=pod

=head1 NAME

Moose::Cookbook::Recipe6 - The Moose::Role example

=head1 SYNOPSIS
  
  package Constraint;
  use strict;
  use warnings;
  use Moose::Role;
  
  has 'value' => (isa => 'Int', is => 'ro');
  
  around 'validate' => sub {
      my $c = shift;
      my ($self, $field) = @_;
      if ($c->($self, $self->validation_value($field))) {
          return undef;
      } 
      else {
          return $self->error_message;
      }        
  };
  
  sub validation_value {
      my ($self, $field) = @_;
      return $field;
  }
  
  sub error_message { confess "Abstract method!" }
  
  package Constraint::OnLength;
  use strict;
  use warnings;
  use Moose::Role;
  
  has 'units' => (isa => 'Str', is => 'ro');
  
  override 'validation_value' => sub {
      return length(super());
  };
  
  override 'error_message' => sub {
      my $self = shift;
      return super() . ' ' . $self->units;
  };    
  
  package Constraint::AtLeast;
  use strict;
  use warnings;
  use Moose;
  
  with 'Constraint';
  
  sub validate {
      my ($self, $field) = @_;
      ($field >= $self->value);
  }
  
  sub error_message { 'must be at least ' . (shift)->value; }
  
  package Constraint::NoMoreThan;
  use strict;
  use warnings;
  use Moose;
  
  with 'Constraint';
  
  sub validate {
      my ($self, $field) = @_;
      ($field <= $self->value);
  }
  
  sub error_message { 'must be no more than ' . (shift)->value; }
  
  package Constraint::LengthNoMoreThan;
  use strict;
  use warnings;
  use Moose;
  
  extends 'Constraint::NoMoreThan';
     with 'Constraint::OnLength';
     
  package Constraint::LengthAtLeast;
  use strict;
  use warnings;
  use Moose;
  
  extends 'Constraint::AtLeast';
     with 'Constraint::OnLength';
  
=head1 DESCRIPTION

Coming Soon. 

(the other 4 recipes kinda burned me out a bit)

=head1 AUTHOR

Stevan Little E<lt>stevan@iinteractive.comE<gt>

=head1 COPYRIGHT AND LICENSE

Copyright 2006 by Infinity Interactive, Inc.

L<http://www.iinteractive.com>

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=cut