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Perl::Critic::PoPerl::UseriContributedMPerleDocumentationcessMainComplexity(3)

NAME
       Perl::Critic::Policy::Modules::ProhibitExcessMainComplexity - Minimize
       complexity in code that is outside of 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 block of	code.  This Policy approximates	the McCabe
       score by	summing	the number of conditional statements and operators
       within a	block of code.	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.

       Whereas Perl::Critic::Policy::Subroutines::ProhibitExcessComplexity
       scores the complexity of	each subroutine, this Policy scores the	total
       complexity of all the code that is outside of any subroutine
       declaration.

       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 score can be set with the "max_mccabe"

       configuration item.  If the sum of all code outside any subroutine has
       a McCabe	score higher than this number, it will generate	a Policy
       violation.  The default is 20.  An example section for a	.perlcriticrc:

	   [Modules::ProhibitExcessMainComplexity]
	   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.

SEE ALSO
       Perl::Critic::Policy::Subroutines::ProhibitExcessComplexity

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::Modules::ProhibitExcessMainComplexity(3)

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

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