Unable to customize error messages on top of error messages generated by ANTLR4 Parser

[ViswaTejaKommireddy]

Generating custom error messages on top of error messages generated by ANTLR4

I am trying to customize the error messages generated by ANTLR4 by categorizing them. I am using syntax error generated by ErrorListner in ANTLR4
class CustomErrorListener<TSymbol = any> implements ErrorListener<TSymbol> { private syntaxErrors: { line: number; column: number; lastCharPosition: number; message: string }[] = []; syntaxError( recognizer: Recognizer<TSymbol>, offendingSymbol: TSymbol, line: number, column: number, message: string, exception?: RecognitionException ): void {}

But I am unable to distinguish the exceptions using the Exception types. Please refer the below code
if (exception instanceof RecognitionException) {
message = "Recoginition Error: " + message;
}
if (exception instanceof NoViableAltException) {
message = "No Viable Alternative Error: " + message;
}

Please let me know if there are any ways to customize the error messages

[kaby76]

I was just looking at error reporting. #3700 (comment). You have to override the error strategy as well since that is where the error message is constructed from the parser state.