Moose::Cookbook - How to cook a Moose


The Moose cookbook is a series of recipes showing various Moose features. Most recipes present some code demonstrating some feature, and then explain the details of the code.

You should probably read the Moose::Manual first. The manual explains Moose concepts without being too code-heavy.


Basic Moose

These recipes will give you a good overview of Moose's capabilities, starting with simple attribute declaration, and moving on to more powerful features like laziness, types, type coercion, method modifiers, and more.

Moose::Cookbook::Basics::Recipe1 - The (always classic) Point example

A simple Moose-based class. Demonstrates Moose attributes and subclassing.

Moose::Cookbook::Basics::Recipe2 - A simple BankAccount example

A slightly more complex Moose class. Demonstrates using a method modifier in a subclass.

Moose::Cookbook::Basics::Recipe3 - A lazy BinaryTree example

Demonstrates several attribute features, including types, weak references, predicates ("does this object have a foo?"), defaults, laziness, and triggers.

Moose::Cookbook::Basics::Recipe4 - Subtypes, and modeling a simple Company class hierarchy

Introduces the creation and use of custom types, a BUILD method, and the use of override in a subclass.

Moose::Cookbook::Basics::Recipe5 - More subtypes, coercion in a Request class

More type examples, including the use of type coercions.

Moose::Cookbook::Basics::Recipe6 - The augment/inner example

Demonstrates the use of augment method modifiers, a way of turning the usual method overriding style "inside-out".

Moose::Cookbook::Basics::Recipe7 - Making Moose fast with immutable

Making a class immutable greatly increases the speed of accessors and object construction.

Moose::Cookbook::Basics::Recipe8 - Builder methods and lazy_build

The builder feature provides an inheritable and role-composable way to provide a default attribute value.

Moose::Cookbook::Basics::Recipe9 - Operator overloading, subtypes, and coercion

Demonstrates using operator overloading, coercion, and subtypes to model how eye color is determined during reproduction.

Moose::Cookbook::Basics::Recipe10 - Using BUILDARGS and BUILD to hook into object construction

This recipe demonstrates the use of BUILDARGS and BUILD to hook into object construction.

Moose::Cookbook::Basics::Recipe11 - Extending a non-Moose base class

In this recipe, we make a Moose-based subclass of DateTime, a module which does not use Moose itself.

Moose Roles

These recipes will show you how to use Moose roles.

Moose::Cookbook::Roles::Recipe1 - The Moose::Role example

Demonstrates roles, which are also sometimes known as traits or mix-ins. Roles provide a method of code re-use which is orthogonal to subclassing.

Moose::Cookbook::Roles::Recipe2 - Advanced Role Composition - method exclusion and aliasing

Sometimes you just want to include part of a role in your class. Sometimes you want the whole role but one of its methods conflicts with one in your class. With method exclusion and aliasing, you can work around these problems.

Moose::Cookbook::Roles::Recipe3 - Applying a role to an object instance

In this recipe, we apply a role to an existing object instance.

Meta Moose

These recipes show you how to write your own meta classes, which lets you extend the object system provided by Moose.

Moose::Cookbook::Meta::Recipe1 - Welcome to the meta-world (Why Go Meta?)

If you're wondering what all this "meta" stuff is, and why you should care about it, read this "recipe".

Moose::Cookbook::Meta::Recipe2 - A meta-attribute, attributes with labels

One way to extend Moose is to provide your own attribute metaclasses. Attribute metaclasses let you extend attribute declarations (with has) and behavior to provide additional attribute functionality.

Moose::Cookbook::Meta::Recipe3 - Labels implemented via attribute traits

Extending Moose's attribute metaclass is a great way to add functionality. However, attributes can only have one metaclass. Applying roles to the attribute metaclass lets you provide composable attribute functionality.

Moose::Cookbook::Meta::Recipe4 - Adding a "table" attribute to the metaclass

If you want to store more information about your classes, you'll have to extend Moose::Meta::Class. Doing so is simple, but you'll probably also want to provide some sugar, so see Moose::Cookbook::Extending::Recipe2 as well.

Moose::Cookbook::Meta::Recipe5 - The "table" attribute implemented as a metaclass trait

This recipe takes the class metaclass we saw in the previous recipe and reimplements it as a metaclass trait.

Moose::Cookbook::Meta::Recipe6 - A method metaclass for marking methods public or private

This recipe shows a custom method metaclass that implements making a method private.

Moose::Cookbook::Meta::Recipe7 - Using a blessed array reference as an object instance

This recipe shows an example of how you create your own meta-instance class. The meta-instance determines the internal structure of object instances and provide access to attribute slots.

Moose::Cookbook::Meta::Recipe8 - Hooking into immutabilization (TODO)

Moose has a feature known as "immutabilization". By calling __PACKAGE__->meta()->make_immutable() after defining your class (attributes, roles, etc), you tell Moose to optimize things like object creation, attribute access, and so on.

If you are creating your own metaclasses, you may need to hook into the immutabilization system. This cuts across a number of spots, including the metaclass class, meta method classes, and possibly the meta-instance class as well.

This recipe shows you how to write extensions which immutabilize properly.

Extending Moose

These recipes cover some more ways to extend Moose, and will be useful if you plan to write your own MooseX module.

Moose::Cookbook::Extending::Recipe1 - Moose extension overview

There are quite a few ways to extend Moose. This recipe provides an overview of each method, and provides recommendations for when each is appropriate.

Moose::Cookbook::Extending::Recipe2 - Providing a base object class role

Many base object class extensions can be implemented as roles. This example shows how to provide a base object class debugging role that is applied to any class that uses a notional MooseX::Debugging module.

Moose::Cookbook::Extending::Recipe3 - Providing an alternate base object class

You may find that you want to provide an alternate base object class along with a meta extension, or maybe you just want to add some functionality to all your classes without typing extends 'MyApp::Base' over and over.

Moose::Cookbook::Extending::Recipe4 - Acting like and providing sugar Moose-style

This recipe shows how to provide a replacement for You may want to do this as part of the API for a MooseX module, especially if you want to default to a new metaclass class or base object class.





Stevan Little <>


Copyright 2006-2010 by Infinity Interactive, Inc.

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