NAME

       Perl::Critic::Policy::Variables::ProhibitPackageVars - Eliminate globals declared with
       "our" or "use vars".

AFFILIATION

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

DESCRIPTION

       Conway suggests avoiding package variables completely, because they expose your internals
       to other packages.  Never use a package variable when a lexical variable will suffice.  If
       your package needs to keep some dynamic state, consider using an object or closures to
       keep the state private.

       This policy assumes that you're using "strict vars" so that naked variable declarations
       are not package variables by default.  Thus, it complains you declare a variable with
       "our" or "use vars", or if you make reference to variable with a fully-qualified package
       name.

           $Some::Package::foo = 1;    # not ok
           our $foo            = 1;    # not ok
           use vars '$foo';            # not ok
           $foo = 1;                   # not allowed by 'strict'
           local $foo = 1;             # bad taste, but technically ok.
           use vars '$FOO';            # ok, because it's ALL CAPS
           my $foo = 1;                # ok

       In practice though, its not really practical to prohibit all package variables.  Common
       variables like $VERSION and @EXPORT need to be global, as do any variables that you want
       to Export.  To work around this, the Policy overlooks any variables that are in ALL_CAPS.
       This forces you to put all your exported variables in ALL_CAPS too, which seems to be the
       usual practice anyway.

CONFIGURATION

       There is room for exceptions.  Some modules, like the core File::Find module, use package
       variables as their only interface, and others like Data::Dumper use package variables as
       their most common interface.  These module can be specified from your .perlcriticrc file,
       and the policy will ignore them.

           [Variables::ProhibitPackageVars]
           packages = Data::Dumper File::Find FindBin Log::Log4perl

       This is the default setting.  Using "packages ="  will override these defaults.

       You can also add packages to the defaults like so:

           [Variables::ProhibitPackageVars]
           add_packages = My::Package

       You can add package "main" to the list of packages, but that will only OK variables
       explicitly in the "main" package.

SEE ALSO

       Perl::Critic::Policy::Variables::ProhibitPunctuationVars

       Perl::Critic::Policy::Variables::ProhibitLocalVars

AUTHOR

       Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>

COPYRIGHT

       Copyright (c) 2005-2011 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.

perl v5.18.1                            Perl::Critic::Policy::Variables::ProhibitPackageVars(3pm)