Removed Meta recipe2 (an attribute metaclass)

[gitmo/Moose.git] / lib / Moose / Cookbook / Meta / Recipe4.pod

package Moose::Cookbook::Meta::Recipe4;

# ABSTRACT: Adding a "table" attribute to the metaclass

__END__


=pod

=head1 SYNOPSIS

  package MyApp::Meta::Class;
  use Moose;
  extends 'Moose::Meta::Class';

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

=head1 DESCRIPTION

In this recipe, we'll create a new metaclass which has a "table"
attribute. This metaclass is for classes associated with a DBMS table,
as one might do for an ORM.

In this example, the table name is just a string, but in a real ORM
the table might be an object describing the table.

=head1 THE METACLASS

This really is as simple as the recipe L</SYNOPSIS> shows. The trick
is getting your classes to use this metaclass, and providing some sort
of sugar for declaring the table. This is covered in
L<Moose::Cookbook::Extending::Recipe2>, which shows how to make a
module like C<Moose.pm> itself, with sugar like C<has_table()>.

=head2 Using this Metaclass in Practice

Accessing this new C<table> attribute is quite simple. Given a class
named C<MyApp::User>, we could simply write the following:

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

As long as C<MyApp::User> has arranged to use C<MyApp::Meta::Class> as
its metaclass, this method call just works. If we want to be more
careful, we can check the metaclass's class:

  $table = MyApp::User->meta->table
      if MyApp::User->meta->isa('MyApp::Meta::Class');

=head1 CONCLUSION

Creating custom metaclass is trivial. Using it is a little harder, and
is covered in other recipes. We will also talk about applying traits
to a class metaclass, which is a more flexible and cooperative
implementation.

=head1 SEE ALSO

L<Moose::Cookbook::Meta::Recipe5> - The "table" attribute implemented
as a metaclass trait

L<Moose::Cookbook::Extending::Recipe2> - Acting like Moose.pm and
providing sugar Moose-style

=pod