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Regexp::Keep.3pm
Langue: en
Version: 2004-05-07 (mandriva - 01/05/08)
Section: 3 (Bibliothèques de fonctions)
NAME
Regexp::Keep - filter to allow the "\K" escape in regexesSYNOPSIS
use Regexp::Keep;
# slow and inefficient my $r = "abc.def.ghi.jkl"; $r =~ s/(.*)\..*/$1/;
# fast and efficient my $s = "abc.def.ghi.jkl"; $s =~ s/.*\K\..*//;
DESCRIPTION
This allows you to use the "\K" escape in your regexes, which fools the regex engine into thinking it has only just started matching your regex. This means you can turn the inefficient replace-with-itself constructs/(save)delete/$1/;
into the more efficient
s/save\Kdelete//;
construct.
IMPLEMENTATION
What "\K" filters into is ".{0}(?{ Regexp::Keep::KEEP })", which is an XS function call embedded into the regex. The function sets "PL_regstartp[0]" to the current location in the string. This means that $& now starts where "\K" is seen. That means a replacement will begin being replaced there.EXAMPLES
Here's are short examples to show you the abilities of "\K":"alphabet" =~ /([^aeiou][a-z][aeiou])[a-z]/; # $1 is "pha", $& is "phab"
"alphabet" =~ /\K([^aeiou][a-z][aeiou])[a-z]/; # $1 is "pha", $& is "phab"
"alphabet" =~ /([^aeiou]\K[a-z][aeiou])[a-z]/; # $1 is "pha", $& is "hab"
"alphabet" =~ /([^aeiou][a-z]\K[aeiou])[a-z]/; # $1 is "pha", $& is "ab"
"alphabet" =~ /([^aeiou][a-z][aeiou])\K[a-z]/; # $1 is "pha", $& is "b"
"alphabet" =~ /([^aeiou][a-z][aeiou])[a-z]\K/; # $1 is "pha", $& is ""
BUGS
I fixed a bug where "\K" following a simple thing (like a letter that isn't followed by a quantifier) didn't work properly.If you're using this module, you don't have a version of Perl with the "\K" escape built-in. Bummer. I should try to make it built-in.
HISTORY
- 0.02
- Fixed "/a\Kb/" to become "/a.{0}\Kb/", which makes a nasty bug disappear.
- 0.01
- Original release.
AUTHOR
Jeff "japhy" Pinyan, japhy@pobox.comCOPYRIGHT AND LICENSE
Copyright (C) 2004 by japhyThis library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.3 or, at your option, any later version of Perl 5 you may have available.
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre