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.

AUTHOR

Elliot Shank <perl@galumph.com>

COPYRIGHT