--- /dev/null
+##############################################################################
+# $URL: http://perlcritic.tigris.org/svn/perlcritic/trunk/Perl-Critic/lib/Perl/Critic/Policy/RegularExpressions/ProhibitFixedStringMatches.pm $
+# $Date: 2008-07-03 10:19:10 -0500 (Thu, 03 Jul 2008) $
+# $Author: clonezone $
+# $Revision: 2489 $
+##############################################################################
+
+package Perl::Critic::Policy::RegularExpressions::ProhibitFixedStringMatches;
+
+use 5.006001;
+use strict;
+use warnings;
+use Readonly;
+
+use English qw(-no_match_vars);
+use Carp;
+
+use Perl::Critic::Utils qw{ :booleans :severities };
+use Perl::Critic::Utils::PPIRegexp qw{ get_match_string get_modifiers };
+use base 'Perl::Critic::Policy';
+
+our $VERSION = '1.088';
+
+#-----------------------------------------------------------------------------
+
+Readonly::Scalar my $DESC => q{Use 'eq' or hash instead of fixed-pattern regexps};
+Readonly::Scalar my $EXPL => [271,272];
+
+Readonly::Scalar my $RE_METACHAR => qr/[\\#\$()*+.?\@\[\]^{|}]/xms;
+
+#-----------------------------------------------------------------------------
+
+sub supported_parameters { return qw() }
+sub default_severity { return $SEVERITY_LOW }
+sub default_themes { return qw( core pbp performance ) }
+sub applies_to { return qw(PPI::Token::Regexp::Match
+ PPI::Token::Regexp::Substitute
+ PPI::Token::QuoteLike::Regexp) }
+
+#-----------------------------------------------------------------------------
+
+sub violates {
+ my ( $self, $elem, undef ) = @_;
+
+ my $re = get_match_string($elem);
+
+ # only flag regexps that are anchored front and back
+ if ($re =~ m{\A \s*
+ (\\A|\^) # front anchor == $1
+ (.*?)
+ (\\z|\$) # end anchor == $2
+ \s* \z}xms) {
+
+ my ($front_anchor, $words, $end_anchor) = ($1, $2, $3);
+
+ # If it's a multiline match, then end-of-line anchors don't represent the whole string
+ if ($front_anchor eq q{^} || $end_anchor eq q{$}) {
+ my %mods = get_modifiers($elem);
+ return if $mods{m};
+ }
+
+ # check for grouping and optional alternation. Grouping may or may not capture
+ if ($words =~ m{\A \s*
+ [(] # start group
+ (?:[?]:)? # optional non-capturing indicator
+ \s* (.*?) \s* # interior of group
+ [)] # end of group
+ \s* \z}xms) {
+ $words = $1;
+ $words =~ s/[|]//gxms; # ignore alternation inside of parens -- just look at words
+ }
+
+ # Regexps that contain metachars are not fixed strings
+ return if $words =~ m/$RE_METACHAR/oxms;
+
+ return $self->violation( $DESC, $EXPL, $elem );
+
+ } else {
+ return; # OK
+ }
+}
+
+1;
+
+__END__
+
+#-----------------------------------------------------------------------------
+
+=pod
+
+=head1 NAME
+
+Perl::Critic::Policy::RegularExpressions::ProhibitFixedStringMatches - Use C<eq> or hash instead of fixed-pattern regexps.
+
+=head1 AFFILIATION
+
+This Policy is part of the core L<Perl::Critic> distribution.
+
+
+=head1 DESCRIPTION
+
+A regular expression that matches just a fixed set of constant strings is wasteful
+of performance and is hard on maintainers. It is much more readable and
+often faster to use C<eq> or a hash to match such strings.
+
+ # Bad
+ my $is_file_function = $token =~ m/\A (?: open | close | read ) \z/xms;
+
+ # Faster and more readable
+ my $is_file_function = $token eq 'open' ||
+ $token eq 'close' ||
+ $token eq 'read';
+
+For larger numbers of strings, a hash is superior:
+
+ # Bad
+ my $is_perl_keyword =
+ $token =~ m/\A (?: chomp | chop | chr | crypt | hex | index
+ lc | lcfirst | length | oct | ord | ... ) \z/xms;
+
+ # Better
+ Readonly::Hash my %PERL_KEYWORDS => map {$_ => 1} qw(
+ chomp chop chr crypt hex index lc lcfirst length oct ord ...
+ );
+ my $is_perl_keyword = $PERL_KEYWORD{$token};
+
+=head2 VARIANTS
+
+This policy detects both grouped and non-grouped strings. The grouping may or
+may not be capturing. The grouped body may or may not be alternating. C<\A>
+and C<\z> are always considered anchoring which C<^> and C<$> are considered
+anchoring is the C<m> regexp option is not in use. Thus, all of these are
+violations:
+
+ m/^foo$/;
+ m/\A foo \z/x;
+ m/\A foo \z/xm;
+ m/\A(foo)\z/;
+ m/\A(?:foo)\z/;
+ m/\A(foo|bar)\z/;
+ m/\A(?:foo|bar)\z/;
+
+Furthermore, this policy detects violations in C<m//>, C<s///> and C<qr//>
+constructs, as you would expect.
+
+
+=head1 CONFIGURATION
+
+This Policy is not configurable except for the standard options.
+
+
+=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