[antlr-interest] Syntactic Predicate does not work but Backtracking does
Alexander Gängel
alexander at gaengel.de
Sat Mar 1 01:00:16 PST 2008
sorry I send a wrong copy of the first version it should be:
expression_comma options
:(
(expression COMMA)=>expression COMMA expression_comma
->expression expression_comma
|expression->expression
)
;
Alexander Gängel schrieb:
> I have a rule in my grammar like this:
>
> expression_comma options
> :(
> (expression COMMA)=>expression (COMMA expression_comma)?
> ->expression expression_comma?
> |expression->expression
> )
> ;
>
>
> my some Input like expression, expression does not work even when both
> parts left and rigth of the comma are expressions.
>
> if I use this rule with backtracking it works.
>
> oclExpression_comma options {backtrack=true;}
> :
> oclExpression (COMMA oclExpression_comma)? ->oclExpression
> oclExpression_comma?
> ;
>
>
> Am I wrong or should both work all right?
> Alexander
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