Add stack implementation for SmartQuote

strmangle/strmangle.go

@@ -17,6 +17,37 @@ var (
 	uppercaseWords = []string{"id", "uid", "uuid", "guid", "ssn", "tz"}
 )
 
+type state int
+type smartStack []state
+
+const (
+	stateNothing = iota
+	stateSubExpression
+	stateFunction
+	stateIdentifier
+)
+
+func (stack *smartStack) push(s state) {
+	*stack = append(*stack, s)
+}
+
+func (stack *smartStack) pop() state {
+	l := len(*stack)
+	if l == 0 {
+		return stateNothing
+	}
+
+	v := (*stack)[l-1]
+	*stack = (*stack)[:l-1]
+	return v
+}
+
+// SmartQuote intelligently quotes identifiers in sql statements
+func SmartQuote(s string) string {
+	// split on comma, treat as individual thing
+	return s
+}
+
 // Identifier is a base conversion from Base 10 integers to Base 26
 // integers that are represented by an alphabet from a-z
 // See tests for example outputs.

strmangle/strmangle_test.go

@@ -5,6 +5,85 @@ import (
 	"testing"
 )
 
+func TestStack(t *testing.T) {
+	t.Parallel()
+
+	stack := smartStack{}
+
+	if stack.pop() != stateNothing {
+		t.Errorf("Expected state nothing for empty stack")
+	}
+
+	stack.push(stateFunction)
+	stack.push(stateSubExpression)
+	stack.push(stateNothing)
+
+	if len(stack) != 3 {
+		t.Errorf("Expected 3 state on stack, got %d", len(stack))
+	}
+
+	if r := stack.pop(); r != stateNothing {
+		t.Errorf("Expected stateNothing, got %v", r)
+	}
+	if len(stack) != 2 {
+		t.Errorf("Expected 2 state on stack, got %d", len(stack))
+	}
+
+	if r := stack.pop(); r != stateSubExpression {
+		t.Errorf("Expected stateSubExpression, got %v", r)
+	}
+	if len(stack) != 1 {
+		t.Errorf("Expected 1 state on stack, got %d", len(stack))
+	}
+
+	stack.push(stateSubExpression)
+	if len(stack) != 2 {
+		t.Errorf("Expected 2 state on stack, got %d", len(stack))
+	}
+
+	if r := stack.pop(); r != stateSubExpression {
+		t.Errorf("Expected stateSubExpression, got %v", r)
+	}
+	if len(stack) != 1 {
+		t.Errorf("Expected 1 state on stack, got %d", len(stack))
+	}
+
+	if r := stack.pop(); r != stateFunction {
+		t.Errorf("Expected stateFunction, got %v", r)
+	}
+	if len(stack) != 0 {
+		t.Errorf("Expected 0 state on stack, got %d", len(stack))
+	}
+	if stack.pop() != stateNothing {
+		t.Errorf("Expected state nothing for empty stack")
+	}
+}
+
+func TestSmartQuote(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		In  string
+		Out string
+	}{
+		{In: `count(*) as thing, thing as stuff`, Out: `count(*) as thing, "thing" as stuff`},
+		{In: `select (select 1) as thing, thing as stuff`, Out: `select (select 1) as thing, "thing" as stuff`},
+		{
+			In:  `select (select stuff as thing from thing where id=1 or name="thing") as stuff`,
+			Out: `select (select "stuff" as thing from thing where id=1 or name="thing") as stuff`,
+		},
+		{In: `thing`, Out: `"thing"`},
+		{In: `thing, stuff`, Out: `"thing", "stuff"`},
+		{In: `*`, Out: `*`},
+	}
+
+	for _, test := range tests {
+		if got := SmartQuote(test.In); got != test.Out {
+			t.Errorf("want: %s, got: %s", test.Out, got)
+		}
+	}
+}
+
 func TestIDGen(t *testing.T) {
 	t.Parallel()