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Debugging_BaseClassReplacement.pod	3.63 KB	-rw-r--r--	2018-05-16 03:46:02	Edit Del
Labeled_AttributeMetaclass.pod	8.95 KB	-rw-r--r--	2018-05-16 03:46:02	Edit Del
Table_ClassMetaclass.pod	2.89 KB	-rw-r--r--	2018-05-16 03:46:02	Edit Del

Editing: Table_ClassMetaclass.pod (2.89 KB)

# PODNAME: Moose::Cookbook::Legacy::Table_ClassMetaclass
# ABSTRACT: Adding a "table" attribute to the metaclass

__END__

=pod

=encoding UTF-8

=head1 NAME

Moose::Cookbook::Legacy::Table_ClassMetaclass - Adding a "table" attribute to the metaclass

=head1 VERSION

version 2.2011

=head1 SYNOPSIS

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

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

=head1 DESCRIPTION

B<WARNING: Subclassing metaclasses (as opposed to providing metaclass traits)
is strongly discouraged. This recipe is provided solely for reference when
encountering older code that does this.>

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 AUTHORS

=over 4

=item *

Stevan Little <stevan.little@iinteractive.com>

=item *

Dave Rolsky <autarch@urth.org>

=item *

Jesse Luehrs <doy@tozt.net>

=item *

Shawn M Moore <code@sartak.org>

=item *

יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>

=item *

Karen Etheridge <ether@cpan.org>

=item *

Florian Ragwitz <rafl@debian.org>

=item *

Hans Dieter Pearcey <hdp@weftsoar.net>

=item *

Chris Prather <chris@prather.org>

=item *

Matt S Trout <mst@shadowcat.co.uk>

=back

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2006 by Infinity Interactive, Inc.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut