[antlr-interest] executing actions during backtrack

[Jim Idle]

Having written database for a living for quite a bit of my life I find myself nodding my head in furious agreement at Martin's comments. To implement such a thing would be more work than the parser generator itself. 
 
My vote would be not to go there at all and perhaps come up with a few grammar examples that show how to go about dealing with such a situation.
 
If we are not talking about arbtrary variables, structure and state in mutliple structures in mutliple target languages but something much simpler, then it woudl seem just simplest of all for the grammar programmar to deal with it in context to me.
 
Jim

 
________________________________

From: antlr-interest-bounces at antlr.org on behalf of Martin Probst
Sent: Thu 5/11/2006 8:50 AM
To: Jeff Barnes
Cc: ANTLR Interest
Subject: Re: [antlr-interest] executing actions during backtrack



Hi,

> We're still talking DFA's right? Depending on whether the DFA is 
> state-centric or transition-centric, you would put the Command 
> stucturally in a State or Transition... Just thinking out loud here.

Well yes, but we're talking about saving arbitrary user data, or not?

> I think the size of the serialization 'file' should be configurable 
> on startup. A circular log would prevent runaway log size. If the 
> user had a really large walk from node to node before a confirmed 
> match, they would have to make sure the log file size was 
> configured large enough.

Sorry, but that sounds a lot like implementing a database, but at all 
like implementing a parser generator, at least to me. And you didn't 
even start about all the concurrency issues with the log ;-)

Martin