Perl::Critic::Policy::Variables::RequireLocalizedPunctuationVars(3)
NAME
Perl::Critic::Policy::Variables::RequireLocalizedPunctuationVars -
Magic variables should be assigned as "local".
AFFILIATION
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION
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.
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.
# 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.
There are exemptions for $_ and @_, and the English equivalent $ARG.
CONFIGURATION
You can configure your own exemptions using the "allow" option:
[Variables::RequireLocalizedPunctuationVars]
allow = @ARGV $ARGV
These are added to the default exemptions.
CREDITS
Initial development of this policy was supported by a grant from the
Perl Foundation.
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.
perl v5.28.Perl::Critic::Policy::Variables::RequireLocalizedPunctuationVars(3)
perl-critic 1.134.0 - Generated Thu Jun 6 14:25:22 CDT 2019