Ruby Cookbook

Recipe 9.1. Simulating Multiple Inheritance with Mixins Problem You want to create a class that derives from two or more sources, but Ruby doesn't support multiple inheritance. Solution Suppose you created a class called Taggable ...

Recipe 9.2. Extending Specific Objects with Modules Credit: Phil Tomson Problem You want to add instance methods from a module (or modules) to specific objects. You don't want to mix the module into the object's class, because you...

Recipe 9.3. Mixing in Class Methods Credit: Phil Tomson Problem You want to mix class methods into a class, instead of mixing in instance methods. Solution The simplest way to accomplish this is to call extend on the class object, a...

Recipe 9.4. Implementing Enumerable: Write One Method, Get 22 Free Problem You want to give a class all the useful iterator and iteration-related features of Ruby's arrays (sort, detect, inject, and so on), but your class can't be a subcla...

Recipe 9.5. Avoiding Naming Collisions with Namespaces Problem You want to define a class or module whose name conflicts with an existing class or module, or you want to prevent someone else from coming along later and defining a class who...

Recipe 9.6. Automatically Loading Libraries as Needed Problem You've written a big library with multiple components. You'd like to split it up so that users don't have to load the entire library into memory just to use part of it. But you ...

Recipe 9.7. Including Namespaces Problem You want to use the objects within a module without constantly qualifying the object names with the name of their module. Solution Use include to copy a module's objects into the current names...

Recipe 9.8. Initializing Instance Variables Defined by a Module Credit: Phil Tomson Problem You have a mixin module that defines some instance variables. Given a class that mixes in the module, you want to initialize the instance variable...