Programming iOS 13

Preface

Aut lego vel scribo; doceo scrutorve sophian.

Sedulius Scottus

With the arrival of Swift 5 in early 2019, the stamp of maturity has been placed upon the Swift language. When Swift was introduced to the public in 2014, it was a sort of second-class citizen. The Cocoa frameworks that give an iOS app its functionality expect to be spoken to in Objective-C, and several megabytes of libraries had to be included in every Swift app, effectively containing the whole of the Swift language and translating everything into Objective-C. But Swift 5 introduces ABI stability, which means that, since iOS 12.2, the Swift language has become part of the system. Swift is now on a par with Objective-C, and Swift apps are smaller and faster.

Swift is the programming language used throughout this book. Still, some awareness of Objective-C (including C) can be useful. The Foundation and Cocoa APIs are still written in C and Objective-C. In order to interact with them, you might have to know what those languages would expect.

The Scope of This Book

Programming iOS 13 is the second of a pair with my other book, iOS 13 Programming Fundamentals with Swift; it picks up where the other book leaves off. If writing an iOS program is like building a house of bricks, iOS 13 Programming Fundamentals with Swift teaches you what a brick is and how to handle it, while Programming iOS 13 hands you some actual bricks and tells you how to assemble them.

So this book, like Homer’s Iliad, begins in the middle ...