[antlr-interest] Template application questions

[Terence Parr]

On Jun 27, 2007, at 8:34 AM, Johannes Luber wrote:

> Hello!
>
> I have the following rule:
>
> element
>    :   e=(atom|block) ebnfSuffix? -> ???
>    ;
>
> I have to generate different a different template depending on the  
> type
> of the optional token. Below there is a version, in which I  
> replaced by
> all of its alternatives. But this results in a wordy rule and requires
> syntactic predicates.
>
> element
>    :   (. OPTIONAL)=> e=(atom|block) OPTIONAL -> Optional(name= 
> {$e.st})
>    |   (. CLOSURE)=> e=(atom|block) CLOSURE -> ZeroOrMore(name= 
> {$e.st})
>    |   (. POSITIVE_CLOSURE)=> e=(atom|block) POSITIVE_CLOSURE
> 	-> OneOrMore(name={$e.st})
>    |   e=(atom|block) -> {$e.st}
>    ;

You could use sem preds after the -> that tests the type of suffix  
matched.  I think input.LA(-1) should do it.

Ter