Perl::Critic::Policy::RegularExpressions::ProhibitCapturUserhContributed)Perl::Critic::Policy::RegularExpressions::ProhibitCaptureWithoutTest(3pm)

NAME

       Perl::Critic::Policy::RegularExpressions::ProhibitCaptureWithoutTest - Capture variable used outside conditional.

AFFILIATION

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

DESCRIPTION

       If a regexp match fails, then any capture variables ($1, $2, ...) will be undefined.  Therefore it's important to check the return value of
       a match before using those variables.

       This policy checks that the previous regexp for which the capture variable is in-scope is either in a conditional or causes an exception or
       other control transfer (i.e. "next", "last", "redo", "return", or sometimes "goto") if the match fails.

       A "goto" is only accepted by this policy if it is a co-routine call (i.e.  "goto &foo") or a "goto LABEL" where the label does not fall
       between the "goto" and the capture variable in the scope of the "goto". A computed "goto" (i.e. something like "goto (qw{foo bar
       baz})[$i]") is not accepted by this policy because its target can not be statically determined.

       This policy does not check whether that conditional is actually testing a regexp result, nor does it check whether a regexp actually has a
       capture in it.  Those checks are too hard.

       This policy also does not check arbitrarily complex conditionals guarding regexp results, for pretty much the same reason.  Simple things
       like

	m/(foo)/ or die "No foo!";
	die "No foo!" unless m/(foo)/;

       will be handled, but something like

	m/(foo) or do {
	  ... lots of complicated calculations here ...
	  die "No foo!";
	};

       are beyond its scope.

CONFIGURATION

       By default, this policy considers "die", "croak", and "confess" to throw exceptions. If you have additional subroutines or methods that may
       be used in lieu of one of these, you can configure them in your perlcriticrc as follows:

	[RegularExpressions::ProhibitCaptureWithoutTest]
	exception_source = my_exception_generator

BUGS

       This policy does not recognize named capture variables. Yet.

AUTHOR

       Chris Dolan <cdolan@cpan.org>

COPYRIGHT

       Copyright (c) 2006-2011 Chris Dolan.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.14.2							    2012-Perl::Critic::Policy::RegularExpressions::ProhibitCaptureWithoutTest(3pm)