[antlr-interest] Can antlr v3 lex star | tristar properly?
Kevin J. Cummings
cummings at kjchome.homeip.net
Wed Nov 21 14:33:41 PST 2007
Guntis Ozols wrote:
> Thanks, guys!
>
> I've finally found (thanks to Jim Idle) a solution that both works and
> is based on syntactic predicates:
> STAR : '*' (('**') => '**' { type = TRISTAR; } | );
>
> Solution by Kay Röpke also works:
> TRISTAR : {input.LA(3) == '*'}? => '*' '*' '*';
> STAR : '*';
>
> I still do not understand why
> STAR : '*' ;
> TRISTAR : ('***') => '***';
> does not work as expected, I think it is a bug in v3.
What happens if you reverse the order of STAR and TRISTAR in the
previous example, ie don't recognize STAR before you've check for
TRISTAR. I was under the impression that ANTLR was dependent upon the
order of certain productions.
--
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
Registered Linux User #1232 (http://counter.li.org)
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