##############################################################################
#      $URL: http://perlcritic.tigris.org/svn/perlcritic/tags/Perl-Critic-1.061/lib/Perl/Critic/Policy/BuiltinFunctions/ProhibitVoidMap.pm $
#     $Date: 2007-07-25 00:05:41 -0700 (Wed, 25 Jul 2007) $
#   $Author: thaljef $
# $Revision: 1789 $
##############################################################################

package Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap;

use strict;
use warnings;
use Perl::Critic::Utils qw{ :severities :classification &is_in_void_context };
use base 'Perl::Critic::Policy';

our $VERSION = 1.061;

#-----------------------------------------------------------------------------

my $desc = q{"map" used in void context};
my $expl = q{Use a "for" loop instead};

#-----------------------------------------------------------------------------

sub supported_parameters { return ()                     }
sub default_severity  { return $SEVERITY_MEDIUM       }
sub default_themes    { return qw( core maintenance ) }
sub applies_to        { return 'PPI::Token::Word'     }

#-----------------------------------------------------------------------------

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

    return if $elem ne 'map';
    return if not is_function_call($elem);
    return if not is_in_void_context($elem);

    return $self->violation( $desc, $expl, $elem );
}


1;

__END__

#-----------------------------------------------------------------------------

=pod

=head1 NAME

Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap

=head1 DESCRIPTION

C<map> and C<grep> are intended to be pure functions, not mutators.
If you want to iterate with side-effects, then you should use a proper
C<for> or C<foreach> loop.

  grep{ print frobulate($_) } @list;           #not ok
  print map{ frobulate($_) } @list;            #ok

  grep{ $_ = lc $_ } @list;                    #not ok
  for( @list ){ $_ = lc $_  };                 #ok

  map{ push @frobbed, frobulate($_) } @list;   #not ok
  @frobbed = map { frobulate($_) } @list;      #ok

=head1 AUTHOR

Jeffrey Ryan Thalhammer <thaljef@cpan.org>

=head1 COPYRIGHT

Copyright (c) 2005-2007 Jeffrey Ryan Thalhammer.  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.

=cut

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