--- /dev/null
+##############################################################################
+# $URL: http://perlcritic.tigris.org/svn/perlcritic/trunk/Perl-Critic/lib/Perl/Critic/Policy/Modules/ProhibitExcessMainComplexity.pm $
+# $Date: 2008-07-03 10:19:10 -0500 (Thu, 03 Jul 2008) $
+# $Author: clonezone $
+# $Revision: 2489 $
+##############################################################################
+
+package Perl::Critic::Policy::Modules::ProhibitExcessMainComplexity;
+
+use 5.006001;
+use strict;
+use warnings;
+use Readonly;
+
+use Perl::Critic::Utils qw{ :severities };
+use Perl::Critic::Utils::McCabe qw{ calculate_mccabe_of_main };
+
+use base 'Perl::Critic::Policy';
+
+#-----------------------------------------------------------------------------
+
+our $VERSION = '1.088';
+
+#-----------------------------------------------------------------------------
+
+Readonly::Scalar my $EXPL => q{Consider refactoring};
+
+#-----------------------------------------------------------------------------
+
+sub supported_parameters {
+ return (
+ {
+ name => 'max_mccabe',
+ description => 'The maximum complexity score allowed.',
+ default_string => '20',
+ behavior => 'integer',
+ integer_minimum => 1,
+ },
+ );
+}
+
+sub default_severity { return $SEVERITY_MEDIUM }
+sub default_themes { return qw(core complexity maintenance) }
+sub applies_to { return 'PPI::Document' }
+
+#-----------------------------------------------------------------------------
+
+sub violates {
+ my ( $self, $doc, undef ) = @_;
+
+ my $score = calculate_mccabe_of_main( $doc );
+
+ # Is it too complex?
+ return if $score <= $self->{_max_mccabe};
+
+ my $desc = qq{Main code has high complexity score ($score)};
+ return $self->violation( $desc, $EXPL, $doc );
+}
+
+
+1;
+
+__END__
+
+#-----------------------------------------------------------------------------
+
+=pod
+
+=for stopwords McCabe
+
+=head1 NAME
+
+Perl::Critic::Policy::Modules::ProhibitExcessMainComplexity - Minimize complexity in code that is B<outside> of subroutines.
+
+=head1 AFFILIATION
+
+This Policy is part of the core L<Perl::Critic> distribution.
+
+
+=head1 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 L<http://www.sei.cmu.edu/str/descriptions/cyclomatic_body.html> for
+some discussion about the McCabe number and other complexity metrics.
+
+Whereas L<Perl::Critic::Policy::Subroutines::ProhibitExcessComplexity> scores
+the complexity of each subroutine, this Policy scores the total complexity of
+all the code that is B<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.
+
+=head1 CONFIGURATION
+
+The maximum acceptable McCabe score can be set with the C<max_mccabe>
+configuration item. If the sum of all code B<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 F<.perlcriticrc>:
+
+ [Modules::ProhibitExcessMainComplexity]
+ max_mccabe = 30
+
+=head1 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 B<might> be a simpler
+way to get the job done.
+
+=head1 SEE ALSO
+
+L<Perl::Critic::Policy::Subroutines::ProhibitExcessComplexity>
+
+=head1 AUTHOR
+
+Jeffrey Ryan Thalhammer <thaljef@cpan.org>
+
+=head1 COPYRIGHT
+
+Copyright (c) 2005-2008 Jeffrey Ryan Thalhammer. 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.
+
+=cut
+
+# Local Variables:
+# mode: cperl
+# cperl-indent-level: 4
+# fill-column: 78
+# indent-tabs-mode: nil
+# c-indentation-style: bsd
+# End:
+# ex: set ts=8 sts=4 sw=4 tw=78 ft=perl expandtab shiftround :
projects / dh-make-perl / blobdiff