| Moose::Cookbook::Extending::Debugging_BaseClassRole - phpMan
Moose::Cookbook::Extending::DebUsernContrMoose::Cookbook::Extending::Debugging_BaseClassRole(3pm)
NAME
Moose::Cookbook::Extending::Debugging_BaseClassRole - Providing a role for the base object
class
VERSION
version 2.1213
SYNOPSIS
package MooseX::Debugging;
use Moose::Exporter;
Moose::Exporter->setup_import_methods(
base_class_roles => ['MooseX::Debugging::Role::Object'],
);
package MooseX::Debugging::Role::Object;
use Moose::Role;
sub BUILD {}
after BUILD => sub {
my $self = shift;
warn "Made a new " . ( ref $self ) . " object\n";
};
DESCRIPTION
In this example, we provide a role for the base object class that adds some simple
debugging output. Every time an object is created, it spits out a warning saying what type
of object it was.
Obviously, a real debugging role would do something more interesting, but this recipe is
all about how we apply that role.
In this case, with the combination of Moose::Exporter and Moose::Util::MetaRole, we ensure
that when a module does "use MooseX::Debugging", it automatically gets the debugging role
applied to its base object class.
There are a few pieces of code worth looking at more closely.
Moose::Exporter->setup_import_methods(
base_class_roles => ['MooseX::Debugging::Role::Object'],
);
This creates an "import" method in the "MooseX::Debugging" package. Since we are not
actually exporting anything, we do not pass "setup_import_methods" any parameters related
to exports, but we need to have an "import" method to ensure that our "init_meta" method
is called. The "init_meta" is created by "setup_import_methods" for us, since we passed
the "base_class_roles" parameter. The generated "init_meta" will in turn call
Moose::Util::MetaRole::apply_base_class_roles.
sub BUILD {}
after BUILD => sub {
...
};
Due to the way role composition currently works, if the class that a role is composed into
contains a "BUILD" method, then that will override the "BUILD" method in any roles it
composes, which is typically not what you want. Using a method modifier on "BUILD" avoids
this issue, since method modifiers compose together rather than being overridden. Method
modifiers require that a method exists in order to wrap, however, so we also provide a
stub method to wrap if no "BUILD" method exists in the class.
AUTHORS
· Stevan Little <stevan.little AT iinteractive.com>
· Dave Rolsky <autarch AT urth.org>
· Jesse Luehrs <doy AT tozt.net>
· Shawn M Moore <code AT sartak.org>
· XXXX XXX'XX (Yuval Kogman) <nothingmuch AT woobling.org>
· Karen Etheridge <ether AT cpan.org>
· Florian Ragwitz <rafl AT debian.org>
· Hans Dieter Pearcey <hdp AT weftsoar.net>
· Chris Prather <chris AT prather.org>
· Matt S Trout <mst AT shadowcat.uk>
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.
perl v5.20.1 Moose::Cookbook::Extending::Debugging_BaseClassRole(3pm)
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