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perl::critic::policy::regularexpressions::prohibitfixedstringmat(3pm) [debian man page]

Perl::Critic::Policy::RegularExpressions::ProhibitFixedSUsergContributed)Perl::Critic::Policy::RegularExpressions::ProhibitFixedStringMatches(3pm)

NAME

       Perl::Critic::Policy::RegularExpressions::ProhibitFixedStringMatches - Use "eq" or hash instead of fixed-pattern regexps.

AFFILIATION

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

DESCRIPTION

       A regular expression that matches just a fixed set of constant strings is wasteful of performance and is hard on maintainers.  It is much
       more readable and often faster to use "eq" or a hash to match such strings.

	   # Bad
	   my $is_file_function = $token =~ m/A (?: open | close | read ) z/xms;

	   # Faster and more readable
	   my $is_file_function = $token eq 'open' ||
				  $token eq 'close' ||
				  $token eq 'read';

       For larger numbers of strings, a hash is superior:

	   # Bad
	   my $is_perl_keyword =
	       $token =~ m/A (?: chomp | chop | chr | crypt | hex | index
				  lc | lcfirst | length | oct | ord | ... ) z/xms;

	   # Better
	   Readonly::Hash my %PERL_KEYWORDS => map {$_ => 1} qw(
	       chomp chop chr crypt hex index lc lcfirst length oct ord ...
	   );
	   my $is_perl_keyword = $PERL_KEYWORD{$token};

       Conway also suggests using "lc()" instead of a case-insensitive match.

   VARIANTS
       This policy detects both grouped and non-grouped strings.  The grouping may or may not be capturing.  The grouped body may or may not be
       alternating.  "A" and "z" are always considered anchoring which "^" and "$" are considered anchoring is the "m" regexp option is not in
       use.  Thus, all of these are violations:

	   m/^foo$/;
	   m/A foo z/x;
	   m/A foo z/xm;
	   m/A(foo)z/;
	   m/A(?:foo)z/;
	   m/A(foo|bar)z/;
	   m/A(?:foo|bar)z/;

       Furthermore, this policy detects violations in "m//", "s///" and "qr//" constructs, as you would expect.

CONFIGURATION

       This Policy is not configurable except for the standard options.

CREDITS

       Initial development of this policy was supported by a grant from the Perl Foundation.

AUTHOR

       Chris Dolan <cdolan@cpan.org>

COPYRIGHT

       Copyright (c) 2007-2011 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

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

Check Out this Related Man Page

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

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 v5.16.3							    2014-06Perl::Critic::Policy::RegularExpressions::ProhibitCaptureWithoutTest(3)
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