Perl::Critic::Policy::ControlStructures::ProhibitNegativeExpressionsInUnlessAndUntilConditions(3pm) User Contributed Perl Documentation Perl::Critic::Policy::ControlStructures::ProhibitNegativeExpressionsInUnlessAndUntilConditions(3pm)

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

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

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

This Policy is not configurable except for the standard options.

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

Elliot Shank "<perl@galumph.com>"

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.

2023-07-26 perl v5.38.0