package MooseX::App::Plugin::MutexGroup;

use Moose::Role;
use namespace::autoclean;

sub plugin_metaroles {
   my ($self, $class) = @_;
   
   return {
      attribute => ['MooseX::App::Plugin::MutexGroup::Meta::Attribute'],
      class     => ['MooseX::App::Plugin::MutexGroup::Meta::Class'],
   }
}

1;

__END__

=encoding utf8

=head1 NAME 

MooseX::App::Plugin::MutexGroup - Adds mutually exclusive options

=head1 SYNOPSIS

In your base class: 

 package MyApp;
 use MooseX::App qw(MutexGroup);

 option 'UseAmmonia' => (
   is         => 'ro',
   isa        => 'Bool',
   mutexgroup => 'NonMixableCleaningChemicals',
 );

 option 'UseChlorine' => (
   is         => 'ro',
   isa        => 'Bool',
   mutexgroup => 'NonMixableCleaningChemicals'
 );

In your script: 
 
 #!/usr/bin/env perl 
  
 use strict; 
 use warnings; 
 
 use MyApp; 

 MyApp->new_with_options( UseAmmonia => 1, UseChlorine => 1 );
 # generates Error 
 # More than one attribute from mutexgroup NonMixableCleaningChemicals('UseAmmonia','UseChlorine') *cannot* be specified

 MyApp->new_with_options();
 # generates Error 
 # One attribute from mutexgroup NonMixableCleaningChemicals('UseAmmonia','UseChlorine') *must* be specified

 MyApp->new_with_options( UseAmmonia => 1 );
 # generates no errors

 MyApp->new_with_options( UseChlorine => 1 );
 # generates no errors

=head1 DESCRIPTION

This plugin adds mutually exclusive options to your application. In the current implementation, all defined
MutexGroups *must* have exactly one initialized option. This means that there is an implicit requiredness
of one option from each MutexGroup.

=cut