Book Image

Swift 4 Protocol-Oriented Programming - Third Edition

By : Jon Hoffman
Book Image

Swift 4 Protocol-Oriented Programming - Third Edition

By: Jon Hoffman

Overview of this book

Swift has become the number one language used in iOS and macOS development. The Swift standard library is developed using protocol-oriented programming techniques, generics, and first-class value semantics; therefore, every Swift developer should understand these powerful concepts and how to take advantage of them in their application design. This book will help you understand the differences between object-oriented programming and protocol-oriented programming. It will demonstrate how to work with protocol-oriented programming using real-world use cases. You will gain a solid knowledge of the various types that can be used in Swift and the differences between value and reference types. You will be taught how protocol-oriented programming techniques can be used to develop very flexible and easy-to-maintain code. By the end of the book, you will have a thorough understanding of protocol-oriented programming and how to utilize it to build powerful and practical applications.
Table of Contents (15 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Conforming to the Equatable protocol


In this section, we will show how we can conform to the Equatable protocol using extensions. When a type conforms to the Equatable protocol, we can use the equal-to (==) operator to compare for equality and the not-equal-to (!=) operator to compare for inequality.

Note

If you will be comparing instances of a custom type, it is a good idea to have that type conform to the Equatable protocol because it makes comparing instances very easy.

Let's start off by creating the type that we will compare. We will name this type Place:

struct Place { 
  let id: String 
  let latitude: Double 
  let longitude: Double 
} 

In the Place type, we have three properties that represent the ID of the place and the latitude and longitude coordinates for its location. If there are two instances of the Place type that have the same ID and coordinates, then they would be considered the same place.

To implement the Equatable protocol, we could create a global function. However, that...