Moose::Cookbook::Legacy::Table_ClassMetaclass - Adding a "table"
attribute to the metaclass
has table => (
is => 'rw',
isa => 'Str',
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.
This really is as simple as the recipe "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
Moose::Cookbook::Extending::Recipe2, which shows how to make a module like
"Moose.pm" itself, with sugar like "has_table()".
Accessing this new "table" attribute is quite simple. Given a class
named "MyApp::User", we could simply write the following:
my $table = MyApp::User->meta->table;
As long as "MyApp::User" has arranged to use
"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
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.
Moose::Cookbook::Meta::Recipe5 - The "table" attribute implemented as
a metaclass trait
Moose::Cookbook::Extending::Recipe2 - Acting like Moose.pm and providing sugar
- Stevan Little <email@example.com>
- Dave Rolsky <firstname.lastname@example.org>
- Jesse Luehrs <email@example.com>
- Shawn M Moore <firstname.lastname@example.org>
- יובל קוג'מן
(Yuval Kogman) <email@example.com>
- Karen Etheridge <firstname.lastname@example.org>
- Florian Ragwitz <email@example.com>
- Hans Dieter Pearcey <firstname.lastname@example.org>
- Chris Prather <email@example.com>
- Matt S Trout <firstname.lastname@example.org>
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.