Tweaks for Classes document

[gitmo/Moose.git] / lib / Moose / Cookbook / Meta / Recipe5.pod

=pod

=head1 NAME

Moose::Cookbook::Meta::Recipe5 - The "table" attribute as a metaclass trait

=head1 SYNOPSIS

  package MyApp::Meta::Class::Trait::HasTable;
  use Moose::Role;

  has table => (
      is  => 'rw',
      isa => 'Str',
  );

  package Moose::Meta::Class::Custom::Trait::HasTable;
  sub register_implementation { 'MyApp::Meta::Class::Trait::HasTable' }

  package MyApp::User;
  use Moose -traits => 'HasTable';

  __PACKAGE__->meta->table('User');

=head1 DESCRIPTION

This recipe takes the metaclass table attribute and reimplements it as
a metaclass trait. Traits are just roles that Moose applies to
something for you. In this case, that "something" is the class's
metaclass object.

The advantage of using traits is that it's easy to combine multiple
traits, whereas combining multiple metaclasses can be tricky (which
subclasses which?).

The disadvantage is that it's not easy to combine a trait with some
sort of sugar (like our notional C<has_table> sugar).

=head2 Using this Metaclass Trait in Practice

Once this trait has been applied to a metaclass, it looks exactly like
the example we saw in L<Moose::Cookbook::Meta::Recipe4>:

  my $table = MyApp::User->meta->table;

=head1 SEE ALSO

L<Moose::Cookbook::Meta::Recipe3> - Labels implemented via attribute
traits

L<Moose::Cookbook::Meta::Recipe4> - Adding a "table" attribute to the
metaclass

=head1 AUTHOR

Dave Rolsky E<lt>autarch@urth.orgE<gt>

=head1 COPYRIGHT AND LICENSE

Copyright 2006-2008 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.

=pod