[antlr-interest] Using an external source for token definitions

lars.vonwedel at bayertechnology.com lars.vonwedel at bayertechnology.com
Tue Dec 2 03:07:06 PST 2008


Hello,

I have successfully implemented an ANTLR grammar for a small part of the 
input language for a tool I am about to reengineer. However, I am a bit 
unsure how to scale my current state to the full input language which has 
several hundred keywords. 

Luckily, all keywords are already available in a machine readable form and 
it would be easy to generate a .tokens file from that source.  However, 
that additional pre-build step is somehow annoying me. Further, I would 
need to generate rules of the form

        statementKeyword : Keyword1 | Keyword2 | ... | KeywordN;

I would like to have (or implement) a rule of the form

        statementKeyword : Keyword1 .. KeywordN;

as it is possible in the lexer, but it seems impossible in the parser. 
This would avoid an extra generation step for the grammar.

Can I subclass the parser and override the statementKeyword method to 
perform a lookup in my existing keywords list ?

Or are there any better ideas ?

Best Regards
Lars von Wedel
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