Re: Code in regexp

You might want to read my bug report, and the discussion it triggered at http://bugs6.perl.org/rt2/Ticket/Display.html?id=10040. However, I think Perl is mistaken to think that (??{ }) generates a zero-width assertion.

Here's another way of doing it:

    /^(\d)(?{local ($x, $c) = ($^N, 0)})
     ((\d)(?(?{$c ++; $^N == $x + $c})|\A))+$/x
[download]

Abigail

Comment on Re: Code in regexp Select or Download Code

Replies are listed 'Best First'.
Re: Re: Code in regexp by demerphq (Chancellor) on Nov 28, 2002 at 19:46 UTC
Is the local() needed abigail? I was playing with this yesterday and didnt seem to need it. --- demerphq my friends call me, usually because I'm late....	[reply]
Re: Code in regexp by Abigail-II (Bishop) on Nov 29, 2002 at 09:50 UTC
No, it's not needed. Just like `use strict` and `my` aren't "needed". But if your code happens to have a `$main::x`, you'll be thankful you used `local`. Abigail	[reply] [d/l] [select]
Re: Re: Code in regexp by demerphq (Chancellor) on Nov 29, 2002 at 11:33 UTC
Er, sarcasm aside, the reason I asked was because the documentation suggested to me that they were automatically localized. --- demerphq my friends call me, usually because I'm late....	[reply]
Re: Code in regexp by Abigail-II (Bishop) on Nov 29, 2002 at 12:18 UTC
Re: Re: Code in regexp by Jasper (Chaplain) on Nov 29, 2002 at 11:06 UTC
Does perl think that (??{ }) generates a zero-width assertion? If that is the case, why should the + qualifier behave any differently to the {1,8} qualifier in pg's regex below? It's surely a bug that one complains about matching empty string repeatedly, while the other seems to behave as non-zero width. Jasper	[reply]
Re: Re: Re: Code in regexp by Jasper (Chaplain) on Dec 12, 2002 at 16:27 UTC
Further to this (not that this thread isn't long dead), in Terje Kristensen's latest minigolf competition he came up with this: `-n $;[map{/./,/[^$&-T]/g}/(?=(.))/g].=$_}{print@` [download] Which does funny non zero width things for (?=) `perl -le 'print for "foo bar"=~/(?=(.))/g' foo bar oo bar o bar bar bar ar r` [download] I had no idea this would happen, anyway. Jasper	[reply] [d/l] [select]