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 v5.24.1                                       2017Perl::Critic::Policy::Variables::ProhibitPackageVars(3pm)