[antlr-interest] [AntlrWorks] Q: What does AW interpreter do with syntactic predicates?

[Kay Röpke]

Hi!

On Aug 17, 2008, at 11:42 PM, Austin Hastings wrote:

> What will the interpreter do? Will it skip the synpred but check for  
> pattern1? Will it skip the whole thing and go straight to pattern2?  
> Or something far more sinister?


AFAIK it will not even work at all, since it can't execute predicate  
code. I believe it would be possible to support synpreds, since the  
support code is "boilerplate" and could be included as a special case  
in the interpreter, but it certainly won't work for semantic  
predicates (unless that's being JIT compiled in some way).
The main reason it's not supported is that no one has stepped up to do  
it and "Debug" normally does what you want without that much of a  
penalty (of course there's a startup cost involved).
I think the same goes for lexer debug support, no one has deemed it  
important enough to actually get it done.

cheers,
-k
-- 
Kay Röpke
http://classdump.org/