Programming Ruby 3.3

Understanding Objects and Classes

Classes and objects are central to Ruby, but at first sight, they can be confusing. It seems like there are a lot of concepts: classes, objects, class objects, instance methods, class methods, singleton classes, and virtual classes. In reality, all these Ruby constructs are part of the same underlying class and object structure.

Internally, a Ruby object has three components: a set of flags, some instance variables, and an associated class. A Ruby class contains all the things an object has plus a set of method definitions and a reference to a superclass (which is itself another class). A Ruby class is itself an instance of the class Class. Let’s look at how that structure lends itself to metaprogramming in ...