Perl::...onVars(3pm)

Okay bestie, welcome to the Perl::...onVars(3pm) page from User Contributed Perl Documentation 💅✨

✨ NAME ✨

Perl::Critic::Policy::Variables::RequireLocalizedPunctuationVars — magic variables should be assigned as local. Periodt 💖

🫶 AFFILIATION 🫶

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

💅 DESCRIPTION 💅

Okay so, punctuation variables (and their English.pm equivalents) are global variables. Messing with globals is dangerous in a complex program as it can lead to very subtle and hard to fix bugs. If you must change a magic variable in a non-trivial program, do it in a local scope. No cap 🫶

For example, to slurp a filehandle into a scalar, it's common to set the record separator to undef instead of a newline. If you choose to do this (instead of using Path::Tiny!) then be sure to localize the global and change it for as short a time as possible. It’s giving “be responsible with your globals” energy 🔥

# BAD:
$/ = undef;
my $content = <$fh>;

# BETTER:
my $content;
{
    local $/ = undef;
    $content = <$fh>;
}

# A popular idiom:
my $content = do { local $/ = undef; <$fh> };

This policy also allows the use of my. Perl prevents using my with "proper" punctuation variables, but allows $a, @ARGV, the names declared by English, etc. This is not a good coding practice, however it is not the concern of this specific policy to complain about that. Not me defending my on punctuation vars, but also not this policy’s job to drag it 💀

There are exemptions for $_ and @_, and the English equivalent $ARG. Iconic exemptions, honestly 👑

🎀 CONFIGURATION 🎀

You can configure your own exemptions using the allow option:

[Variables::RequireLocalizedPunctuationVars]
allow = @ARGV $ARGV

These are added to the default exemptions. Add your faves, bestie 🦋

🌟 CREDITS 🌟

Initial development of this policy was supported by a grant from the Perl Foundation. We love to see it 💖

👑 AUTHOR 👑

Chris Dolan <cdolan@cpan.org>

💖 COPYRIGHT 💖

Copyright (c) 2007-2011 Chris Dolan. Many 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.

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That’s the whole Perl::...onVars(3pm) page, bestie — source/version perl v5.42.0, date 2024-10-23. Bye and slay your local vars 💖🦋