Preface

Since Apple announced the Swift programming language at WWDC 2014, it has gone on to become one of the fastest-growing programming languages. Swift is modern, open-source, and easy to use, and therefore its usefulness can extend beyond Apple's ecosystem, giving it the potential to be used across all platforms and for any scenario.

Swift 5.3 is the latest version of this exciting new programming language, giving you the tools to build performant and responsive apps with safe and clean code.

This book will guide you through Swift's features, building up your knowledge and toolset layer by layer, so you can use Swift to build the next great app or service.

You will be given useful, easy-to-follow recipes for using Swift to accomplish real-world tasks. Each recipe only uses concepts previously covered in the book so you will never feel lost.

Learn what makes Swift one of the fastest-growing and most exciting programming languages available today.

Who this book is for

If you are looking for a book to help you learn about the diverse features offered by Swift 5, along with tips and tricks to efficiently code and build applications, then this book is for you. Knowledge of Swift or general programming concepts will be beneficial.

What this book covers

Chapter 1, Swift Building Blocks, introduces you to the basic building blocks of Swift 5, its syntax, and the functionalities of basic Swift constructs. Also, this chapter will introduce you to Apple’s Xcode IDE and Swift Playgrounds, which provides an ideal way to create, execute, debug, and understand the recipes contained in this book, thus setting you up to initiate the development process. In this chapter, you will learn how to write your first Swift program and understand the various basic elements of the Swift language.

Chapter 2, Mastering the Building Blocks, teaches you how to create more complex structures on the basis of the building blocks that you studied in the first chapter and the functionalities provided by the Swift standard library. You will get an understanding of how to bundle variables into tuples, order data with the help of an array, and store key-value pairs with dictionaries. You will also learn how to use the property observers and control the access to and visibility of your code. Then, you will learn how to extend the functionalities of your code using the extensions.

Chapter 3, Data Wrangling with Swift Control Flow, will teach you that programming is all about making decisions, therefore in this chapter, we will explore how to make decisions on the basis of the information gained and how to alter the control flow of the code. You will learn how to conditionally execute your code with if/else statements. You will also learn how to control the flow of execution of your code with switch statements, and then loop this code by understanding how to use for and while loops. You will then understand how to handle Swift errors with try, throw, do, and catch statements. Also, we will cover how a defer statement can be useful to change state once a function's execution is complete or to clean up values that are no longer needed.

Chapter 4, Generics, Operators, and Nested Types, provides you with an understanding of two advanced features of Swift, which are generics and operators. Using these features, you will learn how to build functionalities that are flexible and well defined. Also, you will understand how nested types allow logical grouping, access, and namespacing for your constructs.

Chapter 5, Beyond the Standard Library, takes you on a journey to explore the functionalities beyond the standard library provided by frameworks such as Foundation and UIKit. Learning how to use these functionalities will help you make full use of the Swift language.

Chapter 6, Building iOS Apps with Swift, is where we'll start the journey into building our very own iOS app. Taking everything we've learned and more from the previous chapters' recipes, this chapter will teach you how to get off the ground using Swift to build an iOS app.

Chapter 7, Swift Playgrounds, is where you will gain a total understanding of using Swift Playgrounds and explore advanced features other than those explored in previous chapters, to create fully interactive experiences.

Chapter 8, Server-Side Swift, introduces you to a totally different aspect of Swift programming: server-side programming with Swift. Also, you will gain an understanding of how to run Swift on Linux by installing the Swift toolchain. You will learn how to use a web server framework to build a REST API and how to host your API via a hosting service. You will also learn how to accomplish your tasks easily by understanding how to use Vapor, one of the most popular frameworks of Swift 5.

Chapter 9, Performance and Responsiveness in Swift, explores the more advanced concepts of Swift programming to provide an understanding of how certain Swift types are implemented and their performance characteristics. Also, you will learn how to perform asynchronous tasks using the Grand Central Dispatch API. Then, we'll explore the multi-threaded environment available on all Apple platforms and how to enhance the performance profile of your Swift constructs to build a fast and responsive app.

Chapter 10, SwiftUI and Combine Framework, dives straight into Apple's new UI framework, SwiftUI. With SwiftUI, we'll learn how to create iOS apps by exploring the declarative syntax used to achieve this. We'll also explore how easy it is for SwiftUI and UIKit to work together. In addition to SwiftUI, we'll also explore the basics of the new Combine framework and how this works alongside SwiftUI.

Chapter 11, Using CoreML and Vision in Swift, will dive into the frameworks offered by Apple and how we can use Swift code to harness machine learning techniques, as machine learning is becoming an increasingly hot topic. In this chapter, we'll cover CoreML and the Vision frameworks, using pre-trained models to identify objects in real time.

To get the most out of this book

To follow along with the examples in this book, you will need a computer running macOS Catalina (specifically version 10.15.4) or greater. You also need an Apple ID to download and install Xcode 12 from the Mac App Store. The chapter on server-side Swift (Chapter 8, Server-Side Swift) also requires a system running Ubuntu 20.04 LTS.

The code in this book has been tested against Swift 5.3, but should work with any newer versions of Swift.

Software/hardware covered in the book	OS requirements
macOS	10.15.4+ (Catalina)
Xcode	12+
Ubuntu (for Chapter 8, Server-Side Swift)	20.04 LTS

If you are using the digital version of this book, we advise you to type the code yourself or access the code via the GitHub repository (link available in the next section). Doing so will help you avoid any potential errors related to the copying and pasting of code.

Download the example code files

You can download the example code files for this book from GitHub at https://github.com/PacktPublishing/Swift-Cookbook-Second-Edition. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Code in Action

Code in Action videos for this book can be viewed at http://bit.ly/3shdTeQ.

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://static.packt-cdn.com/downloads/9781839211195_ColorImages.pdf.

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "We can substitute Grumble wherever we would use [Pug] or Array<Pug>."

A block of code is set as follows:

let fraction = rating / total 
let ratingOutOf5 = fraction * 5 
let roundedRating = round(ratingOutOf5) // Rounds to the nearest 
  // integer.

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

class ProgrammeFetcher { 
     
    typealias FetchResultHandler = (String?, Error?) -> Void 
     
    func fetchCurrentProgrammeName(forChannel channel: Channel, 
                                   resultHandler: FetchResultHandler) { 
        // Get next programme 
        let programmeName = "Sherlock" 
        resultHandler(programmeName, nil) 
    } 

Any command-line input or output is written as follows:

$ mkdir css
$ cd css

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Select System info from the Administration panel."

Warnings or important notes appear like this.

Tips and tricks appear like this.

Sections

In this book, you will find several headings that appear frequently (Getting ready, How to do it..., How it works..., There's more..., and See also).

To give clear instructions on how to complete a recipe, use these sections as follows:

Getting ready

This section tells you what to expect in the recipe and describes how to set up any software or any preliminary settings required for the recipe.

How to do it…

This section contains the steps required to follow the recipe.

How it works…

This section usually consists of a detailed explanation of what happened in the previous section.

There's more…

This section consists of additional information about the recipe in order to make you more knowledgeable about the recipe.

See also

This section provides helpful links to other useful information for the recipe.

Get in touch

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