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Elliot Shank > Perl-Critic-1.116 > Perl::Critic::Policy::Subroutines::ProhibitUnusedPrivateSubroutines



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Module Version: 1.116   Source   Latest Release: Perl-Critic-1.132


Perl::Critic::Policy::Subroutines::ProhibitUnusedPrivateSubroutines - Prevent unused private subroutines.


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


By convention Perl authors (like authors in many other languages) indicate private methods and variables by inserting a leading underscore before the identifier. This policy catches such subroutines which are not used in the file which declares them.

This module defines a 'use' of a subroutine as a subroutine or method call to it (other than from inside the subroutine itself), a reference to it (i.e. my $foo = \&_foo), a goto to it outside the subroutine itself (i.e. goto &_foo), or the use of the subroutine's name as an even-numbered argument to use overload.


You can define what a private subroutine name looks like by specifying a regular expression for the private_name_regex option in your .perlcriticrc:

    private_name_regex = _(?!_)\w+

The above example is a way of saying that subroutines that start with a double underscore are not considered to be private. (Perl::Critic, in its implementation, uses leading double underscores to indicate a distribution-private subroutine -- one that is allowed to be invoked by other Perl::Critic modules, but not by anything outside of Perl::Critic.)

You can configure additional subroutines to accept by specifying them in a space-delimited list to the allow option:

    allow = _bar _baz

These are added to the default list of exemptions from this policy. So the above allows sub _bar {} and sub _baz {}, even if they are not referred to in the module that defines them.


This policy is derived from Perl::Critic::Policy::Subroutines::ProtectPrivateSubs, which looks at the other side of the problem.


Does not forbid sub Foo::_foo{} because it does not know (and can not assume) what is in the Foo package.




Chris Dolan <>


Copyright (c) 2009-2011 Thomas R. Wyant, III.

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.

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