perl::critic::policy::variables::requirenegativeindices(3pm) [debian man page]

Perl::Critic::Policy::Variables::RequireNegativeIndices(User Contributed Perl DocumentPerl::Critic::Policy::Variables::RequireNegativeIndices(3pm)

NAME

       Perl::Critic::Policy::Variables::RequireNegativeIndices - Negative array index should be used.

AFFILIATION

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

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];

CONFIGURATION

       This Policy is not configurable except for the standard options.

AUTHOR

       Chris Dolan <cdolan@cpan.org>

COPYRIGHT

       Copyright (c) 2006-2011 Chris Dolan.

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

perl v5.14.2							    2012-06-07	      Perl::Critic::Policy::Variables::RequireNegativeIndices(3pm)

Perl::Critic::Policy::Variables::ProhibitMatchVars(3)	User Contributed Perl Documentation  Perl::Critic::Policy::Variables::ProhibitMatchVars(3)

NAME

       Perl::Critic::Policy::Variables::ProhibitMatchVars - Avoid "$`", "$&", "$'" and their English equivalents.

AFFILIATION

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

DESCRIPTION

       Using the "match variables" "$`", $&, and/or "$'" can significantly degrade the performance of a program.  This policy forbids using them
       or their English equivalents.  See perldoc English or PBP page 82 for more information.

       It used to forbid plain "use English;" because it ends up causing the performance side-effects of the match variables.  However, the
       message emitted for that situation was not at all clear and there is now Perl::Critic::Policy::Modules::RequireNoMatchVarsWithUseEnglish,
       which addresses this situation directly.

CONFIGURATION

       This Policy is not configurable except for the standard options.

AUTHOR

       Chris Dolan <cdolan@cpan.org>

COPYRIGHT

       Copyright (c) 2006-2011 Chris Dolan.

       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 v5.16.3							    2014-06-09		     Perl::Critic::Policy::Variables::ProhibitMatchVars(3)