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Perl::Critic::PoPerl::UseriContributedSPerluDocumentationitExcessComplexity(3)

NAME
       Perl::Critic::Policy::Subroutines::ProhibitExcessComplexity - Minimize
       complexity by factoring code into smaller subroutines.

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

DESCRIPTION
       All else	being equal, complicated code is more error-prone and more
       expensive to maintain than simpler code.	 The first step	towards
       managing	complexity is to establish formal complexity metrics.  One
       such metric is the McCabe score,	which describes	the number of possible
       paths through a subroutine.  This Policy	approximates the McCabe	score
       by summing the number of	conditional statements and operators within a
       subroutine.  Research has shown that a McCabe score higher than 20 is a
       sign of high-risk, potentially untestable code.	See
       <http://en.wikipedia.org/wiki/Cyclomatic_complexity> for	some
       discussion about	the McCabe number and other complexity metrics.

       The usual prescription for reducing complexity is to refactor code into
       smaller subroutines.  Mark Dominus book "Higher Order Perl" also
       describes callbacks, recursion, memoization, iterators, and other
       techniques that help create simple and extensible Perl code.

CONFIGURATION
       The maximum acceptable McCabe can be set	with the "max_mccabe"
       configuration item.  Any	subroutine with	a McCabe score higher than
       this number will	generate a policy violation.  The default is 20.  An
       example section for a .perlcriticrc:

	 [Subroutines::ProhibitExcessComplexity]
	 max_mccabe = 30

NOTES
	 "Everything should be made as simple as possible, but no simpler."

							 -- Albert Einstein

       Complexity is subjective, but formal complexity metrics are still
       incredibly valuable.  Every problem has an inherent level of
       complexity, so it is not	necessarily optimal to minimize	the McCabe
       number.	So don't get offended if your code triggers this Policy.  Just
       consider	if there might be a simpler way	to get the job done.

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 v5.24.1	Perl::Critic::Policy::Subroutines::ProhibitExcessComplexity(3)

NAME | AFFILIATION | DESCRIPTION | CONFIGURATION | NOTES | AUTHOR | COPYRIGHT

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