--- /dev/null
+##############################################################################
+# $URL: http://perlcritic.tigris.org/svn/perlcritic/trunk/Perl-Critic/lib/Perl/Critic/Policy/RegularExpressions/ProhibitEscapedMetacharacters.pm $
+# $Date: 2008-07-03 10:19:10 -0500 (Thu, 03 Jul 2008) $
+# $Author: clonezone $
+# $Revision: 2489 $
+##############################################################################
+
+package Perl::Critic::Policy::RegularExpressions::ProhibitEscapedMetacharacters;
+
+use 5.006001;
+use strict;
+use warnings;
+use Readonly;
+
+use English qw(-no_match_vars);
+use List::MoreUtils qw(any);
+
+use Perl::Critic::Utils qw{ :booleans :severities hashify };
+use Perl::Critic::Utils::PPIRegexp qw{ ppiify parse_regexp };
+use base 'Perl::Critic::Policy';
+
+our $VERSION = '1.088';
+
+#-----------------------------------------------------------------------------
+
+Readonly::Scalar my $DESC => q{Use character classes for literal metachars instead of escapes};
+Readonly::Scalar my $EXPL => [247];
+
+Readonly::Hash my %REGEXP_METACHARS =>
+ hashify split m/ /xms, '{ } ( ) . * + ? |'; ##no critic(Interpolation)
+
+#-----------------------------------------------------------------------------
+
+sub supported_parameters { return qw() }
+sub default_severity { return $SEVERITY_LOWEST }
+sub default_themes { return qw( core pbp cosmetic ) }
+sub applies_to { return qw(PPI::Token::Regexp::Match
+ PPI::Token::Regexp::Substitute
+ PPI::Token::QuoteLike::Regexp) }
+
+#-----------------------------------------------------------------------------
+
+sub violates {
+ my ( $self, $elem, undef ) = @_;
+
+ # optimization: don't bother parsing the regexp if there are no escapes
+ return if $elem !~ m/\\/xms;
+
+ my $re = ppiify(parse_regexp($elem));
+ return if !$re;
+
+ # Must pass a sub to find() because our node classes don't start with PPI::
+ my $exacts = $re->find(sub {$_[1]->isa('Perl::Critic::PPIRegexp::exact')});
+ return if !$exacts;
+ for my $exact (@{$exacts}) {
+ my @escapes = $exact =~ m/\\(.)/gxms;
+ return $self->violation( $DESC, $EXPL, $elem ) if any { $REGEXP_METACHARS{$_} } @escapes;
+ }
+
+ return; # OK
+}
+
+1;
+
+__END__
+
+#-----------------------------------------------------------------------------
+
+=pod
+
+=for stopwords IPv4
+
+=head1 NAME
+
+Perl::Critic::Policy::RegularExpressions::ProhibitEscapedMetacharacters - Use character classes for literal meta-characters instead of escapes.
+
+=head1 AFFILIATION
+
+This Policy is part of the core L<Perl::Critic> distribution.
+
+
+=head1 DESCRIPTION
+
+Ever heard of leaning toothpick syndrome? That comes from writing
+regular expressions that match on characters that are significant in
+regular expressions. For example, the expression to match four
+forward slashes looks like:
+
+ m/\/\/\/\//;
+
+Well, this policy doesn't solve that problem (write it as C<m{////}>
+instead!) but solves a related one. As seen above, the escapes make
+the expression hard to parse visually. One solution is to use
+character classes. You see, inside of character classes, the only
+characters that are special are C<\>, C<]>, C<^> and C<->, so you don't need
+to escape the others. So instead of the following loose IPv4 address matcher:
+
+ m/ \d+ \. \d+ \. \d+ \. \d+ /x;
+
+You could write:
+
+ m/ \d+ [.] \d+ [.] \d+ [.] \d+ /x;
+
+which is certainly more readable, if less recognizable prior the
+publication of Perl Best Practices. (Of course, you should really use
+L<Regexp::Common::net> to match IPv4 addresses!)
+
+Specifically, this policy forbids backslashes immediately prior to the following characters:
+
+ { } ( ) . * + ? | #
+
+We make special exception for C<$> because C</[$]/> turns into
+C</[5.008006/> for Perl 5.8.6. We also make an exception for C<^>
+because it has special meaning (negation) in a character class.
+Finally, C<[> and C<]> are exempt, of course, because they are awkward
+to represent in character classes.
+
+Note that this policy does not forbid unnecessary escaping. So go
+ahead and (pointlessly) escape C<!> characters.
+
+
+=head1 CONFIGURATION
+
+This Policy is not configurable except for the standard options.
+
+
+=head1 BUGS
+
+Perl treats C<m/[#]/x> in unexpected ways.
+I think it's a bug in Perl itself, but am not 100% sure that I have
+not simply misunderstood...
+
+This part makes sense:
+
+ "#f" =~ m/[#]f/x; # match
+ "#f" =~ m/[#]a/x; # no match
+
+This doesn't:
+
+ $qr = qr/f/;
+ "#f" =~ m/[#]$qr/x; # no match
+
+Neither does this:
+
+ print qr/[#]$qr/x; # yields '(?x-ism:[#]$qr
+ )'
+
+=head1 CREDITS
+
+Initial development of this policy was supported by a grant from the Perl Foundation.
+
+=head1 AUTHOR
+
+Chris Dolan <cdolan@cpan.org>
+
+=head1 COPYRIGHT
+
+Copyright (c) 2007-2008 Chris Dolan. Many rights reserved.
+
+This program is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself. The full text of this license
+can be found in the LICENSE file included with this module
+
+=cut
+
+# Local Variables:
+# mode: cperl
+# cperl-indent-level: 4
+# fill-column: 78
+# indent-tabs-mode: nil
+# c-indentation-style: bsd
+# End:
+# ex: set ts=8 sts=4 sw=4 tw=78 ft=perl expandtab shiftround :
projects / dh-make-perl / blobdiff