Perl::Critic::Policy::ControlStructures::ProhibitUnlessBlocks3pm

Write "if(! $condition)" instead of "unless($condition)".

Affiliation

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

Conway discourages using "unless" because it leads to double-negatives that are hard to understand. Instead, reverse the logic and use "if".

    unless($condition) { do_something() } #not ok
    unless(! $no_flag) { do_something() } #really bad
    if( ! $condition)  { do_something() } #ok

This Policy only covers the block-form of "unless". For the postfix variety, see "ProhibitPostfixControls".

This Policy is not configurable except for the standard options.

10 releases since Debian 5.0 (Lenny); the text changed 9 times.