ANTLR not throwing errors on invalid input

Question

I\'m using ANTLR to parse logical expressions in a Java tool I\'m writing, and I\'m having issues because passing invalid input strings to the generated ANTLR lexer and pars

Answer 1

An easy fix would be to override your lexer's and parser's reportError(...) and throw an exception of your own instead of letting ANTLR trying to recover from the incorrect syntax/input:

grammar YourGrammar;

// options/header/tokens

@parser::members {
  @Override
  public void reportError(RecognitionException e) {
    throw new RuntimeException("I quit!\n" + e.getMessage()); 
  }
}

@lexer::members {
  @Override
  public void reportError(RecognitionException e) {
    throw new RuntimeException("I quit!\n" + e.getMessage()); 
  }
}

// lexer & parser rules

More on error reporting (and recovery): https://theantlrguy.atlassian.net/wiki/display/ANTLR3/Error+reporting+and+recovery