=pod
=head1 NAME
Moose::Cookbook::Meta::Recipe4 - Adding a
"table"
attribute to the metaclass
=head1 SYNOPSIS
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
=head1 AUTHOR
Dave Rolsky E<lt>autarch
@urth
.orgE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2006-2009 by Infinity Interactive, Inc.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=pod