Programming Ruby 3.3

Inheritance and Messages

In a previous chapter, we saw that when the puts method needs to convert an object to a string, it calls that object’s to_s method. But we’ve also written our own classes that don’t explicitly implement to_s. Despite this, instances of these classes respond successfully when we call to_s on them. How this works has to do with inheritance and how Ruby uses it to determine what method to run when you send a message to an object.

Inheritance allows you to create a class that’s a specialization of another class. This specialized class is called a subclass of the original, and the original is a superclass of the subclass. People also refer to this relationship as child and parent classes.

The basic mechanism of subclassing ...