The Well-Grounded Rubyist, Second Edition

3.6. Classes as objects and message receivers

Classes are special objects: they’re the only kind of object that has the power to spawn new objects (instances). Nonetheless, they’re objects. When you create a class, like Ticket, you can send messages to it, add methods to it, pass it around to other objects as a method argument, and generally do anything to it you would to another object.

Like other objects, classes can be created—indeed, in more than one way.

3.6.1. Creating class objects

Every class—Object, Person, Ticket—is an instance of a class called Class. As you’ve already seen, you can create a class object with the special class keyword formula:

class Ticket
  # your code here
end

That formula is a special provision by Ruby—a way to make ...