[antlr-interest] semantic predicate

[Alexey Demakov]

No, rule will not be called when semantic predicate is in alternative
from where rule is called. Semantic predicate in rule have no effect
on call, but is additional state check.

So, rule will not be called in this situation:

another_rule:
     { false }? rule
   | ANOTHER_TOKEN
;

Try to look at ANTLR generated code.

Regards,
Alexey

-----
Alexey Demakov
TreeDL: Tree Description Language: http://treedl.sourceforge.net
RedVerst Group: http://www.unitesk.com


  ----- Original Message ----- 
  From: Lloyd Dupont 
  To: antlr-interest at antlr.org 
  Sent: Tuesday, May 31, 2005 10:39 AM
  Subject: [antlr-interest] semantic predicate


  do they work?


  normaly a rule (or subrule) like
  rule: { false }? SOME_TOKEN;

  should never be called!
  unfortunately, if I added it I have plenty of error messages!

  kind of puzzled...
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