[antlr-interest] Fun with ANTLR3: mystery of the huge lexer

Wincent Colaiuta win at wincent.com
Sun Jul 1 07:59:40 PDT 2007


El 1/7/2007, a las 1:59, Gavin Lambert escribió:

> Lexer rules are implicitly assigned priorities based on what order  
> they appear in the grammar -- rules that appear first are preferred  
> over ones that are listed later.
>
> Having said that, I think there's also a longest-match-wins rule  
> too, and I'm not sure how they interact.

I made some notes in that very subject here:

<http://wincent.com/knowledge-base/ 
ANTLR_lexers_in_depth#Precedence_among_lexer_rules>

Not sure if my conclusions are correct, but I've been making notes  
while working with ANTLR for a few months trying to turn all those  
mysterious "black art" aspects of ANTLR's workings into deterministic  
certainties; it's pretty hard to write a grammar unless you  
understand *exactly* what it happening behind the scenes.

Wincent



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