package Perl::Critic::Policy::RegularExpressions::RequireLineBoundaryMatching;

use 5.006001;
use strict;
use warnings;
use Readonly;

use Perl::Critic::Utils qw{ :severities };

use base 'Perl::Critic::Policy';

our $VERSION = '1.140';


Readonly::Scalar my $DESC => q{Regular expression without "/m" flag};
Readonly::Scalar my $EXPL => [ 237 ];


sub supported_parameters { return ()                    }
sub default_severity     { return $SEVERITY_LOW         }
sub default_themes       { return qw(core pbp cosmetic) }
sub applies_to           { return qw(PPI::Token::Regexp::Match
                                     PPI::Token::QuoteLike::Regexp) }


sub violates {
    my ( $self, $elem, $doc ) = @_;

    my $re = $doc->ppix_regexp_from_element( $elem )
        or return;
    $re->modifier_asserted( 'm' )
        or return $self->violation( $DESC, $EXPL, $elem );

    return; #ok!;





=head1 NAME

Perl::Critic::Policy::RegularExpressions::RequireLineBoundaryMatching - Always use the C</m> modifier with regular expressions.


This Policy is part of the core L<Perl::Critic|Perl::Critic>


Folks coming from a C<sed> or C<awk> background tend to assume that
C<'$'> and C<'^'> match the beginning and end of the line, rather than
then beginning and end of the string.  Adding the '/m' flag to your
regex makes it behave as most people expect it should.

    my $match = m{ ^ $pattern $ }x;  #not ok
    my $match = m{ ^ $pattern $ }xm; #ok


This Policy is not configurable except for the standard options.

=head1 NOTES

For common regular expressions like e-mail addresses, phone numbers,
dates, etc., have a look at the L<Regexp::Common|Regexp::Common> module.
Also, be cautions about slapping modifier flags onto existing regular
expressions, as they can drastically alter their meaning.  See
L<> for an interesting
discussion on the effects of blindly modifying regular expression

=head1 AUTHOR

Jeffrey Ryan Thalhammer  <>


Copyright (c) 2005-2011 Imaginative Software Systems. All 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.


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