Manual Reference Pages - MOOSE::COOKBOOK::META::TABLE_METACLASSTRAIT (3)
Moose::Cookbook::Meta::Table_MetaclassTrait - Adding a "table" attribute as a metaclass trait
# in lib/MyApp/Meta/Class/Trait/HasTable.pm
has table => (
is => rw,
isa => Str,
# in lib/MyApp/User.pm
use Moose -traits => HasTable;
In this recipe, well create a class metaclass trait which has a table
attribute. This trait 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.
THE METACLASS TRAIT
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::Debugging_BaseClassRole, which shows how to
make a module like Moose.pm itself, with sugar like has_table().
Using this Metaclass Trait in Practice
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 apply the
MyApp::Meta::Class::Trait::HasTable to its metaclass, this method call just
works. If we want to be more careful, we can check that the class metaclass
object has a table method:
$table = MyApp::User->meta->table
In theory, this is not entirely correct, since the metaclass might be getting
its table method from a different trait. In practice, you are unlikely
to encounter this sort of problem.
This recipe doesnt work when you paste it all into a single file. This is
because the use Moose -traits => HasTable; line ends up being
executed before the table attribute is defined.
When the two packages are separate files, this just works.
Moose::Cookbook::Meta::Labeled_AttributeTrait - Labels implemented via
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.
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