NAME

       Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidGrep - Don't use "grep" 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.

perl v5.24.1                        Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidGrep(3pm)