[antlr-interest] how to let parser control lexer state.
Loring Craymer
lgcraymer at yahoo.com
Fri Apr 27 10:42:24 PDT 2007
That's what semantic predicates (in the parser) are
for--there are no lexical issues involved in this
case. You want to do the symbol table lookup and test
in a predicate.
--Loring
--- femtowin1 <femtowin1 at gmail.com> wrote:
> Hi all, in antlr3, can parser control lexer state
> and decide how lexer lexing? some grammar has
> ambiguity
> decided upon by parser knowledge.
> for ruby grammar <<
> x << 1
> test
> 1
> if x is a variable, then << is shift operator,
> otherwise it is a heredoc. so lexing must know
> from the symbol table whether x has been defined
> beforehand. But current antlrv3 implementation,
> lexer lexing to a constant token stream, and feed
> it into parser, so can't achieve this effect.
> ______________________________________
> Sent from my www.pageflakes.com startpage
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
More information about the antlr-interest
mailing list