Regexp::Compare - partial ordering for regular expressions
use Regexp::Compare qw(is_less_or_equal); if (is_less_or_equal($rx[i], $rx[j])) { print "duplicate: $rx[i]\n"; }
This module implements a function comparing regular expressions: it returns true if all strings matched by the first regexp are also matched by the second. It's meant to be used for optimization of blacklists implemented by regular expressions (like, for example, http://www.communitywiki.org/cw/BannedContent ).
http://www.communitywiki.org/cw/BannedContent
Both arguments of is_less_or_equal are strings - IOW the call
is_less_or_equal
$rv = is_less_or_equal($rx, /hardcoded/i);
probably won't do what you want - use
$rv = is_less_or_equal($rx, '(?i:hardcoded)');
instead.
False return value does not imply that there's a string matched by the first regexp which isn't matched by the second - many regular expressions (i.e. those containing Perl code) are impossible to compare, and this module doesn't even implement all possible comparisons.
EBCDIC-based platforms not supported
comparison of character classes is simplified and probably has some incorrect corner cases
comparison fails for locale-specific constructs
comparison fails for regexps with backreferences
global variables affecting regexp matching are ignored
function may die for unusual (legal but unexpected) regexp constructs
Vaclav Barta, <vbarta@mangrove.cz>
Copyright (C) 2006 - 2017 by Vaclav Barta
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.22.0 or, at your option, any later version of Perl 5 you may have available.
Rx
To install Regexp::Compare, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Regexp::Compare
CPAN shell
perl -MCPAN -e shell install Regexp::Compare
For more information on module installation, please visit the detailed CPAN module installation guide.