NAME

       Perl::Critic::Policy::ControlStructures::ProhibitNegativeExpressionsInUnlessAndUntilConditions
       - Don't use operators like "not", "!~", and "le" within "until" and "unless".

AFFILIATION

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

DESCRIPTION

           until ($foo ne 'blah') {          #not ok
               ...
           }

           while ($foo eq 'blah') {          #ok
               ...
           }

       A number of people have problems figuring out the meaning of doubly negated expressions.
       "unless" and "until" are both negative constructs, so any negative (e.g. "!~") or
       reversible operators (e.g.  "le") included in their conditional expressions are double
       negations.  Conway considers the following operators to be difficult to understand within
       "unless" and "until":

         ! not
         !~ ne !=
         <   >   <=  >=  <=>
         lt  gt  le  ge  cmp

CONFIGURATION

       This Policy is not configurable except for the standard options.

SEE ALSO

       Perl::Critic::Policy::ControlStructures::ProhibitUnlessBlocks

AUTHOR

       Elliot Shank "<perl@galumph.com>"

COPYRIGHT

       Copyright (c) 2007-2011 Elliot Shank.

       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::Critic::Policy::ControlStructures::ProhibitNegativeExpressionsInUnlessAndUntilConditions(3pm)