[antlr-interest] (no subject)
Daniels, Troy (US SSA)
troy.daniels at baesystems.com
Fri Nov 30 09:15:23 PST 2007
I'm using antlr 2.7.6 and I'm trying to write a parser rule of the form
rule: rule1 rule2* rule3?
With two levels of look ahead, there's ambiguity between rule2 and
rule3. The third token would remove the ambiguity. Is there a way to
increase the look ahead for just one rule? (Setting k only appears to be
valid in the grammar file options, not in rule options).
I tried using a syntactic predicate.
rule: rule1 ((TOK1 TOK2 TOK3)=> rule2*) rule3?
but antlr ignored it, since it doesn't consider (...)* to be multiple
options. Adding a blank alternative seems hackish:
rule: rule1 ((TOK1 TOK2 TOK3)=> rule2*|/* */) rule3?
Is there a good way to handle this sort of problem?
P.S. I also posted this on Jguru, but there doesn't seem to be much
action in the Antlr forum there. Is this a better place for such
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