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Perl::Critic::Policy::Variables::RequireLocalizedPunctuationVars.3pm
Langue: en
Version: 2009-03-07 (debian - 07/07/09)
Section: 3 (Bibliothèques de fonctions)
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 File::Slurp!) 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.
CAVEATS
The current PPI (v1.118) has a bug where $^ variables absorb following whitespace by mistake. This makes it harder to spot those as magic variables. Hopefully this will be fixed by PPI 1.200. In the meantime, we have a workaround in this module.Additionally, PPI v1.118 fails to recognize %! and %^H as magic variables. PPI instead sees the ``%'' as a modulus operator. We have no workaround for that bug right now.
CREDITS
Initial development of this policy was supported by a grant from the Perl Foundation.AUTHOR
Chris Dolan <cdolan@cpan.org>COPYRIGHT
Copyright (c) 2007-2009 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.
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre