Polymorphism

Polymorphism is the ability to appear in various forms. For example, a shape can appear as a square, circle, rectangle, or any other shape:

Figure 7.4: Polymorphism example for shape

Go does not do subclassing like other object-oriented languages because Go does not have classes. Subclassing in object-oriented programming is inheriting from one class to another. By doing subclassing, you are inheriting the fields and methods of another class. Go provides a similar behavior through embedding structs and by using polymorphism through interfaces.

One of the advantages of using polymorphism is that it allows the reuse of methods that have been written once and tested. Code is reused by having an API that accepts an interface; if our type satisfies that interface, it can be passed to that API. There is no need to write additional code for each type; we just need to ensure we meet the interface method's set requirements. Obtaining polymorphism...