Perl::Critic::Policy::Variables::RequireLexicalLoopIterators(3)
NAME
Perl::Critic::Policy::Variables::RequireLexicalLoopIterators - Write
"for my $element (@list) {...}" instead of "for $element (@list)
{...}".
AFFILIATION
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION
This policy asks you to use "my"-style lexical loop iterator variables:
foreach my $zed (...) {
...
}
Unless you use "my", "for"/"foreach" loops use a global variable with
its value "local" to the block. In other words,
foreach $zed (...) {
...
}
is more-or-less equivalent to
{
local $zed
foreach $zed (...) {
...
}
}
This may not seem like a big deal until you see code like
my $bicycle;
for $bicycle (@things_attached_to_the_bike_rack) {
if (
$bicycle->is_red()
and $bicycle->has_baseball_card_in_spokes()
and $bicycle->has_bent_kickstand()
) {
$bicycle->remove_lock();
last;
}
}
if ( $bicycle and $bicycle->is_unlocked() ) {
ride_home($bicycle);
}
which is not going to allow you to arrive in time for dinner with your
family because the $bicycle outside the loop is not changed by the
loop. You may have unlocked your bicycle, but you can't remember which
one it was.
Lexical loop variables were introduced in Perl 5.004. This policy does
not report violations on code which explicitly specifies an earlier
version of Perl (e.g. "require 5.002;").
CONFIGURATION
This Policy is not configurable except for the standard options.
SEE ALSO
"Foreach Loops" in perlsyn(1)
"my() in Control Structures" in perl5004delta(1)
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 v5.28.2 Perl::Critic::Policy::Variables::RequireLexicalLoopIterators(3)
perl-critic 1.134.0 - Generated Thu Jun 6 14:16:56 CDT 2019