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Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidGrep - Don't use grep in void contexts.


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


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


This Policy is not configurable except for the standard options.


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.