Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap(3)

NAME
Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap - Don't use "map" in void contexts.

AFFILIATION
This Policy is part of the core Perl::Critic distribution.

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

CONFIGURATION
This Policy is not configurable except for the standard options.

AUTHOR
Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>

COPYRIGHT
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.