[antlr-interest] newbie question: throwing an exception from parsing behavior

Olivier Lefevre lefevrol at yahoo.com
Sun Feb 24 17:40:33 PST 2008


Blake Meike wrote:
> It all works fine, except that I can't figure our how to throw a useful 
> exception, when the input is invalid.

 From within an action. Subclass RecognitionException to add a message 
string or whatever and, in the action, do

     if (bad) throw new MyException(input, myMsg);

All parsers have an input variable (inherited from Parser).

-- O.L.



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