Perl::Critic::Policy::ControlStructures::ProhibitDeepNests - Don't write deeply nested loops and conditionals.

Perl-Critic documentation Contained in the Perl-Critic distribution.

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NAME

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Perl::Critic::Policy::ControlStructures::ProhibitDeepNests - Don't write deeply nested loops and conditionals.

AFFILIATION

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

DESCRIPTION

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Deeply nested code is often hard to understand and may be a sign that it needs to be refactored. There are several good books on how to refactor code. I like Martin Fowler's "Refactoring: Improving The Design of Existing Code".

CONFIGURATION

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The maximum number of nested control structures can be configured via a value for max_nests in a .perlcriticrc file. Each for-loop, if-else, while, and until block is counted as one nest. Postfix forms of these constructs are not counted. The default maximum is 5. Customization in a .perlcriticrc file looks like this:

    [ControlStructures::ProhibitDeepNests]
    max_nests = 3

AUTHOR

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Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>

COPYRIGHT

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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-Critic documentation Contained in the Perl-Critic distribution. 
##############################################################################
#      $URL: http://perlcritic.tigris.org/svn/perlcritic/trunk/distributions/Perl-Critic/lib/Perl/Critic/Policy/ControlStructures/ProhibitDeepNests.pm $
#     $Date: 2011-05-15 16:34:46 -0500 (Sun, 15 May 2011) $
#   $Author: clonezone $
# $Revision: 4078 $
##############################################################################

package Perl::Critic::Policy::ControlStructures::ProhibitDeepNests;

use 5.006001;
use strict;
use warnings;
use Readonly;

use Perl::Critic::Utils qw{ :severities };
use base 'Perl::Critic::Policy';

our $VERSION = '1.116';

#-----------------------------------------------------------------------------

Readonly::Scalar my $DESC => q{Code structure is deeply nested};
Readonly::Scalar my $EXPL => q{Consider refactoring};

#-----------------------------------------------------------------------------

sub supported_parameters {
    return (
        {
            name            => 'max_nests',
            description     => 'The maximum number of nested constructs to allow.',
            default_string  => '5',
            behavior        => 'integer',
            integer_minimum => 1,
        },
    );
}

sub default_severity { return $SEVERITY_MEDIUM                }
sub default_themes   { return qw(core maintenance complexity) }
sub applies_to       { return 'PPI::Statement::Compound'      }

#-----------------------------------------------------------------------------

sub violates {
    my ( $self, $elem, undef ) = @_;

    my $nest_count = 1;  #For _this_ element
    my $parent = $elem;

    while ( $parent = $parent->parent() ){
        if( $parent->isa('PPI::Statement::Compound') ) {
            $nest_count++;
        }
    }

    if ( $nest_count > $self->{_max_nests} ) {
        return $self->violation( $DESC, $EXPL, $elem );
    }
    return;    #ok!
}


1;

__END__


#-----------------------------------------------------------------------------


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