Re: [boost] [regex] any interest in finite automata-based regexengine?

From: John Maddock (john_at_[hidden])
Date: 2004-11-08 07:50:45

> This is why I suggested that the better way (I do not claim it's the best
> way, though) of connecting parser to state machine is by having
> regex_creator to perform the shift-reduce activity. These actions must
> be present somewhere in some form in any case, and moving them to
> regex_creator allows us to get by without creating additional
> structures (read: trees) if we don't need them explicitly.
>
> The following sample creates a tree as the parser calls creator's
> feature functions. Can your regex compilation process be represented
> this way?
>
> class abstract_regex_creator {
> public:
>    void charset( const charset & ) { throw exception_unsupported; }
>    void repeat( int, int, bool ) { throw exception_unsupported; }
>    void cat() { throw exception_unsupported; }
>    // ...
> };

I think I quite like that idea, although it would require quite a bit of 
rewriting on my part to support it, I'm also concerned that there may be 
some unseen showstoppers hiding somewhere, but that may prove to be 
unfounded.

Right now, I think I really need to concentrate on getting another release 
out; it's already slipped by 9 months or so, and I simply must get my head 
down and right some code!

This is an area I want to explore though, if I can get this next lot of code 
out the door, then I'll create a cvs branch to experiment with this, if you 
want to suggest / experiment with a design for the abstract creator in the 
meantime, then go for it.

John.