[antlr-interest] Re: Performance Question

cintyram <cintyram at yahoo.com> cintyram at yahoo.com
Thu Feb 27 07:19:22 PST 2003


hi,

> Is it better to increase the look ahead or is it better use semantic
> predicates?
the example u gave provides, syntaX predicates .. and the feature is
provided to allow not having to use the same look ahead in all cases,
even when it is not required .. so it is better to use syntax
predicates instead of increased look ahead ;
also where infinite look ahead is required what ever you do to the
look ahead, it cant help and a predicate has to be used ;
but there might be some cases where all the rules will end up
requiring a higher look ahead .. in that case incrasing look ahead
might be better than writing predicates for allt he rules :)
i dont think increasing look ahead can ever substitute for semantic
predicates, because they address different issues 

HTH
cheers
ram


 

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