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THALJEF / Perl-Critic-1.051 / lib / Perl / Critic / Policy / BuiltinFunctions / ProhibitVoidMap.pm 

            

              
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##############################################################################
#      $URL: http://perlcritic.tigris.org/svn/perlcritic/tags/Perl-Critic-1.051/lib/Perl/Critic/Policy/BuiltinFunctions/ProhibitVoidMap.pm $
#     $Date: 2007-04-12 01:26:09 -0700 (Thu, 12 Apr 2007) $
#   $Author: thaljef $
# $Revision: 1467 $
##############################################################################
package Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap;
use strict;
use warnings;
use Perl::Critic::Utils qw{ :severities :classification };
use base 'Perl::Critic::Policy';
our $VERSION = 1.051;
#-----------------------------------------------------------------------------
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);
    if( my $sib = $elem->sprevious_sibling() ){
        return if $sib;
    }
    if( my $parent = $elem->statement()->parent() ){
        return if $parent->isa('PPI::Structure::List');
        return if $parent->isa('PPI::Structure::ForLoop');
        return if $parent->isa('PPI::Structure::Condition');
        return if $parent->isa('PPI::Structure::Constructor');
        if (my $grand_parent = $parent->parent() ){
            return if $parent->isa('PPI::Structure::Block') &&
                !$grand_parent->isa('PPI::Statement::Compound');
        }
    }
    #Otherwise, must be void context
    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
# 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 :