Book Image

Swift Cookbook - Second Edition

By : Keith Moon, Chris Barker
Book Image

Swift Cookbook - Second Edition

By: Keith Moon, Chris Barker

Overview of this book

Swift is an exciting, multi-platform, general-purpose programming language, and with this book, you'll explore the features of its latest version, Swift 5.3. The book begins with an introduction to the basic building blocks of Swift 5.3, its syntax, and the functionalities of Swift constructs. You’ll then discover how Swift Playgrounds provide an ideal platform to write, execute, and debug your Swift code. As you advance through the chapters, the book will show you how to bundle variables into tuples or sets, order your data with an array, store key-value pairs with dictionaries, and use property observers. You’ll also get to grips with the decision-making and control structures in Swift, examine advanced features such as generics and operators, and explore functionalities outside of the standard library. Once you’ve learned how to build iOS applications using UIKit, you'll find out how to use Swift for server-side programming, run Swift on Linux, and investigate Vapor. Finally, you'll discover some of the newest features of Swift 5.3 using SwiftUI and Combine to build adaptive and reactive applications, and find out how to use Swift to build and integrate machine learning models along with Apple’s Vision Framework. By the end of this Swift book, you'll have discovered solutions to boost your productivity while developing code using Swift 5.3.
Table of Contents (14 chapters)
12
About Packt

Enumerating values with enums

Enumerations are a programming construct that lets you define a value type with a finite set of options. Most programming languages have enumerations (usually abbreviated to enums), although the Swift language takes the concept further than most.

An example of an enum from the iOS/macOS SDK is ComparisonResult, which you would use when sorting items. When comparing for the purposes of sorting, there are only three possible results from a comparison:

  • ascending: The items are ordered in ascending order.
  • descending: The items are ordered in descending order.
  • same: The items are the same.

There are a finite number of possible options for a comparison result; therefore, it's a perfect candidate for being represented by an enum:

enum ComparisonResult : Int { 
case orderedAscending
case orderedSame
case orderedDescending
}

Swift takes the enum concept and elevates it to a first-class type. As we will see, this makes enums a very powerful tool...