+        if item.is_prerelease and not prereleases:
+            return False
+
+        # Actually do the comparison to determine if this item is contained
+        # within this Specifier or not.
+        return self._get_operator(self.operator)(item, self.version)
+
+    def filter(self, iterable, prereleases=None):
+        yielded = False
+        found_prereleases = []
+
+        kw = {"prereleases": prereleases if prereleases is not None else True}
+
+        # Attempt to iterate over all the values in the iterable and if any of
+        # them match, yield them.
+        for version in iterable:
+            parsed_version = self._coerce_version(version)
+
+            if self.contains(parsed_version, **kw):
+                # If our version is a prerelease, and we were not set to allow
+                # prereleases, then we'll store it for later incase nothing
+                # else matches this specifier.
+                if (parsed_version.is_prerelease and not
+                        (prereleases or self.prereleases)):
+                    found_prereleases.append(version)
+                # Either this is not a prerelease, or we should have been
+                # accepting prereleases from the begining.
+                else:
+                    yielded = True
+                    yield version
+
+        # Now that we've iterated over everything, determine if we've yielded
+        # any values, and if we have not and we have any prereleases stored up
+        # then we will go ahead and yield the prereleases.
+        if not yielded and found_prereleases:
+            for version in found_prereleases:
+                yield version
+
+
+class LegacySpecifier(_IndividualSpecifier):
+
+    _regex_str = (
+        r"""
+        (?P<operator>(==|!=|<=|>=|<|>))
+        \s*
+        (?P<version>
+            [^,;\s)]* # Since this is a "legacy" specifier, and the version
+                      # string can be just about anything, we match everything
+                      # except for whitespace, a semi-colon for marker support,
+                      # a closing paren since versions can be enclosed in
+                      # them, and a comma since it's a version separator.
+        )
+        """
+    )
+
+    _regex = re.compile(
+        r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
+
+    _operators = {
+        "==": "equal",
+        "!=": "not_equal",
+        "<=": "less_than_equal",
+        ">=": "greater_than_equal",
+        "<": "less_than",
+        ">": "greater_than",
+    }
+
+    def _coerce_version(self, version):
+        if not isinstance(version, LegacyVersion):
+            version = LegacyVersion(str(version))
+        return version
+
+    def _compare_equal(self, prospective, spec):
+        return prospective == self._coerce_version(spec)
+
+    def _compare_not_equal(self, prospective, spec):
+        return prospective != self._coerce_version(spec)
+
+    def _compare_less_than_equal(self, prospective, spec):
+        return prospective <= self._coerce_version(spec)
+
+    def _compare_greater_than_equal(self, prospective, spec):
+        return prospective >= self._coerce_version(spec)
+
+    def _compare_less_than(self, prospective, spec):
+        return prospective < self._coerce_version(spec)
+
+    def _compare_greater_than(self, prospective, spec):
+        return prospective > self._coerce_version(spec)
+
+
+def _require_version_compare(fn):
+    @functools.wraps(fn)
+    def wrapped(self, prospective, spec):
+        if not isinstance(prospective, Version):
+            return False
+        return fn(self, prospective, spec)
+    return wrapped
+
+
+class Specifier(_IndividualSpecifier):
+
+    _regex_str = (
+        r"""
+        (?P<operator>(~=|==|!=|<=|>=|<|>|===))
+        (?P<version>
+            (?:
+                # The identity operators allow for an escape hatch that will
+                # do an exact string match of the version you wish to install.
+                # This will not be parsed by PEP 440 and we cannot determine
+                # any semantic meaning from it. This operator is discouraged
+                # but included entirely as an escape hatch.
+                (?<====)  # Only match for the identity operator
+                \s*
+                [^\s]*    # We just match everything, except for whitespace
+                          # since we are only testing for strict identity.
+            )
+            |
+            (?:
+                # The (non)equality operators allow for wild card and local
+                # versions to be specified so we have to define these two
+                # operators separately to enable that.
+                (?<===|!=)            # Only match for equals and not equals
+
+                \s*
+                v?
+                (?:[0-9]+!)?          # epoch
+                [0-9]+(?:\.[0-9]+)*   # release
+                (?:                   # pre release
+                    [-_\.]?
+                    (a|b|c|rc|alpha|beta|pre|preview)
+                    [-_\.]?
+                    [0-9]*
+                )?
+                (?:                   # post release
+                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
+                )?
+
+                # You cannot use a wild card and a dev or local version
+                # together so group them with a | and make them optional.
+                (?:
+                    (?:[-_\.]?dev[-_\.]?[0-9]*)?         # dev release
+                    (?:\+[a-z0-9]+(?:[-_\.][a-z0-9]+)*)? # local
+                    |
+                    \.\*  # Wild card syntax of .*
+                )?
+            )
+            |
+            (?:
+                # The compatible operator requires at least two digits in the
+                # release segment.
+                (?<=~=)               # Only match for the compatible operator
+
+                \s*
+                v?
+                (?:[0-9]+!)?          # epoch
+                [0-9]+(?:\.[0-9]+)+   # release  (We have a + instead of a *)
+                (?:                   # pre release
+                    [-_\.]?
+                    (a|b|c|rc|alpha|beta|pre|preview)
+                    [-_\.]?
+                    [0-9]*
+                )?
+                (?:                                   # post release
+                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
+                )?
+                (?:[-_\.]?dev[-_\.]?[0-9]*)?          # dev release
+            )
+            |
+            (?:
+                # All other operators only allow a sub set of what the
+                # (non)equality operators do. Specifically they do not allow
+                # local versions to be specified nor do they allow the prefix
+                # matching wild cards.
+                (?<!==|!=|~=)         # We have special cases for these
+                                      # operators so we want to make sure they
+                                      # don't match here.
+
+                \s*
+                v?
+                (?:[0-9]+!)?          # epoch
+                [0-9]+(?:\.[0-9]+)*   # release
+                (?:                   # pre release
+                    [-_\.]?
+                    (a|b|c|rc|alpha|beta|pre|preview)
+                    [-_\.]?
+                    [0-9]*
+                )?
+                (?:                                   # post release
+                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
+                )?
+                (?:[-_\.]?dev[-_\.]?[0-9]*)?          # dev release
+            )
+        )
+        """
+    )
+
+    _regex = re.compile(
+        r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
+
+    _operators = {
+        "~=": "compatible",
+        "==": "equal",
+        "!=": "not_equal",
+        "<=": "less_than_equal",
+        ">=": "greater_than_equal",
+        "<": "less_than",
+        ">": "greater_than",
+        "===": "arbitrary",
+    }
+
+    @_require_version_compare
+    def _compare_compatible(self, prospective, spec):
+        # Compatible releases have an equivalent combination of >= and ==. That
+        # is that ~=2.2 is equivalent to >=2.2,==2.*. This allows us to
+        # implement this in terms of the other specifiers instead of
+        # implementing it ourselves. The only thing we need to do is construct
+        # the other specifiers.
+
+        # We want everything but the last item in the version, but we want to
+        # ignore post and dev releases and we want to treat the pre-release as
+        # it's own separate segment.
+        prefix = ".".join(
+            list(
+                itertools.takewhile(
+                    lambda x: (not x.startswith("post") and not
+                               x.startswith("dev")),
+                    _version_split(spec),
+                )
+            )[:-1]
+        )
+
+        # Add the prefix notation to the end of our string
+        prefix += ".*"
+
+        return (self._get_operator(">=")(prospective, spec) and
+                self._get_operator("==")(prospective, prefix))
+
+    @_require_version_compare
+    def _compare_equal(self, prospective, spec):
+        # We need special logic to handle prefix matching
+        if spec.endswith(".*"):
+            # In the case of prefix matching we want to ignore local segment.
+            prospective = Version(prospective.public)
+            # Split the spec out by dots, and pretend that there is an implicit
+            # dot in between a release segment and a pre-release segment.
+            spec = _version_split(spec[:-2])  # Remove the trailing .*
+
+            # Split the prospective version out by dots, and pretend that there
+            # is an implicit dot in between a release segment and a pre-release
+            # segment.
+            prospective = _version_split(str(prospective))
+
+            # Shorten the prospective version to be the same length as the spec
+            # so that we can determine if the specifier is a prefix of the
+            # prospective version or not.
+            prospective = prospective[:len(spec)]
+
+            # Pad out our two sides with zeros so that they both equal the same
+            # length.
+            spec, prospective = _pad_version(spec, prospective)
+        else:
+            # Convert our spec string into a Version
+            spec = Version(spec)
+
+            # If the specifier does not have a local segment, then we want to
+            # act as if the prospective version also does not have a local
+            # segment.
+            if not spec.local:
+                prospective = Version(prospective.public)
+
+        return prospective == spec
+
+    @_require_version_compare
+    def _compare_not_equal(self, prospective, spec):
+        return not self._compare_equal(prospective, spec)
+
+    @_require_version_compare
+    def _compare_less_than_equal(self, prospective, spec):
+        return prospective <= Version(spec)
+
+    @_require_version_compare
+    def _compare_greater_than_equal(self, prospective, spec):
+        return prospective >= Version(spec)
+
+    @_require_version_compare
+    def _compare_less_than(self, prospective, spec):
+        # Convert our spec to a Version instance, since we'll want to work with
+        # it as a version.
+        spec = Version(spec)
+
+        # Check to see if the prospective version is less than the spec
+        # version. If it's not we can short circuit and just return False now
+        # instead of doing extra unneeded work.
+        if not prospective < spec:
+            return False
+
+        # This special case is here so that, unless the specifier itself
+        # includes is a pre-release version, that we do not accept pre-release
+        # versions for the version mentioned in the specifier (e.g. <3.1 should
+        # not match 3.1.dev0, but should match 3.0.dev0).
+        if not spec.is_prerelease and prospective.is_prerelease:
+            if Version(prospective.base_version) == Version(spec.base_version):
+                return False
+
+        # If we've gotten to here, it means that prospective version is both
+        # less than the spec version *and* it's not a pre-release of the same
+        # version in the spec.
+        return True
+
+    @_require_version_compare
+    def _compare_greater_than(self, prospective, spec):
+        # Convert our spec to a Version instance, since we'll want to work with
+        # it as a version.
+        spec = Version(spec)
+
+        # Check to see if the prospective version is greater than the spec
+        # version. If it's not we can short circuit and just return False now
+        # instead of doing extra unneeded work.
+        if not prospective > spec:
+            return False
+
+        # This special case is here so that, unless the specifier itself
+        # includes is a post-release version, that we do not accept
+        # post-release versions for the version mentioned in the specifier
+        # (e.g. >3.1 should not match 3.0.post0, but should match 3.2.post0).
+        if not spec.is_postrelease and prospective.is_postrelease:
+            if Version(prospective.base_version) == Version(spec.base_version):
+                return False
+
+        # Ensure that we do not allow a local version of the version mentioned
+        # in the specifier, which is techincally greater than, to match.
+        if prospective.local is not None:
+            if Version(prospective.base_version) == Version(spec.base_version):
+                return False
+
+        # If we've gotten to here, it means that prospective version is both
+        # greater than the spec version *and* it's not a pre-release of the
+        # same version in the spec.
+        return True
+
+    def _compare_arbitrary(self, prospective, spec):
+        return str(prospective).lower() == str(spec).lower()
+
+    @property
+    def prereleases(self):
+        # If there is an explicit prereleases set for this, then we'll just
+        # blindly use that.
+        if self._prereleases is not None:
+            return self._prereleases
+
+        # Look at all of our specifiers and determine if they are inclusive
+        # operators, and if they are if they are including an explicit
+        # prerelease.
+        operator, version = self._spec
+        if operator in ["==", ">=", "<=", "~=", "==="]:
+            # The == specifier can include a trailing .*, if it does we
+            # want to remove before parsing.
+            if operator == "==" and version.endswith(".*"):
+                version = version[:-2]
+
+            # Parse the version, and if it is a pre-release than this
+            # specifier allows pre-releases.
+            if parse(version).is_prerelease:
+                return True
+
+        return False
+
+    @prereleases.setter
+    def prereleases(self, value):
+        self._prereleases = value
+
+
+_prefix_regex = re.compile(r"^([0-9]+)((?:a|b|c|rc)[0-9]+)$")
+
+
+def _version_split(version):
+    result = []
+    for item in version.split("."):
+        match = _prefix_regex.search(item)
+        if match:
+            result.extend(match.groups())
+        else:
+            result.append(item)
+    return result
+
+
+def _pad_version(left, right):
+    left_split, right_split = [], []
+
+    # Get the release segment of our versions
+    left_split.append(list(itertools.takewhile(lambda x: x.isdigit(), left)))
+    right_split.append(list(itertools.takewhile(lambda x: x.isdigit(), right)))
+
+    # Get the rest of our versions
+    left_split.append(left[len(left_split[0]):])
+    right_split.append(right[len(right_split[0]):])
+
+    # Insert our padding
+    left_split.insert(
+        1,
+        ["0"] * max(0, len(right_split[0]) - len(left_split[0])),
+    )
+    right_split.insert(
+        1,
+        ["0"] * max(0, len(left_split[0]) - len(right_split[0])),
+    )
+
+    return (
+        list(itertools.chain(*left_split)),
+        list(itertools.chain(*right_split)),
+    )
+
+
+class SpecifierSet(BaseSpecifier):
+
+    def __init__(self, specifiers="", prereleases=None):
+        # Split on , to break each indidivual specifier into it's own item, and
+        # strip each item to remove leading/trailing whitespace.
+        specifiers = [s.strip() for s in specifiers.split(",") if s.strip()]
+
+        # Parsed each individual specifier, attempting first to make it a
+        # Specifier and falling back to a LegacySpecifier.
+        parsed = set()
+        for specifier in specifiers:
+            try:
+                parsed.add(Specifier(specifier))
+            except InvalidSpecifier:
+                parsed.add(LegacySpecifier(specifier))
+
+        # Turn our parsed specifiers into a frozen set and save them for later.
+        self._specs = frozenset(parsed)
+
+        # Store our prereleases value so we can use it later to determine if
+        # we accept prereleases or not.
+        self._prereleases = prereleases
+
+    def __repr__(self):
+        pre = (
+            ", prereleases={0!r}".format(self.prereleases)
+            if self._prereleases is not None
+            else ""
+        )
+
+        return "<SpecifierSet({0!r}{1})>".format(str(self), pre)
+
+    def __str__(self):
+        return ",".join(sorted(str(s) for s in self._specs))
+
+    def __hash__(self):
+        return hash(self._specs)
+
+    def __and__(self, other):
+        if isinstance(other, string_types):
+            other = SpecifierSet(other)
+        elif not isinstance(other, SpecifierSet):
+            return NotImplemented
+
+        specifier = SpecifierSet()
+        specifier._specs = frozenset(self._specs | other._specs)
+
+        if self._prereleases is None and other._prereleases is not None:
+            specifier._prereleases = other._prereleases
+        elif self._prereleases is not None and other._prereleases is None:
+            specifier._prereleases = self._prereleases
+        elif self._prereleases == other._prereleases:
+            specifier._prereleases = self._prereleases
+        else:
+            raise ValueError(
+                "Cannot combine SpecifierSets with True and False prerelease "
+                "overrides."
+            )
+
+        return specifier
+
+    def __eq__(self, other):
+        if isinstance(other, string_types):
+            other = SpecifierSet(other)
+        elif isinstance(other, _IndividualSpecifier):
+            other = SpecifierSet(str(other))
+        elif not isinstance(other, SpecifierSet):
+            return NotImplemented
+
+        return self._specs == other._specs
+
+    def __ne__(self, other):
+        if isinstance(other, string_types):
+            other = SpecifierSet(other)
+        elif isinstance(other, _IndividualSpecifier):
+            other = SpecifierSet(str(other))
+        elif not isinstance(other, SpecifierSet):
+            return NotImplemented
+
+        return self._specs != other._specs
+
+    def __len__(self):
+        return len(self._specs)
+
+    def __iter__(self):
+        return iter(self._specs)
+
+    @property
+    def prereleases(self):
+        # If we have been given an explicit prerelease modifier, then we'll
+        # pass that through here.
+        if self._prereleases is not None:
+            return self._prereleases
+
+        # If we don't have any specifiers, and we don't have a forced value,
+        # then we'll just return None since we don't know if this should have
+        # pre-releases or not.
+        if not self._specs:
+            return None
+
+        # Otherwise we'll see if any of the given specifiers accept
+        # prereleases, if any of them do we'll return True, otherwise False.
+        return any(s.prereleases for s in self._specs)
+
+    @prereleases.setter
+    def prereleases(self, value):
+        self._prereleases = value
+
+    def __contains__(self, item):
+        return self.contains(item)
+
+    def contains(self, item, prereleases=None):
+        # Ensure that our item is a Version or LegacyVersion instance.
+        if not isinstance(item, (LegacyVersion, Version)):
+            item = parse(item)
+
+        # Determine if we're forcing a prerelease or not, if we're not forcing
+        # one for this particular filter call, then we'll use whatever the
+        # SpecifierSet thinks for whether or not we should support prereleases.
+        if prereleases is None:
+            prereleases = self.prereleases
+
+        # We can determine if we're going to allow pre-releases by looking to
+        # see if any of the underlying items supports them. If none of them do
+        # and this item is a pre-release then we do not allow it and we can
+        # short circuit that here.
+        # Note: This means that 1.0.dev1 would not be contained in something
+        #       like >=1.0.devabc however it would be in >=1.0.debabc,>0.0.dev0
+        if not prereleases and item.is_prerelease:
+            return False
+
+        # We simply dispatch to the underlying specs here to make sure that the
+        # given version is contained within all of them.
+        # Note: This use of all() here means that an empty set of specifiers
+        #       will always return True, this is an explicit design decision.
+        return all(
+            s.contains(item, prereleases=prereleases)
+            for s in self._specs
+        )
+
+    def filter(self, iterable, prereleases=None):
+        # Determine if we're forcing a prerelease or not, if we're not forcing
+        # one for this particular filter call, then we'll use whatever the
+        # SpecifierSet thinks for whether or not we should support prereleases.
+        if prereleases is None:
+            prereleases = self.prereleases
+
+        # If we have any specifiers, then we want to wrap our iterable in the
+        # filter method for each one, this will act as a logical AND amongst
+        # each specifier.
+        if self._specs:
+            for spec in self._specs:
+                iterable = spec.filter(iterable, prereleases=bool(prereleases))
+            return iterable
+        # If we do not have any specifiers, then we need to have a rough filter
+        # which will filter out any pre-releases, unless there are no final
+        # releases, and which will filter out LegacyVersion in general.
+        else:
+            filtered = []
+            found_prereleases = []
+
+            for item in iterable:
+                # Ensure that we some kind of Version class for this item.
+                if not isinstance(item, (LegacyVersion, Version)):
+                    parsed_version = parse(item)
+                else:
+                    parsed_version = item
+
+                # Filter out any item which is parsed as a LegacyVersion
+                if isinstance(parsed_version, LegacyVersion):
+                    continue
+
+                # Store any item which is a pre-release for later unless we've
+                # already found a final version or we are accepting prereleases
+                if parsed_version.is_prerelease and not prereleases:
+                    if not filtered:
+                        found_prereleases.append(item)
+                else:
+                    filtered.append(item)
+
+            # If we've found no items except for pre-releases, then we'll go
+            # ahead and use the pre-releases
+            if not filtered and found_prereleases and prereleases is None:
+                return found_prereleases
+
+            return filtered
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/utils.py b/recipes/pkgresources/pkgr/_vendor/packaging/utils.py
new file mode 100644
index 0000000..942387c
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/utils.py
@@ -0,0 +1,14 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import re
+
+
+_canonicalize_regex = re.compile(r"[-_.]+")
+
+
+def canonicalize_name(name):
+    # This is taken from PEP 503.
+    return _canonicalize_regex.sub("-", name).lower()
diff --git a/recipes/pkgresources/pkgr/_vendor/packaging/version.py b/recipes/pkgresources/pkgr/_vendor/packaging/version.py
new file mode 100644
index 0000000..83b5ee8
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/packaging/version.py
@@ -0,0 +1,393 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import collections
+import itertools
+import re
+
+from ._structures import Infinity
+
+
+__all__ = [
+    "parse", "Version", "LegacyVersion", "InvalidVersion", "VERSION_PATTERN"
+]
+
+
+_Version = collections.namedtuple(
+    "_Version",
+    ["epoch", "release", "dev", "pre", "post", "local"],
+)
+
+
+def parse(version):
+    """
+    Parse the given version string and return either a :class:`Version` object
+    or a :class:`LegacyVersion` object depending on if the given version is
+    a valid PEP 440 version or a legacy version.
+    """
+    try:
+        return Version(version)
+    except InvalidVersion:
+        return LegacyVersion(version)
+
+
+class InvalidVersion(ValueError):
+    """
+    An invalid version was found, users should refer to PEP 440.
+    """
+
+
+class _BaseVersion(object):
+
+    def __hash__(self):
+        return hash(self._key)
+
+    def __lt__(self, other):
+        return self._compare(other, lambda s, o: s < o)
+
+    def __le__(self, other):
+        return self._compare(other, lambda s, o: s <= o)
+
+    def __eq__(self, other):
+        return self._compare(other, lambda s, o: s == o)
+
+    def __ge__(self, other):
+        return self._compare(other, lambda s, o: s >= o)
+
+    def __gt__(self, other):
+        return self._compare(other, lambda s, o: s > o)
+
+    def __ne__(self, other):
+        return self._compare(other, lambda s, o: s != o)
+
+    def _compare(self, other, method):
+        if not isinstance(other, _BaseVersion):
+            return NotImplemented
+
+        return method(self._key, other._key)
+
+
+class LegacyVersion(_BaseVersion):
+
+    def __init__(self, version):
+        self._version = str(version)
+        self._key = _legacy_cmpkey(self._version)
+
+    def __str__(self):
+        return self._version
+
+    def __repr__(self):
+        return "<LegacyVersion({0})>".format(repr(str(self)))
+
+    @property
+    def public(self):
+        return self._version
+
+    @property
+    def base_version(self):
+        return self._version
+
+    @property
+    def local(self):
+        return None
+
+    @property
+    def is_prerelease(self):
+        return False
+
+    @property
+    def is_postrelease(self):
+        return False
+
+
+_legacy_version_component_re = re.compile(
+    r"(\d+ | [a-z]+ | \.| -)", re.VERBOSE,
+)
+
+_legacy_version_replacement_map = {
+    "pre": "c", "preview": "c", "-": "final-", "rc": "c", "dev": "@",
+}
+
+
+def _parse_version_parts(s):
+    for part in _legacy_version_component_re.split(s):
+        part = _legacy_version_replacement_map.get(part, part)
+
+        if not part or part == ".":
+            continue
+
+        if part[:1] in "0123456789":
+            # pad for numeric comparison
+            yield part.zfill(8)
+        else:
+            yield "*" + part
+
+    # ensure that alpha/beta/candidate are before final
+    yield "*final"
+
+
+def _legacy_cmpkey(version):
+    # We hardcode an epoch of -1 here. A PEP 440 version can only have a epoch
+    # greater than or equal to 0. This will effectively put the LegacyVersion,
+    # which uses the defacto standard originally implemented by setuptools,
+    # as before all PEP 440 versions.
+    epoch = -1
+
+    # This scheme is taken from pkg_resources.parse_version setuptools prior to
+    # it's adoption of the packaging library.
+    parts = []
+    for part in _parse_version_parts(version.lower()):
+        if part.startswith("*"):
+            # remove "-" before a prerelease tag
+            if part < "*final":
+                while parts and parts[-1] == "*final-":
+                    parts.pop()
+
+            # remove trailing zeros from each series of numeric parts
+            while parts and parts[-1] == "00000000":
+                parts.pop()
+
+        parts.append(part)
+    parts = tuple(parts)
+
+    return epoch, parts
+
+# Deliberately not anchored to the start and end of the string, to make it
+# easier for 3rd party code to reuse
+VERSION_PATTERN = r"""
+    v?
+    (?:
+        (?:(?P<epoch>[0-9]+)!)?                           # epoch
+        (?P<release>[0-9]+(?:\.[0-9]+)*)                  # release segment
+        (?P<pre>                                          # pre-release
+            [-_\.]?
+            (?P<pre_l>(a|b|c|rc|alpha|beta|pre|preview))
+            [-_\.]?
+            (?P<pre_n>[0-9]+)?
+        )?
+        (?P<post>                                         # post release
+            (?:-(?P<post_n1>[0-9]+))
+            |
+            (?:
+                [-_\.]?
+                (?P<post_l>post|rev|r)
+                [-_\.]?
+                (?P<post_n2>[0-9]+)?
+            )
+        )?
+        (?P<dev>                                          # dev release
+            [-_\.]?
+            (?P<dev_l>dev)
+            [-_\.]?
+            (?P<dev_n>[0-9]+)?
+        )?
+    )
+    (?:\+(?P<local>[a-z0-9]+(?:[-_\.][a-z0-9]+)*))?       # local version
+"""
+
+
+class Version(_BaseVersion):
+
+    _regex = re.compile(
+        r"^\s*" + VERSION_PATTERN + r"\s*$",
+        re.VERBOSE | re.IGNORECASE,
+    )
+
+    def __init__(self, version):
+        # Validate the version and parse it into pieces
+        match = self._regex.search(version)
+        if not match:
+            raise InvalidVersion("Invalid version: '{0}'".format(version))
+
+        # Store the parsed out pieces of the version
+        self._version = _Version(
+            epoch=int(match.group("epoch")) if match.group("epoch") else 0,
+            release=tuple(int(i) for i in match.group("release").split(".")),
+            pre=_parse_letter_version(
+                match.group("pre_l"),
+                match.group("pre_n"),
+            ),
+            post=_parse_letter_version(
+                match.group("post_l"),
+                match.group("post_n1") or match.group("post_n2"),
+            ),
+            dev=_parse_letter_version(
+                match.group("dev_l"),
+                match.group("dev_n"),
+            ),
+            local=_parse_local_version(match.group("local")),
+        )
+
+        # Generate a key which will be used for sorting
+        self._key = _cmpkey(
+            self._version.epoch,
+            self._version.release,
+            self._version.pre,
+            self._version.post,
+            self._version.dev,
+            self._version.local,
+        )
+
+    def __repr__(self):
+        return "<Version({0})>".format(repr(str(self)))
+
+    def __str__(self):
+        parts = []
+
+        # Epoch
+        if self._version.epoch != 0:
+            parts.append("{0}!".format(self._version.epoch))
+
+        # Release segment
+        parts.append(".".join(str(x) for x in self._version.release))
+
+        # Pre-release
+        if self._version.pre is not None:
+            parts.append("".join(str(x) for x in self._version.pre))
+
+        # Post-release
+        if self._version.post is not None:
+            parts.append(".post{0}".format(self._version.post[1]))
+
+        # Development release
+        if self._version.dev is not None:
+            parts.append(".dev{0}".format(self._version.dev[1]))
+
+        # Local version segment
+        if self._version.local is not None:
+            parts.append(
+                "+{0}".format(".".join(str(x) for x in self._version.local))
+            )
+
+        return "".join(parts)
+
+    @property
+    def public(self):
+        return str(self).split("+", 1)[0]
+
+    @property
+    def base_version(self):
+        parts = []
+
+        # Epoch
+        if self._version.epoch != 0:
+            parts.append("{0}!".format(self._version.epoch))
+
+        # Release segment
+        parts.append(".".join(str(x) for x in self._version.release))
+
+        return "".join(parts)
+
+    @property
+    def local(self):
+        version_string = str(self)
+        if "+" in version_string:
+            return version_string.split("+", 1)[1]
+
+    @property
+    def is_prerelease(self):
+        return bool(self._version.dev or self._version.pre)
+
+    @property
+    def is_postrelease(self):
+        return bool(self._version.post)
+
+
+def _parse_letter_version(letter, number):
+    if letter:
+        # We consider there to be an implicit 0 in a pre-release if there is
+        # not a numeral associated with it.
+        if number is None:
+            number = 0
+
+        # We normalize any letters to their lower case form
+        letter = letter.lower()
+
+        # We consider some words to be alternate spellings of other words and
+        # in those cases we want to normalize the spellings to our preferred
+        # spelling.
+        if letter == "alpha":
+            letter = "a"
+        elif letter == "beta":
+            letter = "b"
+        elif letter in ["c", "pre", "preview"]:
+            letter = "rc"
+        elif letter in ["rev", "r"]:
+            letter = "post"
+
+        return letter, int(number)
+    if not letter and number:
+        # We assume if we are given a number, but we are not given a letter
+        # then this is using the implicit post release syntax (e.g. 1.0-1)
+        letter = "post"
+
+        return letter, int(number)
+
+
+_local_version_seperators = re.compile(r"[\._-]")
+
+
+def _parse_local_version(local):
+    """
+    Takes a string like abc.1.twelve and turns it into ("abc", 1, "twelve").
+    """
+    if local is not None:
+        return tuple(
+            part.lower() if not part.isdigit() else int(part)
+            for part in _local_version_seperators.split(local)
+        )
+
+
+def _cmpkey(epoch, release, pre, post, dev, local):
+    # When we compare a release version, we want to compare it with all of the
+    # trailing zeros removed. So we'll use a reverse the list, drop all the now
+    # leading zeros until we come to something non zero, then take the rest
+    # re-reverse it back into the correct order and make it a tuple and use
+    # that for our sorting key.
+    release = tuple(
+        reversed(list(
+            itertools.dropwhile(
+                lambda x: x == 0,
+                reversed(release),
+            )
+        ))
+    )
+
+    # We need to "trick" the sorting algorithm to put 1.0.dev0 before 1.0a0.
+    # We'll do this by abusing the pre segment, but we _only_ want to do this
+    # if there is not a pre or a post segment. If we have one of those then
+    # the normal sorting rules will handle this case correctly.
+    if pre is None and post is None and dev is not None:
+        pre = -Infinity
+    # Versions without a pre-release (except as noted above) should sort after
+    # those with one.
+    elif pre is None:
+        pre = Infinity
+
+    # Versions without a post segment should sort before those with one.
+    if post is None:
+        post = -Infinity
+
+    # Versions without a development segment should sort after those with one.
+    if dev is None:
+        dev = Infinity
+
+    if local is None:
+        # Versions without a local segment should sort before those with one.
+        local = -Infinity
+    else:
+        # Versions with a local segment need that segment parsed to implement
+        # the sorting rules in PEP440.
+        # - Alpha numeric segments sort before numeric segments
+        # - Alpha numeric segments sort lexicographically
+        # - Numeric segments sort numerically
+        # - Shorter versions sort before longer versions when the prefixes
+        #   match exactly
+        local = tuple(
+            (i, "") if isinstance(i, int) else (-Infinity, i)
+            for i in local
+        )
+
+    return epoch, release, pre, post, dev, local
diff --git a/recipes/pkgresources/pkgr/_vendor/pyparsing.py b/recipes/pkgresources/pkgr/_vendor/pyparsing.py
new file mode 100644
index 0000000..a212243
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/pyparsing.py
@@ -0,0 +1,5696 @@
+# module pyparsing.py
+#
+# Copyright (c) 2003-2016  Paul T. McGuire
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+__doc__ = \
+"""
+pyparsing module - Classes and methods to define and execute parsing grammars
+
+The pyparsing module is an alternative approach to creating and executing simple grammars,
+vs. the traditional lex/yacc approach, or the use of regular expressions.  With pyparsing, you
+don't need to learn a new syntax for defining grammars or matching expressions - the parsing module
+provides a library of classes that you use to construct the grammar directly in Python.
+
+Here is a program to parse "Hello, World!" (or any greeting of the form 
+C{"<salutation>, <addressee>!"}), built up using L{Word}, L{Literal}, and L{And} elements 
+(L{'+'<ParserElement.__add__>} operator gives L{And} expressions, strings are auto-converted to
+L{Literal} expressions)::
+
+    from pyparsing import Word, alphas
+
+    # define grammar of a greeting
+    greet = Word(alphas) + "," + Word(alphas) + "!"
+
+    hello = "Hello, World!"
+    print (hello, "->", greet.parseString(hello))
+
+The program outputs the following::
+
+    Hello, World! -> ['Hello', ',', 'World', '!']
+
+The Python representation of the grammar is quite readable, owing to the self-explanatory
+class names, and the use of '+', '|' and '^' operators.
+
+The L{ParseResults} object returned from L{ParserElement.parseString<ParserElement.parseString>} can be accessed as a nested list, a dictionary, or an
+object with named attributes.
+
+The pyparsing module handles some of the problems that are typically vexing when writing text parsers:
+ - extra or missing whitespace (the above program will also handle "Hello,World!", "Hello  ,  World  !", etc.)
+ - quoted strings
+ - embedded comments
+"""
+
+__version__ = "2.1.10"
+__versionTime__ = "07 Oct 2016 01:31 UTC"
+__author__ = "Paul McGuire <ptmcg@users.sourceforge.net>"
+
+import string
+from weakref import ref as wkref
+import copy
+import sys
+import warnings
+import re
+import sre_constants
+import collections
+import pprint
+import traceback
+import types
+from datetime import datetime
+
+try:
+    from _thread import RLock
+except ImportError:
+    from threading import RLock
+
+try:
+    from collections import OrderedDict as _OrderedDict
+except ImportError:
+    try:
+        from ordereddict import OrderedDict as _OrderedDict
+    except ImportError:
+        _OrderedDict = None
+
+#~ sys.stderr.write( "testing pyparsing module, version %s, %s\n" % (__version__,__versionTime__ ) )
+
+__all__ = [
+'And', 'CaselessKeyword', 'CaselessLiteral', 'CharsNotIn', 'Combine', 'Dict', 'Each', 'Empty',
+'FollowedBy', 'Forward', 'GoToColumn', 'Group', 'Keyword', 'LineEnd', 'LineStart', 'Literal',
+'MatchFirst', 'NoMatch', 'NotAny', 'OneOrMore', 'OnlyOnce', 'Optional', 'Or',
+'ParseBaseException', 'ParseElementEnhance', 'ParseException', 'ParseExpression', 'ParseFatalException',
+'ParseResults', 'ParseSyntaxException', 'ParserElement', 'QuotedString', 'RecursiveGrammarException',
+'Regex', 'SkipTo', 'StringEnd', 'StringStart', 'Suppress', 'Token', 'TokenConverter', 
+'White', 'Word', 'WordEnd', 'WordStart', 'ZeroOrMore',
+'alphanums', 'alphas', 'alphas8bit', 'anyCloseTag', 'anyOpenTag', 'cStyleComment', 'col',
+'commaSeparatedList', 'commonHTMLEntity', 'countedArray', 'cppStyleComment', 'dblQuotedString',
+'dblSlashComment', 'delimitedList', 'dictOf', 'downcaseTokens', 'empty', 'hexnums',
+'htmlComment', 'javaStyleComment', 'line', 'lineEnd', 'lineStart', 'lineno',
+'makeHTMLTags', 'makeXMLTags', 'matchOnlyAtCol', 'matchPreviousExpr', 'matchPreviousLiteral',
+'nestedExpr', 'nullDebugAction', 'nums', 'oneOf', 'opAssoc', 'operatorPrecedence', 'printables',
+'punc8bit', 'pythonStyleComment', 'quotedString', 'removeQuotes', 'replaceHTMLEntity', 
+'replaceWith', 'restOfLine', 'sglQuotedString', 'srange', 'stringEnd',
+'stringStart', 'traceParseAction', 'unicodeString', 'upcaseTokens', 'withAttribute',
+'indentedBlock', 'originalTextFor', 'ungroup', 'infixNotation','locatedExpr', 'withClass',
+'CloseMatch', 'tokenMap', 'pyparsing_common',
+]
+
+system_version = tuple(sys.version_info)[:3]
+PY_3 = system_version[0] == 3
+if PY_3:
+    _MAX_INT = sys.maxsize
+    basestring = str
+    unichr = chr
+    _ustr = str
+
+    # build list of single arg builtins, that can be used as parse actions
+    singleArgBuiltins = [sum, len, sorted, reversed, list, tuple, set, any, all, min, max]
+
+else:
+    _MAX_INT = sys.maxint
+    range = xrange
+
+    def _ustr(obj):
+        """Drop-in replacement for str(obj) that tries to be Unicode friendly. It first tries
+           str(obj). If that fails with a UnicodeEncodeError, then it tries unicode(obj). It
+           then < returns the unicode object | encodes it with the default encoding | ... >.
+        """
+        if isinstance(obj,unicode):
+            return obj
+
+        try:
+            # If this works, then _ustr(obj) has the same behaviour as str(obj), so
+            # it won't break any existing code.
+            return str(obj)
+
+        except UnicodeEncodeError:
+            # Else encode it
+            ret = unicode(obj).encode(sys.getdefaultencoding(), 'xmlcharrefreplace')
+            xmlcharref = Regex('&#\d+;')
+            xmlcharref.setParseAction(lambda t: '\\u' + hex(int(t[0][2:-1]))[2:])
+            return xmlcharref.transformString(ret)
+
+    # build list of single arg builtins, tolerant of Python version, that can be used as parse actions
+    singleArgBuiltins = []
+    import __builtin__
+    for fname in "sum len sorted reversed list tuple set any all min max".split():
+        try:
+            singleArgBuiltins.append(getattr(__builtin__,fname))
+        except AttributeError:
+            continue
+            
+_generatorType = type((y for y in range(1)))
+ 
+def _xml_escape(data):
+    """Escape &, <, >, ", ', etc. in a string of data."""
+
+    # ampersand must be replaced first
+    from_symbols = '&><"\''
+    to_symbols = ('&'+s+';' for s in "amp gt lt quot apos".split())
+    for from_,to_ in zip(from_symbols, to_symbols):
+        data = data.replace(from_, to_)
+    return data
+
+class _Constants(object):
+    pass
+
+alphas     = string.ascii_uppercase + string.ascii_lowercase
+nums       = "0123456789"
+hexnums    = nums + "ABCDEFabcdef"
+alphanums  = alphas + nums
+_bslash    = chr(92)
+printables = "".join(c for c in string.printable if c not in string.whitespace)
+
+class ParseBaseException(Exception):
+    """base exception class for all parsing runtime exceptions"""
+    # Performance tuning: we construct a *lot* of these, so keep this
+    # constructor as small and fast as possible
+    def __init__( self, pstr, loc=0, msg=None, elem=None ):
+        self.loc = loc
+        if msg is None:
+            self.msg = pstr
+            self.pstr = ""
+        else:
+            self.msg = msg
+            self.pstr = pstr
+        self.parserElement = elem
+        self.args = (pstr, loc, msg)
+
+    @classmethod
+    def _from_exception(cls, pe):
+        """
+        internal factory method to simplify creating one type of ParseException 
+        from another - avoids having __init__ signature conflicts among subclasses
+        """
+        return cls(pe.pstr, pe.loc, pe.msg, pe.parserElement)
+
+    def __getattr__( self, aname ):
+        """supported attributes by name are:
+            - lineno - returns the line number of the exception text
+            - col - returns the column number of the exception text
+            - line - returns the line containing the exception text
+        """
+        if( aname == "lineno" ):
+            return lineno( self.loc, self.pstr )
+        elif( aname in ("col", "column") ):
+            return col( self.loc, self.pstr )
+        elif( aname == "line" ):
+            return line( self.loc, self.pstr )
+        else:
+            raise AttributeError(aname)
+
+    def __str__( self ):
+        return "%s (at char %d), (line:%d, col:%d)" % \
+                ( self.msg, self.loc, self.lineno, self.column )
+    def __repr__( self ):
+        return _ustr(self)
+    def markInputline( self, markerString = ">!<" ):
+        """Extracts the exception line from the input string, and marks
+           the location of the exception with a special symbol.
+        """
+        line_str = self.line
+        line_column = self.column - 1
+        if markerString:
+            line_str = "".join((line_str[:line_column],
+                                markerString, line_str[line_column:]))
+        return line_str.strip()
+    def __dir__(self):
+        return "lineno col line".split() + dir(type(self))
+
+class ParseException(ParseBaseException):
+    """
+    Exception thrown when parse expressions don't match class;
+    supported attributes by name are:
+     - lineno - returns the line number of the exception text
+     - col - returns the column number of the exception text
+     - line - returns the line containing the exception text
+        
+    Example::
+        try:
+            Word(nums).setName("integer").parseString("ABC")
+        except ParseException as pe:
+            print(pe)
+            print("column: {}".format(pe.col))
+            
+    prints::
+       Expected integer (at char 0), (line:1, col:1)
+        column: 1
+    """
+    pass
+
+class ParseFatalException(ParseBaseException):
+    """user-throwable exception thrown when inconsistent parse content
+       is found; stops all parsing immediately"""
+    pass
+
+class ParseSyntaxException(ParseFatalException):
+    """just like L{ParseFatalException}, but thrown internally when an
+       L{ErrorStop<And._ErrorStop>} ('-' operator) indicates that parsing is to stop 
+       immediately because an unbacktrackable syntax error has been found"""
+    pass
+
+#~ class ReparseException(ParseBaseException):
+    #~ """Experimental class - parse actions can raise this exception to cause
+       #~ pyparsing to reparse the input string:
+        #~ - with a modified input string, and/or
+        #~ - with a modified start location
+       #~ Set the values of the ReparseException in the constructor, and raise the
+       #~ exception in a parse action to cause pyparsing to use the new string/location.
+       #~ Setting the values as None causes no change to be made.
+       #~ """
+    #~ def __init_( self, newstring, restartLoc ):
+        #~ self.newParseText = newstring
+        #~ self.reparseLoc = restartLoc
+
+class RecursiveGrammarException(Exception):
+    """exception thrown by L{ParserElement.validate} if the grammar could be improperly recursive"""
+    def __init__( self, parseElementList ):
+        self.parseElementTrace = parseElementList
+
+    def __str__( self ):
+        return "RecursiveGrammarException: %s" % self.parseElementTrace
+
+class _ParseResultsWithOffset(object):
+    def __init__(self,p1,p2):
+        self.tup = (p1,p2)
+    def __getitem__(self,i):
+        return self.tup[i]
+    def __repr__(self):
+        return repr(self.tup[0])
+    def setOffset(self,i):
+        self.tup = (self.tup[0],i)
+
+class ParseResults(object):
+    """
+    Structured parse results, to provide multiple means of access to the parsed data:
+       - as a list (C{len(results)})
+       - by list index (C{results[0], results[1]}, etc.)
+       - by attribute (C{results.<resultsName>} - see L{ParserElement.setResultsName})
+
+    Example::
+        integer = Word(nums)
+        date_str = (integer.setResultsName("year") + '/' 
+                        + integer.setResultsName("month") + '/' 
+                        + integer.setResultsName("day"))
+        # equivalent form:
+        # date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
+
+        # parseString returns a ParseResults object
+        result = date_str.parseString("1999/12/31")
+
+        def test(s, fn=repr):
+            print("%s -> %s" % (s, fn(eval(s))))
+        test("list(result)")
+        test("result[0]")
+        test("result['month']")
+        test("result.day")
+        test("'month' in result")
+        test("'minutes' in result")
+        test("result.dump()", str)
+    prints::
+        list(result) -> ['1999', '/', '12', '/', '31']
+        result[0] -> '1999'
+        result['month'] -> '12'
+        result.day -> '31'
+        'month' in result -> True
+        'minutes' in result -> False
+        result.dump() -> ['1999', '/', '12', '/', '31']
+        - day: 31
+        - month: 12
+        - year: 1999
+    """
+    def __new__(cls, toklist=None, name=None, asList=True, modal=True ):
+        if isinstance(toklist, cls):
+            return toklist
+        retobj = object.__new__(cls)
+        retobj.__doinit = True
+        return retobj
+
+    # Performance tuning: we construct a *lot* of these, so keep this
+    # constructor as small and fast as possible
+    def __init__( self, toklist=None, name=None, asList=True, modal=True, isinstance=isinstance ):
+        if self.__doinit:
+            self.__doinit = False
+            self.__name = None
+            self.__parent = None
+            self.__accumNames = {}
+            self.__asList = asList
+            self.__modal = modal
+            if toklist is None:
+                toklist = []
+            if isinstance(toklist, list):
+                self.__toklist = toklist[:]
+            elif isinstance(toklist, _generatorType):
+                self.__toklist = list(toklist)
+            else:
+                self.__toklist = [toklist]
+            self.__tokdict = dict()
+
+        if name is not None and name:
+            if not modal:
+                self.__accumNames[name] = 0
+            if isinstance(name,int):
+                name = _ustr(name) # will always return a str, but use _ustr for consistency
+            self.__name = name
+            if not (isinstance(toklist, (type(None), basestring, list)) and toklist in (None,'',[])):
+                if isinstance(toklist,basestring):
+                    toklist = [ toklist ]
+                if asList:
+                    if isinstance(toklist,ParseResults):
+                        self[name] = _ParseResultsWithOffset(toklist.copy(),0)
+                    else:
+                        self[name] = _ParseResultsWithOffset(ParseResults(toklist[0]),0)
+                    self[name].__name = name
+                else:
+                    try:
+                        self[name] = toklist[0]
+                    except (KeyError,TypeError,IndexError):
+                        self[name] = toklist
+
+    def __getitem__( self, i ):
+        if isinstance( i, (int,slice) ):
+            return self.__toklist[i]
+        else:
+            if i not in self.__accumNames:
+                return self.__tokdict[i][-1][0]
+            else:
+                return ParseResults([ v[0] for v in self.__tokdict[i] ])
+
+    def __setitem__( self, k, v, isinstance=isinstance ):
+        if isinstance(v,_ParseResultsWithOffset):
+            self.__tokdict[k] = self.__tokdict.get(k,list()) + [v]
+            sub = v[0]
+        elif isinstance(k,(int,slice)):
+            self.__toklist[k] = v
+            sub = v
+        else:
+            self.__tokdict[k] = self.__tokdict.get(k,list()) + [_ParseResultsWithOffset(v,0)]
+            sub = v
+        if isinstance(sub,ParseResults):
+            sub.__parent = wkref(self)
+
+    def __delitem__( self, i ):
+        if isinstance(i,(int,slice)):
+            mylen = len( self.__toklist )
+            del self.__toklist[i]
+
+            # convert int to slice
+            if isinstance(i, int):
+                if i < 0:
+                    i += mylen
+                i = slice(i, i+1)
+            # get removed indices
+            removed = list(range(*i.indices(mylen)))
+            removed.reverse()
+            # fixup indices in token dictionary
+            for name,occurrences in self.__tokdict.items():
+                for j in removed:
+                    for k, (value, position) in enumerate(occurrences):
+                        occurrences[k] = _ParseResultsWithOffset(value, position - (position > j))
+        else:
+            del self.__tokdict[i]
+
+    def __contains__( self, k ):
+        return k in self.__tokdict
+
+    def __len__( self ): return len( self.__toklist )
+    def __bool__(self): return ( not not self.__toklist )
+    __nonzero__ = __bool__
+    def __iter__( self ): return iter( self.__toklist )
+    def __reversed__( self ): return iter( self.__toklist[::-1] )
+    def _iterkeys( self ):
+        if hasattr(self.__tokdict, "iterkeys"):
+            return self.__tokdict.iterkeys()
+        else:
+            return iter(self.__tokdict)
+
+    def _itervalues( self ):
+        return (self[k] for k in self._iterkeys())
+            
+    def _iteritems( self ):
+        return ((k, self[k]) for k in self._iterkeys())
+
+    if PY_3:
+        keys = _iterkeys       
+        """Returns an iterator of all named result keys (Python 3.x only)."""
+
+        values = _itervalues
+        """Returns an iterator of all named result values (Python 3.x only)."""
+
+        items = _iteritems
+        """Returns an iterator of all named result key-value tuples (Python 3.x only)."""
+
+    else:
+        iterkeys = _iterkeys
+        """Returns an iterator of all named result keys (Python 2.x only)."""
+
+        itervalues = _itervalues
+        """Returns an iterator of all named result values (Python 2.x only)."""
+
+        iteritems = _iteritems
+        """Returns an iterator of all named result key-value tuples (Python 2.x only)."""
+
+        def keys( self ):
+            """Returns all named result keys (as a list in Python 2.x, as an iterator in Python 3.x)."""
+            return list(self.iterkeys())
+
+        def values( self ):
+            """Returns all named result values (as a list in Python 2.x, as an iterator in Python 3.x)."""
+            return list(self.itervalues())
+                
+        def items( self ):
+            """Returns all named result key-values (as a list of tuples in Python 2.x, as an iterator in Python 3.x)."""
+            return list(self.iteritems())
+
+    def haskeys( self ):
+        """Since keys() returns an iterator, this method is helpful in bypassing
+           code that looks for the existence of any defined results names."""
+        return bool(self.__tokdict)
+        
+    def pop( self, *args, **kwargs):
+        """
+        Removes and returns item at specified index (default=C{last}).
+        Supports both C{list} and C{dict} semantics for C{pop()}. If passed no
+        argument or an integer argument, it will use C{list} semantics
+        and pop tokens from the list of parsed tokens. If passed a 
+        non-integer argument (most likely a string), it will use C{dict}
+        semantics and pop the corresponding value from any defined 
+        results names. A second default return value argument is 
+        supported, just as in C{dict.pop()}.
+
+        Example::
+            def remove_first(tokens):
+                tokens.pop(0)
+            print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']
+            print(OneOrMore(Word(nums)).addParseAction(remove_first).parseString("0 123 321")) # -> ['123', '321']
+
+            label = Word(alphas)
+            patt = label("LABEL") + OneOrMore(Word(nums))
+            print(patt.parseString("AAB 123 321").dump())
+
+            # Use pop() in a parse action to remove named result (note that corresponding value is not
+            # removed from list form of results)
+            def remove_LABEL(tokens):
+                tokens.pop("LABEL")
+                return tokens
+            patt.addParseAction(remove_LABEL)
+            print(patt.parseString("AAB 123 321").dump())
+        prints::
+            ['AAB', '123', '321']
+            - LABEL: AAB
+
+            ['AAB', '123', '321']
+        """
+        if not args:
+            args = [-1]
+        for k,v in kwargs.items():
+            if k == 'default':
+                args = (args[0], v)
+            else:
+                raise TypeError("pop() got an unexpected keyword argument '%s'" % k)
+        if (isinstance(args[0], int) or 
+                        len(args) == 1 or 
+                        args[0] in self):
+            index = args[0]
+            ret = self[index]
+            del self[index]
+            return ret
+        else:
+            defaultvalue = args[1]
+            return defaultvalue
+
+    def get(self, key, defaultValue=None):
+        """
+        Returns named result matching the given key, or if there is no
+        such name, then returns the given C{defaultValue} or C{None} if no
+        C{defaultValue} is specified.
+
+        Similar to C{dict.get()}.
+        
+        Example::
+            integer = Word(nums)
+            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")           
+
+            result = date_str.parseString("1999/12/31")
+            print(result.get("year")) # -> '1999'
+            print(result.get("hour", "not specified")) # -> 'not specified'
+            print(result.get("hour")) # -> None
+        """
+        if key in self:
+            return self[key]
+        else:
+            return defaultValue
+
+    def insert( self, index, insStr ):
+        """
+        Inserts new element at location index in the list of parsed tokens.
+        
+        Similar to C{list.insert()}.
+
+        Example::
+            print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']
+
+            # use a parse action to insert the parse location in the front of the parsed results
+            def insert_locn(locn, tokens):
+                tokens.insert(0, locn)
+            print(OneOrMore(Word(nums)).addParseAction(insert_locn).parseString("0 123 321")) # -> [0, '0', '123', '321']
+        """
+        self.__toklist.insert(index, insStr)
+        # fixup indices in token dictionary
+        for name,occurrences in self.__tokdict.items():
+            for k, (value, position) in enumerate(occurrences):
+                occurrences[k] = _ParseResultsWithOffset(value, position + (position > index))
+
+    def append( self, item ):
+        """
+        Add single element to end of ParseResults list of elements.
+
+        Example::
+            print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']
+            
+            # use a parse action to compute the sum of the parsed integers, and add it to the end
+            def append_sum(tokens):
+                tokens.append(sum(map(int, tokens)))
+            print(OneOrMore(Word(nums)).addParseAction(append_sum).parseString("0 123 321")) # -> ['0', '123', '321', 444]
+        """
+        self.__toklist.append(item)
+
+    def extend( self, itemseq ):
+        """
+        Add sequence of elements to end of ParseResults list of elements.
+
+        Example::
+            patt = OneOrMore(Word(alphas))
+            
+            # use a parse action to append the reverse of the matched strings, to make a palindrome
+            def make_palindrome(tokens):
+                tokens.extend(reversed([t[::-1] for t in tokens]))
+                return ''.join(tokens)
+            print(patt.addParseAction(make_palindrome).parseString("lskdj sdlkjf lksd")) # -> 'lskdjsdlkjflksddsklfjkldsjdksl'
+        """
+        if isinstance(itemseq, ParseResults):
+            self += itemseq
+        else:
+            self.__toklist.extend(itemseq)
+
+    def clear( self ):
+        """
+        Clear all elements and results names.
+        """
+        del self.__toklist[:]
+        self.__tokdict.clear()
+
+    def __getattr__( self, name ):
+        try:
+            return self[name]
+        except KeyError:
+            return ""
+            
+        if name in self.__tokdict:
+            if name not in self.__accumNames:
+                return self.__tokdict[name][-1][0]
+            else:
+                return ParseResults([ v[0] for v in self.__tokdict[name] ])
+        else:
+            return ""
+
+    def __add__( self, other ):
+        ret = self.copy()
+        ret += other
+        return ret
+
+    def __iadd__( self, other ):
+        if other.__tokdict:
+            offset = len(self.__toklist)
+            addoffset = lambda a: offset if a<0 else a+offset
+            otheritems = other.__tokdict.items()
+            otherdictitems = [(k, _ParseResultsWithOffset(v[0],addoffset(v[1])) )
+                                for (k,vlist) in otheritems for v in vlist]
+            for k,v in otherdictitems:
+                self[k] = v
+                if isinstance(v[0],ParseResults):
+                    v[0].__parent = wkref(self)
+            
+        self.__toklist += other.__toklist
+        self.__accumNames.update( other.__accumNames )
+        return self
+
+    def __radd__(self, other):
+        if isinstance(other,int) and other == 0:
+            # useful for merging many ParseResults using sum() builtin
+            return self.copy()
+        else:
+            # this may raise a TypeError - so be it
+            return other + self
+        
+    def __repr__( self ):
+        return "(%s, %s)" % ( repr( self.__toklist ), repr( self.__tokdict ) )
+
+    def __str__( self ):
+        return '[' + ', '.join(_ustr(i) if isinstance(i, ParseResults) else repr(i) for i in self.__toklist) + ']'
+
+    def _asStringList( self, sep='' ):
+        out = []
+        for item in self.__toklist:
+            if out and sep:
+                out.append(sep)
+            if isinstance( item, ParseResults ):
+                out += item._asStringList()
+            else:
+                out.append( _ustr(item) )
+        return out
+
+    def asList( self ):
+        """
+        Returns the parse results as a nested list of matching tokens, all converted to strings.
+
+        Example::
+            patt = OneOrMore(Word(alphas))
+            result = patt.parseString("sldkj lsdkj sldkj")
+            # even though the result prints in string-like form, it is actually a pyparsing ParseResults
+            print(type(result), result) # -> <class 'pyparsing.ParseResults'> ['sldkj', 'lsdkj', 'sldkj']
+            
+            # Use asList() to create an actual list
+            result_list = result.asList()
+            print(type(result_list), result_list) # -> <class 'list'> ['sldkj', 'lsdkj', 'sldkj']
+        """
+        return [res.asList() if isinstance(res,ParseResults) else res for res in self.__toklist]
+
+    def asDict( self ):
+        """
+        Returns the named parse results as a nested dictionary.
+
+        Example::
+            integer = Word(nums)
+            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
+            
+            result = date_str.parseString('12/31/1999')
+            print(type(result), repr(result)) # -> <class 'pyparsing.ParseResults'> (['12', '/', '31', '/', '1999'], {'day': [('1999', 4)], 'year': [('12', 0)], 'month': [('31', 2)]})
+            
+            result_dict = result.asDict()
+            print(type(result_dict), repr(result_dict)) # -> <class 'dict'> {'day': '1999', 'year': '12', 'month': '31'}
+
+            # even though a ParseResults supports dict-like access, sometime you just need to have a dict
+            import json
+            print(json.dumps(result)) # -> Exception: TypeError: ... is not JSON serializable
+            print(json.dumps(result.asDict())) # -> {"month": "31", "day": "1999", "year": "12"}
+        """
+        if PY_3:
+            item_fn = self.items
+        else:
+            item_fn = self.iteritems
+            
+        def toItem(obj):
+            if isinstance(obj, ParseResults):
+                if obj.haskeys():
+                    return obj.asDict()
+                else:
+                    return [toItem(v) for v in obj]
+            else:
+                return obj
+                
+        return dict((k,toItem(v)) for k,v in item_fn())
+
+    def copy( self ):
+        """
+        Returns a new copy of a C{ParseResults} object.
+        """
+        ret = ParseResults( self.__toklist )
+        ret.__tokdict = self.__tokdict.copy()
+        ret.__parent = self.__parent
+        ret.__accumNames.update( self.__accumNames )
+        ret.__name = self.__name
+        return ret
+
+    def asXML( self, doctag=None, namedItemsOnly=False, indent="", formatted=True ):
+        """
+        (Deprecated) Returns the parse results as XML. Tags are created for tokens and lists that have defined results names.
+        """
+        nl = "\n"
+        out = []
+        namedItems = dict((v[1],k) for (k,vlist) in self.__tokdict.items()
+                                                            for v in vlist)
+        nextLevelIndent = indent + "  "
+
+        # collapse out indents if formatting is not desired
+        if not formatted:
+            indent = ""
+            nextLevelIndent = ""
+            nl = ""
+
+        selfTag = None
+        if doctag is not None:
+            selfTag = doctag
+        else:
+            if self.__name:
+                selfTag = self.__name
+
+        if not selfTag:
+            if namedItemsOnly:
+                return ""
+            else:
+                selfTag = "ITEM"
+
+        out += [ nl, indent, "<", selfTag, ">" ]
+
+        for i,res in enumerate(self.__toklist):
+            if isinstance(res,ParseResults):
+                if i in namedItems:
+                    out += [ res.asXML(namedItems[i],
+                                        namedItemsOnly and doctag is None,
+                                        nextLevelIndent,
+                                        formatted)]
+                else:
+                    out += [ res.asXML(None,
+                                        namedItemsOnly and doctag is None,
+                                        nextLevelIndent,
+                                        formatted)]
+            else:
+                # individual token, see if there is a name for it
+                resTag = None
+                if i in namedItems:
+                    resTag = namedItems[i]
+                if not resTag:
+                    if namedItemsOnly:
+                        continue
+                    else:
+                        resTag = "ITEM"
+                xmlBodyText = _xml_escape(_ustr(res))
+                out += [ nl, nextLevelIndent, "<", resTag, ">",
+                                                xmlBodyText,
+                                                "</", resTag, ">" ]
+
+        out += [ nl, indent, "</", selfTag, ">" ]
+        return "".join(out)
+
+    def __lookup(self,sub):
+        for k,vlist in self.__tokdict.items():
+            for v,loc in vlist:
+                if sub is v:
+                    return k
+        return None
+
+    def getName(self):
+        """
+        Returns the results name for this token expression. Useful when several 
+        different expressions might match at a particular location.
+
+        Example::
+            integer = Word(nums)
+            ssn_expr = Regex(r"\d\d\d-\d\d-\d\d\d\d")
+            house_number_expr = Suppress('#') + Word(nums, alphanums)
+            user_data = (Group(house_number_expr)("house_number") 
+                        | Group(ssn_expr)("ssn")
+                        | Group(integer)("age"))
+            user_info = OneOrMore(user_data)
+            
+            result = user_info.parseString("22 111-22-3333 #221B")
+            for item in result:
+                print(item.getName(), ':', item[0])
+        prints::
+            age : 22
+            ssn : 111-22-3333
+            house_number : 221B
+        """
+        if self.__name:
+            return self.__name
+        elif self.__parent:
+            par = self.__parent()
+            if par:
+                return par.__lookup(self)
+            else:
+                return None
+        elif (len(self) == 1 and
+               len(self.__tokdict) == 1 and
+               next(iter(self.__tokdict.values()))[0][1] in (0,-1)):
+            return next(iter(self.__tokdict.keys()))
+        else:
+            return None
+
+    def dump(self, indent='', depth=0, full=True):
+        """
+        Diagnostic method for listing out the contents of a C{ParseResults}.
+        Accepts an optional C{indent} argument so that this string can be embedded
+        in a nested display of other data.
+
+        Example::
+            integer = Word(nums)
+            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
+            
+            result = date_str.parseString('12/31/1999')
+            print(result.dump())
+        prints::
+            ['12', '/', '31', '/', '1999']
+            - day: 1999
+            - month: 31
+            - year: 12
+        """
+        out = []
+        NL = '\n'
+        out.append( indent+_ustr(self.asList()) )
+        if full:
+            if self.haskeys():
+                items = sorted((str(k), v) for k,v in self.items())
+                for k,v in items:
+                    if out:
+                        out.append(NL)
+                    out.append( "%s%s- %s: " % (indent,('  '*depth), k) )
+                    if isinstance(v,ParseResults):
+                        if v:
+                            out.append( v.dump(indent,depth+1) )
+                        else:
+                            out.append(_ustr(v))
+                    else:
+                        out.append(repr(v))
+            elif any(isinstance(vv,ParseResults) for vv in self):
+                v = self
+                for i,vv in enumerate(v):
+                    if isinstance(vv,ParseResults):
+                        out.append("\n%s%s[%d]:\n%s%s%s" % (indent,('  '*(depth)),i,indent,('  '*(depth+1)),vv.dump(indent,depth+1) ))
+                    else:
+                        out.append("\n%s%s[%d]:\n%s%s%s" % (indent,('  '*(depth)),i,indent,('  '*(depth+1)),_ustr(vv)))
+            
+        return "".join(out)
+
+    def pprint(self, *args, **kwargs):
+        """
+        Pretty-printer for parsed results as a list, using the C{pprint} module.
+        Accepts additional positional or keyword args as defined for the 
+        C{pprint.pprint} method. (U{http://docs.python.org/3/library/pprint.html#pprint.pprint})
+
+        Example::
+            ident = Word(alphas, alphanums)
+            num = Word(nums)
+            func = Forward()
+            term = ident | num | Group('(' + func + ')')
+            func <<= ident + Group(Optional(delimitedList(term)))
+            result = func.parseString("fna a,b,(fnb c,d,200),100")
+            result.pprint(width=40)
+        prints::
+            ['fna',
+             ['a',
+              'b',
+              ['(', 'fnb', ['c', 'd', '200'], ')'],
+              '100']]
+        """
+        pprint.pprint(self.asList(), *args, **kwargs)
+
+    # add support for pickle protocol
+    def __getstate__(self):
+        return ( self.__toklist,
+                 ( self.__tokdict.copy(),
+                   self.__parent is not None and self.__parent() or None,
+                   self.__accumNames,
+                   self.__name ) )
+
+    def __setstate__(self,state):
+        self.__toklist = state[0]
+        (self.__tokdict,
+         par,
+         inAccumNames,
+         self.__name) = state[1]
+        self.__accumNames = {}
+        self.__accumNames.update(inAccumNames)
+        if par is not None:
+            self.__parent = wkref(par)
+        else:
+            self.__parent = None
+
+    def __getnewargs__(self):
+        return self.__toklist, self.__name, self.__asList, self.__modal
+
+    def __dir__(self):
+        return (dir(type(self)) + list(self.keys()))
+
+collections.MutableMapping.register(ParseResults)
+
+def col (loc,strg):
+    """Returns current column within a string, counting newlines as line separators.
+   The first column is number 1.
+
+   Note: the default parsing behavior is to expand tabs in the input string
+   before starting the parsing process.  See L{I{ParserElement.parseString}<ParserElement.parseString>} for more information
+   on parsing strings containing C{<TAB>}s, and suggested methods to maintain a
+   consistent view of the parsed string, the parse location, and line and column
+   positions within the parsed string.
+   """
+    s = strg
+    return 1 if 0<loc<len(s) and s[loc-1] == '\n' else loc - s.rfind("\n", 0, loc)
+
+def lineno(loc,strg):
+    """Returns current line number within a string, counting newlines as line separators.
+   The first line is number 1.
+
+   Note: the default parsing behavior is to expand tabs in the input string
+   before starting the parsing process.  See L{I{ParserElement.parseString}<ParserElement.parseString>} for more information
+   on parsing strings containing C{<TAB>}s, and suggested methods to maintain a
+   consistent view of the parsed string, the parse location, and line and column
+   positions within the parsed string.
+   """
+    return strg.count("\n",0,loc) + 1
+
+def line( loc, strg ):
+    """Returns the line of text containing loc within a string, counting newlines as line separators.
+       """
+    lastCR = strg.rfind("\n", 0, loc)
+    nextCR = strg.find("\n", loc)
+    if nextCR >= 0:
+        return strg[lastCR+1:nextCR]
+    else:
+        return strg[lastCR+1:]
+
+def _defaultStartDebugAction( instring, loc, expr ):
+    print (("Match " + _ustr(expr) + " at loc " + _ustr(loc) + "(%d,%d)" % ( lineno(loc,instring), col(loc,instring) )))
+
+def _defaultSuccessDebugAction( instring, startloc, endloc, expr, toks ):
+    print ("Matched " + _ustr(expr) + " -> " + str(toks.asList()))
+
+def _defaultExceptionDebugAction( instring, loc, expr, exc ):
+    print ("Exception raised:" + _ustr(exc))
+
+def nullDebugAction(*args):
+    """'Do-nothing' debug action, to suppress debugging output during parsing."""
+    pass
+
+# Only works on Python 3.x - nonlocal is toxic to Python 2 installs
+#~ 'decorator to trim function calls to match the arity of the target'
+#~ def _trim_arity(func, maxargs=3):
+    #~ if func in singleArgBuiltins:
+        #~ return lambda s,l,t: func(t)
+    #~ limit = 0
+    #~ foundArity = False
+    #~ def wrapper(*args):
+        #~ nonlocal limit,foundArity
+        #~ while 1:
+            #~ try:
+                #~ ret = func(*args[limit:])
+                #~ foundArity = True
+                #~ return ret
+            #~ except TypeError:
+                #~ if limit == maxargs or foundArity:
+                    #~ raise
+                #~ limit += 1
+                #~ continue
+    #~ return wrapper
+
+# this version is Python 2.x-3.x cross-compatible
+'decorator to trim function calls to match the arity of the target'
+def _trim_arity(func, maxargs=2):
+    if func in singleArgBuiltins:
+        return lambda s,l,t: func(t)
+    limit = [0]
+    foundArity = [False]
+    
+    # traceback return data structure changed in Py3.5 - normalize back to plain tuples
+    if system_version[:2] >= (3,5):
+        def extract_stack(limit=0):
+            # special handling for Python 3.5.0 - extra deep call stack by 1
+            offset = -3 if system_version == (3,5,0) else -2
+            frame_summary = traceback.extract_stack(limit=-offset+limit-1)[offset]
+            return [(frame_summary.filename, frame_summary.lineno)]
+        def extract_tb(tb, limit=0):
+            frames = traceback.extract_tb(tb, limit=limit)
+            frame_summary = frames[-1]
+            return [(frame_summary.filename, frame_summary.lineno)]
+    else:
+        extract_stack = traceback.extract_stack
+        extract_tb = traceback.extract_tb
+    
+    # synthesize what would be returned by traceback.extract_stack at the call to 
+    # user's parse action 'func', so that we don't incur call penalty at parse time
+    
+    LINE_DIFF = 6
+    # IF ANY CODE CHANGES, EVEN JUST COMMENTS OR BLANK LINES, BETWEEN THE NEXT LINE AND 
+    # THE CALL TO FUNC INSIDE WRAPPER, LINE_DIFF MUST BE MODIFIED!!!!
+    this_line = extract_stack(limit=2)[-1]
+    pa_call_line_synth = (this_line[0], this_line[1]+LINE_DIFF)
+
+    def wrapper(*args):
+        while 1:
+            try:
+                ret = func(*args[limit[0]:])
+                foundArity[0] = True
+                return ret
+            except TypeError:
+                # re-raise TypeErrors if they did not come from our arity testing
+                if foundArity[0]:
+                    raise
+                else:
+                    try:
+                        tb = sys.exc_info()[-1]
+                        if not extract_tb(tb, limit=2)[-1][:2] == pa_call_line_synth:
+                            raise
+                    finally:
+                        del tb
+
+                if limit[0] <= maxargs:
+                    limit[0] += 1
+                    continue
+                raise
+
+    # copy func name to wrapper for sensible debug output
+    func_name = "<parse action>"
+    try:
+        func_name = getattr(func, '__name__', 
+                            getattr(func, '__class__').__name__)
+    except Exception:
+        func_name = str(func)
+    wrapper.__name__ = func_name
+
+    return wrapper
+
+class ParserElement(object):
+    """Abstract base level parser element class."""
+    DEFAULT_WHITE_CHARS = " \n\t\r"
+    verbose_stacktrace = False
+
+    @staticmethod
+    def setDefaultWhitespaceChars( chars ):
+        r"""
+        Overrides the default whitespace chars
+
+        Example::
+            # default whitespace chars are space, <TAB> and newline
+            OneOrMore(Word(alphas)).parseString("abc def\nghi jkl")  # -> ['abc', 'def', 'ghi', 'jkl']
+            
+            # change to just treat newline as significant
+            ParserElement.setDefaultWhitespaceChars(" \t")
+            OneOrMore(Word(alphas)).parseString("abc def\nghi jkl")  # -> ['abc', 'def']
+        """
+        ParserElement.DEFAULT_WHITE_CHARS = chars
+
+    @staticmethod
+    def inlineLiteralsUsing(cls):
+        """
+        Set class to be used for inclusion of string literals into a parser.
+        
+        Example::
+            # default literal class used is Literal
+            integer = Word(nums)
+            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")           
+
+            date_str.parseString("1999/12/31")  # -> ['1999', '/', '12', '/', '31']
+
+
+            # change to Suppress
+            ParserElement.inlineLiteralsUsing(Suppress)
+            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")           
+
+            date_str.parseString("1999/12/31")  # -> ['1999', '12', '31']
+        """
+        ParserElement._literalStringClass = cls
+
+    def __init__( self, savelist=False ):
+        self.parseAction = list()
+        self.failAction = None
+        #~ self.name = "<unknown>"  # don't define self.name, let subclasses try/except upcall
+        self.strRepr = None
+        self.resultsName = None
+        self.saveAsList = savelist
+        self.skipWhitespace = True
+        self.whiteChars = ParserElement.DEFAULT_WHITE_CHARS
+        self.copyDefaultWhiteChars = True
+        self.mayReturnEmpty = False # used when checking for left-recursion
+        self.keepTabs = False
+        self.ignoreExprs = list()
+        self.debug = False
+        self.streamlined = False
+        self.mayIndexError = True # used to optimize exception handling for subclasses that don't advance parse index
+        self.errmsg = ""
+        self.modalResults = True # used to mark results names as modal (report only last) or cumulative (list all)
+        self.debugActions = ( None, None, None ) #custom debug actions
+        self.re = None
+        self.callPreparse = True # used to avoid redundant calls to preParse
+        self.callDuringTry = False
+
+    def copy( self ):
+        """
+        Make a copy of this C{ParserElement}.  Useful for defining different parse actions
+        for the same parsing pattern, using copies of the original parse element.
+        
+        Example::
+            integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
+            integerK = integer.copy().addParseAction(lambda toks: toks[0]*1024) + Suppress("K")
+            integerM = integer.copy().addParseAction(lambda toks: toks[0]*1024*1024) + Suppress("M")
+            
+            print(OneOrMore(integerK | integerM | integer).parseString("5K 100 640K 256M"))
+        prints::
+            [5120, 100, 655360, 268435456]
+        Equivalent form of C{expr.copy()} is just C{expr()}::
+            integerM = integer().addParseAction(lambda toks: toks[0]*1024*1024) + Suppress("M")
+        """
+        cpy = copy.copy( self )
+        cpy.parseAction = self.parseAction[:]
+        cpy.ignoreExprs = self.ignoreExprs[:]
+        if self.copyDefaultWhiteChars:
+            cpy.whiteChars = ParserElement.DEFAULT_WHITE_CHARS
+        return cpy
+
+    def setName( self, name ):
+        """
+        Define name for this expression, makes debugging and exception messages clearer.
+        
+        Example::
+            Word(nums).parseString("ABC")  # -> Exception: Expected W:(0123...) (at char 0), (line:1, col:1)
+            Word(nums).setName("integer").parseString("ABC")  # -> Exception: Expected integer (at char 0), (line:1, col:1)
+        """
+        self.name = name
+        self.errmsg = "Expected " + self.name
+        if hasattr(self,"exception"):
+            self.exception.msg = self.errmsg
+        return self
+
+    def setResultsName( self, name, listAllMatches=False ):
+        """
+        Define name for referencing matching tokens as a nested attribute
+        of the returned parse results.
+        NOTE: this returns a *copy* of the original C{ParserElement} object;
+        this is so that the client can define a basic element, such as an
+        integer, and reference it in multiple places with different names.
+
+        You can also set results names using the abbreviated syntax,
+        C{expr("name")} in place of C{expr.setResultsName("name")} - 
+        see L{I{__call__}<__call__>}.
+
+        Example::
+            date_str = (integer.setResultsName("year") + '/' 
+                        + integer.setResultsName("month") + '/' 
+                        + integer.setResultsName("day"))
+
+            # equivalent form:
+            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
+        """
+        newself = self.copy()
+        if name.endswith("*"):
+            name = name[:-1]
+            listAllMatches=True
+        newself.resultsName = name
+        newself.modalResults = not listAllMatches
+        return newself
+
+    def setBreak(self,breakFlag = True):
+        """Method to invoke the Python pdb debugger when this element is
+           about to be parsed. Set C{breakFlag} to True to enable, False to
+           disable.
+        """
+        if breakFlag:
+            _parseMethod = self._parse
+            def breaker(instring, loc, doActions=True, callPreParse=True):
+                import pdb
+                pdb.set_trace()
+                return _parseMethod( instring, loc, doActions, callPreParse )
+            breaker._originalParseMethod = _parseMethod
+            self._parse = breaker
+        else:
+            if hasattr(self._parse,"_originalParseMethod"):
+                self._parse = self._parse._originalParseMethod
+        return self
+
+    def setParseAction( self, *fns, **kwargs ):
+        """
+        Define action to perform when successfully matching parse element definition.
+        Parse action fn is a callable method with 0-3 arguments, called as C{fn(s,loc,toks)},
+        C{fn(loc,toks)}, C{fn(toks)}, or just C{fn()}, where:
+         - s   = the original string being parsed (see note below)
+         - loc = the location of the matching substring
+         - toks = a list of the matched tokens, packaged as a C{L{ParseResults}} object
+        If the functions in fns modify the tokens, they can return them as the return
+        value from fn, and the modified list of tokens will replace the original.
+        Otherwise, fn does not need to return any value.
+
+        Optional keyword arguments:
+         - callDuringTry = (default=C{False}) indicate if parse action should be run during lookaheads and alternate testing
+
+        Note: the default parsing behavior is to expand tabs in the input string
+        before starting the parsing process.  See L{I{parseString}<parseString>} for more information
+        on parsing strings containing C{<TAB>}s, and suggested methods to maintain a
+        consistent view of the parsed string, the parse location, and line and column
+        positions within the parsed string.
+        
+        Example::
+            integer = Word(nums)
+            date_str = integer + '/' + integer + '/' + integer
+
+            date_str.parseString("1999/12/31")  # -> ['1999', '/', '12', '/', '31']
+
+            # use parse action to convert to ints at parse time
+            integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
+            date_str = integer + '/' + integer + '/' + integer
+
+            # note that integer fields are now ints, not strings
+            date_str.parseString("1999/12/31")  # -> [1999, '/', 12, '/', 31]
+        """
+        self.parseAction = list(map(_trim_arity, list(fns)))
+        self.callDuringTry = kwargs.get("callDuringTry", False)
+        return self
+
+    def addParseAction( self, *fns, **kwargs ):
+        """
+        Add parse action to expression's list of parse actions. See L{I{setParseAction}<setParseAction>}.
+        
+        See examples in L{I{copy}<copy>}.
+        """
+        self.parseAction += list(map(_trim_arity, list(fns)))
+        self.callDuringTry = self.callDuringTry or kwargs.get("callDuringTry", False)
+        return self
+
+    def addCondition(self, *fns, **kwargs):
+        """Add a boolean predicate function to expression's list of parse actions. See 
+        L{I{setParseAction}<setParseAction>} for function call signatures. Unlike C{setParseAction}, 
+        functions passed to C{addCondition} need to return boolean success/fail of the condition.
+
+        Optional keyword arguments:
+         - message = define a custom message to be used in the raised exception
+         - fatal   = if True, will raise ParseFatalException to stop parsing immediately; otherwise will raise ParseException
+         
+        Example::
+            integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
+            year_int = integer.copy()
+            year_int.addCondition(lambda toks: toks[0] >= 2000, message="Only support years 2000 and later")
+            date_str = year_int + '/' + integer + '/' + integer
+
+            result = date_str.parseString("1999/12/31")  # -> Exception: Only support years 2000 and later (at char 0), (line:1, col:1)
+        """
+        msg = kwargs.get("message", "failed user-defined condition")
+        exc_type = ParseFatalException if kwargs.get("fatal", False) else ParseException
+        for fn in fns:
+            def pa(s,l,t):
+                if not bool(_trim_arity(fn)(s,l,t)):
+                    raise exc_type(s,l,msg)
+            self.parseAction.append(pa)
+        self.callDuringTry = self.callDuringTry or kwargs.get("callDuringTry", False)
+        return self
+
+    def setFailAction( self, fn ):
+        """Define action to perform if parsing fails at this expression.
+           Fail acton fn is a callable function that takes the arguments
+           C{fn(s,loc,expr,err)} where:
+            - s = string being parsed
+            - loc = location where expression match was attempted and failed
+            - expr = the parse expression that failed
+            - err = the exception thrown
+           The function returns no value.  It may throw C{L{ParseFatalException}}
+           if it is desired to stop parsing immediately."""
+        self.failAction = fn
+        return self
+
+    def _skipIgnorables( self, instring, loc ):
+        exprsFound = True
+        while exprsFound:
+            exprsFound = False
+            for e in self.ignoreExprs:
+                try:
+                    while 1:
+                        loc,dummy = e._parse( instring, loc )
+                        exprsFound = True
+                except ParseException:
+                    pass
+        return loc
+
+    def preParse( self, instring, loc ):
+        if self.ignoreExprs:
+            loc = self._skipIgnorables( instring, loc )
+
+        if self.skipWhitespace:
+            wt = self.whiteChars
+            instrlen = len(instring)
+            while loc < instrlen and instring[loc] in wt:
+                loc += 1
+
+        return loc
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        return loc, []
+
+    def postParse( self, instring, loc, tokenlist ):
+        return tokenlist
+
+    #~ @profile
+    def _parseNoCache( self, instring, loc, doActions=True, callPreParse=True ):
+        debugging = ( self.debug ) #and doActions )
+
+        if debugging or self.failAction:
+            #~ print ("Match",self,"at loc",loc,"(%d,%d)" % ( lineno(loc,instring), col(loc,instring) ))
+            if (self.debugActions[0] ):
+                self.debugActions[0]( instring, loc, self )
+            if callPreParse and self.callPreparse:
+                preloc = self.preParse( instring, loc )
+            else:
+                preloc = loc
+            tokensStart = preloc
+            try:
+                try:
+                    loc,tokens = self.parseImpl( instring, preloc, doActions )
+                except IndexError:
+                    raise ParseException( instring, len(instring), self.errmsg, self )
+            except ParseBaseException as err:
+                #~ print ("Exception raised:", err)
+                if self.debugActions[2]:
+                    self.debugActions[2]( instring, tokensStart, self, err )
+                if self.failAction:
+                    self.failAction( instring, tokensStart, self, err )
+                raise
+        else:
+            if callPreParse and self.callPreparse:
+                preloc = self.preParse( instring, loc )
+            else:
+                preloc = loc
+            tokensStart = preloc
+            if self.mayIndexError or loc >= len(instring):
+                try:
+                    loc,tokens = self.parseImpl( instring, preloc, doActions )
+                except IndexError:
+                    raise ParseException( instring, len(instring), self.errmsg, self )
+            else:
+                loc,tokens = self.parseImpl( instring, preloc, doActions )
+
+        tokens = self.postParse( instring, loc, tokens )
+
+        retTokens = ParseResults( tokens, self.resultsName, asList=self.saveAsList, modal=self.modalResults )
+        if self.parseAction and (doActions or self.callDuringTry):
+            if debugging:
+                try:
+                    for fn in self.parseAction:
+                        tokens = fn( instring, tokensStart, retTokens )
+                        if tokens is not None:
+                            retTokens = ParseResults( tokens,
+                                                      self.resultsName,
+                                                      asList=self.saveAsList and isinstance(tokens,(ParseResults,list)),
+                                                      modal=self.modalResults )
+                except ParseBaseException as err:
+                    #~ print "Exception raised in user parse action:", err
+                    if (self.debugActions[2] ):
+                        self.debugActions[2]( instring, tokensStart, self, err )
+                    raise
+            else:
+                for fn in self.parseAction:
+                    tokens = fn( instring, tokensStart, retTokens )
+                    if tokens is not None:
+                        retTokens = ParseResults( tokens,
+                                                  self.resultsName,
+                                                  asList=self.saveAsList and isinstance(tokens,(ParseResults,list)),
+                                                  modal=self.modalResults )
+
+        if debugging:
+            #~ print ("Matched",self,"->",retTokens.asList())
+            if (self.debugActions[1] ):
+                self.debugActions[1]( instring, tokensStart, loc, self, retTokens )
+
+        return loc, retTokens
+
+    def tryParse( self, instring, loc ):
+        try:
+            return self._parse( instring, loc, doActions=False )[0]
+        except ParseFatalException:
+            raise ParseException( instring, loc, self.errmsg, self)
+    
+    def canParseNext(self, instring, loc):
+        try:
+            self.tryParse(instring, loc)
+        except (ParseException, IndexError):
+            return False
+        else:
+            return True
+
+    class _UnboundedCache(object):
+        def __init__(self):
+            cache = {}
+            self.not_in_cache = not_in_cache = object()
+
+            def get(self, key):
+                return cache.get(key, not_in_cache)
+
+            def set(self, key, value):
+                cache[key] = value
+
+            def clear(self):
+                cache.clear()
+
+            self.get = types.MethodType(get, self)
+            self.set = types.MethodType(set, self)
+            self.clear = types.MethodType(clear, self)
+
+    if _OrderedDict is not None:
+        class _FifoCache(object):
+            def __init__(self, size):
+                self.not_in_cache = not_in_cache = object()
+
+                cache = _OrderedDict()
+
+                def get(self, key):
+                    return cache.get(key, not_in_cache)
+
+                def set(self, key, value):
+                    cache[key] = value
+                    if len(cache) > size:
+                        cache.popitem(False)
+
+                def clear(self):
+                    cache.clear()
+
+                self.get = types.MethodType(get, self)
+                self.set = types.MethodType(set, self)
+                self.clear = types.MethodType(clear, self)
+
+    else:
+        class _FifoCache(object):
+            def __init__(self, size):
+                self.not_in_cache = not_in_cache = object()
+
+                cache = {}
+                key_fifo = collections.deque([], size)
+
+                def get(self, key):
+                    return cache.get(key, not_in_cache)
+
+                def set(self, key, value):
+                    cache[key] = value
+                    if len(cache) > size:
+                        cache.pop(key_fifo.popleft(), None)
+                    key_fifo.append(key)
+
+                def clear(self):
+                    cache.clear()
+                    key_fifo.clear()
+
+                self.get = types.MethodType(get, self)
+                self.set = types.MethodType(set, self)
+                self.clear = types.MethodType(clear, self)
+
+    # argument cache for optimizing repeated calls when backtracking through recursive expressions
+    packrat_cache = {} # this is set later by enabledPackrat(); this is here so that resetCache() doesn't fail
+    packrat_cache_lock = RLock()
+    packrat_cache_stats = [0, 0]
+
+    # this method gets repeatedly called during backtracking with the same arguments -
+    # we can cache these arguments and save ourselves the trouble of re-parsing the contained expression
+    def _parseCache( self, instring, loc, doActions=True, callPreParse=True ):
+        HIT, MISS = 0, 1
+        lookup = (self, instring, loc, callPreParse, doActions)
+        with ParserElement.packrat_cache_lock:
+            cache = ParserElement.packrat_cache
+            value = cache.get(lookup)
+            if value is cache.not_in_cache:
+                ParserElement.packrat_cache_stats[MISS] += 1
+                try:
+                    value = self._parseNoCache(instring, loc, doActions, callPreParse)
+                except ParseBaseException as pe:
+                    # cache a copy of the exception, without the traceback
+                    cache.set(lookup, pe.__class__(*pe.args))
+                    raise
+                else:
+                    cache.set(lookup, (value[0], value[1].copy()))
+                    return value
+            else:
+                ParserElement.packrat_cache_stats[HIT] += 1
+                if isinstance(value, Exception):
+                    raise value
+                return (value[0], value[1].copy())
+
+    _parse = _parseNoCache
+
+    @staticmethod
+    def resetCache():
+        ParserElement.packrat_cache.clear()
+        ParserElement.packrat_cache_stats[:] = [0] * len(ParserElement.packrat_cache_stats)
+
+    _packratEnabled = False
+    @staticmethod
+    def enablePackrat(cache_size_limit=128):
+        """Enables "packrat" parsing, which adds memoizing to the parsing logic.
+           Repeated parse attempts at the same string location (which happens
+           often in many complex grammars) can immediately return a cached value,
+           instead of re-executing parsing/validating code.  Memoizing is done of
+           both valid results and parsing exceptions.
+           
+           Parameters:
+            - cache_size_limit - (default=C{128}) - if an integer value is provided
+              will limit the size of the packrat cache; if None is passed, then
+              the cache size will be unbounded; if 0 is passed, the cache will
+              be effectively disabled.
+            
+           This speedup may break existing programs that use parse actions that
+           have side-effects.  For this reason, packrat parsing is disabled when
+           you first import pyparsing.  To activate the packrat feature, your
+           program must call the class method C{ParserElement.enablePackrat()}.  If
+           your program uses C{psyco} to "compile as you go", you must call
+           C{enablePackrat} before calling C{psyco.full()}.  If you do not do this,
+           Python will crash.  For best results, call C{enablePackrat()} immediately
+           after importing pyparsing.
+           
+           Example::
+               import pyparsing
+               pyparsing.ParserElement.enablePackrat()
+        """
+        if not ParserElement._packratEnabled:
+            ParserElement._packratEnabled = True
+            if cache_size_limit is None:
+                ParserElement.packrat_cache = ParserElement._UnboundedCache()
+            else:
+                ParserElement.packrat_cache = ParserElement._FifoCache(cache_size_limit)
+            ParserElement._parse = ParserElement._parseCache
+
+    def parseString( self, instring, parseAll=False ):
+        """
+        Execute the parse expression with the given string.
+        This is the main interface to the client code, once the complete
+        expression has been built.
+
+        If you want the grammar to require that the entire input string be
+        successfully parsed, then set C{parseAll} to True (equivalent to ending
+        the grammar with C{L{StringEnd()}}).
+
+        Note: C{parseString} implicitly calls C{expandtabs()} on the input string,
+        in order to report proper column numbers in parse actions.
+        If the input string contains tabs and
+        the grammar uses parse actions that use the C{loc} argument to index into the
+        string being parsed, you can ensure you have a consistent view of the input
+        string by:
+         - calling C{parseWithTabs} on your grammar before calling C{parseString}
+           (see L{I{parseWithTabs}<parseWithTabs>})
+         - define your parse action using the full C{(s,loc,toks)} signature, and
+           reference the input string using the parse action's C{s} argument
+         - explictly expand the tabs in your input string before calling
+           C{parseString}
+        
+        Example::
+            Word('a').parseString('aaaaabaaa')  # -> ['aaaaa']
+            Word('a').parseString('aaaaabaaa', parseAll=True)  # -> Exception: Expected end of text
+        """
+        ParserElement.resetCache()
+        if not self.streamlined:
+            self.streamline()
+            #~ self.saveAsList = True
+        for e in self.ignoreExprs:
+            e.streamline()
+        if not self.keepTabs:
+            instring = instring.expandtabs()
+        try:
+            loc, tokens = self._parse( instring, 0 )
+            if parseAll:
+                loc = self.preParse( instring, loc )
+                se = Empty() + StringEnd()
+                se._parse( instring, loc )
+        except ParseBaseException as exc:
+            if ParserElement.verbose_stacktrace:
+                raise
+            else:
+                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                raise exc
+        else:
+            return tokens
+
+    def scanString( self, instring, maxMatches=_MAX_INT, overlap=False ):
+        """
+        Scan the input string for expression matches.  Each match will return the
+        matching tokens, start location, and end location.  May be called with optional
+        C{maxMatches} argument, to clip scanning after 'n' matches are found.  If
+        C{overlap} is specified, then overlapping matches will be reported.
+
+        Note that the start and end locations are reported relative to the string
+        being parsed.  See L{I{parseString}<parseString>} for more information on parsing
+        strings with embedded tabs.
+
+        Example::
+            source = "sldjf123lsdjjkf345sldkjf879lkjsfd987"
+            print(source)
+            for tokens,start,end in Word(alphas).scanString(source):
+                print(' '*start + '^'*(end-start))
+                print(' '*start + tokens[0])
+        
+        prints::
+        
+            sldjf123lsdjjkf345sldkjf879lkjsfd987
+            ^^^^^
+            sldjf
+                    ^^^^^^^
+                    lsdjjkf
+                              ^^^^^^
+                              sldkjf
+                                       ^^^^^^
+                                       lkjsfd
+        """
+        if not self.streamlined:
+            self.streamline()
+        for e in self.ignoreExprs:
+            e.streamline()
+
+        if not self.keepTabs:
+            instring = _ustr(instring).expandtabs()
+        instrlen = len(instring)
+        loc = 0
+        preparseFn = self.preParse
+        parseFn = self._parse
+        ParserElement.resetCache()
+        matches = 0
+        try:
+            while loc <= instrlen and matches < maxMatches:
+                try:
+                    preloc = preparseFn( instring, loc )
+                    nextLoc,tokens = parseFn( instring, preloc, callPreParse=False )
+                except ParseException:
+                    loc = preloc+1
+                else:
+                    if nextLoc > loc:
+                        matches += 1
+                        yield tokens, preloc, nextLoc
+                        if overlap:
+                            nextloc = preparseFn( instring, loc )
+                            if nextloc > loc:
+                                loc = nextLoc
+                            else:
+                                loc += 1
+                        else:
+                            loc = nextLoc
+                    else:
+                        loc = preloc+1
+        except ParseBaseException as exc:
+            if ParserElement.verbose_stacktrace:
+                raise
+            else:
+                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                raise exc
+
+    def transformString( self, instring ):
+        """
+        Extension to C{L{scanString}}, to modify matching text with modified tokens that may
+        be returned from a parse action.  To use C{transformString}, define a grammar and
+        attach a parse action to it that modifies the returned token list.
+        Invoking C{transformString()} on a target string will then scan for matches,
+        and replace the matched text patterns according to the logic in the parse
+        action.  C{transformString()} returns the resulting transformed string.
+        
+        Example::
+            wd = Word(alphas)
+            wd.setParseAction(lambda toks: toks[0].title())
+            
+            print(wd.transformString("now is the winter of our discontent made glorious summer by this sun of york."))
+        Prints::
+            Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York.
+        """
+        out = []
+        lastE = 0
+        # force preservation of <TAB>s, to minimize unwanted transformation of string, and to
+        # keep string locs straight between transformString and scanString
+        self.keepTabs = True
+        try:
+            for t,s,e in self.scanString( instring ):
+                out.append( instring[lastE:s] )
+                if t:
+                    if isinstance(t,ParseResults):
+                        out += t.asList()
+                    elif isinstance(t,list):
+                        out += t
+                    else:
+                        out.append(t)
+                lastE = e
+            out.append(instring[lastE:])
+            out = [o for o in out if o]
+            return "".join(map(_ustr,_flatten(out)))
+        except ParseBaseException as exc:
+            if ParserElement.verbose_stacktrace:
+                raise
+            else:
+                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                raise exc
+
+    def searchString( self, instring, maxMatches=_MAX_INT ):
+        """
+        Another extension to C{L{scanString}}, simplifying the access to the tokens found
+        to match the given parse expression.  May be called with optional
+        C{maxMatches} argument, to clip searching after 'n' matches are found.
+        
+        Example::
+            # a capitalized word starts with an uppercase letter, followed by zero or more lowercase letters
+            cap_word = Word(alphas.upper(), alphas.lower())
+            
+            print(cap_word.searchString("More than Iron, more than Lead, more than Gold I need Electricity"))
+        prints::
+            ['More', 'Iron', 'Lead', 'Gold', 'I']
+        """
+        try:
+            return ParseResults([ t for t,s,e in self.scanString( instring, maxMatches ) ])
+        except ParseBaseException as exc:
+            if ParserElement.verbose_stacktrace:
+                raise
+            else:
+                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                raise exc
+
+    def split(self, instring, maxsplit=_MAX_INT, includeSeparators=False):
+        """
+        Generator method to split a string using the given expression as a separator.
+        May be called with optional C{maxsplit} argument, to limit the number of splits;
+        and the optional C{includeSeparators} argument (default=C{False}), if the separating
+        matching text should be included in the split results.
+        
+        Example::        
+            punc = oneOf(list(".,;:/-!?"))
+            print(list(punc.split("This, this?, this sentence, is badly punctuated!")))
+        prints::
+            ['This', ' this', '', ' this sentence', ' is badly punctuated', '']
+        """
+        splits = 0
+        last = 0
+        for t,s,e in self.scanString(instring, maxMatches=maxsplit):
+            yield instring[last:s]
+            if includeSeparators:
+                yield t[0]
+            last = e
+        yield instring[last:]
+
+    def __add__(self, other ):
+        """
+        Implementation of + operator - returns C{L{And}}. Adding strings to a ParserElement
+        converts them to L{Literal}s by default.
+        
+        Example::
+            greet = Word(alphas) + "," + Word(alphas) + "!"
+            hello = "Hello, World!"
+            print (hello, "->", greet.parseString(hello))
+        Prints::
+            Hello, World! -> ['Hello', ',', 'World', '!']
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return And( [ self, other ] )
+
+    def __radd__(self, other ):
+        """
+        Implementation of + operator when left operand is not a C{L{ParserElement}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return other + self
+
+    def __sub__(self, other):
+        """
+        Implementation of - operator, returns C{L{And}} with error stop
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return And( [ self, And._ErrorStop(), other ] )
+
+    def __rsub__(self, other ):
+        """
+        Implementation of - operator when left operand is not a C{L{ParserElement}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return other - self
+
+    def __mul__(self,other):
+        """
+        Implementation of * operator, allows use of C{expr * 3} in place of
+        C{expr + expr + expr}.  Expressions may also me multiplied by a 2-integer
+        tuple, similar to C{{min,max}} multipliers in regular expressions.  Tuples
+        may also include C{None} as in:
+         - C{expr*(n,None)} or C{expr*(n,)} is equivalent
+              to C{expr*n + L{ZeroOrMore}(expr)}
+              (read as "at least n instances of C{expr}")
+         - C{expr*(None,n)} is equivalent to C{expr*(0,n)}
+              (read as "0 to n instances of C{expr}")
+         - C{expr*(None,None)} is equivalent to C{L{ZeroOrMore}(expr)}
+         - C{expr*(1,None)} is equivalent to C{L{OneOrMore}(expr)}
+
+        Note that C{expr*(None,n)} does not raise an exception if
+        more than n exprs exist in the input stream; that is,
+        C{expr*(None,n)} does not enforce a maximum number of expr
+        occurrences.  If this behavior is desired, then write
+        C{expr*(None,n) + ~expr}
+        """
+        if isinstance(other,int):
+            minElements, optElements = other,0
+        elif isinstance(other,tuple):
+            other = (other + (None, None))[:2]
+            if other[0] is None:
+                other = (0, other[1])
+            if isinstance(other[0],int) and other[1] is None:
+                if other[0] == 0:
+                    return ZeroOrMore(self)
+                if other[0] == 1:
+                    return OneOrMore(self)
+                else:
+                    return self*other[0] + ZeroOrMore(self)
+            elif isinstance(other[0],int) and isinstance(other[1],int):
+                minElements, optElements = other
+                optElements -= minElements
+            else:
+                raise TypeError("cannot multiply 'ParserElement' and ('%s','%s') objects", type(other[0]),type(other[1]))
+        else:
+            raise TypeError("cannot multiply 'ParserElement' and '%s' objects", type(other))
+
+        if minElements < 0:
+            raise ValueError("cannot multiply ParserElement by negative value")
+        if optElements < 0:
+            raise ValueError("second tuple value must be greater or equal to first tuple value")
+        if minElements == optElements == 0:
+            raise ValueError("cannot multiply ParserElement by 0 or (0,0)")
+
+        if (optElements):
+            def makeOptionalList(n):
+                if n>1:
+                    return Optional(self + makeOptionalList(n-1))
+                else:
+                    return Optional(self)
+            if minElements:
+                if minElements == 1:
+                    ret = self + makeOptionalList(optElements)
+                else:
+                    ret = And([self]*minElements) + makeOptionalList(optElements)
+            else:
+                ret = makeOptionalList(optElements)
+        else:
+            if minElements == 1:
+                ret = self
+            else:
+                ret = And([self]*minElements)
+        return ret
+
+    def __rmul__(self, other):
+        return self.__mul__(other)
+
+    def __or__(self, other ):
+        """
+        Implementation of | operator - returns C{L{MatchFirst}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return MatchFirst( [ self, other ] )
+
+    def __ror__(self, other ):
+        """
+        Implementation of | operator when left operand is not a C{L{ParserElement}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return other | self
+
+    def __xor__(self, other ):
+        """
+        Implementation of ^ operator - returns C{L{Or}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return Or( [ self, other ] )
+
+    def __rxor__(self, other ):
+        """
+        Implementation of ^ operator when left operand is not a C{L{ParserElement}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return other ^ self
+
+    def __and__(self, other ):
+        """
+        Implementation of & operator - returns C{L{Each}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return Each( [ self, other ] )
+
+    def __rand__(self, other ):
+        """
+        Implementation of & operator when left operand is not a C{L{ParserElement}}
+        """
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        if not isinstance( other, ParserElement ):
+            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
+                    SyntaxWarning, stacklevel=2)
+            return None
+        return other & self
+
+    def __invert__( self ):
+        """
+        Implementation of ~ operator - returns C{L{NotAny}}
+        """
+        return NotAny( self )
+
+    def __call__(self, name=None):
+        """
+        Shortcut for C{L{setResultsName}}, with C{listAllMatches=False}.
+        
+        If C{name} is given with a trailing C{'*'} character, then C{listAllMatches} will be
+        passed as C{True}.
+           
+        If C{name} is omitted, same as calling C{L{copy}}.
+
+        Example::
+            # these are equivalent
+            userdata = Word(alphas).setResultsName("name") + Word(nums+"-").setResultsName("socsecno")
+            userdata = Word(alphas)("name") + Word(nums+"-")("socsecno")             
+        """
+        if name is not None:
+            return self.setResultsName(name)
+        else:
+            return self.copy()
+
+    def suppress( self ):
+        """
+        Suppresses the output of this C{ParserElement}; useful to keep punctuation from
+        cluttering up returned output.
+        """
+        return Suppress( self )
+
+    def leaveWhitespace( self ):
+        """
+        Disables the skipping of whitespace before matching the characters in the
+        C{ParserElement}'s defined pattern.  This is normally only used internally by
+        the pyparsing module, but may be needed in some whitespace-sensitive grammars.
+        """
+        self.skipWhitespace = False
+        return self
+
+    def setWhitespaceChars( self, chars ):
+        """
+        Overrides the default whitespace chars
+        """
+        self.skipWhitespace = True
+        self.whiteChars = chars
+        self.copyDefaultWhiteChars = False
+        return self
+
+    def parseWithTabs( self ):
+        """
+        Overrides default behavior to expand C{<TAB>}s to spaces before parsing the input string.
+        Must be called before C{parseString} when the input grammar contains elements that
+        match C{<TAB>} characters.
+        """
+        self.keepTabs = True
+        return self
+
+    def ignore( self, other ):
+        """
+        Define expression to be ignored (e.g., comments) while doing pattern
+        matching; may be called repeatedly, to define multiple comment or other
+        ignorable patterns.
+        
+        Example::
+            patt = OneOrMore(Word(alphas))
+            patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj']
+            
+            patt.ignore(cStyleComment)
+            patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj', 'lskjd']
+        """
+        if isinstance(other, basestring):
+            other = Suppress(other)
+
+        if isinstance( other, Suppress ):
+            if other not in self.ignoreExprs:
+                self.ignoreExprs.append(other)
+        else:
+            self.ignoreExprs.append( Suppress( other.copy() ) )
+        return self
+
+    def setDebugActions( self, startAction, successAction, exceptionAction ):
+        """
+        Enable display of debugging messages while doing pattern matching.
+        """
+        self.debugActions = (startAction or _defaultStartDebugAction,
+                             successAction or _defaultSuccessDebugAction,
+                             exceptionAction or _defaultExceptionDebugAction)
+        self.debug = True
+        return self
+
+    def setDebug( self, flag=True ):
+        """
+        Enable display of debugging messages while doing pattern matching.
+        Set C{flag} to True to enable, False to disable.
+
+        Example::
+            wd = Word(alphas).setName("alphaword")
+            integer = Word(nums).setName("numword")
+            term = wd | integer
+            
+            # turn on debugging for wd
+            wd.setDebug()
+
+            OneOrMore(term).parseString("abc 123 xyz 890")
+        
+        prints::
+            Match alphaword at loc 0(1,1)
+            Matched alphaword -> ['abc']
+            Match alphaword at loc 3(1,4)
+            Exception raised:Expected alphaword (at char 4), (line:1, col:5)
+            Match alphaword at loc 7(1,8)
+            Matched alphaword -> ['xyz']
+            Match alphaword at loc 11(1,12)
+            Exception raised:Expected alphaword (at char 12), (line:1, col:13)
+            Match alphaword at loc 15(1,16)
+            Exception raised:Expected alphaword (at char 15), (line:1, col:16)
+
+        The output shown is that produced by the default debug actions - custom debug actions can be
+        specified using L{setDebugActions}. Prior to attempting
+        to match the C{wd} expression, the debugging message C{"Match <exprname> at loc <n>(<line>,<col>)"}
+        is shown. Then if the parse succeeds, a C{"Matched"} message is shown, or an C{"Exception raised"}
+        message is shown. Also note the use of L{setName} to assign a human-readable name to the expression,
+        which makes debugging and exception messages easier to understand - for instance, the default
+        name created for the C{Word} expression without calling C{setName} is C{"W:(ABCD...)"}.
+        """
+        if flag:
+            self.setDebugActions( _defaultStartDebugAction, _defaultSuccessDebugAction, _defaultExceptionDebugAction )
+        else:
+            self.debug = False
+        return self
+
+    def __str__( self ):
+        return self.name
+
+    def __repr__( self ):
+        return _ustr(self)
+
+    def streamline( self ):
+        self.streamlined = True
+        self.strRepr = None
+        return self
+
+    def checkRecursion( self, parseElementList ):
+        pass
+
+    def validate( self, validateTrace=[] ):
+        """
+        Check defined expressions for valid structure, check for infinite recursive definitions.
+        """
+        self.checkRecursion( [] )
+
+    def parseFile( self, file_or_filename, parseAll=False ):
+        """
+        Execute the parse expression on the given file or filename.
+        If a filename is specified (instead of a file object),
+        the entire file is opened, read, and closed before parsing.
+        """
+        try:
+            file_contents = file_or_filename.read()
+        except AttributeError:
+            with open(file_or_filename, "r") as f:
+                file_contents = f.read()
+        try:
+            return self.parseString(file_contents, parseAll)
+        except ParseBaseException as exc:
+            if ParserElement.verbose_stacktrace:
+                raise
+            else:
+                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                raise exc
+
+    def __eq__(self,other):
+        if isinstance(other, ParserElement):
+            return self is other or vars(self) == vars(other)
+        elif isinstance(other, basestring):
+            return self.matches(other)
+        else:
+            return super(ParserElement,self)==other
+
+    def __ne__(self,other):
+        return not (self == other)
+
+    def __hash__(self):
+        return hash(id(self))
+
+    def __req__(self,other):
+        return self == other
+
+    def __rne__(self,other):
+        return not (self == other)
+
+    def matches(self, testString, parseAll=True):
+        """
+        Method for quick testing of a parser against a test string. Good for simple 
+        inline microtests of sub expressions while building up larger parser.
+           
+        Parameters:
+         - testString - to test against this expression for a match
+         - parseAll - (default=C{True}) - flag to pass to C{L{parseString}} when running tests
+            
+        Example::
+            expr = Word(nums)
+            assert expr.matches("100")
+        """
+        try:
+            self.parseString(_ustr(testString), parseAll=parseAll)
+            return True
+        except ParseBaseException:
+            return False
+                
+    def runTests(self, tests, parseAll=True, comment='#', fullDump=True, printResults=True, failureTests=False):
+        """
+        Execute the parse expression on a series of test strings, showing each
+        test, the parsed results or where the parse failed. Quick and easy way to
+        run a parse expression against a list of sample strings.
+           
+        Parameters:
+         - tests - a list of separate test strings, or a multiline string of test strings
+         - parseAll - (default=C{True}) - flag to pass to C{L{parseString}} when running tests           
+         - comment - (default=C{'#'}) - expression for indicating embedded comments in the test 
+              string; pass None to disable comment filtering
+         - fullDump - (default=C{True}) - dump results as list followed by results names in nested outline;
+              if False, only dump nested list
+         - printResults - (default=C{True}) prints test output to stdout
+         - failureTests - (default=C{False}) indicates if these tests are expected to fail parsing
+
+        Returns: a (success, results) tuple, where success indicates that all tests succeeded
+        (or failed if C{failureTests} is True), and the results contain a list of lines of each 
+        test's output
+        
+        Example::
+            number_expr = pyparsing_common.number.copy()
+
+            result = number_expr.runTests('''
+                # unsigned integer
+                100
+                # negative integer
+                -100
+                # float with scientific notation
+                6.02e23
+                # integer with scientific notation
+                1e-12
+                ''')
+            print("Success" if result[0] else "Failed!")
+
+            result = number_expr.runTests('''
+                # stray character
+                100Z
+                # missing leading digit before '.'
+                -.100
+                # too many '.'
+                3.14.159
+                ''', failureTests=True)
+            print("Success" if result[0] else "Failed!")
+        prints::
+            # unsigned integer
+            100
+            [100]
+
+            # negative integer
+            -100
+            [-100]
+
+            # float with scientific notation
+            6.02e23
+            [6.02e+23]
+
+            # integer with scientific notation
+            1e-12
+            [1e-12]
+
+            Success
+            
+            # stray character
+            100Z
+               ^
+            FAIL: Expected end of text (at char 3), (line:1, col:4)
+
+            # missing leading digit before '.'
+            -.100
+            ^
+            FAIL: Expected {real number with scientific notation | real number | signed integer} (at char 0), (line:1, col:1)
+
+            # too many '.'
+            3.14.159
+                ^
+            FAIL: Expected end of text (at char 4), (line:1, col:5)
+
+            Success
+
+        Each test string must be on a single line. If you want to test a string that spans multiple
+        lines, create a test like this::
+
+            expr.runTest(r"this is a test\\n of strings that spans \\n 3 lines")
+        
+        (Note that this is a raw string literal, you must include the leading 'r'.)
+        """
+        if isinstance(tests, basestring):
+            tests = list(map(str.strip, tests.rstrip().splitlines()))
+        if isinstance(comment, basestring):
+            comment = Literal(comment)
+        allResults = []
+        comments = []
+        success = True
+        for t in tests:
+            if comment is not None and comment.matches(t, False) or comments and not t:
+                comments.append(t)
+                continue
+            if not t:
+                continue
+            out = ['\n'.join(comments), t]
+            comments = []
+            try:
+                t = t.replace(r'\n','\n')
+                result = self.parseString(t, parseAll=parseAll)
+                out.append(result.dump(full=fullDump))
+                success = success and not failureTests
+            except ParseBaseException as pe:
+                fatal = "(FATAL)" if isinstance(pe, ParseFatalException) else ""
+                if '\n' in t:
+                    out.append(line(pe.loc, t))
+                    out.append(' '*(col(pe.loc,t)-1) + '^' + fatal)
+                else:
+                    out.append(' '*pe.loc + '^' + fatal)
+                out.append("FAIL: " + str(pe))
+                success = success and failureTests
+                result = pe
+            except Exception as exc:
+                out.append("FAIL-EXCEPTION: " + str(exc))
+                success = success and failureTests
+                result = exc
+
+            if printResults:
+                if fullDump:
+                    out.append('')
+                print('\n'.join(out))
+
+            allResults.append((t, result))
+        
+        return success, allResults
+
+        
+class Token(ParserElement):
+    """
+    Abstract C{ParserElement} subclass, for defining atomic matching patterns.
+    """
+    def __init__( self ):
+        super(Token,self).__init__( savelist=False )
+
+
+class Empty(Token):
+    """
+    An empty token, will always match.
+    """
+    def __init__( self ):
+        super(Empty,self).__init__()
+        self.name = "Empty"
+        self.mayReturnEmpty = True
+        self.mayIndexError = False
+
+
+class NoMatch(Token):
+    """
+    A token that will never match.
+    """
+    def __init__( self ):
+        super(NoMatch,self).__init__()
+        self.name = "NoMatch"
+        self.mayReturnEmpty = True
+        self.mayIndexError = False
+        self.errmsg = "Unmatchable token"
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        raise ParseException(instring, loc, self.errmsg, self)
+
+
+class Literal(Token):
+    """
+    Token to exactly match a specified string.
+    
+    Example::
+        Literal('blah').parseString('blah')  # -> ['blah']
+        Literal('blah').parseString('blahfooblah')  # -> ['blah']
+        Literal('blah').parseString('bla')  # -> Exception: Expected "blah"
+    
+    For case-insensitive matching, use L{CaselessLiteral}.
+    
+    For keyword matching (force word break before and after the matched string),
+    use L{Keyword} or L{CaselessKeyword}.
+    """
+    def __init__( self, matchString ):
+        super(Literal,self).__init__()
+        self.match = matchString
+        self.matchLen = len(matchString)
+        try:
+            self.firstMatchChar = matchString[0]
+        except IndexError:
+            warnings.warn("null string passed to Literal; use Empty() instead",
+                            SyntaxWarning, stacklevel=2)
+            self.__class__ = Empty
+        self.name = '"%s"' % _ustr(self.match)
+        self.errmsg = "Expected " + self.name
+        self.mayReturnEmpty = False
+        self.mayIndexError = False
+
+    # Performance tuning: this routine gets called a *lot*
+    # if this is a single character match string  and the first character matches,
+    # short-circuit as quickly as possible, and avoid calling startswith
+    #~ @profile
+    def parseImpl( self, instring, loc, doActions=True ):
+        if (instring[loc] == self.firstMatchChar and
+            (self.matchLen==1 or instring.startswith(self.match,loc)) ):
+            return loc+self.matchLen, self.match
+        raise ParseException(instring, loc, self.errmsg, self)
+_L = Literal
+ParserElement._literalStringClass = Literal
+
+class Keyword(Token):
+    """
+    Token to exactly match a specified string as a keyword, that is, it must be
+    immediately followed by a non-keyword character.  Compare with C{L{Literal}}:
+     - C{Literal("if")} will match the leading C{'if'} in C{'ifAndOnlyIf'}.
+     - C{Keyword("if")} will not; it will only match the leading C{'if'} in C{'if x=1'}, or C{'if(y==2)'}
+    Accepts two optional constructor arguments in addition to the keyword string:
+     - C{identChars} is a string of characters that would be valid identifier characters,
+          defaulting to all alphanumerics + "_" and "$"
+     - C{caseless} allows case-insensitive matching, default is C{False}.
+       
+    Example::
+        Keyword("start").parseString("start")  # -> ['start']
+        Keyword("start").parseString("starting")  # -> Exception
+
+    For case-insensitive matching, use L{CaselessKeyword}.
+    """
+    DEFAULT_KEYWORD_CHARS = alphanums+"_$"
+
+    def __init__( self, matchString, identChars=None, caseless=False ):
+        super(Keyword,self).__init__()
+        if identChars is None:
+            identChars = Keyword.DEFAULT_KEYWORD_CHARS
+        self.match = matchString
+        self.matchLen = len(matchString)
+        try:
+            self.firstMatchChar = matchString[0]
+        except IndexError:
+            warnings.warn("null string passed to Keyword; use Empty() instead",
+                            SyntaxWarning, stacklevel=2)
+        self.name = '"%s"' % self.match
+        self.errmsg = "Expected " + self.name
+        self.mayReturnEmpty = False
+        self.mayIndexError = False
+        self.caseless = caseless
+        if caseless:
+            self.caselessmatch = matchString.upper()
+            identChars = identChars.upper()
+        self.identChars = set(identChars)
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if self.caseless:
+            if ( (instring[ loc:loc+self.matchLen ].upper() == self.caselessmatch) and
+                 (loc >= len(instring)-self.matchLen or instring[loc+self.matchLen].upper() not in self.identChars) and
+                 (loc == 0 or instring[loc-1].upper() not in self.identChars) ):
+                return loc+self.matchLen, self.match
+        else:
+            if (instring[loc] == self.firstMatchChar and
+                (self.matchLen==1 or instring.startswith(self.match,loc)) and
+                (loc >= len(instring)-self.matchLen or instring[loc+self.matchLen] not in self.identChars) and
+                (loc == 0 or instring[loc-1] not in self.identChars) ):
+                return loc+self.matchLen, self.match
+        raise ParseException(instring, loc, self.errmsg, self)
+
+    def copy(self):
+        c = super(Keyword,self).copy()
+        c.identChars = Keyword.DEFAULT_KEYWORD_CHARS
+        return c
+
+    @staticmethod
+    def setDefaultKeywordChars( chars ):
+        """Overrides the default Keyword chars
+        """
+        Keyword.DEFAULT_KEYWORD_CHARS = chars
+
+class CaselessLiteral(Literal):
+    """
+    Token to match a specified string, ignoring case of letters.
+    Note: the matched results will always be in the case of the given
+    match string, NOT the case of the input text.
+
+    Example::
+        OneOrMore(CaselessLiteral("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD', 'CMD']
+        
+    (Contrast with example for L{CaselessKeyword}.)
+    """
+    def __init__( self, matchString ):
+        super(CaselessLiteral,self).__init__( matchString.upper() )
+        # Preserve the defining literal.
+        self.returnString = matchString
+        self.name = "'%s'" % self.returnString
+        self.errmsg = "Expected " + self.name
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if instring[ loc:loc+self.matchLen ].upper() == self.match:
+            return loc+self.matchLen, self.returnString
+        raise ParseException(instring, loc, self.errmsg, self)
+
+class CaselessKeyword(Keyword):
+    """
+    Caseless version of L{Keyword}.
+
+    Example::
+        OneOrMore(CaselessKeyword("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD']
+        
+    (Contrast with example for L{CaselessLiteral}.)
+    """
+    def __init__( self, matchString, identChars=None ):
+        super(CaselessKeyword,self).__init__( matchString, identChars, caseless=True )
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if ( (instring[ loc:loc+self.matchLen ].upper() == self.caselessmatch) and
+             (loc >= len(instring)-self.matchLen or instring[loc+self.matchLen].upper() not in self.identChars) ):
+            return loc+self.matchLen, self.match
+        raise ParseException(instring, loc, self.errmsg, self)
+
+class CloseMatch(Token):
+    """
+    A variation on L{Literal} which matches "close" matches, that is, 
+    strings with at most 'n' mismatching characters. C{CloseMatch} takes parameters:
+     - C{match_string} - string to be matched
+     - C{maxMismatches} - (C{default=1}) maximum number of mismatches allowed to count as a match
+    
+    The results from a successful parse will contain the matched text from the input string and the following named results:
+     - C{mismatches} - a list of the positions within the match_string where mismatches were found
+     - C{original} - the original match_string used to compare against the input string
+    
+    If C{mismatches} is an empty list, then the match was an exact match.
+    
+    Example::
+        patt = CloseMatch("ATCATCGAATGGA")
+        patt.parseString("ATCATCGAAXGGA") # -> (['ATCATCGAAXGGA'], {'mismatches': [[9]], 'original': ['ATCATCGAATGGA']})
+        patt.parseString("ATCAXCGAAXGGA") # -> Exception: Expected 'ATCATCGAATGGA' (with up to 1 mismatches) (at char 0), (line:1, col:1)
+
+        # exact match
+        patt.parseString("ATCATCGAATGGA") # -> (['ATCATCGAATGGA'], {'mismatches': [[]], 'original': ['ATCATCGAATGGA']})
+
+        # close match allowing up to 2 mismatches
+        patt = CloseMatch("ATCATCGAATGGA", maxMismatches=2)
+        patt.parseString("ATCAXCGAAXGGA") # -> (['ATCAXCGAAXGGA'], {'mismatches': [[4, 9]], 'original': ['ATCATCGAATGGA']})
+    """
+    def __init__(self, match_string, maxMismatches=1):
+        super(CloseMatch,self).__init__()
+        self.name = match_string
+        self.match_string = match_string
+        self.maxMismatches = maxMismatches
+        self.errmsg = "Expected %r (with up to %d mismatches)" % (self.match_string, self.maxMismatches)
+        self.mayIndexError = False
+        self.mayReturnEmpty = False
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        start = loc
+        instrlen = len(instring)
+        maxloc = start + len(self.match_string)
+
+        if maxloc <= instrlen:
+            match_string = self.match_string
+            match_stringloc = 0
+            mismatches = []
+            maxMismatches = self.maxMismatches
+
+            for match_stringloc,s_m in enumerate(zip(instring[loc:maxloc], self.match_string)):
+                src,mat = s_m
+                if src != mat:
+                    mismatches.append(match_stringloc)
+                    if len(mismatches) > maxMismatches:
+                        break
+            else:
+                loc = match_stringloc + 1
+                results = ParseResults([instring[start:loc]])
+                results['original'] = self.match_string
+                results['mismatches'] = mismatches
+                return loc, results
+
+        raise ParseException(instring, loc, self.errmsg, self)
+
+
+class Word(Token):
+    """
+    Token for matching words composed of allowed character sets.
+    Defined with string containing all allowed initial characters,
+    an optional string containing allowed body characters (if omitted,
+    defaults to the initial character set), and an optional minimum,
+    maximum, and/or exact length.  The default value for C{min} is 1 (a
+    minimum value < 1 is not valid); the default values for C{max} and C{exact}
+    are 0, meaning no maximum or exact length restriction. An optional
+    C{excludeChars} parameter can list characters that might be found in 
+    the input C{bodyChars} string; useful to define a word of all printables
+    except for one or two characters, for instance.
+    
+    L{srange} is useful for defining custom character set strings for defining 
+    C{Word} expressions, using range notation from regular expression character sets.
+    
+    A common mistake is to use C{Word} to match a specific literal string, as in 
+    C{Word("Address")}. Remember that C{Word} uses the string argument to define
+    I{sets} of matchable characters. This expression would match "Add", "AAA",
+    "dAred", or any other word made up of the characters 'A', 'd', 'r', 'e', and 's'.
+    To match an exact literal string, use L{Literal} or L{Keyword}.
+
+    pyparsing includes helper strings for building Words:
+     - L{alphas}
+     - L{nums}
+     - L{alphanums}
+     - L{hexnums}
+     - L{alphas8bit} (alphabetic characters in ASCII range 128-255 - accented, tilded, umlauted, etc.)
+     - L{punc8bit} (non-alphabetic characters in ASCII range 128-255 - currency, symbols, superscripts, diacriticals, etc.)
+     - L{printables} (any non-whitespace character)
+
+    Example::
+        # a word composed of digits
+        integer = Word(nums) # equivalent to Word("0123456789") or Word(srange("0-9"))
+        
+        # a word with a leading capital, and zero or more lowercase
+        capital_word = Word(alphas.upper(), alphas.lower())
+
+        # hostnames are alphanumeric, with leading alpha, and '-'
+        hostname = Word(alphas, alphanums+'-')
+        
+        # roman numeral (not a strict parser, accepts invalid mix of characters)
+        roman = Word("IVXLCDM")
+        
+        # any string of non-whitespace characters, except for ','
+        csv_value = Word(printables, excludeChars=",")
+    """
+    def __init__( self, initChars, bodyChars=None, min=1, max=0, exact=0, asKeyword=False, excludeChars=None ):
+        super(Word,self).__init__()
+        if excludeChars:
+            initChars = ''.join(c for c in initChars if c not in excludeChars)
+            if bodyChars:
+                bodyChars = ''.join(c for c in bodyChars if c not in excludeChars)
+        self.initCharsOrig = initChars
+        self.initChars = set(initChars)
+        if bodyChars :
+            self.bodyCharsOrig = bodyChars
+            self.bodyChars = set(bodyChars)
+        else:
+            self.bodyCharsOrig = initChars
+            self.bodyChars = set(initChars)
+
+        self.maxSpecified = max > 0
+
+        if min < 1:
+            raise ValueError("cannot specify a minimum length < 1; use Optional(Word()) if zero-length word is permitted")
+
+        self.minLen = min
+
+        if max > 0:
+            self.maxLen = max
+        else:
+            self.maxLen = _MAX_INT
+
+        if exact > 0:
+            self.maxLen = exact
+            self.minLen = exact
+
+        self.name = _ustr(self)
+        self.errmsg = "Expected " + self.name
+        self.mayIndexError = False
+        self.asKeyword = asKeyword
+
+        if ' ' not in self.initCharsOrig+self.bodyCharsOrig and (min==1 and max==0 and exact==0):
+            if self.bodyCharsOrig == self.initCharsOrig:
+                self.reString = "[%s]+" % _escapeRegexRangeChars(self.initCharsOrig)
+            elif len(self.initCharsOrig) == 1:
+                self.reString = "%s[%s]*" % \
+                                      (re.escape(self.initCharsOrig),
+                                      _escapeRegexRangeChars(self.bodyCharsOrig),)
+            else:
+                self.reString = "[%s][%s]*" % \
+                                      (_escapeRegexRangeChars(self.initCharsOrig),
+                                      _escapeRegexRangeChars(self.bodyCharsOrig),)
+            if self.asKeyword:
+                self.reString = r"\b"+self.reString+r"\b"
+            try:
+                self.re = re.compile( self.reString )
+            except Exception:
+                self.re = None
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if self.re:
+            result = self.re.match(instring,loc)
+            if not result:
+                raise ParseException(instring, loc, self.errmsg, self)
+
+            loc = result.end()
+            return loc, result.group()
+
+        if not(instring[ loc ] in self.initChars):
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        start = loc
+        loc += 1
+        instrlen = len(instring)
+        bodychars = self.bodyChars
+        maxloc = start + self.maxLen
+        maxloc = min( maxloc, instrlen )
+        while loc < maxloc and instring[loc] in bodychars:
+            loc += 1
+
+        throwException = False
+        if loc - start < self.minLen:
+            throwException = True
+        if self.maxSpecified and loc < instrlen and instring[loc] in bodychars:
+            throwException = True
+        if self.asKeyword:
+            if (start>0 and instring[start-1] in bodychars) or (loc<instrlen and instring[loc] in bodychars):
+                throwException = True
+
+        if throwException:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        return loc, instring[start:loc]
+
+    def __str__( self ):
+        try:
+            return super(Word,self).__str__()
+        except Exception:
+            pass
+
+
+        if self.strRepr is None:
+
+            def charsAsStr(s):
+                if len(s)>4:
+                    return s[:4]+"..."
+                else:
+                    return s
+
+            if ( self.initCharsOrig != self.bodyCharsOrig ):
+                self.strRepr = "W:(%s,%s)" % ( charsAsStr(self.initCharsOrig), charsAsStr(self.bodyCharsOrig) )
+            else:
+                self.strRepr = "W:(%s)" % charsAsStr(self.initCharsOrig)
+
+        return self.strRepr
+
+
+class Regex(Token):
+    """
+    Token for matching strings that match a given regular expression.
+    Defined with string specifying the regular expression in a form recognized by the inbuilt Python re module.
+    If the given regex contains named groups (defined using C{(?P<name>...)}), these will be preserved as 
+    named parse results.
+
+    Example::
+        realnum = Regex(r"[+-]?\d+\.\d*")
+        date = Regex(r'(?P<year>\d{4})-(?P<month>\d\d?)-(?P<day>\d\d?)')
+        # ref: http://stackoverflow.com/questions/267399/how-do-you-match-only-valid-roman-numerals-with-a-regular-expression
+        roman = Regex(r"M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})")
+    """
+    compiledREtype = type(re.compile("[A-Z]"))
+    def __init__( self, pattern, flags=0):
+        """The parameters C{pattern} and C{flags} are passed to the C{re.compile()} function as-is. See the Python C{re} module for an explanation of the acceptable patterns and flags."""
+        super(Regex,self).__init__()
+
+        if isinstance(pattern, basestring):
+            if not pattern:
+                warnings.warn("null string passed to Regex; use Empty() instead",
+                        SyntaxWarning, stacklevel=2)
+
+            self.pattern = pattern
+            self.flags = flags
+
+            try:
+                self.re = re.compile(self.pattern, self.flags)
+                self.reString = self.pattern
+            except sre_constants.error:
+                warnings.warn("invalid pattern (%s) passed to Regex" % pattern,
+                    SyntaxWarning, stacklevel=2)
+                raise
+
+        elif isinstance(pattern, Regex.compiledREtype):
+            self.re = pattern
+            self.pattern = \
+            self.reString = str(pattern)
+            self.flags = flags
+            
+        else:
+            raise ValueError("Regex may only be constructed with a string or a compiled RE object")
+
+        self.name = _ustr(self)
+        self.errmsg = "Expected " + self.name
+        self.mayIndexError = False
+        self.mayReturnEmpty = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        result = self.re.match(instring,loc)
+        if not result:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        loc = result.end()
+        d = result.groupdict()
+        ret = ParseResults(result.group())
+        if d:
+            for k in d:
+                ret[k] = d[k]
+        return loc,ret
+
+    def __str__( self ):
+        try:
+            return super(Regex,self).__str__()
+        except Exception:
+            pass
+
+        if self.strRepr is None:
+            self.strRepr = "Re:(%s)" % repr(self.pattern)
+
+        return self.strRepr
+
+
+class QuotedString(Token):
+    r"""
+    Token for matching strings that are delimited by quoting characters.
+    
+    Defined with the following parameters:
+        - quoteChar - string of one or more characters defining the quote delimiting string
+        - escChar - character to escape quotes, typically backslash (default=C{None})
+        - escQuote - special quote sequence to escape an embedded quote string (such as SQL's "" to escape an embedded ") (default=C{None})
+        - multiline - boolean indicating whether quotes can span multiple lines (default=C{False})
+        - unquoteResults - boolean indicating whether the matched text should be unquoted (default=C{True})
+        - endQuoteChar - string of one or more characters defining the end of the quote delimited string (default=C{None} => same as quoteChar)
+        - convertWhitespaceEscapes - convert escaped whitespace (C{'\t'}, C{'\n'}, etc.) to actual whitespace (default=C{True})
+
+    Example::
+        qs = QuotedString('"')
+        print(qs.searchString('lsjdf "This is the quote" sldjf'))
+        complex_qs = QuotedString('{{', endQuoteChar='}}')
+        print(complex_qs.searchString('lsjdf {{This is the "quote"}} sldjf'))
+        sql_qs = QuotedString('"', escQuote='""')
+        print(sql_qs.searchString('lsjdf "This is the quote with ""embedded"" quotes" sldjf'))
+    prints::
+        [['This is the quote']]
+        [['This is the "quote"']]
+        [['This is the quote with "embedded" quotes']]
+    """
+    def __init__( self, quoteChar, escChar=None, escQuote=None, multiline=False, unquoteResults=True, endQuoteChar=None, convertWhitespaceEscapes=True):
+        super(QuotedString,self).__init__()
+
+        # remove white space from quote chars - wont work anyway
+        quoteChar = quoteChar.strip()
+        if not quoteChar:
+            warnings.warn("quoteChar cannot be the empty string",SyntaxWarning,stacklevel=2)
+            raise SyntaxError()
+
+        if endQuoteChar is None:
+            endQuoteChar = quoteChar
+        else:
+            endQuoteChar = endQuoteChar.strip()
+            if not endQuoteChar:
+                warnings.warn("endQuoteChar cannot be the empty string",SyntaxWarning,stacklevel=2)
+                raise SyntaxError()
+
+        self.quoteChar = quoteChar
+        self.quoteCharLen = len(quoteChar)
+        self.firstQuoteChar = quoteChar[0]
+        self.endQuoteChar = endQuoteChar
+        self.endQuoteCharLen = len(endQuoteChar)
+        self.escChar = escChar
+        self.escQuote = escQuote
+        self.unquoteResults = unquoteResults
+        self.convertWhitespaceEscapes = convertWhitespaceEscapes
+
+        if multiline:
+            self.flags = re.MULTILINE | re.DOTALL
+            self.pattern = r'%s(?:[^%s%s]' % \
+                ( re.escape(self.quoteChar),
+                  _escapeRegexRangeChars(self.endQuoteChar[0]),
+                  (escChar is not None and _escapeRegexRangeChars(escChar) or '') )
+        else:
+            self.flags = 0
+            self.pattern = r'%s(?:[^%s\n\r%s]' % \
+                ( re.escape(self.quoteChar),
+                  _escapeRegexRangeChars(self.endQuoteChar[0]),
+                  (escChar is not None and _escapeRegexRangeChars(escChar) or '') )
+        if len(self.endQuoteChar) > 1:
+            self.pattern += (
+                '|(?:' + ')|(?:'.join("%s[^%s]" % (re.escape(self.endQuoteChar[:i]),
+                                               _escapeRegexRangeChars(self.endQuoteChar[i]))
+                                    for i in range(len(self.endQuoteChar)-1,0,-1)) + ')'
+                )
+        if escQuote:
+            self.pattern += (r'|(?:%s)' % re.escape(escQuote))
+        if escChar:
+            self.pattern += (r'|(?:%s.)' % re.escape(escChar))
+            self.escCharReplacePattern = re.escape(self.escChar)+"(.)"
+        self.pattern += (r')*%s' % re.escape(self.endQuoteChar))
+
+        try:
+            self.re = re.compile(self.pattern, self.flags)
+            self.reString = self.pattern
+        except sre_constants.error:
+            warnings.warn("invalid pattern (%s) passed to Regex" % self.pattern,
+                SyntaxWarning, stacklevel=2)
+            raise
+
+        self.name = _ustr(self)
+        self.errmsg = "Expected " + self.name
+        self.mayIndexError = False
+        self.mayReturnEmpty = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        result = instring[loc] == self.firstQuoteChar and self.re.match(instring,loc) or None
+        if not result:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        loc = result.end()
+        ret = result.group()
+
+        if self.unquoteResults:
+
+            # strip off quotes
+            ret = ret[self.quoteCharLen:-self.endQuoteCharLen]
+
+            if isinstance(ret,basestring):
+                # replace escaped whitespace
+                if '\\' in ret and self.convertWhitespaceEscapes:
+                    ws_map = {
+                        r'\t' : '\t',
+                        r'\n' : '\n',
+                        r'\f' : '\f',
+                        r'\r' : '\r',
+                    }
+                    for wslit,wschar in ws_map.items():
+                        ret = ret.replace(wslit, wschar)
+
+                # replace escaped characters
+                if self.escChar:
+                    ret = re.sub(self.escCharReplacePattern,"\g<1>",ret)
+
+                # replace escaped quotes
+                if self.escQuote:
+                    ret = ret.replace(self.escQuote, self.endQuoteChar)
+
+        return loc, ret
+
+    def __str__( self ):
+        try:
+            return super(QuotedString,self).__str__()
+        except Exception:
+            pass
+
+        if self.strRepr is None:
+            self.strRepr = "quoted string, starting with %s ending with %s" % (self.quoteChar, self.endQuoteChar)
+
+        return self.strRepr
+
+
+class CharsNotIn(Token):
+    """
+    Token for matching words composed of characters I{not} in a given set (will
+    include whitespace in matched characters if not listed in the provided exclusion set - see example).
+    Defined with string containing all disallowed characters, and an optional
+    minimum, maximum, and/or exact length.  The default value for C{min} is 1 (a
+    minimum value < 1 is not valid); the default values for C{max} and C{exact}
+    are 0, meaning no maximum or exact length restriction.
+
+    Example::
+        # define a comma-separated-value as anything that is not a ','
+        csv_value = CharsNotIn(',')
+        print(delimitedList(csv_value).parseString("dkls,lsdkjf,s12 34,@!#,213"))
+    prints::
+        ['dkls', 'lsdkjf', 's12 34', '@!#', '213']
+    """
+    def __init__( self, notChars, min=1, max=0, exact=0 ):
+        super(CharsNotIn,self).__init__()
+        self.skipWhitespace = False
+        self.notChars = notChars
+
+        if min < 1:
+            raise ValueError("cannot specify a minimum length < 1; use Optional(CharsNotIn()) if zero-length char group is permitted")
+
+        self.minLen = min
+
+        if max > 0:
+            self.maxLen = max
+        else:
+            self.maxLen = _MAX_INT
+
+        if exact > 0:
+            self.maxLen = exact
+            self.minLen = exact
+
+        self.name = _ustr(self)
+        self.errmsg = "Expected " + self.name
+        self.mayReturnEmpty = ( self.minLen == 0 )
+        self.mayIndexError = False
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if instring[loc] in self.notChars:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        start = loc
+        loc += 1
+        notchars = self.notChars
+        maxlen = min( start+self.maxLen, len(instring) )
+        while loc < maxlen and \
+              (instring[loc] not in notchars):
+            loc += 1
+
+        if loc - start < self.minLen:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        return loc, instring[start:loc]
+
+    def __str__( self ):
+        try:
+            return super(CharsNotIn, self).__str__()
+        except Exception:
+            pass
+
+        if self.strRepr is None:
+            if len(self.notChars) > 4:
+                self.strRepr = "!W:(%s...)" % self.notChars[:4]
+            else:
+                self.strRepr = "!W:(%s)" % self.notChars
+
+        return self.strRepr
+
+class White(Token):
+    """
+    Special matching class for matching whitespace.  Normally, whitespace is ignored
+    by pyparsing grammars.  This class is included when some whitespace structures
+    are significant.  Define with a string containing the whitespace characters to be
+    matched; default is C{" \\t\\r\\n"}.  Also takes optional C{min}, C{max}, and C{exact} arguments,
+    as defined for the C{L{Word}} class.
+    """
+    whiteStrs = {
+        " " : "<SPC>",
+        "\t": "<TAB>",
+        "\n": "<LF>",
+        "\r": "<CR>",
+        "\f": "<FF>",
+        }
+    def __init__(self, ws=" \t\r\n", min=1, max=0, exact=0):
+        super(White,self).__init__()
+        self.matchWhite = ws
+        self.setWhitespaceChars( "".join(c for c in self.whiteChars if c not in self.matchWhite) )
+        #~ self.leaveWhitespace()
+        self.name = ("".join(White.whiteStrs[c] for c in self.matchWhite))
+        self.mayReturnEmpty = True
+        self.errmsg = "Expected " + self.name
+
+        self.minLen = min
+
+        if max > 0:
+            self.maxLen = max
+        else:
+            self.maxLen = _MAX_INT
+
+        if exact > 0:
+            self.maxLen = exact
+            self.minLen = exact
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if not(instring[ loc ] in self.matchWhite):
+            raise ParseException(instring, loc, self.errmsg, self)
+        start = loc
+        loc += 1
+        maxloc = start + self.maxLen
+        maxloc = min( maxloc, len(instring) )
+        while loc < maxloc and instring[loc] in self.matchWhite:
+            loc += 1
+
+        if loc - start < self.minLen:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        return loc, instring[start:loc]
+
+
+class _PositionToken(Token):
+    def __init__( self ):
+        super(_PositionToken,self).__init__()
+        self.name=self.__class__.__name__
+        self.mayReturnEmpty = True
+        self.mayIndexError = False
+
+class GoToColumn(_PositionToken):
+    """
+    Token to advance to a specific column of input text; useful for tabular report scraping.
+    """
+    def __init__( self, colno ):
+        super(GoToColumn,self).__init__()
+        self.col = colno
+
+    def preParse( self, instring, loc ):
+        if col(loc,instring) != self.col:
+            instrlen = len(instring)
+            if self.ignoreExprs:
+                loc = self._skipIgnorables( instring, loc )
+            while loc < instrlen and instring[loc].isspace() and col( loc, instring ) != self.col :
+                loc += 1
+        return loc
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        thiscol = col( loc, instring )
+        if thiscol > self.col:
+            raise ParseException( instring, loc, "Text not in expected column", self )
+        newloc = loc + self.col - thiscol
+        ret = instring[ loc: newloc ]
+        return newloc, ret
+
+
+class LineStart(_PositionToken):
+    """
+    Matches if current position is at the beginning of a line within the parse string
+    
+    Example::
+    
+        test = '''\
+        AAA this line
+        AAA and this line
+          AAA but not this one
+        B AAA and definitely not this one
+        '''
+
+        for t in (LineStart() + 'AAA' + restOfLine).searchString(test):
+            print(t)
+    
+    Prints::
+        ['AAA', ' this line']
+        ['AAA', ' and this line']    
+
+    """
+    def __init__( self ):
+        super(LineStart,self).__init__()
+        self.errmsg = "Expected start of line"
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if col(loc, instring) == 1:
+            return loc, []
+        raise ParseException(instring, loc, self.errmsg, self)
+
+class LineEnd(_PositionToken):
+    """
+    Matches if current position is at the end of a line within the parse string
+    """
+    def __init__( self ):
+        super(LineEnd,self).__init__()
+        self.setWhitespaceChars( ParserElement.DEFAULT_WHITE_CHARS.replace("\n","") )
+        self.errmsg = "Expected end of line"
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if loc<len(instring):
+            if instring[loc] == "\n":
+                return loc+1, "\n"
+            else:
+                raise ParseException(instring, loc, self.errmsg, self)
+        elif loc == len(instring):
+            return loc+1, []
+        else:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+class StringStart(_PositionToken):
+    """
+    Matches if current position is at the beginning of the parse string
+    """
+    def __init__( self ):
+        super(StringStart,self).__init__()
+        self.errmsg = "Expected start of text"
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if loc != 0:
+            # see if entire string up to here is just whitespace and ignoreables
+            if loc != self.preParse( instring, 0 ):
+                raise ParseException(instring, loc, self.errmsg, self)
+        return loc, []
+
+class StringEnd(_PositionToken):
+    """
+    Matches if current position is at the end of the parse string
+    """
+    def __init__( self ):
+        super(StringEnd,self).__init__()
+        self.errmsg = "Expected end of text"
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if loc < len(instring):
+            raise ParseException(instring, loc, self.errmsg, self)
+        elif loc == len(instring):
+            return loc+1, []
+        elif loc > len(instring):
+            return loc, []
+        else:
+            raise ParseException(instring, loc, self.errmsg, self)
+
+class WordStart(_PositionToken):
+    """
+    Matches if the current position is at the beginning of a Word, and
+    is not preceded by any character in a given set of C{wordChars}
+    (default=C{printables}). To emulate the C{\b} behavior of regular expressions,
+    use C{WordStart(alphanums)}. C{WordStart} will also match at the beginning of
+    the string being parsed, or at the beginning of a line.
+    """
+    def __init__(self, wordChars = printables):
+        super(WordStart,self).__init__()
+        self.wordChars = set(wordChars)
+        self.errmsg = "Not at the start of a word"
+
+    def parseImpl(self, instring, loc, doActions=True ):
+        if loc != 0:
+            if (instring[loc-1] in self.wordChars or
+                instring[loc] not in self.wordChars):
+                raise ParseException(instring, loc, self.errmsg, self)
+        return loc, []
+
+class WordEnd(_PositionToken):
+    """
+    Matches if the current position is at the end of a Word, and
+    is not followed by any character in a given set of C{wordChars}
+    (default=C{printables}). To emulate the C{\b} behavior of regular expressions,
+    use C{WordEnd(alphanums)}. C{WordEnd} will also match at the end of
+    the string being parsed, or at the end of a line.
+    """
+    def __init__(self, wordChars = printables):
+        super(WordEnd,self).__init__()
+        self.wordChars = set(wordChars)
+        self.skipWhitespace = False
+        self.errmsg = "Not at the end of a word"
+
+    def parseImpl(self, instring, loc, doActions=True ):
+        instrlen = len(instring)
+        if instrlen>0 and loc<instrlen:
+            if (instring[loc] in self.wordChars or
+                instring[loc-1] not in self.wordChars):
+                raise ParseException(instring, loc, self.errmsg, self)
+        return loc, []
+
+
+class ParseExpression(ParserElement):
+    """
+    Abstract subclass of ParserElement, for combining and post-processing parsed tokens.
+    """
+    def __init__( self, exprs, savelist = False ):
+        super(ParseExpression,self).__init__(savelist)
+        if isinstance( exprs, _generatorType ):
+            exprs = list(exprs)
+
+        if isinstance( exprs, basestring ):
+            self.exprs = [ ParserElement._literalStringClass( exprs ) ]
+        elif isinstance( exprs, collections.Iterable ):
+            exprs = list(exprs)
+            # if sequence of strings provided, wrap with Literal
+            if all(isinstance(expr, basestring) for expr in exprs):
+                exprs = map(ParserElement._literalStringClass, exprs)
+            self.exprs = list(exprs)
+        else:
+            try:
+                self.exprs = list( exprs )
+            except TypeError:
+                self.exprs = [ exprs ]
+        self.callPreparse = False
+
+    def __getitem__( self, i ):
+        return self.exprs[i]
+
+    def append( self, other ):
+        self.exprs.append( other )
+        self.strRepr = None
+        return self
+
+    def leaveWhitespace( self ):
+        """Extends C{leaveWhitespace} defined in base class, and also invokes C{leaveWhitespace} on
+           all contained expressions."""
+        self.skipWhitespace = False
+        self.exprs = [ e.copy() for e in self.exprs ]
+        for e in self.exprs:
+            e.leaveWhitespace()
+        return self
+
+    def ignore( self, other ):
+        if isinstance( other, Suppress ):
+            if other not in self.ignoreExprs:
+                super( ParseExpression, self).ignore( other )
+                for e in self.exprs:
+                    e.ignore( self.ignoreExprs[-1] )
+        else:
+            super( ParseExpression, self).ignore( other )
+            for e in self.exprs:
+                e.ignore( self.ignoreExprs[-1] )
+        return self
+
+    def __str__( self ):
+        try:
+            return super(ParseExpression,self).__str__()
+        except Exception:
+            pass
+
+        if self.strRepr is None:
+            self.strRepr = "%s:(%s)" % ( self.__class__.__name__, _ustr(self.exprs) )
+        return self.strRepr
+
+    def streamline( self ):
+        super(ParseExpression,self).streamline()
+
+        for e in self.exprs:
+            e.streamline()
+
+        # collapse nested And's of the form And( And( And( a,b), c), d) to And( a,b,c,d )
+        # but only if there are no parse actions or resultsNames on the nested And's
+        # (likewise for Or's and MatchFirst's)
+        if ( len(self.exprs) == 2 ):
+            other = self.exprs[0]
+            if ( isinstance( other, self.__class__ ) and
+                  not(other.parseAction) and
+                  other.resultsName is None and
+                  not other.debug ):
+                self.exprs = other.exprs[:] + [ self.exprs[1] ]
+                self.strRepr = None
+                self.mayReturnEmpty |= other.mayReturnEmpty
+                self.mayIndexError  |= other.mayIndexError
+
+            other = self.exprs[-1]
+            if ( isinstance( other, self.__class__ ) and
+                  not(other.parseAction) and
+                  other.resultsName is None and
+                  not other.debug ):
+                self.exprs = self.exprs[:-1] + other.exprs[:]
+                self.strRepr = None
+                self.mayReturnEmpty |= other.mayReturnEmpty
+                self.mayIndexError  |= other.mayIndexError
+
+        self.errmsg = "Expected " + _ustr(self)
+        
+        return self
+
+    def setResultsName( self, name, listAllMatches=False ):
+        ret = super(ParseExpression,self).setResultsName(name,listAllMatches)
+        return ret
+
+    def validate( self, validateTrace=[] ):
+        tmp = validateTrace[:]+[self]
+        for e in self.exprs:
+            e.validate(tmp)
+        self.checkRecursion( [] )
+        
+    def copy(self):
+        ret = super(ParseExpression,self).copy()
+        ret.exprs = [e.copy() for e in self.exprs]
+        return ret
+
+class And(ParseExpression):
+    """
+    Requires all given C{ParseExpression}s to be found in the given order.
+    Expressions may be separated by whitespace.
+    May be constructed using the C{'+'} operator.
+    May also be constructed using the C{'-'} operator, which will suppress backtracking.
+
+    Example::
+        integer = Word(nums)
+        name_expr = OneOrMore(Word(alphas))
+
+        expr = And([integer("id"),name_expr("name"),integer("age")])
+        # more easily written as:
+        expr = integer("id") + name_expr("name") + integer("age")
+    """
+
+    class _ErrorStop(Empty):
+        def __init__(self, *args, **kwargs):
+            super(And._ErrorStop,self).__init__(*args, **kwargs)
+            self.name = '-'
+            self.leaveWhitespace()
+
+    def __init__( self, exprs, savelist = True ):
+        super(And,self).__init__(exprs, savelist)
+        self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
+        self.setWhitespaceChars( self.exprs[0].whiteChars )
+        self.skipWhitespace = self.exprs[0].skipWhitespace
+        self.callPreparse = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        # pass False as last arg to _parse for first element, since we already
+        # pre-parsed the string as part of our And pre-parsing
+        loc, resultlist = self.exprs[0]._parse( instring, loc, doActions, callPreParse=False )
+        errorStop = False
+        for e in self.exprs[1:]:
+            if isinstance(e, And._ErrorStop):
+                errorStop = True
+                continue
+            if errorStop:
+                try:
+                    loc, exprtokens = e._parse( instring, loc, doActions )
+                except ParseSyntaxException:
+                    raise
+                except ParseBaseException as pe:
+                    pe.__traceback__ = None
+                    raise ParseSyntaxException._from_exception(pe)
+                except IndexError:
+                    raise ParseSyntaxException(instring, len(instring), self.errmsg, self)
+            else:
+                loc, exprtokens = e._parse( instring, loc, doActions )
+            if exprtokens or exprtokens.haskeys():
+                resultlist += exprtokens
+        return loc, resultlist
+
+    def __iadd__(self, other ):
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        return self.append( other ) #And( [ self, other ] )
+
+    def checkRecursion( self, parseElementList ):
+        subRecCheckList = parseElementList[:] + [ self ]
+        for e in self.exprs:
+            e.checkRecursion( subRecCheckList )
+            if not e.mayReturnEmpty:
+                break
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "{" + " ".join(_ustr(e) for e in self.exprs) + "}"
+
+        return self.strRepr
+
+
+class Or(ParseExpression):
+    """
+    Requires that at least one C{ParseExpression} is found.
+    If two expressions match, the expression that matches the longest string will be used.
+    May be constructed using the C{'^'} operator.
+
+    Example::
+        # construct Or using '^' operator
+        
+        number = Word(nums) ^ Combine(Word(nums) + '.' + Word(nums))
+        print(number.searchString("123 3.1416 789"))
+    prints::
+        [['123'], ['3.1416'], ['789']]
+    """
+    def __init__( self, exprs, savelist = False ):
+        super(Or,self).__init__(exprs, savelist)
+        if self.exprs:
+            self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
+        else:
+            self.mayReturnEmpty = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        maxExcLoc = -1
+        maxException = None
+        matches = []
+        for e in self.exprs:
+            try:
+                loc2 = e.tryParse( instring, loc )
+            except ParseException as err:
+                err.__traceback__ = None
+                if err.loc > maxExcLoc:
+                    maxException = err
+                    maxExcLoc = err.loc
+            except IndexError:
+                if len(instring) > maxExcLoc:
+                    maxException = ParseException(instring,len(instring),e.errmsg,self)
+                    maxExcLoc = len(instring)
+            else:
+                # save match among all matches, to retry longest to shortest
+                matches.append((loc2, e))
+
+        if matches:
+            matches.sort(key=lambda x: -x[0])
+            for _,e in matches:
+                try:
+                    return e._parse( instring, loc, doActions )
+                except ParseException as err:
+                    err.__traceback__ = None
+                    if err.loc > maxExcLoc:
+                        maxException = err
+                        maxExcLoc = err.loc
+
+        if maxException is not None:
+            maxException.msg = self.errmsg
+            raise maxException
+        else:
+            raise ParseException(instring, loc, "no defined alternatives to match", self)
+
+
+    def __ixor__(self, other ):
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        return self.append( other ) #Or( [ self, other ] )
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "{" + " ^ ".join(_ustr(e) for e in self.exprs) + "}"
+
+        return self.strRepr
+
+    def checkRecursion( self, parseElementList ):
+        subRecCheckList = parseElementList[:] + [ self ]
+        for e in self.exprs:
+            e.checkRecursion( subRecCheckList )
+
+
+class MatchFirst(ParseExpression):
+    """
+    Requires that at least one C{ParseExpression} is found.
+    If two expressions match, the first one listed is the one that will match.
+    May be constructed using the C{'|'} operator.
+
+    Example::
+        # construct MatchFirst using '|' operator
+        
+        # watch the order of expressions to match
+        number = Word(nums) | Combine(Word(nums) + '.' + Word(nums))
+        print(number.searchString("123 3.1416 789")) #  Fail! -> [['123'], ['3'], ['1416'], ['789']]
+
+        # put more selective expression first
+        number = Combine(Word(nums) + '.' + Word(nums)) | Word(nums)
+        print(number.searchString("123 3.1416 789")) #  Better -> [['123'], ['3.1416'], ['789']]
+    """
+    def __init__( self, exprs, savelist = False ):
+        super(MatchFirst,self).__init__(exprs, savelist)
+        if self.exprs:
+            self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
+        else:
+            self.mayReturnEmpty = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        maxExcLoc = -1
+        maxException = None
+        for e in self.exprs:
+            try:
+                ret = e._parse( instring, loc, doActions )
+                return ret
+            except ParseException as err:
+                if err.loc > maxExcLoc:
+                    maxException = err
+                    maxExcLoc = err.loc
+            except IndexError:
+                if len(instring) > maxExcLoc:
+                    maxException = ParseException(instring,len(instring),e.errmsg,self)
+                    maxExcLoc = len(instring)
+
+        # only got here if no expression matched, raise exception for match that made it the furthest
+        else:
+            if maxException is not None:
+                maxException.msg = self.errmsg
+                raise maxException
+            else:
+                raise ParseException(instring, loc, "no defined alternatives to match", self)
+
+    def __ior__(self, other ):
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass( other )
+        return self.append( other ) #MatchFirst( [ self, other ] )
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "{" + " | ".join(_ustr(e) for e in self.exprs) + "}"
+
+        return self.strRepr
+
+    def checkRecursion( self, parseElementList ):
+        subRecCheckList = parseElementList[:] + [ self ]
+        for e in self.exprs:
+            e.checkRecursion( subRecCheckList )
+
+
+class Each(ParseExpression):
+    """
+    Requires all given C{ParseExpression}s to be found, but in any order.
+    Expressions may be separated by whitespace.
+    May be constructed using the C{'&'} operator.
+
+    Example::
+        color = oneOf("RED ORANGE YELLOW GREEN BLUE PURPLE BLACK WHITE BROWN")
+        shape_type = oneOf("SQUARE CIRCLE TRIANGLE STAR HEXAGON OCTAGON")
+        integer = Word(nums)
+        shape_attr = "shape:" + shape_type("shape")
+        posn_attr = "posn:" + Group(integer("x") + ',' + integer("y"))("posn")
+        color_attr = "color:" + color("color")
+        size_attr = "size:" + integer("size")
+
+        # use Each (using operator '&') to accept attributes in any order 
+        # (shape and posn are required, color and size are optional)
+        shape_spec = shape_attr & posn_attr & Optional(color_attr) & Optional(size_attr)
+
+        shape_spec.runTests('''
+            shape: SQUARE color: BLACK posn: 100, 120
+            shape: CIRCLE size: 50 color: BLUE posn: 50,80
+            color:GREEN size:20 shape:TRIANGLE posn:20,40
+            '''
+            )
+    prints::
+        shape: SQUARE color: BLACK posn: 100, 120
+        ['shape:', 'SQUARE', 'color:', 'BLACK', 'posn:', ['100', ',', '120']]
+        - color: BLACK
+        - posn: ['100', ',', '120']
+          - x: 100
+          - y: 120
+        - shape: SQUARE
+
+
+        shape: CIRCLE size: 50 color: BLUE posn: 50,80
+        ['shape:', 'CIRCLE', 'size:', '50', 'color:', 'BLUE', 'posn:', ['50', ',', '80']]
+        - color: BLUE
+        - posn: ['50', ',', '80']
+          - x: 50
+          - y: 80
+        - shape: CIRCLE
+        - size: 50
+
+
+        color: GREEN size: 20 shape: TRIANGLE posn: 20,40
+        ['color:', 'GREEN', 'size:', '20', 'shape:', 'TRIANGLE', 'posn:', ['20', ',', '40']]
+        - color: GREEN
+        - posn: ['20', ',', '40']
+          - x: 20
+          - y: 40
+        - shape: TRIANGLE
+        - size: 20
+    """
+    def __init__( self, exprs, savelist = True ):
+        super(Each,self).__init__(exprs, savelist)
+        self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
+        self.skipWhitespace = True
+        self.initExprGroups = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if self.initExprGroups:
+            self.opt1map = dict((id(e.expr),e) for e in self.exprs if isinstance(e,Optional))
+            opt1 = [ e.expr for e in self.exprs if isinstance(e,Optional) ]
+            opt2 = [ e for e in self.exprs if e.mayReturnEmpty and not isinstance(e,Optional)]
+            self.optionals = opt1 + opt2
+            self.multioptionals = [ e.expr for e in self.exprs if isinstance(e,ZeroOrMore) ]
+            self.multirequired = [ e.expr for e in self.exprs if isinstance(e,OneOrMore) ]
+            self.required = [ e for e in self.exprs if not isinstance(e,(Optional,ZeroOrMore,OneOrMore)) ]
+            self.required += self.multirequired
+            self.initExprGroups = False
+        tmpLoc = loc
+        tmpReqd = self.required[:]
+        tmpOpt  = self.optionals[:]
+        matchOrder = []
+
+        keepMatching = True
+        while keepMatching:
+            tmpExprs = tmpReqd + tmpOpt + self.multioptionals + self.multirequired
+            failed = []
+            for e in tmpExprs:
+                try:
+                    tmpLoc = e.tryParse( instring, tmpLoc )
+                except ParseException:
+                    failed.append(e)
+                else:
+                    matchOrder.append(self.opt1map.get(id(e),e))
+                    if e in tmpReqd:
+                        tmpReqd.remove(e)
+                    elif e in tmpOpt:
+                        tmpOpt.remove(e)
+            if len(failed) == len(tmpExprs):
+                keepMatching = False
+
+        if tmpReqd:
+            missing = ", ".join(_ustr(e) for e in tmpReqd)
+            raise ParseException(instring,loc,"Missing one or more required elements (%s)" % missing )
+
+        # add any unmatched Optionals, in case they have default values defined
+        matchOrder += [e for e in self.exprs if isinstance(e,Optional) and e.expr in tmpOpt]
+
+        resultlist = []
+        for e in matchOrder:
+            loc,results = e._parse(instring,loc,doActions)
+            resultlist.append(results)
+
+        finalResults = sum(resultlist, ParseResults([]))
+        return loc, finalResults
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "{" + " & ".join(_ustr(e) for e in self.exprs) + "}"
+
+        return self.strRepr
+
+    def checkRecursion( self, parseElementList ):
+        subRecCheckList = parseElementList[:] + [ self ]
+        for e in self.exprs:
+            e.checkRecursion( subRecCheckList )
+
+
+class ParseElementEnhance(ParserElement):
+    """
+    Abstract subclass of C{ParserElement}, for combining and post-processing parsed tokens.
+    """
+    def __init__( self, expr, savelist=False ):
+        super(ParseElementEnhance,self).__init__(savelist)
+        if isinstance( expr, basestring ):
+            if issubclass(ParserElement._literalStringClass, Token):
+                expr = ParserElement._literalStringClass(expr)
+            else:
+                expr = ParserElement._literalStringClass(Literal(expr))
+        self.expr = expr
+        self.strRepr = None
+        if expr is not None:
+            self.mayIndexError = expr.mayIndexError
+            self.mayReturnEmpty = expr.mayReturnEmpty
+            self.setWhitespaceChars( expr.whiteChars )
+            self.skipWhitespace = expr.skipWhitespace
+            self.saveAsList = expr.saveAsList
+            self.callPreparse = expr.callPreparse
+            self.ignoreExprs.extend(expr.ignoreExprs)
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if self.expr is not None:
+            return self.expr._parse( instring, loc, doActions, callPreParse=False )
+        else:
+            raise ParseException("",loc,self.errmsg,self)
+
+    def leaveWhitespace( self ):
+        self.skipWhitespace = False
+        self.expr = self.expr.copy()
+        if self.expr is not None:
+            self.expr.leaveWhitespace()
+        return self
+
+    def ignore( self, other ):
+        if isinstance( other, Suppress ):
+            if other not in self.ignoreExprs:
+                super( ParseElementEnhance, self).ignore( other )
+                if self.expr is not None:
+                    self.expr.ignore( self.ignoreExprs[-1] )
+        else:
+            super( ParseElementEnhance, self).ignore( other )
+            if self.expr is not None:
+                self.expr.ignore( self.ignoreExprs[-1] )
+        return self
+
+    def streamline( self ):
+        super(ParseElementEnhance,self).streamline()
+        if self.expr is not None:
+            self.expr.streamline()
+        return self
+
+    def checkRecursion( self, parseElementList ):
+        if self in parseElementList:
+            raise RecursiveGrammarException( parseElementList+[self] )
+        subRecCheckList = parseElementList[:] + [ self ]
+        if self.expr is not None:
+            self.expr.checkRecursion( subRecCheckList )
+
+    def validate( self, validateTrace=[] ):
+        tmp = validateTrace[:]+[self]
+        if self.expr is not None:
+            self.expr.validate(tmp)
+        self.checkRecursion( [] )
+
+    def __str__( self ):
+        try:
+            return super(ParseElementEnhance,self).__str__()
+        except Exception:
+            pass
+
+        if self.strRepr is None and self.expr is not None:
+            self.strRepr = "%s:(%s)" % ( self.__class__.__name__, _ustr(self.expr) )
+        return self.strRepr
+
+
+class FollowedBy(ParseElementEnhance):
+    """
+    Lookahead matching of the given parse expression.  C{FollowedBy}
+    does I{not} advance the parsing position within the input string, it only
+    verifies that the specified parse expression matches at the current
+    position.  C{FollowedBy} always returns a null token list.
+
+    Example::
+        # use FollowedBy to match a label only if it is followed by a ':'
+        data_word = Word(alphas)
+        label = data_word + FollowedBy(':')
+        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
+        
+        OneOrMore(attr_expr).parseString("shape: SQUARE color: BLACK posn: upper left").pprint()
+    prints::
+        [['shape', 'SQUARE'], ['color', 'BLACK'], ['posn', 'upper left']]
+    """
+    def __init__( self, expr ):
+        super(FollowedBy,self).__init__(expr)
+        self.mayReturnEmpty = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        self.expr.tryParse( instring, loc )
+        return loc, []
+
+
+class NotAny(ParseElementEnhance):
+    """
+    Lookahead to disallow matching with the given parse expression.  C{NotAny}
+    does I{not} advance the parsing position within the input string, it only
+    verifies that the specified parse expression does I{not} match at the current
+    position.  Also, C{NotAny} does I{not} skip over leading whitespace. C{NotAny}
+    always returns a null token list.  May be constructed using the '~' operator.
+
+    Example::
+        
+    """
+    def __init__( self, expr ):
+        super(NotAny,self).__init__(expr)
+        #~ self.leaveWhitespace()
+        self.skipWhitespace = False  # do NOT use self.leaveWhitespace(), don't want to propagate to exprs
+        self.mayReturnEmpty = True
+        self.errmsg = "Found unwanted token, "+_ustr(self.expr)
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        if self.expr.canParseNext(instring, loc):
+            raise ParseException(instring, loc, self.errmsg, self)
+        return loc, []
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "~{" + _ustr(self.expr) + "}"
+
+        return self.strRepr
+
+class _MultipleMatch(ParseElementEnhance):
+    def __init__( self, expr, stopOn=None):
+        super(_MultipleMatch, self).__init__(expr)
+        self.saveAsList = True
+        ender = stopOn
+        if isinstance(ender, basestring):
+            ender = ParserElement._literalStringClass(ender)
+        self.not_ender = ~ender if ender is not None else None
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        self_expr_parse = self.expr._parse
+        self_skip_ignorables = self._skipIgnorables
+        check_ender = self.not_ender is not None
+        if check_ender:
+            try_not_ender = self.not_ender.tryParse
+        
+        # must be at least one (but first see if we are the stopOn sentinel;
+        # if so, fail)
+        if check_ender:
+            try_not_ender(instring, loc)
+        loc, tokens = self_expr_parse( instring, loc, doActions, callPreParse=False )
+        try:
+            hasIgnoreExprs = (not not self.ignoreExprs)
+            while 1:
+                if check_ender:
+                    try_not_ender(instring, loc)
+                if hasIgnoreExprs:
+                    preloc = self_skip_ignorables( instring, loc )
+                else:
+                    preloc = loc
+                loc, tmptokens = self_expr_parse( instring, preloc, doActions )
+                if tmptokens or tmptokens.haskeys():
+                    tokens += tmptokens
+        except (ParseException,IndexError):
+            pass
+
+        return loc, tokens
+        
+class OneOrMore(_MultipleMatch):
+    """
+    Repetition of one or more of the given expression.
+    
+    Parameters:
+     - expr - expression that must match one or more times
+     - stopOn - (default=C{None}) - expression for a terminating sentinel
+          (only required if the sentinel would ordinarily match the repetition 
+          expression)          
+
+    Example::
+        data_word = Word(alphas)
+        label = data_word + FollowedBy(':')
+        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word).setParseAction(' '.join))
+
+        text = "shape: SQUARE posn: upper left color: BLACK"
+        OneOrMore(attr_expr).parseString(text).pprint()  # Fail! read 'color' as data instead of next label -> [['shape', 'SQUARE color']]
+
+        # use stopOn attribute for OneOrMore to avoid reading label string as part of the data
+        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
+        OneOrMore(attr_expr).parseString(text).pprint() # Better -> [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'BLACK']]
+        
+        # could also be written as
+        (attr_expr * (1,)).parseString(text).pprint()
+    """
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "{" + _ustr(self.expr) + "}..."
+
+        return self.strRepr
+
+class ZeroOrMore(_MultipleMatch):
+    """
+    Optional repetition of zero or more of the given expression.
+    
+    Parameters:
+     - expr - expression that must match zero or more times
+     - stopOn - (default=C{None}) - expression for a terminating sentinel
+          (only required if the sentinel would ordinarily match the repetition 
+          expression)          
+
+    Example: similar to L{OneOrMore}
+    """
+    def __init__( self, expr, stopOn=None):
+        super(ZeroOrMore,self).__init__(expr, stopOn=stopOn)
+        self.mayReturnEmpty = True
+        
+    def parseImpl( self, instring, loc, doActions=True ):
+        try:
+            return super(ZeroOrMore, self).parseImpl(instring, loc, doActions)
+        except (ParseException,IndexError):
+            return loc, []
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "[" + _ustr(self.expr) + "]..."
+
+        return self.strRepr
+
+class _NullToken(object):
+    def __bool__(self):
+        return False
+    __nonzero__ = __bool__
+    def __str__(self):
+        return ""
+
+_optionalNotMatched = _NullToken()
+class Optional(ParseElementEnhance):
+    """
+    Optional matching of the given expression.
+
+    Parameters:
+     - expr - expression that must match zero or more times
+     - default (optional) - value to be returned if the optional expression is not found.
+
+    Example::
+        # US postal code can be a 5-digit zip, plus optional 4-digit qualifier
+        zip = Combine(Word(nums, exact=5) + Optional('-' + Word(nums, exact=4)))
+        zip.runTests('''
+            # traditional ZIP code
+            12345
+            
+            # ZIP+4 form
+            12101-0001
+            
+            # invalid ZIP
+            98765-
+            ''')
+    prints::
+        # traditional ZIP code
+        12345
+        ['12345']
+
+        # ZIP+4 form
+        12101-0001
+        ['12101-0001']
+
+        # invalid ZIP
+        98765-
+             ^
+        FAIL: Expected end of text (at char 5), (line:1, col:6)
+    """
+    def __init__( self, expr, default=_optionalNotMatched ):
+        super(Optional,self).__init__( expr, savelist=False )
+        self.saveAsList = self.expr.saveAsList
+        self.defaultValue = default
+        self.mayReturnEmpty = True
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        try:
+            loc, tokens = self.expr._parse( instring, loc, doActions, callPreParse=False )
+        except (ParseException,IndexError):
+            if self.defaultValue is not _optionalNotMatched:
+                if self.expr.resultsName:
+                    tokens = ParseResults([ self.defaultValue ])
+                    tokens[self.expr.resultsName] = self.defaultValue
+                else:
+                    tokens = [ self.defaultValue ]
+            else:
+                tokens = []
+        return loc, tokens
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+
+        if self.strRepr is None:
+            self.strRepr = "[" + _ustr(self.expr) + "]"
+
+        return self.strRepr
+
+class SkipTo(ParseElementEnhance):
+    """
+    Token for skipping over all undefined text until the matched expression is found.
+
+    Parameters:
+     - expr - target expression marking the end of the data to be skipped
+     - include - (default=C{False}) if True, the target expression is also parsed 
+          (the skipped text and target expression are returned as a 2-element list).
+     - ignore - (default=C{None}) used to define grammars (typically quoted strings and 
+          comments) that might contain false matches to the target expression
+     - failOn - (default=C{None}) define expressions that are not allowed to be 
+          included in the skipped test; if found before the target expression is found, 
+          the SkipTo is not a match
+
+    Example::
+        report = '''
+            Outstanding Issues Report - 1 Jan 2000
+
+               # | Severity | Description                               |  Days Open
+            -----+----------+-------------------------------------------+-----------
+             101 | Critical | Intermittent system crash                 |          6
+              94 | Cosmetic | Spelling error on Login ('log|n')         |         14
+              79 | Minor    | System slow when running too many reports |         47
+            '''
+        integer = Word(nums)
+        SEP = Suppress('|')
+        # use SkipTo to simply match everything up until the next SEP
+        # - ignore quoted strings, so that a '|' character inside a quoted string does not match
+        # - parse action will call token.strip() for each matched token, i.e., the description body
+        string_data = SkipTo(SEP, ignore=quotedString)
+        string_data.setParseAction(tokenMap(str.strip))
+        ticket_expr = (integer("issue_num") + SEP 
+                      + string_data("sev") + SEP 
+                      + string_data("desc") + SEP 
+                      + integer("days_open"))
+        
+        for tkt in ticket_expr.searchString(report):
+            print tkt.dump()
+    prints::
+        ['101', 'Critical', 'Intermittent system crash', '6']
+        - days_open: 6
+        - desc: Intermittent system crash
+        - issue_num: 101
+        - sev: Critical
+        ['94', 'Cosmetic', "Spelling error on Login ('log|n')", '14']
+        - days_open: 14
+        - desc: Spelling error on Login ('log|n')
+        - issue_num: 94
+        - sev: Cosmetic
+        ['79', 'Minor', 'System slow when running too many reports', '47']
+        - days_open: 47
+        - desc: System slow when running too many reports
+        - issue_num: 79
+        - sev: Minor
+    """
+    def __init__( self, other, include=False, ignore=None, failOn=None ):
+        super( SkipTo, self ).__init__( other )
+        self.ignoreExpr = ignore
+        self.mayReturnEmpty = True
+        self.mayIndexError = False
+        self.includeMatch = include
+        self.asList = False
+        if isinstance(failOn, basestring):
+            self.failOn = ParserElement._literalStringClass(failOn)
+        else:
+            self.failOn = failOn
+        self.errmsg = "No match found for "+_ustr(self.expr)
+
+    def parseImpl( self, instring, loc, doActions=True ):
+        startloc = loc
+        instrlen = len(instring)
+        expr = self.expr
+        expr_parse = self.expr._parse
+        self_failOn_canParseNext = self.failOn.canParseNext if self.failOn is not None else None
+        self_ignoreExpr_tryParse = self.ignoreExpr.tryParse if self.ignoreExpr is not None else None
+        
+        tmploc = loc
+        while tmploc <= instrlen:
+            if self_failOn_canParseNext is not None:
+                # break if failOn expression matches
+                if self_failOn_canParseNext(instring, tmploc):
+                    break
+                    
+            if self_ignoreExpr_tryParse is not None:
+                # advance past ignore expressions
+                while 1:
+                    try:
+                        tmploc = self_ignoreExpr_tryParse(instring, tmploc)
+                    except ParseBaseException:
+                        break
+            
+            try:
+                expr_parse(instring, tmploc, doActions=False, callPreParse=False)
+            except (ParseException, IndexError):
+                # no match, advance loc in string
+                tmploc += 1
+            else:
+                # matched skipto expr, done
+                break
+
+        else:
+            # ran off the end of the input string without matching skipto expr, fail
+            raise ParseException(instring, loc, self.errmsg, self)
+
+        # build up return values
+        loc = tmploc
+        skiptext = instring[startloc:loc]
+        skipresult = ParseResults(skiptext)
+        
+        if self.includeMatch:
+            loc, mat = expr_parse(instring,loc,doActions,callPreParse=False)
+            skipresult += mat
+
+        return loc, skipresult
+
+class Forward(ParseElementEnhance):
+    """
+    Forward declaration of an expression to be defined later -
+    used for recursive grammars, such as algebraic infix notation.
+    When the expression is known, it is assigned to the C{Forward} variable using the '<<' operator.
+
+    Note: take care when assigning to C{Forward} not to overlook precedence of operators.
+    Specifically, '|' has a lower precedence than '<<', so that::
+        fwdExpr << a | b | c
+    will actually be evaluated as::
+        (fwdExpr << a) | b | c
+    thereby leaving b and c out as parseable alternatives.  It is recommended that you
+    explicitly group the values inserted into the C{Forward}::
+        fwdExpr << (a | b | c)
+    Converting to use the '<<=' operator instead will avoid this problem.
+
+    See L{ParseResults.pprint} for an example of a recursive parser created using
+    C{Forward}.
+    """
+    def __init__( self, other=None ):
+        super(Forward,self).__init__( other, savelist=False )
+
+    def __lshift__( self, other ):
+        if isinstance( other, basestring ):
+            other = ParserElement._literalStringClass(other)
+        self.expr = other
+        self.strRepr = None
+        self.mayIndexError = self.expr.mayIndexError
+        self.mayReturnEmpty = self.expr.mayReturnEmpty
+        self.setWhitespaceChars( self.expr.whiteChars )
+        self.skipWhitespace = self.expr.skipWhitespace
+        self.saveAsList = self.expr.saveAsList
+        self.ignoreExprs.extend(self.expr.ignoreExprs)
+        return self
+        
+    def __ilshift__(self, other):
+        return self << other
+    
+    def leaveWhitespace( self ):
+        self.skipWhitespace = False
+        return self
+
+    def streamline( self ):
+        if not self.streamlined:
+            self.streamlined = True
+            if self.expr is not None:
+                self.expr.streamline()
+        return self
+
+    def validate( self, validateTrace=[] ):
+        if self not in validateTrace:
+            tmp = validateTrace[:]+[self]
+            if self.expr is not None:
+                self.expr.validate(tmp)
+        self.checkRecursion([])
+
+    def __str__( self ):
+        if hasattr(self,"name"):
+            return self.name
+        return self.__class__.__name__ + ": ..."
+
+        # stubbed out for now - creates awful memory and perf issues
+        self._revertClass = self.__class__
+        self.__class__ = _ForwardNoRecurse
+        try:
+            if self.expr is not None:
+                retString = _ustr(self.expr)
+            else:
+                retString = "None"
+        finally:
+            self.__class__ = self._revertClass
+        return self.__class__.__name__ + ": " + retString
+
+    def copy(self):
+        if self.expr is not None:
+            return super(Forward,self).copy()
+        else:
+            ret = Forward()
+            ret <<= self
+            return ret
+
+class _ForwardNoRecurse(Forward):
+    def __str__( self ):
+        return "..."
+
+class TokenConverter(ParseElementEnhance):
+    """
+    Abstract subclass of C{ParseExpression}, for converting parsed results.
+    """
+    def __init__( self, expr, savelist=False ):
+        super(TokenConverter,self).__init__( expr )#, savelist )
+        self.saveAsList = False
+
+class Combine(TokenConverter):
+    """
+    Converter to concatenate all matching tokens to a single string.
+    By default, the matching patterns must also be contiguous in the input string;
+    this can be disabled by specifying C{'adjacent=False'} in the constructor.
+
+    Example::
+        real = Word(nums) + '.' + Word(nums)
+        print(real.parseString('3.1416')) # -> ['3', '.', '1416']
+        # will also erroneously match the following
+        print(real.parseString('3. 1416')) # -> ['3', '.', '1416']
+
+        real = Combine(Word(nums) + '.' + Word(nums))
+        print(real.parseString('3.1416')) # -> ['3.1416']
+        # no match when there are internal spaces
+        print(real.parseString('3. 1416')) # -> Exception: Expected W:(0123...)
+    """
+    def __init__( self, expr, joinString="", adjacent=True ):
+        super(Combine,self).__init__( expr )
+        # suppress whitespace-stripping in contained parse expressions, but re-enable it on the Combine itself
+        if adjacent:
+            self.leaveWhitespace()
+        self.adjacent = adjacent
+        self.skipWhitespace = True
+        self.joinString = joinString
+        self.callPreparse = True
+
+    def ignore( self, other ):
+        if self.adjacent:
+            ParserElement.ignore(self, other)
+        else:
+            super( Combine, self).ignore( other )
+        return self
+
+    def postParse( self, instring, loc, tokenlist ):
+        retToks = tokenlist.copy()
+        del retToks[:]
+        retToks += ParseResults([ "".join(tokenlist._asStringList(self.joinString)) ], modal=self.modalResults)
+
+        if self.resultsName and retToks.haskeys():
+            return [ retToks ]
+        else:
+            return retToks
+
+class Group(TokenConverter):
+    """
+    Converter to return the matched tokens as a list - useful for returning tokens of C{L{ZeroOrMore}} and C{L{OneOrMore}} expressions.
+
+    Example::
+        ident = Word(alphas)
+        num = Word(nums)
+        term = ident | num
+        func = ident + Optional(delimitedList(term))
+        print(func.parseString("fn a,b,100"))  # -> ['fn', 'a', 'b', '100']
+
+        func = ident + Group(Optional(delimitedList(term)))
+        print(func.parseString("fn a,b,100"))  # -> ['fn', ['a', 'b', '100']]
+    """
+    def __init__( self, expr ):
+        super(Group,self).__init__( expr )
+        self.saveAsList = True
+
+    def postParse( self, instring, loc, tokenlist ):
+        return [ tokenlist ]
+
+class Dict(TokenConverter):
+    """
+    Converter to return a repetitive expression as a list, but also as a dictionary.
+    Each element can also be referenced using the first token in the expression as its key.
+    Useful for tabular report scraping when the first column can be used as a item key.
+
+    Example::
+        data_word = Word(alphas)
+        label = data_word + FollowedBy(':')
+        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word).setParseAction(' '.join))
+
+        text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
+        attr_expr = (label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
+        
+        # print attributes as plain groups
+        print(OneOrMore(attr_expr).parseString(text).dump())
+        
+        # instead of OneOrMore(expr), parse using Dict(OneOrMore(Group(expr))) - Dict will auto-assign names
+        result = Dict(OneOrMore(Group(attr_expr))).parseString(text)
+        print(result.dump())
+        
+        # access named fields as dict entries, or output as dict
+        print(result['shape'])        
+        print(result.asDict())
+    prints::
+        ['shape', 'SQUARE', 'posn', 'upper left', 'color', 'light blue', 'texture', 'burlap']
+
+        [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
+        - color: light blue
+        - posn: upper left
+        - shape: SQUARE
+        - texture: burlap
+        SQUARE
+        {'color': 'light blue', 'posn': 'upper left', 'texture': 'burlap', 'shape': 'SQUARE'}
+    See more examples at L{ParseResults} of accessing fields by results name.
+    """
+    def __init__( self, expr ):
+        super(Dict,self).__init__( expr )
+        self.saveAsList = True
+
+    def postParse( self, instring, loc, tokenlist ):
+        for i,tok in enumerate(tokenlist):
+            if len(tok) == 0:
+                continue
+            ikey = tok[0]
+            if isinstance(ikey,int):
+                ikey = _ustr(tok[0]).strip()
+            if len(tok)==1:
+                tokenlist[ikey] = _ParseResultsWithOffset("",i)
+            elif len(tok)==2 and not isinstance(tok[1],ParseResults):
+                tokenlist[ikey] = _ParseResultsWithOffset(tok[1],i)
+            else:
+                dictvalue = tok.copy() #ParseResults(i)
+                del dictvalue[0]
+                if len(dictvalue)!= 1 or (isinstance(dictvalue,ParseResults) and dictvalue.haskeys()):
+                    tokenlist[ikey] = _ParseResultsWithOffset(dictvalue,i)
+                else:
+                    tokenlist[ikey] = _ParseResultsWithOffset(dictvalue[0],i)
+
+        if self.resultsName:
+            return [ tokenlist ]
+        else:
+            return tokenlist
+
+
+class Suppress(TokenConverter):
+    """
+    Converter for ignoring the results of a parsed expression.
+
+    Example::
+        source = "a, b, c,d"
+        wd = Word(alphas)
+        wd_list1 = wd + ZeroOrMore(',' + wd)
+        print(wd_list1.parseString(source))
+
+        # often, delimiters that are useful during parsing are just in the
+        # way afterward - use Suppress to keep them out of the parsed output
+        wd_list2 = wd + ZeroOrMore(Suppress(',') + wd)
+        print(wd_list2.parseString(source))
+    prints::
+        ['a', ',', 'b', ',', 'c', ',', 'd']
+        ['a', 'b', 'c', 'd']
+    (See also L{delimitedList}.)
+    """
+    def postParse( self, instring, loc, tokenlist ):
+        return []
+
+    def suppress( self ):
+        return self
+
+
+class OnlyOnce(object):
+    """
+    Wrapper for parse actions, to ensure they are only called once.
+    """
+    def __init__(self, methodCall):
+        self.callable = _trim_arity(methodCall)
+        self.called = False
+    def __call__(self,s,l,t):
+        if not self.called:
+            results = self.callable(s,l,t)
+            self.called = True
+            return results
+        raise ParseException(s,l,"")
+    def reset(self):
+        self.called = False
+
+def traceParseAction(f):
+    """
+    Decorator for debugging parse actions. 
+    
+    When the parse action is called, this decorator will print C{">> entering I{method-name}(line:I{current_source_line}, I{parse_location}, I{matched_tokens})".}
+    When the parse action completes, the decorator will print C{"<<"} followed by the returned value, or any exception that the parse action raised.
+
+    Example::
+        wd = Word(alphas)
+
+        @traceParseAction
+        def remove_duplicate_chars(tokens):
+            return ''.join(sorted(set(''.join(tokens)))
+
+        wds = OneOrMore(wd).setParseAction(remove_duplicate_chars)
+        print(wds.parseString("slkdjs sld sldd sdlf sdljf"))
+    prints::
+        >>entering remove_duplicate_chars(line: 'slkdjs sld sldd sdlf sdljf', 0, (['slkdjs', 'sld', 'sldd', 'sdlf', 'sdljf'], {}))
+        <<leaving remove_duplicate_chars (ret: 'dfjkls')
+        ['dfjkls']
+    """
+    f = _trim_arity(f)
+    def z(*paArgs):
+        thisFunc = f.__name__
+        s,l,t = paArgs[-3:]
+        if len(paArgs)>3:
+            thisFunc = paArgs[0].__class__.__name__ + '.' + thisFunc
+        sys.stderr.write( ">>entering %s(line: '%s', %d, %r)\n" % (thisFunc,line(l,s),l,t) )
+        try:
+            ret = f(*paArgs)
+        except Exception as exc:
+            sys.stderr.write( "<<leaving %s (exception: %s)\n" % (thisFunc,exc) )
+            raise
+        sys.stderr.write( "<<leaving %s (ret: %r)\n" % (thisFunc,ret) )
+        return ret
+    try:
+        z.__name__ = f.__name__
+    except AttributeError:
+        pass
+    return z
+
+#
+# global helpers
+#
+def delimitedList( expr, delim=",", combine=False ):
+    """
+    Helper to define a delimited list of expressions - the delimiter defaults to ','.
+    By default, the list elements and delimiters can have intervening whitespace, and
+    comments, but this can be overridden by passing C{combine=True} in the constructor.
+    If C{combine} is set to C{True}, the matching tokens are returned as a single token
+    string, with the delimiters included; otherwise, the matching tokens are returned
+    as a list of tokens, with the delimiters suppressed.
+
+    Example::
+        delimitedList(Word(alphas)).parseString("aa,bb,cc") # -> ['aa', 'bb', 'cc']
+        delimitedList(Word(hexnums), delim=':', combine=True).parseString("AA:BB:CC:DD:EE") # -> ['AA:BB:CC:DD:EE']
+    """
+    dlName = _ustr(expr)+" ["+_ustr(delim)+" "+_ustr(expr)+"]..."
+    if combine:
+        return Combine( expr + ZeroOrMore( delim + expr ) ).setName(dlName)
+    else:
+        return ( expr + ZeroOrMore( Suppress( delim ) + expr ) ).setName(dlName)
+
+def countedArray( expr, intExpr=None ):
+    """
+    Helper to define a counted list of expressions.
+    This helper defines a pattern of the form::
+        integer expr expr expr...
+    where the leading integer tells how many expr expressions follow.
+    The matched tokens returns the array of expr tokens as a list - the leading count token is suppressed.
+    
+    If C{intExpr} is specified, it should be a pyparsing expression that produces an integer value.
+
+    Example::
+        countedArray(Word(alphas)).parseString('2 ab cd ef')  # -> ['ab', 'cd']
+
+        # in this parser, the leading integer value is given in binary,
+        # '10' indicating that 2 values are in the array
+        binaryConstant = Word('01').setParseAction(lambda t: int(t[0], 2))
+        countedArray(Word(alphas), intExpr=binaryConstant).parseString('10 ab cd ef')  # -> ['ab', 'cd']
+    """
+    arrayExpr = Forward()
+    def countFieldParseAction(s,l,t):
+        n = t[0]
+        arrayExpr << (n and Group(And([expr]*n)) or Group(empty))
+        return []
+    if intExpr is None:
+        intExpr = Word(nums).setParseAction(lambda t:int(t[0]))
+    else:
+        intExpr = intExpr.copy()
+    intExpr.setName("arrayLen")
+    intExpr.addParseAction(countFieldParseAction, callDuringTry=True)
+    return ( intExpr + arrayExpr ).setName('(len) ' + _ustr(expr) + '...')
+
+def _flatten(L):
+    ret = []
+    for i in L:
+        if isinstance(i,list):
+            ret.extend(_flatten(i))
+        else:
+            ret.append(i)
+    return ret
+
+def matchPreviousLiteral(expr):
+    """
+    Helper to define an expression that is indirectly defined from
+    the tokens matched in a previous expression, that is, it looks
+    for a 'repeat' of a previous expression.  For example::
+        first = Word(nums)
+        second = matchPreviousLiteral(first)
+        matchExpr = first + ":" + second
+    will match C{"1:1"}, but not C{"1:2"}.  Because this matches a
+    previous literal, will also match the leading C{"1:1"} in C{"1:10"}.
+    If this is not desired, use C{matchPreviousExpr}.
+    Do I{not} use with packrat parsing enabled.
+    """
+    rep = Forward()
+    def copyTokenToRepeater(s,l,t):
+        if t:
+            if len(t) == 1:
+                rep << t[0]
+            else:
+                # flatten t tokens
+                tflat = _flatten(t.asList())
+                rep << And(Literal(tt) for tt in tflat)
+        else:
+            rep << Empty()
+    expr.addParseAction(copyTokenToRepeater, callDuringTry=True)
+    rep.setName('(prev) ' + _ustr(expr))
+    return rep
+
+def matchPreviousExpr(expr):
+    """
+    Helper to define an expression that is indirectly defined from
+    the tokens matched in a previous expression, that is, it looks
+    for a 'repeat' of a previous expression.  For example::
+        first = Word(nums)
+        second = matchPreviousExpr(first)
+        matchExpr = first + ":" + second
+    will match C{"1:1"}, but not C{"1:2"}.  Because this matches by
+    expressions, will I{not} match the leading C{"1:1"} in C{"1:10"};
+    the expressions are evaluated first, and then compared, so
+    C{"1"} is compared with C{"10"}.
+    Do I{not} use with packrat parsing enabled.
+    """
+    rep = Forward()
+    e2 = expr.copy()
+    rep <<= e2
+    def copyTokenToRepeater(s,l,t):
+        matchTokens = _flatten(t.asList())
+        def mustMatchTheseTokens(s,l,t):
+            theseTokens = _flatten(t.asList())
+            if  theseTokens != matchTokens:
+                raise ParseException("",0,"")
+        rep.setParseAction( mustMatchTheseTokens, callDuringTry=True )
+    expr.addParseAction(copyTokenToRepeater, callDuringTry=True)
+    rep.setName('(prev) ' + _ustr(expr))
+    return rep
+
+def _escapeRegexRangeChars(s):
+    #~  escape these chars: ^-]
+    for c in r"\^-]":
+        s = s.replace(c,_bslash+c)
+    s = s.replace("\n",r"\n")
+    s = s.replace("\t",r"\t")
+    return _ustr(s)
+
+def oneOf( strs, caseless=False, useRegex=True ):
+    """
+    Helper to quickly define a set of alternative Literals, and makes sure to do
+    longest-first testing when there is a conflict, regardless of the input order,
+    but returns a C{L{MatchFirst}} for best performance.
+
+    Parameters:
+     - strs - a string of space-delimited literals, or a collection of string literals
+     - caseless - (default=C{False}) - treat all literals as caseless
+     - useRegex - (default=C{True}) - as an optimization, will generate a Regex
+          object; otherwise, will generate a C{MatchFirst} object (if C{caseless=True}, or
+          if creating a C{Regex} raises an exception)
+
+    Example::
+        comp_oper = oneOf("< = > <= >= !=")
+        var = Word(alphas)
+        number = Word(nums)
+        term = var | number
+        comparison_expr = term + comp_oper + term
+        print(comparison_expr.searchString("B = 12  AA=23 B<=AA AA>12"))
+    prints::
+        [['B', '=', '12'], ['AA', '=', '23'], ['B', '<=', 'AA'], ['AA', '>', '12']]
+    """
+    if caseless:
+        isequal = ( lambda a,b: a.upper() == b.upper() )
+        masks = ( lambda a,b: b.upper().startswith(a.upper()) )
+        parseElementClass = CaselessLiteral
+    else:
+        isequal = ( lambda a,b: a == b )
+        masks = ( lambda a,b: b.startswith(a) )
+        parseElementClass = Literal
+
+    symbols = []
+    if isinstance(strs,basestring):
+        symbols = strs.split()
+    elif isinstance(strs, collections.Iterable):
+        symbols = list(strs)
+    else:
+        warnings.warn("Invalid argument to oneOf, expected string or iterable",
+                SyntaxWarning, stacklevel=2)
+    if not symbols:
+        return NoMatch()
+
+    i = 0
+    while i < len(symbols)-1:
+        cur = symbols[i]
+        for j,other in enumerate(symbols[i+1:]):
+            if ( isequal(other, cur) ):
+                del symbols[i+j+1]
+                break
+            elif ( masks(cur, other) ):
+                del symbols[i+j+1]
+                symbols.insert(i,other)
+                cur = other
+                break
+        else:
+            i += 1
+
+    if not caseless and useRegex:
+        #~ print (strs,"->", "|".join( [ _escapeRegexChars(sym) for sym in symbols] ))
+        try:
+            if len(symbols)==len("".join(symbols)):
+                return Regex( "[%s]" % "".join(_escapeRegexRangeChars(sym) for sym in symbols) ).setName(' | '.join(symbols))
+            else:
+                return Regex( "|".join(re.escape(sym) for sym in symbols) ).setName(' | '.join(symbols))
+        except Exception:
+            warnings.warn("Exception creating Regex for oneOf, building MatchFirst",
+                    SyntaxWarning, stacklevel=2)
+
+
+    # last resort, just use MatchFirst
+    return MatchFirst(parseElementClass(sym) for sym in symbols).setName(' | '.join(symbols))
+
+def dictOf( key, value ):
+    """
+    Helper to easily and clearly define a dictionary by specifying the respective patterns
+    for the key and value.  Takes care of defining the C{L{Dict}}, C{L{ZeroOrMore}}, and C{L{Group}} tokens
+    in the proper order.  The key pattern can include delimiting markers or punctuation,
+    as long as they are suppressed, thereby leaving the significant key text.  The value
+    pattern can include named results, so that the C{Dict} results can include named token
+    fields.
+
+    Example::
+        text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
+        attr_expr = (label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
+        print(OneOrMore(attr_expr).parseString(text).dump())
+        
+        attr_label = label
+        attr_value = Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join)
+
+        # similar to Dict, but simpler call format
+        result = dictOf(attr_label, attr_value).parseString(text)
+        print(result.dump())
+        print(result['shape'])
+        print(result.shape)  # object attribute access works too
+        print(result.asDict())
+    prints::
+        [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
+        - color: light blue
+        - posn: upper left
+        - shape: SQUARE
+        - texture: burlap
+        SQUARE
+        SQUARE
+        {'color': 'light blue', 'shape': 'SQUARE', 'posn': 'upper left', 'texture': 'burlap'}
+    """
+    return Dict( ZeroOrMore( Group ( key + value ) ) )
+
+def originalTextFor(expr, asString=True):
+    """
+    Helper to return the original, untokenized text for a given expression.  Useful to
+    restore the parsed fields of an HTML start tag into the raw tag text itself, or to
+    revert separate tokens with intervening whitespace back to the original matching
+    input text. By default, returns astring containing the original parsed text.  
+       
+    If the optional C{asString} argument is passed as C{False}, then the return value is a 
+    C{L{ParseResults}} containing any results names that were originally matched, and a 
+    single token containing the original matched text from the input string.  So if 
+    the expression passed to C{L{originalTextFor}} contains expressions with defined
+    results names, you must set C{asString} to C{False} if you want to preserve those
+    results name values.
+
+    Example::
+        src = "this is test <b> bold <i>text</i> </b> normal text "
+        for tag in ("b","i"):
+            opener,closer = makeHTMLTags(tag)
+            patt = originalTextFor(opener + SkipTo(closer) + closer)
+            print(patt.searchString(src)[0])
+    prints::
+        ['<b> bold <i>text</i> </b>']
+        ['<i>text</i>']
+    """
+    locMarker = Empty().setParseAction(lambda s,loc,t: loc)
+    endlocMarker = locMarker.copy()
+    endlocMarker.callPreparse = False
+    matchExpr = locMarker("_original_start") + expr + endlocMarker("_original_end")
+    if asString:
+        extractText = lambda s,l,t: s[t._original_start:t._original_end]
+    else:
+        def extractText(s,l,t):
+            t[:] = [s[t.pop('_original_start'):t.pop('_original_end')]]
+    matchExpr.setParseAction(extractText)
+    matchExpr.ignoreExprs = expr.ignoreExprs
+    return matchExpr
+
+def ungroup(expr): 
+    """
+    Helper to undo pyparsing's default grouping of And expressions, even
+    if all but one are non-empty.
+    """
+    return TokenConverter(expr).setParseAction(lambda t:t[0])
+
+def locatedExpr(expr):
+    """
+    Helper to decorate a returned token with its starting and ending locations in the input string.
+    This helper adds the following results names:
+     - locn_start = location where matched expression begins
+     - locn_end = location where matched expression ends
+     - value = the actual parsed results
+
+    Be careful if the input text contains C{<TAB>} characters, you may want to call
+    C{L{ParserElement.parseWithTabs}}
+
+    Example::
+        wd = Word(alphas)
+        for match in locatedExpr(wd).searchString("ljsdf123lksdjjf123lkkjj1222"):
+            print(match)
+    prints::
+        [[0, 'ljsdf', 5]]
+        [[8, 'lksdjjf', 15]]
+        [[18, 'lkkjj', 23]]
+    """
+    locator = Empty().setParseAction(lambda s,l,t: l)
+    return Group(locator("locn_start") + expr("value") + locator.copy().leaveWhitespace()("locn_end"))
+
+
+# convenience constants for positional expressions
+empty       = Empty().setName("empty")
+lineStart   = LineStart().setName("lineStart")
+lineEnd     = LineEnd().setName("lineEnd")
+stringStart = StringStart().setName("stringStart")
+stringEnd   = StringEnd().setName("stringEnd")
+
+_escapedPunc = Word( _bslash, r"\[]-*.$+^?()~ ", exact=2 ).setParseAction(lambda s,l,t:t[0][1])
+_escapedHexChar = Regex(r"\\0?[xX][0-9a-fA-F]+").setParseAction(lambda s,l,t:unichr(int(t[0].lstrip(r'\0x'),16)))
+_escapedOctChar = Regex(r"\\0[0-7]+").setParseAction(lambda s,l,t:unichr(int(t[0][1:],8)))
+_singleChar = _escapedPunc | _escapedHexChar | _escapedOctChar | Word(printables, excludeChars=r'\]', exact=1) | Regex(r"\w", re.UNICODE)
+_charRange = Group(_singleChar + Suppress("-") + _singleChar)
+_reBracketExpr = Literal("[") + Optional("^").setResultsName("negate") + Group( OneOrMore( _charRange | _singleChar ) ).setResultsName("body") + "]"
+
+def srange(s):
+    r"""
+    Helper to easily define string ranges for use in Word construction.  Borrows
+    syntax from regexp '[]' string range definitions::
+        srange("[0-9]")   -> "0123456789"
+        srange("[a-z]")   -> "abcdefghijklmnopqrstuvwxyz"
+        srange("[a-z$_]") -> "abcdefghijklmnopqrstuvwxyz$_"
+    The input string must be enclosed in []'s, and the returned string is the expanded
+    character set joined into a single string.
+    The values enclosed in the []'s may be:
+     - a single character
+     - an escaped character with a leading backslash (such as C{\-} or C{\]})
+     - an escaped hex character with a leading C{'\x'} (C{\x21}, which is a C{'!'} character) 
+         (C{\0x##} is also supported for backwards compatibility) 
+     - an escaped octal character with a leading C{'\0'} (C{\041}, which is a C{'!'} character)
+     - a range of any of the above, separated by a dash (C{'a-z'}, etc.)
+     - any combination of the above (C{'aeiouy'}, C{'a-zA-Z0-9_$'}, etc.)
+    """
+    _expanded = lambda p: p if not isinstance(p,ParseResults) else ''.join(unichr(c) for c in range(ord(p[0]),ord(p[1])+1))
+    try:
+        return "".join(_expanded(part) for part in _reBracketExpr.parseString(s).body)
+    except Exception:
+        return ""
+
+def matchOnlyAtCol(n):
+    """
+    Helper method for defining parse actions that require matching at a specific
+    column in the input text.
+    """
+    def verifyCol(strg,locn,toks):
+        if col(locn,strg) != n:
+            raise ParseException(strg,locn,"matched token not at column %d" % n)
+    return verifyCol
+
+def replaceWith(replStr):
+    """
+    Helper method for common parse actions that simply return a literal value.  Especially
+    useful when used with C{L{transformString<ParserElement.transformString>}()}.
+
+    Example::
+        num = Word(nums).setParseAction(lambda toks: int(toks[0]))
+        na = oneOf("N/A NA").setParseAction(replaceWith(math.nan))
+        term = na | num
+        
+        OneOrMore(term).parseString("324 234 N/A 234") # -> [324, 234, nan, 234]
+    """
+    return lambda s,l,t: [replStr]
+
+def removeQuotes(s,l,t):
+    """
+    Helper parse action for removing quotation marks from parsed quoted strings.
+
+    Example::
+        # by default, quotation marks are included in parsed results
+        quotedString.parseString("'Now is the Winter of our Discontent'") # -> ["'Now is the Winter of our Discontent'"]
+
+        # use removeQuotes to strip quotation marks from parsed results
+        quotedString.setParseAction(removeQuotes)
+        quotedString.parseString("'Now is the Winter of our Discontent'") # -> ["Now is the Winter of our Discontent"]
+    """
+    return t[0][1:-1]
+
+def tokenMap(func, *args):
+    """
+    Helper to define a parse action by mapping a function to all elements of a ParseResults list.If any additional 
+    args are passed, they are forwarded to the given function as additional arguments after
+    the token, as in C{hex_integer = Word(hexnums).setParseAction(tokenMap(int, 16))}, which will convert the
+    parsed data to an integer using base 16.
+
+    Example (compare the last to example in L{ParserElement.transformString}::
+        hex_ints = OneOrMore(Word(hexnums)).setParseAction(tokenMap(int, 16))
+        hex_ints.runTests('''
+            00 11 22 aa FF 0a 0d 1a
+            ''')
+        
+        upperword = Word(alphas).setParseAction(tokenMap(str.upper))
+        OneOrMore(upperword).runTests('''
+            my kingdom for a horse
+            ''')
+
+        wd = Word(alphas).setParseAction(tokenMap(str.title))
+        OneOrMore(wd).setParseAction(' '.join).runTests('''
+            now is the winter of our discontent made glorious summer by this sun of york
+            ''')
+    prints::
+        00 11 22 aa FF 0a 0d 1a
+        [0, 17, 34, 170, 255, 10, 13, 26]
+
+        my kingdom for a horse
+        ['MY', 'KINGDOM', 'FOR', 'A', 'HORSE']
+
+        now is the winter of our discontent made glorious summer by this sun of york
+        ['Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York']
+    """
+    def pa(s,l,t):
+        return [func(tokn, *args) for tokn in t]
+
+    try:
+        func_name = getattr(func, '__name__', 
+                            getattr(func, '__class__').__name__)
+    except Exception:
+        func_name = str(func)
+    pa.__name__ = func_name
+
+    return pa
+
+upcaseTokens = tokenMap(lambda t: _ustr(t).upper())
+"""(Deprecated) Helper parse action to convert tokens to upper case. Deprecated in favor of L{pyparsing_common.upcaseTokens}"""
+
+downcaseTokens = tokenMap(lambda t: _ustr(t).lower())
+"""(Deprecated) Helper parse action to convert tokens to lower case. Deprecated in favor of L{pyparsing_common.downcaseTokens}"""
+    
+def _makeTags(tagStr, xml):
+    """Internal helper to construct opening and closing tag expressions, given a tag name"""
+    if isinstance(tagStr,basestring):
+        resname = tagStr
+        tagStr = Keyword(tagStr, caseless=not xml)
+    else:
+        resname = tagStr.name
+
+    tagAttrName = Word(alphas,alphanums+"_-:")
+    if (xml):
+        tagAttrValue = dblQuotedString.copy().setParseAction( removeQuotes )
+        openTag = Suppress("<") + tagStr("tag") + \
+                Dict(ZeroOrMore(Group( tagAttrName + Suppress("=") + tagAttrValue ))) + \
+                Optional("/",default=[False]).setResultsName("empty").setParseAction(lambda s,l,t:t[0]=='/') + Suppress(">")
+    else:
+        printablesLessRAbrack = "".join(c for c in printables if c not in ">")
+        tagAttrValue = quotedString.copy().setParseAction( removeQuotes ) | Word(printablesLessRAbrack)
+        openTag = Suppress("<") + tagStr("tag") + \
+                Dict(ZeroOrMore(Group( tagAttrName.setParseAction(downcaseTokens) + \
+                Optional( Suppress("=") + tagAttrValue ) ))) + \
+                Optional("/",default=[False]).setResultsName("empty").setParseAction(lambda s,l,t:t[0]=='/') + Suppress(">")
+    closeTag = Combine(_L("</") + tagStr + ">")
+
+    openTag = openTag.setResultsName("start"+"".join(resname.replace(":"," ").title().split())).setName("<%s>" % resname)
+    closeTag = closeTag.setResultsName("end"+"".join(resname.replace(":"," ").title().split())).setName("</%s>" % resname)
+    openTag.tag = resname
+    closeTag.tag = resname
+    return openTag, closeTag
+
+def makeHTMLTags(tagStr):
+    """
+    Helper to construct opening and closing tag expressions for HTML, given a tag name. Matches
+    tags in either upper or lower case, attributes with namespaces and with quoted or unquoted values.
+
+    Example::
+        text = '<td>More info at the <a href="http://pyparsing.wikispaces.com">pyparsing</a> wiki page</td>'
+        # makeHTMLTags returns pyparsing expressions for the opening and closing tags as a 2-tuple
+        a,a_end = makeHTMLTags("A")
+        link_expr = a + SkipTo(a_end)("link_text") + a_end
+        
+        for link in link_expr.searchString(text):
+            # attributes in the <A> tag (like "href" shown here) are also accessible as named results
+            print(link.link_text, '->', link.href)
+    prints::
+        pyparsing -> http://pyparsing.wikispaces.com
+    """
+    return _makeTags( tagStr, False )
+
+def makeXMLTags(tagStr):
+    """
+    Helper to construct opening and closing tag expressions for XML, given a tag name. Matches
+    tags only in the given upper/lower case.
+
+    Example: similar to L{makeHTMLTags}
+    """
+    return _makeTags( tagStr, True )
+
+def withAttribute(*args,**attrDict):
+    """
+    Helper to create a validating parse action to be used with start tags created
+    with C{L{makeXMLTags}} or C{L{makeHTMLTags}}. Use C{withAttribute} to qualify a starting tag
+    with a required attribute value, to avoid false matches on common tags such as
+    C{<TD>} or C{<DIV>}.
+
+    Call C{withAttribute} with a series of attribute names and values. Specify the list
+    of filter attributes names and values as:
+     - keyword arguments, as in C{(align="right")}, or
+     - as an explicit dict with C{**} operator, when an attribute name is also a Python
+          reserved word, as in C{**{"class":"Customer", "align":"right"}}
+     - a list of name-value tuples, as in ( ("ns1:class", "Customer"), ("ns2:align","right") )
+    For attribute names with a namespace prefix, you must use the second form.  Attribute
+    names are matched insensitive to upper/lower case.
+       
+    If just testing for C{class} (with or without a namespace), use C{L{withClass}}.
+
+    To verify that the attribute exists, but without specifying a value, pass
+    C{withAttribute.ANY_VALUE} as the value.
+
+    Example::
+        html = '''
+            <div>
+            Some text
+            <div type="grid">1 4 0 1 0</div>
+            <div type="graph">1,3 2,3 1,1</div>
+            <div>this has no type</div>
+            </div>
+                
+        '''
+        div,div_end = makeHTMLTags("div")
+
+        # only match div tag having a type attribute with value "grid"
+        div_grid = div().setParseAction(withAttribute(type="grid"))
+        grid_expr = div_grid + SkipTo(div | div_end)("body")
+        for grid_header in grid_expr.searchString(html):
+            print(grid_header.body)
+        
+        # construct a match with any div tag having a type attribute, regardless of the value
+        div_any_type = div().setParseAction(withAttribute(type=withAttribute.ANY_VALUE))
+        div_expr = div_any_type + SkipTo(div | div_end)("body")
+        for div_header in div_expr.searchString(html):
+            print(div_header.body)
+    prints::
+        1 4 0 1 0
+
+        1 4 0 1 0
+        1,3 2,3 1,1
+    """
+    if args:
+        attrs = args[:]
+    else:
+        attrs = attrDict.items()
+    attrs = [(k,v) for k,v in attrs]
+    def pa(s,l,tokens):
+        for attrName,attrValue in attrs:
+            if attrName not in tokens:
+                raise ParseException(s,l,"no matching attribute " + attrName)
+            if attrValue != withAttribute.ANY_VALUE and tokens[attrName] != attrValue:
+                raise ParseException(s,l,"attribute '%s' has value '%s', must be '%s'" %
+                                            (attrName, tokens[attrName], attrValue))
+    return pa
+withAttribute.ANY_VALUE = object()
+
+def withClass(classname, namespace=''):
+    """
+    Simplified version of C{L{withAttribute}} when matching on a div class - made
+    difficult because C{class} is a reserved word in Python.
+
+    Example::
+        html = '''
+            <div>
+            Some text
+            <div class="grid">1 4 0 1 0</div>
+            <div class="graph">1,3 2,3 1,1</div>
+            <div>this &lt;div&gt; has no class</div>
+            </div>
+                
+        '''
+        div,div_end = makeHTMLTags("div")
+        div_grid = div().setParseAction(withClass("grid"))
+        
+        grid_expr = div_grid + SkipTo(div | div_end)("body")
+        for grid_header in grid_expr.searchString(html):
+            print(grid_header.body)
+        
+        div_any_type = div().setParseAction(withClass(withAttribute.ANY_VALUE))
+        div_expr = div_any_type + SkipTo(div | div_end)("body")
+        for div_header in div_expr.searchString(html):
+            print(div_header.body)
+    prints::
+        1 4 0 1 0
+
+        1 4 0 1 0
+        1,3 2,3 1,1
+    """
+    classattr = "%s:class" % namespace if namespace else "class"
+    return withAttribute(**{classattr : classname})        
+
+opAssoc = _Constants()
+opAssoc.LEFT = object()
+opAssoc.RIGHT = object()
+
+def infixNotation( baseExpr, opList, lpar=Suppress('('), rpar=Suppress(')') ):
+    """
+    Helper method for constructing grammars of expressions made up of
+    operators working in a precedence hierarchy.  Operators may be unary or
+    binary, left- or right-associative.  Parse actions can also be attached
+    to operator expressions. The generated parser will also recognize the use 
+    of parentheses to override operator precedences (see example below).
+    
+    Note: if you define a deep operator list, you may see performance issues
+    when using infixNotation. See L{ParserElement.enablePackrat} for a
+    mechanism to potentially improve your parser performance.
+
+    Parameters:
+     - baseExpr - expression representing the most basic element for the nested
+     - opList - list of tuples, one for each operator precedence level in the
+      expression grammar; each tuple is of the form
+      (opExpr, numTerms, rightLeftAssoc, parseAction), where:
+       - opExpr is the pyparsing expression for the operator;
+          may also be a string, which will be converted to a Literal;
+          if numTerms is 3, opExpr is a tuple of two expressions, for the
+          two operators separating the 3 terms
+       - numTerms is the number of terms for this operator (must
+          be 1, 2, or 3)
+       - rightLeftAssoc is the indicator whether the operator is
+          right or left associative, using the pyparsing-defined
+          constants C{opAssoc.RIGHT} and C{opAssoc.LEFT}.
+       - parseAction is the parse action to be associated with
+          expressions matching this operator expression (the
+          parse action tuple member may be omitted)
+     - lpar - expression for matching left-parentheses (default=C{Suppress('(')})
+     - rpar - expression for matching right-parentheses (default=C{Suppress(')')})
+
+    Example::
+        # simple example of four-function arithmetic with ints and variable names
+        integer = pyparsing_common.signed_integer
+        varname = pyparsing_common.identifier 
+        
+        arith_expr = infixNotation(integer | varname,
+            [
+            ('-', 1, opAssoc.RIGHT),
+            (oneOf('* /'), 2, opAssoc.LEFT),
+            (oneOf('+ -'), 2, opAssoc.LEFT),
+            ])
+        
+        arith_expr.runTests('''
+            5+3*6
+            (5+3)*6
+            -2--11
+            ''', fullDump=False)
+    prints::
+        5+3*6
+        [[5, '+', [3, '*', 6]]]
+
+        (5+3)*6
+        [[[5, '+', 3], '*', 6]]
+
+        -2--11
+        [[['-', 2], '-', ['-', 11]]]
+    """
+    ret = Forward()
+    lastExpr = baseExpr | ( lpar + ret + rpar )
+    for i,operDef in enumerate(opList):
+        opExpr,arity,rightLeftAssoc,pa = (operDef + (None,))[:4]
+        termName = "%s term" % opExpr if arity < 3 else "%s%s term" % opExpr
+        if arity == 3:
+            if opExpr is None or len(opExpr) != 2:
+                raise ValueError("if numterms=3, opExpr must be a tuple or list of two expressions")
+            opExpr1, opExpr2 = opExpr
+        thisExpr = Forward().setName(termName)
+        if rightLeftAssoc == opAssoc.LEFT:
+            if arity == 1:
+                matchExpr = FollowedBy(lastExpr + opExpr) + Group( lastExpr + OneOrMore( opExpr ) )
+            elif arity == 2:
+                if opExpr is not None:
+                    matchExpr = FollowedBy(lastExpr + opExpr + lastExpr) + Group( lastExpr + OneOrMore( opExpr + lastExpr ) )
+                else:
+                    matchExpr = FollowedBy(lastExpr+lastExpr) + Group( lastExpr + OneOrMore(lastExpr) )
+            elif arity == 3:
+                matchExpr = FollowedBy(lastExpr + opExpr1 + lastExpr + opExpr2 + lastExpr) + \
+                            Group( lastExpr + opExpr1 + lastExpr + opExpr2 + lastExpr )
+            else:
+                raise ValueError("operator must be unary (1), binary (2), or ternary (3)")
+        elif rightLeftAssoc == opAssoc.RIGHT:
+            if arity == 1:
+                # try to avoid LR with this extra test
+                if not isinstance(opExpr, Optional):
+                    opExpr = Optional(opExpr)
+                matchExpr = FollowedBy(opExpr.expr + thisExpr) + Group( opExpr + thisExpr )
+            elif arity == 2:
+                if opExpr is not None:
+                    matchExpr = FollowedBy(lastExpr + opExpr + thisExpr) + Group( lastExpr + OneOrMore( opExpr + thisExpr ) )
+                else:
+                    matchExpr = FollowedBy(lastExpr + thisExpr) + Group( lastExpr + OneOrMore( thisExpr ) )
+            elif arity == 3:
+                matchExpr = FollowedBy(lastExpr + opExpr1 + thisExpr + opExpr2 + thisExpr) + \
+                            Group( lastExpr + opExpr1 + thisExpr + opExpr2 + thisExpr )
+            else:
+                raise ValueError("operator must be unary (1), binary (2), or ternary (3)")
+        else:
+            raise ValueError("operator must indicate right or left associativity")
+        if pa:
+            matchExpr.setParseAction( pa )
+        thisExpr <<= ( matchExpr.setName(termName) | lastExpr )
+        lastExpr = thisExpr
+    ret <<= lastExpr
+    return ret
+
+operatorPrecedence = infixNotation
+"""(Deprecated) Former name of C{L{infixNotation}}, will be dropped in a future release."""
+
+dblQuotedString = Combine(Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*')+'"').setName("string enclosed in double quotes")
+sglQuotedString = Combine(Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*")+"'").setName("string enclosed in single quotes")
+quotedString = Combine(Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*')+'"'|
+                       Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*")+"'").setName("quotedString using single or double quotes")
+unicodeString = Combine(_L('u') + quotedString.copy()).setName("unicode string literal")
+
+def nestedExpr(opener="(", closer=")", content=None, ignoreExpr=quotedString.copy()):
+    """
+    Helper method for defining nested lists enclosed in opening and closing
+    delimiters ("(" and ")" are the default).
+
+    Parameters:
+     - opener - opening character for a nested list (default=C{"("}); can also be a pyparsing expression
+     - closer - closing character for a nested list (default=C{")"}); can also be a pyparsing expression
+     - content - expression for items within the nested lists (default=C{None})
+     - ignoreExpr - expression for ignoring opening and closing delimiters (default=C{quotedString})
+
+    If an expression is not provided for the content argument, the nested
+    expression will capture all whitespace-delimited content between delimiters
+    as a list of separate values.
+
+    Use the C{ignoreExpr} argument to define expressions that may contain
+    opening or closing characters that should not be treated as opening
+    or closing characters for nesting, such as quotedString or a comment
+    expression.  Specify multiple expressions using an C{L{Or}} or C{L{MatchFirst}}.
+    The default is L{quotedString}, but if no expressions are to be ignored,
+    then pass C{None} for this argument.
+
+    Example::
+        data_type = oneOf("void int short long char float double")
+        decl_data_type = Combine(data_type + Optional(Word('*')))
+        ident = Word(alphas+'_', alphanums+'_')
+        number = pyparsing_common.number
+        arg = Group(decl_data_type + ident)
+        LPAR,RPAR = map(Suppress, "()")
+
+        code_body = nestedExpr('{', '}', ignoreExpr=(quotedString | cStyleComment))
+
+        c_function = (decl_data_type("type") 
+                      + ident("name")
+                      + LPAR + Optional(delimitedList(arg), [])("args") + RPAR 
+                      + code_body("body"))
+        c_function.ignore(cStyleComment)
+        
+        source_code = '''
+            int is_odd(int x) { 
+                return (x%2); 
+            }
+                
+            int dec_to_hex(char hchar) { 
+                if (hchar >= '0' && hchar <= '9') { 
+                    return (ord(hchar)-ord('0')); 
+                } else { 
+                    return (10+ord(hchar)-ord('A'));
+                } 
+            }
+        '''
+        for func in c_function.searchString(source_code):
+            print("%(name)s (%(type)s) args: %(args)s" % func)
+
+    prints::
+        is_odd (int) args: [['int', 'x']]
+        dec_to_hex (int) args: [['char', 'hchar']]
+    """
+    if opener == closer:
+        raise ValueError("opening and closing strings cannot be the same")
+    if content is None:
+        if isinstance(opener,basestring) and isinstance(closer,basestring):
+            if len(opener) == 1 and len(closer)==1:
+                if ignoreExpr is not None:
+                    content = (Combine(OneOrMore(~ignoreExpr +
+                                    CharsNotIn(opener+closer+ParserElement.DEFAULT_WHITE_CHARS,exact=1))
+                                ).setParseAction(lambda t:t[0].strip()))
+                else:
+                    content = (empty.copy()+CharsNotIn(opener+closer+ParserElement.DEFAULT_WHITE_CHARS
+                                ).setParseAction(lambda t:t[0].strip()))
+            else:
+                if ignoreExpr is not None:
+                    content = (Combine(OneOrMore(~ignoreExpr + 
+                                    ~Literal(opener) + ~Literal(closer) +
+                                    CharsNotIn(ParserElement.DEFAULT_WHITE_CHARS,exact=1))
+                                ).setParseAction(lambda t:t[0].strip()))
+                else:
+                    content = (Combine(OneOrMore(~Literal(opener) + ~Literal(closer) +
+                                    CharsNotIn(ParserElement.DEFAULT_WHITE_CHARS,exact=1))
+                                ).setParseAction(lambda t:t[0].strip()))
+        else:
+            raise ValueError("opening and closing arguments must be strings if no content expression is given")
+    ret = Forward()
+    if ignoreExpr is not None:
+        ret <<= Group( Suppress(opener) + ZeroOrMore( ignoreExpr | ret | content ) + Suppress(closer) )
+    else:
+        ret <<= Group( Suppress(opener) + ZeroOrMore( ret | content )  + Suppress(closer) )
+    ret.setName('nested %s%s expression' % (opener,closer))
+    return ret
+
+def indentedBlock(blockStatementExpr, indentStack, indent=True):
+    """
+    Helper method for defining space-delimited indentation blocks, such as
+    those used to define block statements in Python source code.
+
+    Parameters:
+     - blockStatementExpr - expression defining syntax of statement that
+            is repeated within the indented block
+     - indentStack - list created by caller to manage indentation stack
+            (multiple statementWithIndentedBlock expressions within a single grammar
+            should share a common indentStack)
+     - indent - boolean indicating whether block must be indented beyond the
+            the current level; set to False for block of left-most statements
+            (default=C{True})
+
+    A valid block must contain at least one C{blockStatement}.
+
+    Example::
+        data = '''
+        def A(z):
+          A1
+          B = 100
+          G = A2
+          A2
+          A3
+        B
+        def BB(a,b,c):
+          BB1
+          def BBA():
+            bba1
+            bba2
+            bba3
+        C
+        D
+        def spam(x,y):
+             def eggs(z):
+                 pass
+        '''
+
+
+        indentStack = [1]
+        stmt = Forward()
+
+        identifier = Word(alphas, alphanums)
+        funcDecl = ("def" + identifier + Group( "(" + Optional( delimitedList(identifier) ) + ")" ) + ":")
+        func_body = indentedBlock(stmt, indentStack)
+        funcDef = Group( funcDecl + func_body )
+
+        rvalue = Forward()
+        funcCall = Group(identifier + "(" + Optional(delimitedList(rvalue)) + ")")
+        rvalue << (funcCall | identifier | Word(nums))
+        assignment = Group(identifier + "=" + rvalue)
+        stmt << ( funcDef | assignment | identifier )
+
+        module_body = OneOrMore(stmt)
+
+        parseTree = module_body.parseString(data)
+        parseTree.pprint()
+    prints::
+        [['def',
+          'A',
+          ['(', 'z', ')'],
+          ':',
+          [['A1'], [['B', '=', '100']], [['G', '=', 'A2']], ['A2'], ['A3']]],
+         'B',
+         ['def',
+          'BB',
+          ['(', 'a', 'b', 'c', ')'],
+          ':',
+          [['BB1'], [['def', 'BBA', ['(', ')'], ':', [['bba1'], ['bba2'], ['bba3']]]]]],
+         'C',
+         'D',
+         ['def',
+          'spam',
+          ['(', 'x', 'y', ')'],
+          ':',
+          [[['def', 'eggs', ['(', 'z', ')'], ':', [['pass']]]]]]] 
+    """
+    def checkPeerIndent(s,l,t):
+        if l >= len(s): return
+        curCol = col(l,s)
+        if curCol != indentStack[-1]:
+            if curCol > indentStack[-1]:
+                raise ParseFatalException(s,l,"illegal nesting")
+            raise ParseException(s,l,"not a peer entry")
+
+    def checkSubIndent(s,l,t):
+        curCol = col(l,s)
+        if curCol > indentStack[-1]:
+            indentStack.append( curCol )
+        else:
+            raise ParseException(s,l,"not a subentry")
+
+    def checkUnindent(s,l,t):
+        if l >= len(s): return
+        curCol = col(l,s)
+        if not(indentStack and curCol < indentStack[-1] and curCol <= indentStack[-2]):
+            raise ParseException(s,l,"not an unindent")
+        indentStack.pop()
+
+    NL = OneOrMore(LineEnd().setWhitespaceChars("\t ").suppress())
+    INDENT = (Empty() + Empty().setParseAction(checkSubIndent)).setName('INDENT')
+    PEER   = Empty().setParseAction(checkPeerIndent).setName('')
+    UNDENT = Empty().setParseAction(checkUnindent).setName('UNINDENT')
+    if indent:
+        smExpr = Group( Optional(NL) +
+            #~ FollowedBy(blockStatementExpr) +
+            INDENT + (OneOrMore( PEER + Group(blockStatementExpr) + Optional(NL) )) + UNDENT)
+    else:
+        smExpr = Group( Optional(NL) +
+            (OneOrMore( PEER + Group(blockStatementExpr) + Optional(NL) )) )
+    blockStatementExpr.ignore(_bslash + LineEnd())
+    return smExpr.setName('indented block')
+
+alphas8bit = srange(r"[\0xc0-\0xd6\0xd8-\0xf6\0xf8-\0xff]")
+punc8bit = srange(r"[\0xa1-\0xbf\0xd7\0xf7]")
+
+anyOpenTag,anyCloseTag = makeHTMLTags(Word(alphas,alphanums+"_:").setName('any tag'))
+_htmlEntityMap = dict(zip("gt lt amp nbsp quot apos".split(),'><& "\''))
+commonHTMLEntity = Regex('&(?P<entity>' + '|'.join(_htmlEntityMap.keys()) +");").setName("common HTML entity")
+def replaceHTMLEntity(t):
+    """Helper parser action to replace common HTML entities with their special characters"""
+    return _htmlEntityMap.get(t.entity)
+
+# it's easy to get these comment structures wrong - they're very common, so may as well make them available
+cStyleComment = Combine(Regex(r"/\*(?:[^*]|\*(?!/))*") + '*/').setName("C style comment")
+"Comment of the form C{/* ... */}"
+
+htmlComment = Regex(r"<!--[\s\S]*?-->").setName("HTML comment")
+"Comment of the form C{<!-- ... -->}"
+
+restOfLine = Regex(r".*").leaveWhitespace().setName("rest of line")
+dblSlashComment = Regex(r"//(?:\\\n|[^\n])*").setName("// comment")
+"Comment of the form C{// ... (to end of line)}"
+
+cppStyleComment = Combine(Regex(r"/\*(?:[^*]|\*(?!/))*") + '*/'| dblSlashComment).setName("C++ style comment")
+"Comment of either form C{L{cStyleComment}} or C{L{dblSlashComment}}"
+
+javaStyleComment = cppStyleComment
+"Same as C{L{cppStyleComment}}"
+
+pythonStyleComment = Regex(r"#.*").setName("Python style comment")
+"Comment of the form C{# ... (to end of line)}"
+
+_commasepitem = Combine(OneOrMore(Word(printables, excludeChars=',') +
+                                  Optional( Word(" \t") +
+                                            ~Literal(",") + ~LineEnd() ) ) ).streamline().setName("commaItem")
+commaSeparatedList = delimitedList( Optional( quotedString.copy() | _commasepitem, default="") ).setName("commaSeparatedList")
+"""(Deprecated) Predefined expression of 1 or more printable words or quoted strings, separated by commas.
+   This expression is deprecated in favor of L{pyparsing_common.comma_separated_list}."""
+
+# some other useful expressions - using lower-case class name since we are really using this as a namespace
+class pyparsing_common:
+    """
+    Here are some common low-level expressions that may be useful in jump-starting parser development:
+     - numeric forms (L{integers<integer>}, L{reals<real>}, L{scientific notation<sci_real>})
+     - common L{programming identifiers<identifier>}
+     - network addresses (L{MAC<mac_address>}, L{IPv4<ipv4_address>}, L{IPv6<ipv6_address>})
+     - ISO8601 L{dates<iso8601_date>} and L{datetime<iso8601_datetime>}
+     - L{UUID<uuid>}
+     - L{comma-separated list<comma_separated_list>}
+    Parse actions:
+     - C{L{convertToInteger}}
+     - C{L{convertToFloat}}
+     - C{L{convertToDate}}
+     - C{L{convertToDatetime}}
+     - C{L{stripHTMLTags}}
+     - C{L{upcaseTokens}}
+     - C{L{downcaseTokens}}
+
+    Example::
+        pyparsing_common.number.runTests('''
+            # any int or real number, returned as the appropriate type
+            100
+            -100
+            +100
+            3.14159
+            6.02e23
+            1e-12
+            ''')
+
+        pyparsing_common.fnumber.runTests('''
+            # any int or real number, returned as float
+            100
+            -100
+            +100
+            3.14159
+            6.02e23
+            1e-12
+            ''')
+
+        pyparsing_common.hex_integer.runTests('''
+            # hex numbers
+            100
+            FF
+            ''')
+
+        pyparsing_common.fraction.runTests('''
+            # fractions
+            1/2
+            -3/4
+            ''')
+
+        pyparsing_common.mixed_integer.runTests('''
+            # mixed fractions
+            1
+            1/2
+            -3/4
+            1-3/4
+            ''')
+
+        import uuid
+        pyparsing_common.uuid.setParseAction(tokenMap(uuid.UUID))
+        pyparsing_common.uuid.runTests('''
+            # uuid
+            12345678-1234-5678-1234-567812345678
+            ''')
+    prints::
+        # any int or real number, returned as the appropriate type
+        100
+        [100]
+
+        -100
+        [-100]
+
+        +100
+        [100]
+
+        3.14159
+        [3.14159]
+
+        6.02e23
+        [6.02e+23]
+
+        1e-12
+        [1e-12]
+
+        # any int or real number, returned as float
+        100
+        [100.0]
+
+        -100
+        [-100.0]
+
+        +100
+        [100.0]
+
+        3.14159
+        [3.14159]
+
+        6.02e23
+        [6.02e+23]
+
+        1e-12
+        [1e-12]
+
+        # hex numbers
+        100
+        [256]
+
+        FF
+        [255]
+
+        # fractions
+        1/2
+        [0.5]
+
+        -3/4
+        [-0.75]
+
+        # mixed fractions
+        1
+        [1]
+
+        1/2
+        [0.5]
+
+        -3/4
+        [-0.75]
+
+        1-3/4
+        [1.75]
+
+        # uuid
+        12345678-1234-5678-1234-567812345678
+        [UUID('12345678-1234-5678-1234-567812345678')]
+    """
+
+    convertToInteger = tokenMap(int)
+    """
+    Parse action for converting parsed integers to Python int
+    """
+
+    convertToFloat = tokenMap(float)
+    """
+    Parse action for converting parsed numbers to Python float
+    """
+
+    integer = Word(nums).setName("integer").setParseAction(convertToInteger)
+    """expression that parses an unsigned integer, returns an int"""
+
+    hex_integer = Word(hexnums).setName("hex integer").setParseAction(tokenMap(int,16))
+    """expression that parses a hexadecimal integer, returns an int"""
+
+    signed_integer = Regex(r'[+-]?\d+').setName("signed integer").setParseAction(convertToInteger)
+    """expression that parses an integer with optional leading sign, returns an int"""
+
+    fraction = (signed_integer().setParseAction(convertToFloat) + '/' + signed_integer().setParseAction(convertToFloat)).setName("fraction")
+    """fractional expression of an integer divided by an integer, returns a float"""
+    fraction.addParseAction(lambda t: t[0]/t[-1])
+
+    mixed_integer = (fraction | signed_integer + Optional(Optional('-').suppress() + fraction)).setName("fraction or mixed integer-fraction")
+    """mixed integer of the form 'integer - fraction', with optional leading integer, returns float"""
+    mixed_integer.addParseAction(sum)
+
+    real = Regex(r'[+-]?\d+\.\d*').setName("real number").setParseAction(convertToFloat)
+    """expression that parses a floating point number and returns a float"""
+
+    sci_real = Regex(r'[+-]?\d+([eE][+-]?\d+|\.\d*([eE][+-]?\d+)?)').setName("real number with scientific notation").setParseAction(convertToFloat)
+    """expression that parses a floating point number with optional scientific notation and returns a float"""
+
+    # streamlining this expression makes the docs nicer-looking
+    number = (sci_real | real | signed_integer).streamline()
+    """any numeric expression, returns the corresponding Python type"""
+
+    fnumber = Regex(r'[+-]?\d+\.?\d*([eE][+-]?\d+)?').setName("fnumber").setParseAction(convertToFloat)
+    """any int or real number, returned as float"""
+    
+    identifier = Word(alphas+'_', alphanums+'_').setName("identifier")
+    """typical code identifier (leading alpha or '_', followed by 0 or more alphas, nums, or '_')"""
+    
+    ipv4_address = Regex(r'(25[0-5]|2[0-4][0-9]|1?[0-9]{1,2})(\.(25[0-5]|2[0-4][0-9]|1?[0-9]{1,2})){3}').setName("IPv4 address")
+    "IPv4 address (C{0.0.0.0 - 255.255.255.255})"
+
+    _ipv6_part = Regex(r'[0-9a-fA-F]{1,4}').setName("hex_integer")
+    _full_ipv6_address = (_ipv6_part + (':' + _ipv6_part)*7).setName("full IPv6 address")
+    _short_ipv6_address = (Optional(_ipv6_part + (':' + _ipv6_part)*(0,6)) + "::" + Optional(_ipv6_part + (':' + _ipv6_part)*(0,6))).setName("short IPv6 address")
+    _short_ipv6_address.addCondition(lambda t: sum(1 for tt in t if pyparsing_common._ipv6_part.matches(tt)) < 8)
+    _mixed_ipv6_address = ("::ffff:" + ipv4_address).setName("mixed IPv6 address")
+    ipv6_address = Combine((_full_ipv6_address | _mixed_ipv6_address | _short_ipv6_address).setName("IPv6 address")).setName("IPv6 address")
+    "IPv6 address (long, short, or mixed form)"
+    
+    mac_address = Regex(r'[0-9a-fA-F]{2}([:.-])[0-9a-fA-F]{2}(?:\1[0-9a-fA-F]{2}){4}').setName("MAC address")
+    "MAC address xx:xx:xx:xx:xx (may also have '-' or '.' delimiters)"
+
+    @staticmethod
+    def convertToDate(fmt="%Y-%m-%d"):
+        """
+        Helper to create a parse action for converting parsed date string to Python datetime.date
+
+        Params -
+         - fmt - format to be passed to datetime.strptime (default=C{"%Y-%m-%d"})
+
+        Example::
+            date_expr = pyparsing_common.iso8601_date.copy()
+            date_expr.setParseAction(pyparsing_common.convertToDate())
+            print(date_expr.parseString("1999-12-31"))
+        prints::
+            [datetime.date(1999, 12, 31)]
+        """
+        def cvt_fn(s,l,t):
+            try:
+                return datetime.strptime(t[0], fmt).date()
+            except ValueError as ve:
+                raise ParseException(s, l, str(ve))
+        return cvt_fn
+
+    @staticmethod
+    def convertToDatetime(fmt="%Y-%m-%dT%H:%M:%S.%f"):
+        """
+        Helper to create a parse action for converting parsed datetime string to Python datetime.datetime
+
+        Params -
+         - fmt - format to be passed to datetime.strptime (default=C{"%Y-%m-%dT%H:%M:%S.%f"})
+
+        Example::
+            dt_expr = pyparsing_common.iso8601_datetime.copy()
+            dt_expr.setParseAction(pyparsing_common.convertToDatetime())
+            print(dt_expr.parseString("1999-12-31T23:59:59.999"))
+        prints::
+            [datetime.datetime(1999, 12, 31, 23, 59, 59, 999000)]
+        """
+        def cvt_fn(s,l,t):
+            try:
+                return datetime.strptime(t[0], fmt)
+            except ValueError as ve:
+                raise ParseException(s, l, str(ve))
+        return cvt_fn
+
+    iso8601_date = Regex(r'(?P<year>\d{4})(?:-(?P<month>\d\d)(?:-(?P<day>\d\d))?)?').setName("ISO8601 date")
+    "ISO8601 date (C{yyyy-mm-dd})"
+
+    iso8601_datetime = Regex(r'(?P<year>\d{4})-(?P<month>\d\d)-(?P<day>\d\d)[T ](?P<hour>\d\d):(?P<minute>\d\d)(:(?P<second>\d\d(\.\d*)?)?)?(?P<tz>Z|[+-]\d\d:?\d\d)?').setName("ISO8601 datetime")
+    "ISO8601 datetime (C{yyyy-mm-ddThh:mm:ss.s(Z|+-00:00)}) - trailing seconds, milliseconds, and timezone optional; accepts separating C{'T'} or C{' '}"
+
+    uuid = Regex(r'[0-9a-fA-F]{8}(-[0-9a-fA-F]{4}){3}-[0-9a-fA-F]{12}').setName("UUID")
+    "UUID (C{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx})"
+
+    _html_stripper = anyOpenTag.suppress() | anyCloseTag.suppress()
+    @staticmethod
+    def stripHTMLTags(s, l, tokens):
+        """
+        Parse action to remove HTML tags from web page HTML source
+
+        Example::
+            # strip HTML links from normal text 
+            text = '<td>More info at the <a href="http://pyparsing.wikispaces.com">pyparsing</a> wiki page</td>'
+            td,td_end = makeHTMLTags("TD")
+            table_text = td + SkipTo(td_end).setParseAction(pyparsing_common.stripHTMLTags)("body") + td_end
+            
+            print(table_text.parseString(text).body) # -> 'More info at the pyparsing wiki page'
+        """
+        return pyparsing_common._html_stripper.transformString(tokens[0])
+
+    _commasepitem = Combine(OneOrMore(~Literal(",") + ~LineEnd() + Word(printables, excludeChars=',') 
+                                        + Optional( White(" \t") ) ) ).streamline().setName("commaItem")
+    comma_separated_list = delimitedList( Optional( quotedString.copy() | _commasepitem, default="") ).setName("comma separated list")
+    """Predefined expression of 1 or more printable words or quoted strings, separated by commas."""
+
+    upcaseTokens = staticmethod(tokenMap(lambda t: _ustr(t).upper()))
+    """Parse action to convert tokens to upper case."""
+
+    downcaseTokens = staticmethod(tokenMap(lambda t: _ustr(t).lower()))
+    """Parse action to convert tokens to lower case."""
+
+
+if __name__ == "__main__":
+
+    selectToken    = CaselessLiteral("select")
+    fromToken      = CaselessLiteral("from")
+
+    ident          = Word(alphas, alphanums + "_$")
+
+    columnName     = delimitedList(ident, ".", combine=True).setParseAction(upcaseTokens)
+    columnNameList = Group(delimitedList(columnName)).setName("columns")
+    columnSpec     = ('*' | columnNameList)
+
+    tableName      = delimitedList(ident, ".", combine=True).setParseAction(upcaseTokens)
+    tableNameList  = Group(delimitedList(tableName)).setName("tables")
+    
+    simpleSQL      = selectToken("command") + columnSpec("columns") + fromToken + tableNameList("tables")
+
+    # demo runTests method, including embedded comments in test string
+    simpleSQL.runTests("""
+        # '*' as column list and dotted table name
+        select * from SYS.XYZZY
+
+        # caseless match on "SELECT", and casts back to "select"
+        SELECT * from XYZZY, ABC
+
+        # list of column names, and mixed case SELECT keyword
+        Select AA,BB,CC from Sys.dual
+
+        # multiple tables
+        Select A, B, C from Sys.dual, Table2
+
+        # invalid SELECT keyword - should fail
+        Xelect A, B, C from Sys.dual
+
+        # incomplete command - should fail
+        Select
+
+        # invalid column name - should fail
+        Select ^^^ frox Sys.dual
+
+        """)
+
+    pyparsing_common.number.runTests("""
+        100
+        -100
+        +100
+        3.14159
+        6.02e23
+        1e-12
+        """)
+
+    # any int or real number, returned as float
+    pyparsing_common.fnumber.runTests("""
+        100
+        -100
+        +100
+        3.14159
+        6.02e23
+        1e-12
+        """)
+
+    pyparsing_common.hex_integer.runTests("""
+        100
+        FF
+        """)
+
+    import uuid
+    pyparsing_common.uuid.setParseAction(tokenMap(uuid.UUID))
+    pyparsing_common.uuid.runTests("""
+        12345678-1234-5678-1234-567812345678
+        """)
diff --git a/recipes/pkgresources/pkgr/_vendor/six.py b/recipes/pkgresources/pkgr/_vendor/six.py
new file mode 100644
index 0000000..190c023
--- /dev/null
+++ b/recipes/pkgresources/pkgr/_vendor/six.py
@@ -0,0 +1,868 @@
+"""Utilities for writing code that runs on Python 2 and 3"""
+
+# Copyright (c) 2010-2015 Benjamin Peterson
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+from __future__ import absolute_import
+
+import functools
+import itertools
+import operator
+import sys
+import types
+
+__author__ = "Benjamin Peterson <benjamin@python.org>"
+__version__ = "1.10.0"
+
+
+# Useful for very coarse version differentiation.
+PY2 = sys.version_info[0] == 2
+PY3 = sys.version_info[0] == 3
+PY34 = sys.version_info[0:2] >= (3, 4)
+
+if PY3:
+    string_types = str,
+    integer_types = int,
+    class_types = type,
+    text_type = str
+    binary_type = bytes
+
+    MAXSIZE = sys.maxsize
+else:
+    string_types = basestring,
+    integer_types = (int, long)
+    class_types = (type, types.ClassType)
+    text_type = unicode
+    binary_type = str
+
+    if sys.platform.startswith("java"):
+        # Jython always uses 32 bits.
+        MAXSIZE = int((1 << 31) - 1)
+    else:
+        # It's possible to have sizeof(long) != sizeof(Py_ssize_t).
+        class X(object):
+
+            def __len__(self):
+                return 1 << 31
+        try:
+            len(X())
+        except OverflowError:
+            # 32-bit
+            MAXSIZE = int((1 << 31) - 1)
+        else:
+            # 64-bit
+            MAXSIZE = int((1 << 63) - 1)
+        del X
+
+
+def _add_doc(func, doc):
+    """Add documentation to a function."""
+    func.__doc__ = doc
+
+
+def _import_module(name):
+    """Import module, returning the module after the last dot."""
+    __import__(name)
+    return sys.modules[name]
+
+
+class _LazyDescr(object):
+
+    def __init__(self, name):
+        self.name = name
+
+    def __get__(self, obj, tp):
+        result = self._resolve()
+        setattr(obj, self.name, result)  # Invokes __set__.
+        try:
+            # This is a bit ugly, but it avoids running this again by
+            # removing this descriptor.
+            delattr(obj.__class__, self.name)
+        except AttributeError:
+            pass
+        return result
+
+
+class MovedModule(_LazyDescr):
+
+    def __init__(self, name, old, new=None):
+        super(MovedModule, self).__init__(name)
+        if PY3:
+            if new is None:
+                new = name
+            self.mod = new
+        else:
+            self.mod = old
+
+    def _resolve(self):
+        return _import_module(self.mod)
+
+    def __getattr__(self, attr):
+        _module = self._resolve()
+        value = getattr(_module, attr)
+        setattr(self, attr, value)
+        return value
+
+
+class _LazyModule(types.ModuleType):
+
+    def __init__(self, name):
+        super(_LazyModule, self).__init__(name)
+        self.__doc__ = self.__class__.__doc__
+
+    def __dir__(self):
+        attrs = ["__doc__", "__name__"]
+        attrs += [attr.name for attr in self._moved_attributes]
+        return attrs
+
+    # Subclasses should override this
+    _moved_attributes = []
+
+
+class MovedAttribute(_LazyDescr):
+
+    def __init__(self, name, old_mod, new_mod, old_attr=None, new_attr=None):
+        super(MovedAttribute, self).__init__(name)
+        if PY3:
+            if new_mod is None:
+                new_mod = name
+            self.mod = new_mod
+            if new_attr is None:
+                if old_attr is None:
+                    new_attr = name
+                else:
+                    new_attr = old_attr
+            self.attr = new_attr
+        else:
+            self.mod = old_mod
+            if old_attr is None:
+                old_attr = name
+            self.attr = old_attr
+
+    def _resolve(self):
+        module = _import_module(self.mod)
+        return getattr(module, self.attr)
+
+
+class _SixMetaPathImporter(object):
+
+    """
+    A meta path importer to import six.moves and its submodules.
+
+    This class implements a PEP302 finder and loader. It should be compatible
+    with Python 2.5 and all existing versions of Python3
+    """
+
+    def __init__(self, six_module_name):
+        self.name = six_module_name
+        self.known_modules = {}
+
+    def _add_module(self, mod, *fullnames):
+        for fullname in fullnames:
+            self.known_modules[self.name + "." + fullname] = mod
+
+    def _get_module(self, fullname):
+        return self.known_modules[self.name + "." + fullname]
+
+    def find_module(self, fullname, path=None):
+        if fullname in self.known_modules:
+            return self
+        return None
+
+    def __get_module(self, fullname):
+        try:
+            return self.known_modules[fullname]
+        except KeyError:
+            raise ImportError("This loader does not know module " + fullname)
+
+    def load_module(self, fullname):
+        try:
+            # in case of a reload
+            return sys.modules[fullname]
+        except KeyError:
+            pass
+        mod = self.__get_module(fullname)
+        if isinstance(mod, MovedModule):
+            mod = mod._resolve()
+        else:
+            mod.__loader__ = self
+        sys.modules[fullname] = mod
+        return mod
+
+    def is_package(self, fullname):
+        """
+        Return true, if the named module is a package.
+
+        We need this method to get correct spec objects with
+        Python 3.4 (see PEP451)
+        """
+        return hasattr(self.__get_module(fullname), "__path__")
+
+    def get_code(self, fullname):
+        """Return None
+
+        Required, if is_package is implemented"""
+        self.__get_module(fullname)  # eventually raises ImportError
+        return None
+    get_source = get_code  # same as get_code
+
+_importer = _SixMetaPathImporter(__name__)
+
+
+class _MovedItems(_LazyModule):
+
+    """Lazy loading of moved objects"""
+    __path__ = []  # mark as package
+
+
+_moved_attributes = [
+    MovedAttribute("cStringIO", "cStringIO", "io", "StringIO"),
+    MovedAttribute("filter", "itertools", "builtins", "ifilter", "filter"),
+    MovedAttribute("filterfalse", "itertools", "itertools", "ifilterfalse", "filterfalse"),
+    MovedAttribute("input", "__builtin__", "builtins", "raw_input", "input"),
+    MovedAttribute("intern", "__builtin__", "sys"),
+    MovedAttribute("map", "itertools", "builtins", "imap", "map"),
+    MovedAttribute("getcwd", "os", "os", "getcwdu", "getcwd"),
+    MovedAttribute("getcwdb", "os", "os", "getcwd", "getcwdb"),
+    MovedAttribute("range", "__builtin__", "builtins", "xrange", "range"),
+    MovedAttribute("reload_module", "__builtin__", "importlib" if PY34 else "imp", "reload"),
+    MovedAttribute("reduce", "__builtin__", "functools"),
+    MovedAttribute("shlex_quote", "pipes", "shlex", "quote"),
+    MovedAttribute("StringIO", "StringIO", "io"),
+    MovedAttribute("UserDict", "UserDict", "collections"),
+    MovedAttribute("UserList", "UserList", "collections"),
+    MovedAttribute("UserString", "UserString", "collections"),
+    MovedAttribute("xrange", "__builtin__", "builtins", "xrange", "range"),
+    MovedAttribute("zip", "itertools", "builtins", "izip", "zip"),
+    MovedAttribute("zip_longest", "itertools", "itertools", "izip_longest", "zip_longest"),
+    MovedModule("builtins", "__builtin__"),
+    MovedModule("configparser", "ConfigParser"),
+    MovedModule("copyreg", "copy_reg"),
+    MovedModule("dbm_gnu", "gdbm", "dbm.gnu"),
+    MovedModule("_dummy_thread", "dummy_thread", "_dummy_thread"),
+    MovedModule("http_cookiejar", "cookielib", "http.cookiejar"),
+    MovedModule("http_cookies", "Cookie", "http.cookies"),
+    MovedModule("html_entities", "htmlentitydefs", "html.entities"),
+    MovedModule("html_parser", "HTMLParser", "html.parser"),
+    MovedModule("http_client", "httplib", "http.client"),
+    MovedModule("email_mime_multipart", "email.MIMEMultipart", "email.mime.multipart"),
+    MovedModule("email_mime_nonmultipart", "email.MIMENonMultipart", "email.mime.nonmultipart"),
+    MovedModule("email_mime_text", "email.MIMEText", "email.mime.text"),
+    MovedModule("email_mime_base", "email.MIMEBase", "email.mime.base"),
+    MovedModule("BaseHTTPServer", "BaseHTTPServer", "http.server"),
+    MovedModule("CGIHTTPServer", "CGIHTTPServer", "http.server"),
+    MovedModule("SimpleHTTPServer", "SimpleHTTPServer", "http.server"),
+    MovedModule("cPickle", "cPickle", "pickle"),
+    MovedModule("queue", "Queue"),
+    MovedModule("reprlib", "repr"),
+    MovedModule("socketserver", "SocketServer"),
+    MovedModule("_thread", "thread", "_thread"),
+    MovedModule("tkinter", "Tkinter"),
+    MovedModule("tkinter_dialog", "Dialog", "tkinter.dialog"),
+    MovedModule("tkinter_filedialog", "FileDialog", "tkinter.filedialog"),
+    MovedModule("tkinter_scrolledtext", "ScrolledText", "tkinter.scrolledtext"),
+    MovedModule("tkinter_simpledialog", "SimpleDialog", "tkinter.simpledialog"),
+    MovedModule("tkinter_tix", "Tix", "tkinter.tix"),
+    MovedModule("tkinter_ttk", "ttk", "tkinter.ttk"),
+    MovedModule("tkinter_constants", "Tkconstants", "tkinter.constants"),
+    MovedModule("tkinter_dnd", "Tkdnd", "tkinter.dnd"),
+    MovedModule("tkinter_colorchooser", "tkColorChooser",
+                "tkinter.colorchooser"),
+    MovedModule("tkinter_commondialog", "tkCommonDialog",
+                "tkinter.commondialog"),
+    MovedModule("tkinter_tkfiledialog", "tkFileDialog", "tkinter.filedialog"),
+    MovedModule("tkinter_font", "tkFont", "tkinter.font"),
+    MovedModule("tkinter_messagebox", "tkMessageBox", "tkinter.messagebox"),
+    MovedModule("tkinter_tksimpledialog", "tkSimpleDialog",
+                "tkinter.simpledialog"),
+    MovedModule("urllib_parse", __name__ + ".moves.urllib_parse", "urllib.parse"),
+    MovedModule("urllib_error", __name__ + ".moves.urllib_error", "urllib.error"),
+    MovedModule("urllib", __name__ + ".moves.urllib", __name__ + ".moves.urllib"),
+    MovedModule("urllib_robotparser", "robotparser", "urllib.robotparser"),
+    MovedModule("xmlrpc_client", "xmlrpclib", "xmlrpc.client"),
+    MovedModule("xmlrpc_server", "SimpleXMLRPCServer", "xmlrpc.server"),
+]
+# Add windows specific modules.
+if sys.platform == "win32":
+    _moved_attributes += [
+        MovedModule("winreg", "_winreg"),
+    ]
+
+for attr in _moved_attributes:
+    setattr(_MovedItems, attr.name, attr)
+    if isinstance(attr, MovedModule):
+        _importer._add_module(attr, "moves." + attr.name)
+del attr
+
+_MovedItems._moved_attributes = _moved_attributes
+
+moves = _MovedItems(__name__ + ".moves")
+_importer._add_module(moves, "moves")
+
+
+class Module_six_moves_urllib_parse(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_parse"""
+
+
+_urllib_parse_moved_attributes = [
+    MovedAttribute("ParseResult", "urlparse", "urllib.parse"),
+    MovedAttribute("SplitResult", "urlparse", "urllib.parse"),
+    MovedAttribute("parse_qs", "urlparse", "urllib.parse"),
+    MovedAttribute("parse_qsl", "urlparse", "urllib.parse"),
+    MovedAttribute("urldefrag", "urlparse", "urllib.parse"),
+    MovedAttribute("urljoin", "urlparse", "urllib.parse"),
+    MovedAttribute("urlparse", "urlparse", "urllib.parse"),
+    MovedAttribute("urlsplit", "urlparse", "urllib.parse"),
+    MovedAttribute("urlunparse", "urlparse", "urllib.parse"),
+    MovedAttribute("urlunsplit", "urlparse", "urllib.parse"),
+    MovedAttribute("quote", "urllib", "urllib.parse"),
+    MovedAttribute("quote_plus", "urllib", "urllib.parse"),
+    MovedAttribute("unquote", "urllib", "urllib.parse"),
+    MovedAttribute("unquote_plus", "urllib", "urllib.parse"),
+    MovedAttribute("urlencode", "urllib", "urllib.parse"),
+    MovedAttribute("splitquery", "urllib", "urllib.parse"),
+    MovedAttribute("splittag", "urllib", "urllib.parse"),
+    MovedAttribute("splituser", "urllib", "urllib.parse"),
+    MovedAttribute("uses_fragment", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_netloc", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_params", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_query", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_relative", "urlparse", "urllib.parse"),
+]
+for attr in _urllib_parse_moved_attributes:
+    setattr(Module_six_moves_urllib_parse, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_parse._moved_attributes = _urllib_parse_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_parse(__name__ + ".moves.urllib_parse"),
+                      "moves.urllib_parse", "moves.urllib.parse")
+
+
+class Module_six_moves_urllib_error(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_error"""
+
+
+_urllib_error_moved_attributes = [
+    MovedAttribute("URLError", "urllib2", "urllib.error"),
+    MovedAttribute("HTTPError", "urllib2", "urllib.error"),
+    MovedAttribute("ContentTooShortError", "urllib", "urllib.error"),
+]
+for attr in _urllib_error_moved_attributes:
+    setattr(Module_six_moves_urllib_error, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_error._moved_attributes = _urllib_error_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_error(__name__ + ".moves.urllib.error"),
+                      "moves.urllib_error", "moves.urllib.error")
+
+
+class Module_six_moves_urllib_request(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_request"""
+
+
+_urllib_request_moved_attributes = [
+    MovedAttribute("urlopen", "urllib2", "urllib.request"),
+    MovedAttribute("install_opener", "urllib2", "urllib.request"),
+    MovedAttribute("build_opener", "urllib2", "urllib.request"),
+    MovedAttribute("pathname2url", "urllib", "urllib.request"),
+    MovedAttribute("url2pathname", "urllib", "urllib.request"),
+    MovedAttribute("getproxies", "urllib", "urllib.request"),
+    MovedAttribute("Request", "urllib2", "urllib.request"),
+    MovedAttribute("OpenerDirector", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPDefaultErrorHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPRedirectHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPCookieProcessor", "urllib2", "urllib.request"),
+    MovedAttribute("ProxyHandler", "urllib2", "urllib.request"),
+    MovedAttribute("BaseHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPPasswordMgr", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPPasswordMgrWithDefaultRealm", "urllib2", "urllib.request"),
+    MovedAttribute("AbstractBasicAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPBasicAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("ProxyBasicAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("AbstractDigestAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPDigestAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("ProxyDigestAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPSHandler", "urllib2", "urllib.request"),
+    MovedAttribute("FileHandler", "urllib2", "urllib.request"),
+    MovedAttribute("FTPHandler", "urllib2", "urllib.request"),
+    MovedAttribute("CacheFTPHandler", "urllib2", "urllib.request"),
+    MovedAttribute("UnknownHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPErrorProcessor", "urllib2", "urllib.request"),
+    MovedAttribute("urlretrieve", "urllib", "urllib.request"),
+    MovedAttribute("urlcleanup", "urllib", "urllib.request"),
+    MovedAttribute("URLopener", "urllib", "urllib.request"),
+    MovedAttribute("FancyURLopener", "urllib", "urllib.request"),
+    MovedAttribute("proxy_bypass", "urllib", "urllib.request"),
+]
+for attr in _urllib_request_moved_attributes:
+    setattr(Module_six_moves_urllib_request, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_request._moved_attributes = _urllib_request_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_request(__name__ + ".moves.urllib.request"),
+                      "moves.urllib_request", "moves.urllib.request")
+
+
+class Module_six_moves_urllib_response(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_response"""
+
+
+_urllib_response_moved_attributes = [
+    MovedAttribute("addbase", "urllib", "urllib.response"),
+    MovedAttribute("addclosehook", "urllib", "urllib.response"),
+    MovedAttribute("addinfo", "urllib", "urllib.response"),
+    MovedAttribute("addinfourl", "urllib", "urllib.response"),
+]
+for attr in _urllib_response_moved_attributes:
+    setattr(Module_six_moves_urllib_response, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_response._moved_attributes = _urllib_response_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_response(__name__ + ".moves.urllib.response"),
+                      "moves.urllib_response", "moves.urllib.response")
+
+
+class Module_six_moves_urllib_robotparser(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_robotparser"""
+
+
+_urllib_robotparser_moved_attributes = [
+    MovedAttribute("RobotFileParser", "robotparser", "urllib.robotparser"),
+]
+for attr in _urllib_robotparser_moved_attributes:
+    setattr(Module_six_moves_urllib_robotparser, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_robotparser._moved_attributes = _urllib_robotparser_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_robotparser(__name__ + ".moves.urllib.robotparser"),
+                      "moves.urllib_robotparser", "moves.urllib.robotparser")
+
+
+class Module_six_moves_urllib(types.ModuleType):
+
+    """Create a six.moves.urllib namespace that resembles the Python 3 namespace"""
+    __path__ = []  # mark as package
+    parse = _importer._get_module("moves.urllib_parse")
+    error = _importer._get_module("moves.urllib_error")
+    request = _importer._get_module("moves.urllib_request")
+    response = _importer._get_module("moves.urllib_response")
+    robotparser = _importer._get_module("moves.urllib_robotparser")
+
+    def __dir__(self):
+        return ['parse', 'error', 'request', 'response', 'robotparser']
+
+_importer._add_module(Module_six_moves_urllib(__name__ + ".moves.urllib"),
+                      "moves.urllib")
+
+
+def add_move(move):
+    """Add an item to six.moves."""
+    setattr(_MovedItems, move.name, move)
+
+
+def remove_move(name):
+    """Remove item from six.moves."""
+    try:
+        delattr(_MovedItems, name)
+    except AttributeError:
+        try:
+            del moves.__dict__[name]
+        except KeyError:
+            raise AttributeError("no such move, %r" % (name,))
+
+
+if PY3:
+    _meth_func = "__func__"
+    _meth_self = "__self__"
+
+    _func_closure = "__closure__"
+    _func_code = "__code__"
+    _func_defaults = "__defaults__"
+    _func_globals = "__globals__"
+else:
+    _meth_func = "im_func"
+    _meth_self = "im_self"
+
+    _func_closure = "func_closure"
+    _func_code = "func_code"
+    _func_defaults = "func_defaults"
+    _func_globals = "func_globals"
+
+
+try:
+    advance_iterator = next
+except NameError:
+    def advance_iterator(it):
+        return it.next()
+next = advance_iterator
+
+
+try:
+    callable = callable
+except NameError:
+    def callable(obj):
+        return any("__call__" in klass.__dict__ for klass in type(obj).__mro__)
+
+
+if PY3:
+    def get_unbound_function(unbound):
+        return unbound
+
+    create_bound_method = types.MethodType
+
+    def create_unbound_method(func, cls):
+        return func
+
+    Iterator = object
+else:
+    def get_unbound_function(unbound):
+        return unbound.im_func
+
+    def create_bound_method(func, obj):
+        return types.MethodType(func, obj, obj.__class__)
+
+    def create_unbound_method(func, cls):
+        return types.MethodType(func, None, cls)
+
+    class Iterator(object):
+
+        def next(self):
+            return type(self).__next__(self)
+
+    callable = callable
+_add_doc(get_unbound_function,
+         """Get the function out of a possibly unbound function""")
+
+
+get_method_function = operator.attrgetter(_meth_func)
+get_method_self = operator.attrgetter(_meth_self)
+get_function_closure = operator.attrgetter(_func_closure)
+get_function_code = operator.attrgetter(_func_code)
+get_function_defaults = operator.attrgetter(_func_defaults)
+get_function_globals = operator.attrgetter(_func_globals)
+
+
+if PY3:
+    def iterkeys(d, **kw):
+        return iter(d.keys(**kw))
+
+    def itervalues(d, **kw):
+        return iter(d.values(**kw))
+
+    def iteritems(d, **kw):
+        return iter(d.items(**kw))
+
+    def iterlists(d, **kw):
+        return iter(d.lists(**kw))
+
+    viewkeys = operator.methodcaller("keys")
+
+    viewvalues = operator.methodcaller("values")
+
+    viewitems = operator.methodcaller("items")
+else:
+    def iterkeys(d, **kw):
+        return d.iterkeys(**kw)
+
+    def itervalues(d, **kw):
+        return d.itervalues(**kw)
+
+    def iteritems(d, **kw):
+        return d.iteritems(**kw)
+
+    def iterlists(d, **kw):
+        return d.iterlists(**kw)
+
+    viewkeys = operator.methodcaller("viewkeys")
+
+    viewvalues = operator.methodcaller("viewvalues")
+
+    viewitems = operator.methodcaller("viewitems")
+
+_add_doc(iterkeys, "Return an iterator over the keys of a dictionary.")
+_add_doc(itervalues, "Return an iterator over the values of a dictionary.")
+_add_doc(iteritems,
+         "Return an iterator over the (key, value) pairs of a dictionary.")
+_add_doc(iterlists,
+         "Return an iterator over the (key, [values]) pairs of a dictionary.")
+
+
+if PY3:
+    def b(s):
+        return s.encode("latin-1")
+
+    def u(s):
+        return s
+    unichr = chr
+    import struct
+    int2byte = struct.Struct(">B").pack
+    del struct
+    byte2int = operator.itemgetter(0)
+    indexbytes = operator.getitem
+    iterbytes = iter
+    import io
+    StringIO = io.StringIO
+    BytesIO = io.BytesIO
+    _assertCountEqual = "assertCountEqual"
+    if sys.version_info[1] <= 1:
+        _assertRaisesRegex = "assertRaisesRegexp"
+        _assertRegex = "assertRegexpMatches"
+    else:
+        _assertRaisesRegex = "assertRaisesRegex"
+        _assertRegex = "assertRegex"
+else:
+    def b(s):
+        return s
+    # Workaround for standalone backslash
+
+    def u(s):
+        return unicode(s.replace(r'\\', r'\\\\'), "unicode_escape")
+    unichr = unichr
+    int2byte = chr
+
+    def byte2int(bs):
+        return ord(bs[0])
+
+    def indexbytes(buf, i):
+        return ord(buf[i])
+    iterbytes = functools.partial(itertools.imap, ord)
+    import StringIO
+    StringIO = BytesIO = StringIO.StringIO
+    _assertCountEqual = "assertItemsEqual"
+    _assertRaisesRegex = "assertRaisesRegexp"
+    _assertRegex = "assertRegexpMatches"
+_add_doc(b, """Byte literal""")
+_add_doc(u, """Text literal""")
+
+
+def assertCountEqual(self, *args, **kwargs):
+    return getattr(self, _assertCountEqual)(*args, **kwargs)
+
+
+def assertRaisesRegex(self, *args, **kwargs):
+    return getattr(self, _assertRaisesRegex)(*args, **kwargs)
+
+
+def assertRegex(self, *args, **kwargs):
+    return getattr(self, _assertRegex)(*args, **kwargs)
+
+
+if PY3:
+    exec_ = getattr(moves.builtins, "exec")
+
+    def reraise(tp, value, tb=None):
+        if value is None:
+            value = tp()
+        if value.__traceback__ is not tb:
+            raise value.with_traceback(tb)
+        raise value
+
+else:
+    def exec_(_code_, _globs_=None, _locs_=None):
+        """Execute code in a namespace."""
+        if _globs_ is None:
+            frame = sys._getframe(1)
+            _globs_ = frame.f_globals
+            if _locs_ is None:
+                _locs_ = frame.f_locals
+            del frame
+        elif _locs_ is None:
+            _locs_ = _globs_
+        exec("""exec _code_ in _globs_, _locs_""")
+
+    exec_("""def reraise(tp, value, tb=None):
+    raise tp, value, tb
+""")
+
+
+if sys.version_info[:2] == (3, 2):
+    exec_("""def raise_from(value, from_value):
+    if from_value is None:
+        raise value
+    raise value from from_value
+""")
+elif sys.version_info[:2] > (3, 2):
+    exec_("""def raise_from(value, from_value):
+    raise value from from_value
+""")
+else:
+    def raise_from(value, from_value):
+        raise value
+
+
+print_ = getattr(moves.builtins, "print", None)
+if print_ is None:
+    def print_(*args, **kwargs):
+        """The new-style print function for Python 2.4 and 2.5."""
+        fp = kwargs.pop("file", sys.stdout)
+        if fp is None:
+            return
+
+        def write(data):
+            if not isinstance(data, basestring):
+                data = str(data)
+            # If the file has an encoding, encode unicode with it.
+            if (isinstance(fp, file) and
+                    isinstance(data, unicode) and
+                    fp.encoding is not None):
+                errors = getattr(fp, "errors", None)
+                if errors is None:
+                    errors = "strict"
+                data = data.encode(fp.encoding, errors)
+            fp.write(data)
+        want_unicode = False
+        sep = kwargs.pop("sep", None)
+        if sep is not None:
+            if isinstance(sep, unicode):
+                want_unicode = True
+            elif not isinstance(sep, str):
+                raise TypeError("sep must be None or a string")
+        end = kwargs.pop("end", None)
+        if end is not None:
+            if isinstance(end, unicode):
+                want_unicode = True
+            elif not isinstance(end, str):
+                raise TypeError("end must be None or a string")
+        if kwargs:
+            raise TypeError("invalid keyword arguments to print()")
+        if not want_unicode:
+            for arg in args:
+                if isinstance(arg, unicode):
+                    want_unicode = True
+                    break
+        if want_unicode:
+            newline = unicode("\n")
+            space = unicode(" ")
+        else:
+            newline = "\n"
+            space = " "
+        if sep is None:
+            sep = space
+        if end is None:
+            end = newline
+        for i, arg in enumerate(args):
+            if i:
+                write(sep)
+            write(arg)
+        write(end)
+if sys.version_info[:2] < (3, 3):
+    _print = print_
+
+    def print_(*args, **kwargs):
+        fp = kwargs.get("file", sys.stdout)
+        flush = kwargs.pop("flush", False)
+        _print(*args, **kwargs)
+        if flush and fp is not None:
+            fp.flush()
+
+_add_doc(reraise, """Reraise an exception.""")
+
+if sys.version_info[0:2] < (3, 4):
+    def wraps(wrapped, assigned=functools.WRAPPER_ASSIGNMENTS,
+              updated=functools.WRAPPER_UPDATES):
+        def wrapper(f):
+            f = functools.wraps(wrapped, assigned, updated)(f)
+            f.__wrapped__ = wrapped
+            return f
+        return wrapper
+else:
+    wraps = functools.wraps
+
+
+def with_metaclass(meta, *bases):
+    """Create a base class with a metaclass."""
+    # This requires a bit of explanation: the basic idea is to make a dummy
+    # metaclass for one level of class instantiation that replaces itself with
+    # the actual metaclass.
+    class metaclass(meta):
+
+        def __new__(cls, name, this_bases, d):
+            return meta(name, bases, d)
+    return type.__new__(metaclass, 'temporary_class', (), {})
+
+
+def add_metaclass(metaclass):
+    """Class decorator for creating a class with a metaclass."""
+    def wrapper(cls):
+        orig_vars = cls.__dict__.copy()
+        slots = orig_vars.get('__slots__')
+        if slots is not None:
+            if isinstance(slots, str):
+                slots = [slots]
+            for slots_var in slots:
+                orig_vars.pop(slots_var)
+        orig_vars.pop('__dict__', None)
+        orig_vars.pop('__weakref__', None)
+        return metaclass(cls.__name__, cls.__bases__, orig_vars)
+    return wrapper
+
+
+def python_2_unicode_compatible(klass):
+    """
+    A decorator that defines __unicode__ and __str__ methods under Python 2.
+    Under Python 3 it does nothing.
+
+    To support Python 2 and 3 with a single code base, define a __str__ method
+    returning text and apply this decorator to the class.
+    """
+    if PY2:
+        if '__str__' not in klass.__dict__:
+            raise ValueError("@python_2_unicode_compatible cannot be applied "
+                             "to %s because it doesn't define __str__()." %
+                             klass.__name__)
+        klass.__unicode__ = klass.__str__
+        klass.__str__ = lambda self: self.__unicode__().encode('utf-8')
+    return klass
+
+
+# Complete the moves implementation.
+# This code is at the end of this module to speed up module loading.
+# Turn this module into a package.
+__path__ = []  # required for PEP 302 and PEP 451
+__package__ = __name__  # see PEP 366 @ReservedAssignment
+if globals().get("__spec__") is not None:
+    __spec__.submodule_search_locations = []  # PEP 451 @UndefinedVariable
+# Remove other six meta path importers, since they cause problems. This can
+# happen if six is removed from sys.modules and then reloaded. (Setuptools does
+# this for some reason.)
+if sys.meta_path:
+    for i, importer in enumerate(sys.meta_path):
+        # Here's some real nastiness: Another "instance" of the six module might
+        # be floating around. Therefore, we can't use isinstance() to check for
+        # the six meta path importer, since the other six instance will have
+        # inserted an importer with different class.
+        if (type(importer).__name__ == "_SixMetaPathImporter" and
+                importer.name == __name__):
+            del sys.meta_path[i]
+            break
+    del i, importer
+# Finally, add the importer to the meta path import hook.
+sys.meta_path.append(_importer)
diff --git a/recipes/pkgresources/pkgr/extern/__init__.py b/recipes/pkgresources/pkgr/extern/__init__.py
new file mode 100644
index 0000000..b4156fe
--- /dev/null
+++ b/recipes/pkgresources/pkgr/extern/__init__.py
@@ -0,0 +1,73 @@
+import sys
+
+
+class VendorImporter:
+    """
+    A PEP 302 meta path importer for finding optionally-vendored
+    or otherwise naturally-installed packages from root_name.
+    """
+
+    def __init__(self, root_name, vendored_names=(), vendor_pkg=None):
+        self.root_name = root_name
+        self.vendored_names = set(vendored_names)
+        self.vendor_pkg = vendor_pkg or root_name.replace('extern', '_vendor')
+
+    @property
+    def search_path(self):
+        """
+        Search first the vendor package then as a natural package.
+        """
+        yield self.vendor_pkg + '.'
+        yield ''
+
+    def find_module(self, fullname, path=None):
+        """
+        Return self when fullname starts with root_name and the
+        target module is one vendored through this importer.
+        """
+        root, base, target = fullname.partition(self.root_name + '.')
+        if root:
+            return
+        if not any(map(target.startswith, self.vendored_names)):
+            return
+        return self
+
+    def load_module(self, fullname):
+        """
+        Iterate over the search path to locate and load fullname.
+        """
+        root, base, target = fullname.partition(self.root_name + '.')
+        for prefix in self.search_path:
+            try:
+                extant = prefix + target
+                __import__(extant)
+                mod = sys.modules[extant]
+                sys.modules[fullname] = mod
+                # mysterious hack:
+                # Remove the reference to the extant package/module
+                # on later Python versions to cause relative imports
+                # in the vendor package to resolve the same modules
+                # as those going through this importer.
+                if sys.version_info > (3, 3):
+                    del sys.modules[extant]
+                return mod
+            except ImportError:
+                pass
+        else:
+            raise ImportError(
+                "The '{target}' package is required; "
+                "normally this is bundled with this package so if you get "
+                "this warning, consult the packager of your "
+                "distribution.".format(**locals())
+            )
+
+    def install(self):
+        """
+        Install this importer into sys.meta_path if not already present.
+        """
+        if self not in sys.meta_path:
+            sys.meta_path.append(self)
+
+
+names = 'packaging', 'pyparsing', 'six', 'appdirs'
+VendorImporter(__name__, names).install()