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Perl::Critic::Policy::Variables::RequireLexicalLoopIterators.3pm

NAME

Perl::Critic::Policy::Variables::RequireLexicalLoopIterators - Write "for my $element (@list) {...}" instead of "for $element (@list) {...}".

AFFILIATION

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

DESCRIPTION

"for"/"foreach" loops always create new lexical variables for named iterators. In other words

     for $zed (...) {
         ...
     }
 
 

is equivalent to

     for my $zed (...) {
         ...
     }
 
 

This may not seem like a big deal until you see code like

     my $bicycle;
     for $bicycle (@things_attached_to_the_bike_rack) {
         if (
                 $bicycle->is_red()
             and $bicycle->has_baseball_card_in_spokes()
             and $bicycle->has_bent_kickstand()
         ) {
             $bicycle->remove_lock();
 
             last;
         }
     }
 
     if ( $bicycle and $bicycle->is_unlocked() ) {
         ride_home($bicycle);
     }
 
 

which is not going to allow you to arrive in time for dinner with your family because the $bicycle outside the loop is different from the $bicycle inside the loop. You may have freed your bicycle, but you can't remember which one it was.

CONFIGURATION

This Policy is not configurable except for the standard options.

AUTHOR

Jeffrey Ryan Thalhammer <thaljef@cpan.org>

COPYRIGHT

Copyright (c) 2005-2009 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.