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 if the match fails.

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.

CONFIGURATION

By default, this policy considers die, croak, and confess to throw exceptions. If you have additional routines 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

Needs to allow this construct:

for ( ... ) {
    next unless /(....)/;
    if ( $1 ) {
        ....
    }
}

Right now, Perl::Critic thinks that the $1 isn't legal to use because it's "outside" of the match. The thing is, we can only get to the if if the regex matched.

while ( $str =~ /(expression)/ )

This policy does not recognize named capture variables. Yet.

AUTHOR

Chris Dolan <cdolan@cpan.org>

COPYRIGHT

Copyright (c) 2006-2009 Chris Dolan.

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