Hands-On Design Patterns with Swift

Getting started with protocol-oriented programming

Protocols are widespread and available in many languages, such as Swift, Objective-C, and Clojure. In order to have a common definition, let's go back to the source, the Swift language guide (https://docs.swift.org/swift-book/LanguageGuide/Protocols.html) :

"A protocol defines a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality. The protocol can then be adopted by a class, structure, or enumeration to provide an actual implementation of those requirements. Any type that satisfies the requirements of a protocol is said to conform to that protocol."

This first part of the definition is telling us that, contrary to classes or structures, ...