Bug #20847 for Regexp-Assemble: optimise (?:a(?:...)|a+) as (?:a(?:a*|...))

Fri Aug 04 10:30:35 2006 book [...] cpan.org - Ticket created

Subject:

optimise (?:a(?:...)|a+) as (?:a(?:a*|...))

Here's a short description: 16:15 <@BooK> assemble a ab acd abd a+ ab+c 16:15 < assemble> BooK: (?:a(?:b+c|bd?|cd)?|a+) 16:16 <@BooK> tiens, ça peut s'optimiser en (?:a(?:b+c|bd?|cd|a*) non ? Actually if you make this kind of optimisation, b+c|bd? becomes b(?:b*c|d?) or b(?:b*c|d)?, so that should probably produce (?:a(?:a*|b(?:b*c|d?)|cd)) or (?:a(?:a*|b(?:b*c|d)?|cd)) Does that make any sense?

Wed Oct 11 03:11:04 2006 dland [...] cpan.org - Correspondence added

On Fri Aug 04 10:30:35 2006, BOOK wrote: Show quoted text

> b+c|bd? becomes > b(?:b*c|d?) or b(?:b*c|d)?, so that should probably produce > (?:a(?:a*|b(?:b*c|d?)|cd)) or (?:a(?:a*|b(?:b*c|d)?|cd)) > > Does that make any sense?

Hi Book, yes, this makes perfect sense. What needs to happen is to do an 'unfold_plus' step during lexing, which would map a+ -> a a*. Then everything would proceed as before. There would be a 'refold_plus' step during output, which would look for a a* and coalesce that back into a+, otherwise this would bulk up patterns that make heavy use of + modifiers (when no such reductions occur as you outline). But maybe refolding could be optional too. I'll have to benchmark the differences. Thanks for the idea.

Wed Oct 11 03:11:05 2006 The RT System itself - Status changed from 'new' to 'open'

Wed Oct 11 03:11:05 2006 dland [...] cpan.org - Status changed from 'open' to 'new'

Wed Oct 11 03:11:36 2006 dland [...] cpan.org - Taken

Wed Oct 11 03:12:04 2006 dland [...] cpan.org - Status changed from 'new' to 'open'

Tue Jul 03 17:51:46 2007 dland [...] cpan.org - Priority changed from (no value) to '3'

Tue Jul 31 08:42:33 2007 dland [...] cpan.org - Fixed in 0.32 added

Tue Jul 31 08:42:34 2007 dland [...] cpan.org - Status changed from 'open' to 'resolved'

Tue Jul 31 08:46:08 2007 dland [...] cpan.org - Correspondence added

This feature requested has been added in release 0.32, now available on CPAN. It is not complete, in that there is room for improvement, but it's a start. Thanks, David

Tue Jul 31 08:46:10 2007 The RT System itself - Status changed from 'resolved' to 'open'

Tue Jul 31 08:47:57 2007 dland [...] cpan.org - Status changed from 'open' to 'resolved'