| /usr/local/perl/lib/site_perl/5.8.5/Perl/Critic/Policy/BuiltinFunctions/ProhibitBooleanGrep.pm |
Perl::Critic::Policy::BuiltinFunctions::ProhibitBooleanGrep
Using grep in boolean context is a common idiom for checking if any
elements in a list match a condition. This works because boolean context is a
subset of scalar context, and grep returns the number of matches in scalar
context. A non-zero number of matches means a match.
But consider the case of a long array where the first element is a match.
Boolean grep still checks all of the rest of the elements needlessly.
Instead, a better solution is to use the any function from
the List::MoreUtils manpage, which short-circuits after the first successful match to
save time.
The algorithm for detecting boolean context takes a LOT of shortcuts. There are lots of known false negatives. But, I was conservative in writing this, so I hope there are no false positives.
Chris Dolan <cdolan@cpan.org>
Initial development of this policy was supported by a grant from the Perl Foundation.
Copyright (c) 2007 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.
| /usr/local/perl/lib/site_perl/5.8.5/Perl/Critic/Policy/BuiltinFunctions/ProhibitBooleanGrep.pm |