Handle escaped strings

lift.go

@@ -32,12 +32,6 @@ type LiftedArgs interface {
 // expressions to increase cache hit rates.
 func liftLiterals(expr string) (string, LiftedArgs) {
 	// TODO: Lift numeric literals out of expressions.
-	// If this contains an escape sequence (eg. `\` or `\'`), skip the lifting
-	// of literals out of the expression.
-	if strings.Contains(expr, `\"`) || strings.Contains(expr, `\'`) {
-		return expr, nil
-	}
-
 	lp := liftParser{expr: expr}
 	return lp.lift()
 }
@@ -103,23 +97,27 @@ func (l *liftParser) addLiftedVar(val argMapValue) {
 func (l *liftParser) consumeString(quoteChar byte) argMapValue {
 	offset := l.idx
 	length := 0
+
 	for l.idx < len(l.expr) {
 		char := l.expr[l.idx]
 
-		// Grab the next char for evaluation.
-		l.idx++
-
 		if char == '\\' && l.peek() == quoteChar {
 			// If we're escaping the quote character, ignore it.
-			l.idx++
-			length++
+			l.idx += 2
+			length += 2
 			continue
 		}
 
 		if char == quoteChar {
+			// Skip over the end quote.
+			l.idx++
+			// Return the substring offset/length
 			return argMapValue{offset, length}
 		}
 
+		// Grab the next char for evaluation.
+		l.idx++
+
 		// Only now has the length of the inner quote increased.
 		length++
 	}

parser_test.go

@@ -1086,9 +1086,11 @@ func TestParsedCELAST(t *testing.T) {
 
 	p := NewCachingParser(env, nil)
 
-	ast, iss, args := p.Parse("event.data.id == 'ok'")
+	ast, iss, args := p.Parse(`event.data.id == "ok\" please"`)
 	require.Nil(t, iss)
-	require.EqualValues(t, map[string]any{"a": "ok"}, args.Map())
+	require.NotNil(t, ast)
+	require.NotNil(t, args)
+	require.EqualValues(t, map[string]any{"a": `ok\" please`}, args.Map())
 
 	program, err := env.Program(
 		ast,
@@ -1100,7 +1102,7 @@ func TestParsedCELAST(t *testing.T) {
 		result, _, err := program.Eval(map[string]any{
 			"event": map[string]any{
 				"data": map[string]any{
-					"id": "ok",
+					"id": `ok\" please`,
 				},
 			},
 			"vars": args.Map(),