The Ruby Way: Solutions and Techniques in Ruby Programming, Second Edition

1.3. OOP in Ruby

Ruby has all the elements more generally associated with OOP languages, such as objects with encapsulation and data hiding, methods with polymorphism and overriding, and classes with hierarchy and inheritance. It goes further and adds limited metaclass features, singleton methods, modules, and mixins.

Similar concepts are known by other names in other OOP languages, but concepts of the same name may have subtle differences from one language to another. This section elaborates on the Ruby understanding and usage of these elements of OOP.

1.3.1. Objects

In Ruby, all numbers, strings, arrays, regular expressions, and many other entities are actually objects. Work is done by executing the methods belonging to the object:

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