111

Author: lvan100

lib/vidl/parser.go

@@ -107,22 +107,22 @@ func (e InnerExpr) Text() string {
 }
 
 // Parse parses the input string and returns an Expr AST.
-func Parse(s string) (expr Expr, err error) {
-	e := &ErrorListener{}
+func Parse(data string) (expr Expr, err error) {
+	e := &ErrorListener{Data: data}
 
-	// Recover from panics to return a proper error
+	// Recover from parser panics to provide better error reporting
 	defer func() {
 		if r := recover(); r != nil {
 			expr = nil
 			err = fmt.Errorf("[PANIC]: %v\n%s", r, debug.Stack())
-			if e.err != nil {
-				err = fmt.Errorf("%w\n%w", e.err, err)
+			if e.Error != nil {
+				err = fmt.Errorf("%w\n%w", e.Error, err)
 			}
 		}
 	}()
 
 	// Step 1: Create lexer and token stream
-	input := antlr.NewInputStream(s)
+	input := antlr.NewInputStream(data)
 	lexer := NewVLexer(input)
 	lexer.RemoveErrorListeners()
 	lexer.AddErrorListener(e)
@@ -141,25 +141,26 @@ func Parse(s string) (expr Expr, err error) {
 	antlr.ParseTreeWalkerDefault.Walk(l, p.ValidateExpr())
 
 	// Step 4: Return parsed expression or error
-	if e.err != nil {
-		return nil, e.err
+	if e.Error != nil {
+		return nil, e.Error
 	}
 	return l.Expr, nil
 }
 
 // ErrorListener implements a custom ANTLR error listener that records syntax errors.
 type ErrorListener struct {
 	*antlr.DefaultErrorListener
-	err error
+	Error error
+	Data  string
 }
 
 // SyntaxError is called by ANTLR when a syntax error occurs.
 func (l *ErrorListener) SyntaxError(_ antlr.Recognizer, _ any, line, column int, msg string, e antlr.RecognitionException) {
-	if l.err == nil {
-		l.err = fmt.Errorf("line %d:%d %s", line, column, msg)
+	if l.Error == nil {
+		l.Error = fmt.Errorf("line %d:%d %s << text: %q", line, column, msg, l.Data)
 		return
 	}
-	l.err = fmt.Errorf("%w\nline %d:%d %s", l.err, line, column, msg)
+	l.Error = fmt.Errorf("%w\nline %d:%d %s << text: %q", l.Error, line, column, msg, l.Data)
 }
 
 // ParseTreeListener walks the parse tree and constructs the expression AST.

lib/vidl/parser_test.go

@@ -280,22 +280,22 @@ func TestParse(t *testing.T) {
 		{
 			name:        "syntax_error_missing_paren",
 			input:       "(a",
-			expectError: errors.New("line 1:2 missing ')' at '<EOF>'"),
+			expectError: errors.New("line 1:2 missing ')' at '<EOF>' << text: \"(a\""),
 		},
 		{
 			name:        "syntax_error_unexpected_token",
 			input:       "a + b",
-			expectError: errors.New("line 1:2 token recognition error at: '+ '"),
+			expectError: errors.New("line 1:2 token recognition error at: '+ ' << text: \"a + b\""),
 		},
 		{
 			name:        "syntax_error_empty",
 			input:       "",
-			expectError: errors.New("line 1:0 mismatched input '<EOF>' expecting {'$', 'nil', '!', '(', STRING, INTEGER, FLOAT, IDENTIFIER}"),
+			expectError: errors.New("line 1:0 mismatched input '<EOF>' expecting {'$', 'nil', '!', '(', STRING, INTEGER, FLOAT, IDENTIFIER} << text: \"\""),
 		},
 		{
 			name:        "syntax_error_missing_comma_in_function",
 			input:       "func(a b)",
-			expectError: errors.New("line 1:7 extraneous input 'b' expecting {')', ','}"),
+			expectError: errors.New("line 1:7 extraneous input 'b' expecting {')', ','} << text: \"func(a b)\""),
 		},
 	}