Perl::Critic::Policy::Modules::RequireExplicitPackage
In general, the first statement of any Perl module or library should be a package statement. Otherwise, all the code that comes before the package statement is getting executed in the caller's package, and you have no idea who that is. Good encapsulation and common decency require your module to keep its innards to itself.
package
As for programs, most people understand that the default package is main, so this Policy doesn't apply to files that begin with a perl shebang. If you want to require an explicit package declaration in all files, including programs, then add the following to your .perlcriticrc file
main
[Modules::RequireExplicitPackage] exempt_scripts = 0
There are some valid reasons for not having a package statement at all. But make sure you understand them before assuming that you should do it too.
This policy was formerly called ProhibitUnpackagedCode which sounded a bit odd. If you get lots of "Cannot load policy module" errors, then you probably need to change ProhibitUnpackagedCode to RequireExplicitPackage in your .perlcriticrc file.
ProhibitUnpackagedCode
RequireExplicitPackage
Jeffrey Ryan Thalhammer <thaljef@cpan.org>
Copyright (c) 2005-2007 Jeffrey Ryan Thalhammer. 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.
To install Perl::Critic, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Perl::Critic
CPAN shell
perl -MCPAN -e shell install Perl::Critic
For more information on module installation, please visit the detailed CPAN module installation guide.