Apple announced Swift 2 at the World Wide Developers Conference (WWDC) in 2015. They also declared that Swift was the world's first protocol-oriented programming language. Judging by the name, someone might assume that protocol-oriented programming is all about the protocol or is simply object-oriented programming under a different name. These assumptions would be wrong. Protocol-oriented programming is about so much more than just the protocol; it is actually a new way of not only writing applications but thinking about the design of our application.
In the first five chapters of this book, we take an in-depth look at each of the components of the protocol-oriented programming paradigm. These chapters are designed to give you a solid understanding of the different components of protocol-oriented programming, so that you can understand how to use these components in your applications. One of the biggest misconceptions about protocol-oriented programming is that it is just another name for object-oriented programming. In Chapter 6, Object-Oriented Programming, and Chapter 7, Protocol-Oriented Programming, we take on this myth by comparing protocol-oriented programming to object-oriented programming to see what is similar and what is different. We also discuss the advantages and disadvantages of both programming paradigms.
The last two chapters are written to help you understand how you can design your application in a protocol-oriented programming way. Chapter 8, Adopting Design Patterns in Swift, looks at how we can implement several design patterns in a protocol-oriented way, and Chapter 9, Case Studies, looks at three real-world case studies to reinforce everything previously discussed in the book.