lexer: add Hint to Error, which is expanded as "%s" instead of "%q"

Signed-off-by: Alejandro Mery <amery@jpi.io>

lexer/error.go

@@ -29,23 +29,21 @@ type Error struct {
 	Err     error
 }
 
-func (err Error) prefix() string {
+func (err Error) Error() string {
+	var s []string
+	var prefix string
+
 	switch {
 	case err.Line > 0 || err.Column > 0:
 		if err.Filename != "" {
-			return fmt.Sprintf("%s:%v:%v", err.Filename, err.Line, err.Column)
+			prefix = fmt.Sprintf("%s:%v:%v", err.Filename, err.Line, err.Column)
+		} else {
+			prefix = fmt.Sprintf("%v:%v", err.Line, err.Column)
 		}
-
-		return fmt.Sprintf("%v:%v", err.Line, err.Column)
-	default:
-		return err.Filename
+	case err.Filename != "":
+		prefix = err.Filename
 	}
-}
 
-func (err Error) Error() string {
-	var s []string
-
-	prefix := err.prefix()
 	if prefix != "" {
 		s = append(s, prefix)
 	}