Manual Reference Pages - MOOSE::MANUAL::CLASSES (3)
Moose::Manual::Classes - Making your classes use Moose (and subclassing)
Using Moose is very simple, you just use Moose:
Thats it, youve made a class with Moose!
Theres actually a lot going on here under the hood, so lets step
When you load Moose, a bunch of sugar functions are exported into your
class, such as extends, has, with, and more. These functions are what
you use to define your class. For example, you might define an attribute ...
has ssn => ( is => rw );
Attributes are described in the Moose::Manual::Attributes
Loading Moose also enables the strict and warnings pragmas in your
When you load Moose, your class will become a subclass of
Moose::Object. The Moose::Object class provides a default
constructor and destructor, as well as object construction helper
methods. You can read more about this in the
As a convenience, Moose creates a new class type for your class. See
the Moose::Manual::Types document to learn more about types.
It also creates a Moose::Meta::Class object for your class. This
metaclass object is now available by calling a meta method on your
class, for example Person->meta.
The metaclass object provides an introspection API for your class. It
is also used by Moose itself under the hood to add attributes, define
parent classes, and so on. In fact, all of Mooses sugar does the real
work by calling methods on this metaclass object (and other meta API
Moose provides a simple sugar function for declaring your parent
has username => ( is => rw );
Note that each call to extends will reset your parents. For
multiple inheritance you must provide all the parents at once,
extends Foo, Bar.
When you call extends Moose will try to load any classes you pass.
You can use Moose to extend a non-Moose parent. However, when you do
this, you will inherit the parent classs constructor (assuming it is
also called new). In that case, you will have to take care of
initializing attributes manually, either in the parents constructor,
or in your subclass, and you will lose a lot of Moose magic.
See the MooseX::NonMoose module on CPAN if youre interested in extending
non-Moose parent classes with Moose child classes.
CLEANING UP MOOSE DROPPINGS
Moose exports a number of functions into your class. Its a good idea to
remove these sugar functions from your classs namespace, so that Person->can(has) will no longer return true.
There are several ways to do this. We recommend using namespace::autoclean,
a CPAN module. Not only will it remove Moose exports, it will also remove
any other exports.
If you absolutely cant use a CPAN module (but can use Moose?), you can write
no Moose at the end of your class. This will remove any Moose exports in
has ssn => ( is => rw );
MAKING IT FASTER
Moose has a feature called immutabilization that you can use to
greatly speed up your classes at runtime. However, using it incurs
a cost when your class is first being loaded. When you make your class
immutable you tell Moose that you will not be changing it in the
future. You will not be adding any more attributes, methods, roles, etc.
This allows Moose to generate code specific to your class. In
particular, it creates an inline constructor, making object
construction much faster.
To make your class immutable you simply call make_immutable on your
classs metaclass object.
Immutabilization and CWnew()
If you override new() in your class, then the immutabilization code
will not be able to provide an optimized constructor for your
class. Instead, you should use a BUILD() method, which will be
called from the inlined constructor.
Alternately, if you really need to provide a different new(), you
can also provide your own immutabilization method. Doing so requires
extending the Moose metaclasses, and is well beyond the scope of this
When youre ready to use Moose classes in an application, reference them in
your code in the regular Perl OO way by including a use directive
at the top of the file where the objects should be created.
my $person = Person->new(
# attribute values at instantiation
# go here
ssn => 123456789,
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 v5.20.3 ||MOOSE::MANUAL::CLASSES (3) ||2016-02-16 |
Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.