/ 
Moose-0.03_01
River stage four • 2960 direct dependents • 3982 total dependents
/ Moose

NAME

Moose - Moose, it's the new Camel

SYNOPSIS

package Point;
use Moose;
	
has 'x' => (isa => 'Int', is => 'rw');
has 'y' => (isa => 'Int', is => 'rw');

sub clear {
    my $self = shift;
    $self->x(0);
    $self->y(0);    
}

package Point3D;
use Moose;

extends 'Point';

has 'z' => (isa => 'Int');

after 'clear' => sub {
    my $self = shift;
    $self->{z} = 0;
};

CAVEAT

This is an early release of this module, it still needs some fine tuning and lots more documentation. I am adopting the release early and release often approach with this module, so keep an eye on your favorite CPAN mirror!

DESCRIPTION

Moose is an extension of the Perl 5 object system.

Another object system!?!?

Yes, I know there has been an explosion recently of new ways to build object's in Perl 5, most of them based on inside-out objects, and other such things. Moose is different because it is not a new object system for Perl 5, but instead an extension of the existing object system.

Moose is built on top of Class::MOP, which is a metaclass system for Perl 5. This means that Moose not only makes building normal Perl 5 objects better, but it also provides the power of metaclass programming.

What does Moose stand for??

Moose doesn't stand for one thing in particular, however, if you want, here are a few of my favorites, feel free to contribute more :)

Make Other Object Systems Envious
Makes Object Orientation So Easy
Makes Object Orientation Spiffy- Er (sorry ingy)
Most Other Object Systems Emasculate
My Overcraft Overfilled (with) Some Eels
Moose Often Ovulate Sorta Early
Many Overloaded Object Systems Exists
Moose Offers Often Super Extensions

BUILDING CLASSES WITH MOOSE

Moose makes every attempt to provide as much convience during class construction/definition, but still stay out of your way if you want it to. Here are some of the features Moose provides:

Unless specified with extends, any class which uses Moose will inherit from Moose::Object.

Moose will also manage all attributes (including inherited ones) that are defined with has. And assuming that you call new which is inherited from Moose::Object, then this includes properly initializing all instance slots, setting defaults where approprtiate and performing any type constraint checking or coercion.

For more details, see the ever expanding Moose::Cookbook.

EXPORTED FUNCTIONS

Moose will export a number of functions into the class's namespace, which can then be used to set up the class. These functions all work directly on the current class.

meta

This is a method which provides access to the current class's metaclass.

extends (@superclasses)

This function will set the superclass(es) for the current class.

This approach is recommended instead of use base, because use base actually pushes onto the class's @ISA, whereas extends will replace it. This is important to ensure that classes which do not have superclasses properly inherit from Moose::Object.

with ($role)

This will apply a given $role to the local class. Role support is currently very experimental, see Moose::Role for more details.

has ($name, %options)

This will install an attribute of a given $name into the current class. The list of %options are the same as those provided by both Class::MOP::Attribute and Moose::Meta::Attribute, in addition to a few convience ones provided by Moose which are listed below:

is => 'rw'|'ro'

The is option accepts either rw (for read/write) or ro (for read only). These will create either a read/write accessor or a read-only accessor respectively, using the same name as the $name of the attribute.

If you need more control over how your accessors are named, you can use the reader, writer and accessor options inherited from Moose::Meta::Attribute.

isa => $type_name

The isa option uses Moose's type constraint facilities to set up runtime type checking for this attribute. Moose will perform the checks during class construction, and within any accessors. The $type_name argument must be a string. The string can be either a class name, or a type defined using Moose's type defintion features.

before $name|@names => sub { ... }
after $name|@names => sub { ... }
around $name|@names => sub { ... }

This three items are syntactic sugar for the before, after and around method modifier features that Class::MOP provides. More information on these can be found in the Class::MOP documentation for now.

super

The keyword super is a noop when called outside of an override method. In the context of an override method, it will call the next most appropriate superclass method with the same arguments as the original method.

override ($name, &sub)

An override method, is a way of explictly saying "I am overriding this method from my superclass". You can call super within this method, and it will work as expected. The same thing can be accomplished with a normal method call and the SUPER:: pseudo-package, it is really your choice.

inner

The keyword inner, much like super, is a no-op outside of the context of an augment method. You can think of inner as being the inverse of super, the details of how inner and augment work is best described in the Moose::Cookbook.

augment ($name, &sub)

An augment method, is a way of explictly saying "I am augmenting this method from my superclass". Once again, the details of how inner and augment work is best described in the Moose::Cookbook.

confess

This is the Carp::confess function, and exported here beause I use it all the time. This feature may change in the future, so you have been warned.

blessed

This is the Scalar::Uti::blessed function, it is exported here beause I use it all the time. It is highly recommended that this is used instead of ref anywhere you need to test for an object's class name.

ACKNOWLEDGEMENTS

I blame Sam Vilain for introducing me to the insanity that is meta-models.
I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
Without Yuval "nothingmuch" Kogman this module would not be possible, and it certainly wouldn't have this name ;P
The basis of the TypeContraints module was Rob Kinyon's idea originally, I just ran with it.
Thanks to mst & chansen and the whole #moose poose for all the ideas/feature-requests/encouragement

SEE ALSO

Class::MOP documentation
The #moose channel on irc.perl.org
http://forum2.org/moose/
http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf

This paper (suggested by lbr on #moose) was what lead to the implementation of the super/overrride and inner/augment features. If you really want to understand this feature, I suggest you read this.

BUGS

All complex software has bugs lurking in it, and this module is no exception. If you find a bug please either email me, or add the bug to cpan-RT.

AUTHOR

Stevan Little <stevan@iinteractive.com>

COPYRIGHT AND LICENSE

Copyright 2006 by Infinity Interactive, Inc.

http://www.iinteractive.com

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