Re: Integrating match counts into regex matching

If that is what you want, then that is what you want. But the cure is worse than the disease.

/^(?>(?:a(?{
         $count--
     })|b(?{
         $count++
     }))+)(??{
         $count==1 ? "" : "a"
     })\z/
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Don't forget to have a local our $count; in front of that. And don't forget to buy a bullet-proof vest in case the maintenance programmer ever tracks you down.

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Re^2: Integrating match counts into regex matching by pat_mc (Pilgrim) on Dec 18, 2008 at 23:57 UTC
Phew, tilly - This looks like a tricky one. Not sure I fully decipher it but I venture a transcript of your code here: "If the regex matches an 'a', decrease `$count`, if it matches a 'b', increase `$count`. Repeat as long as you can. When all the matching is done, check the value of `$count`. If it is '1' return the empty string, else return 'a'. Is this anywhere near the truth? Also not sure what the `\z` does. Thanks for your help though! Cheers - Pat	[reply] [d/l] [select]
Re^3: Integrating match counts into regex matching by tilly (Archbishop) on Dec 19, 2008 at 00:06 UTC
That is correct. The \z means end of string. It keeps you from matching things like "ben". But I misread your problem. I will match things like "bab" which is not according to your spec.	[reply]