This book is about protocol-oriented programming. When 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. By its name, we may assume that protocol-oriented programming is all about the protocol; however, that would be wrong assumption. 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 programming as well.
One of the biggest misconceptions about protocol-oriented programming is that it is just another name for object-oriented programming. Chapter 1, Object-Oriented and Protocol-Oriented Programming, immediately takes on this myth by comparing protocol-oriented programming to object-oriented programming to see what is similar and what the differences are. We will also discuss the advantages and disadvantages of both programming paradigms.
From Chapter 2, Our Type Choices, to Chapter 5, Let's Extend Some Types, we will take an in-depth look at each of the components of the protocol-oriented programming paradigm. These chapters are designed to give the reader a solid understanding of the different components of protocol-oriented programming, so users will understand how they can use these components in their applications.
The last two chapters are written to help the reader understand how they can design their application in a protocol-oriented programming way. Chapter 6, Adopting Design Patterns in Swift, looks at how we would implement several design patterns in a protocol-oriented way and Chapter 7, Case Studies, looks at three real-world case studies to reinforce everything previously discussed in the book.
Chapter 1, Object-Oriented and Protocol-Oriented Programming, will show the differences between object-oriented programming and protocol-oriented programming, giving the reader a good understanding of the different paradigms. By the end of the chapter, the reader should have a basic understanding of protocol-oriented programming and what it offers.
Chapter 2, Our Type Choices, will look at the different types that Swift offers (structs, classes, enums, and tuples). We will show several examples of when to use the various types and when not to.
Chapter 3, Catching Our Errors, will look at the various ways we can catch and report errors. This chapter will not only cover the new Swift 2 do-try-catch blocks, but also the older error handling patterns.
Chapter 4, All about the Protocol, will be all about the protocol. We will show the advantages of using protocols and why, in our design, we should start with the protocol.
Chapter 5, Let's Extend Some Types, will cover extensions in great detail. We will look at how to extend standard Swift types, such as structures and classes. We will also look at protocol extensions and discuss why they are so important in protocol-oriented programming.
Chapter 6, Adopting Design Patterns in Swift, will be implementing several design patterns using protocol-oriented programming. For each of the design patterns, we will look at the problem they are designed to solve and how to implement the pattern.
Chapter 7, Case Studies, will explore three case studies. This chapter is designed to pull everything from the first six chapters together to show the reader how to use protocol-oriented programming with design patterns in real-world situations.
To follow along with the examples in this book, the reader will need to have an Apple computer with OS X 10.10 or higher installed. They will also need to install Xcode version 7.0 or higher with Swift version 2 or higher and have at least basic knowledge of the Swift programming language.
The examples, as they are shown in this book, should work with the Linux port of the Swift language however the downloadable code for this book requires Xcode which is only available on the Apple platform.
This book is for Swift developers who have at least an introductory knowledge of the Swift programming language, who want to learn and implement protocol-oriented programming in their real-world applications. It is also for developers who not only want to understand protocol-oriented programming, but also want to fully understand the different components of the programming paradigm. This book is written for developers who learn best by looking at and working with code, because every concept covered in the book is backed by example code written to give the reader a solid understanding of the current topic and to demonstrate how to properly implement it.
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "We can include other contexts through the use of the include directive."
A block of code is set as follows:
class Jolt {
var volume: Double
var caffeine: Double
var temperature: Double
var canSize: Double
var description: StringNew terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "The answer to this question is polymorphism.".
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