NAME

Perl::Critic::Policy::Variables::RequireNegativeIndices

DESCRIPTION

Conway points out that

  $arr[$#arr];
  $arr[$#arr-1];
  $arr[@arr-1];
  $arr[@arr-2];

are equivalent to

  $arr[-1];
  $arr[-2];
  $arr[-1];
  $arr[-2];

and the latter are more readable, performant and maintainable. The latter is because the programmer no longer needs to keep two variable names matched.

This policy notices all of the simple forms of the above problem, but does not recognize any of these more complex examples:

   $some->[$data_structure]->[$#{$some->[$data_structure]} -1];
   my $ref = \@arr;
   $ref->[$#arr];

AUTHOR

Chris Dolan <cdolan@cpan.org>

COPYRIGHT

Copyright (C) 2006 Chris Dolan. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.