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package Perl::Critic::Policy::ControlStructures::ProhibitCascadingIfElse;

use 5.006001;
use strict;
use warnings;

use Readonly;

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

our $VERSION = '1.121';

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

Readonly::Scalar my $DESC => q{Cascading if-elsif chain};
Readonly::Scalar my $EXPL => [ 117, 118 ];

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

sub supported_parameters {
    return (
        {
            name            => 'max_elsif',
            description     => 'The maximum number of alternatives that will be allowed.',
            default_string  => '2',
            behavior        => 'integer',
            integer_minimum => 1,
        },
    );
}

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

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

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

    return if ($elem->type() ne 'if');

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

sub _count_elsifs {
    my $elem = shift;
    return
      grep { $_->isa('PPI::Token::Word') && $_ eq 'elsif' } $elem->schildren();
}

1;

__END__

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

=pod

=for stopwords lookup

=head1 NAME

Perl::Critic::Policy::ControlStructures::ProhibitCascadingIfElse - Don't write long "if-elsif-elsif-elsif-elsif...else" chains.

=head1 AFFILIATION

This Policy is part of the core L<Perl::Critic|Perl::Critic>
distribution.


=head1 DESCRIPTION

Long C<if-elsif> chains are hard to digest, especially if they are
longer than a single page or screen.  If testing for equality, use a
hash lookup instead.  If you're using perl 5.10 or later, use
C<given>/C<when>.

    if ($condition1) {         #ok
        $foo = 1;
    }
    elsif ($condition2) {      #ok
        $foo = 2;
    }
    elsif ($condition3) {      #ok
        $foo = 3;
    }
    elsif ($condition4) {      #too many!
        $foo = 4;
    }
    else {                     #ok
        $foo = $default;
    }

=head1 CONFIGURATION

This policy can be configured with a maximum number of C<elsif>
alternatives to allow.  The default is 2.  This can be specified via a
C<max_elsif> item in the F<.perlcriticrc> file:

    [ControlStructures::ProhibitCascadingIfElse]
    max_elsif = 3

=head1 AUTHOR

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

=head1 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.

=cut

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