Perl::Critic::Policy::Subroutines::ProhibitBuiltinHomonyms - Don't declare your own open function.


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


Common sense dictates that you shouldn't declare subroutines with the same name as one of Perl's built-in functions or keywords. See perlfunc for a list of built-in functions; see perlsyn for keywords.

  sub open {}    #not ok
  sub exit {}    #not ok
  sub print {}   #not ok
  sub foreach {} #not ok
  sub if {}      #not ok

  #You get the idea...

Exceptions are made for BEGIN, END, INIT and CHECK blocks, as well as AUTOLOAD, DESTROY, and import subroutines.


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

    allow = default index

These are added to the default list of exemptions from this policy. So the above allows sub default {} and sub index {}.


It is reasonable to declare an object method with the same name as a Perl built-in function, since they are easily distinguished from each other. However, at this time, Perl::Critic cannot tell whether a subroutine is static or an object method.


Jeffrey Ryan Thalhammer <>


Copyright (c) 2005-2022 Imaginative Software Systems. All rights reserved.

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.