[antlr-interest] syntactic predicate question
damarcus Leacock
damalee5 at gmail.com
Tue May 15 15:48:58 PDT 2007
Hi,
I'm sure this question has been asked before, I just couldn't find it in the
documentation or mailing list. I wonder why the following doesn't work (see
below). The fragment is useless, but it is a problem that I isolated from a
real grammar I am working on. I just can't understand why the syntactic
predicate does not come to the rescue here. Surely the look-ahead is fixed,
so it should be possible to generate a recursive descent parser for this no?
What do I fail to see?
Many thanks,
d.
(ps. doubt that it matters, but I am using antler 2.5.7 under Java)
-----------------------------------------------------------
class AmbiguousParser extends Parser;
options {
buildAST = true;
k = 1;
}
expr
: sexpr (OP^ sexpr)*
;
sexpr
: Literal {/* do something */}
| ( Literal DOT^ ) => Literal DOT expr {/* do something else */}
;
class AmbiguousLexer extends Lexer;
DOT : '.';
OP : "*";
Literal
: ( "a" | "b" )
;
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.antlr.org/pipermail/antlr-interest/attachments/20070515/3b51af4e/attachment.html
More information about the antlr-interest
mailing list