[antlr-interest] Repost: ANTLRworks: Why do these rules behave differently in the embedded interpreter?

Gavin Lambert antlr at mirality.co.nz
Sat Jan 2 02:11:11 PST 2010

At 14:53 2/01/2010, Kyle Ferrio wrote:
 >So, I thought, why not just build and run the target?
 >Sure, codegen takes a second, and compiling to bytecode takes
 >another second.  So what?  Small price for knowing it's right.
 >Ok, but what about drawing concrete syntax trees?  No problem,
 >just insert actions.

Either I'm misinterpreting what you're talking about, or you're 
describing what the ANTLRWorks debugger already does.

 >In fact, it might even be possible to make predicates work in
 >such an interp, by either "gating off" the callbacks or just
 >"marking in the debugger" when we're processing a predicate.

The problem with predicates is that they're arbitrary target 
language code; ANTLR simply doesn't have enough information to 
emulate their functionality (for semantic predicates, at least; 
syntactic predicates could be dealt with correctly).  But that's 
what the Debug Remote feature is for.

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