How to collect errors during run time given by a parser in Antlr4

Question

I have upgraded from Antlr 3 to Antlr 4. I was using this code to catch exceptions using this code. But this is not working for Antlr 4.

partial class XPars         


        

Answer 1

You need to implement IAntlrErrorListener<IToken>. If all you want to is report errors like you have above, then you should focus on the SyntaxError method. Several base classes are available if you want to extend one.

• ConsoleErrorListener
• BaseErrorListener
• DiagnosticErrorListener

The error listener is attached to the parser instance by calling parser.AddErrorListener(listener).

Edit: You need to create a new class which implements the error listener interface. You then attach the listener to the parser. The parser itself will not implement the error listener interface.