Moose::Cookbook::Meta::Recipe5 - The "table" attribute as a metaclass trait
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');
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 has_table sugar).
has_table
Once this trait has been applied to a metaclass, it looks exactly like the example we saw in Moose::Cookbook::Meta::Recipe4:
my $table = MyApp::User->meta()->table();
Moose::Cookbook::Meta::Recipe3 - Labels implemented via attribute traits
Moose::Cookbook::Meta::Recipe4 - Adding a "table" attribute to the metaclass
Dave Rolsky <autarch@urth.org>
Copyright 2006-2008 by Infinity Interactive, Inc.
http://www.iinteractive.com
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cpanm
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CPAN shell
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