Jon Manning - Head First Swift

by Paris Buttfield-Addison and Jon Manning

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• December 2021: First Edition

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Swift is a programming language you can rely on. Its a programming language that you can take home to meet your family. Safe, reliable, speedy, friendly, easy to talk to. And, while Swift is most well known for being the programming language of choice for Apples platforms (such as iOS, macOS, watchOS, and tvOS), the open source Swift project also runs on Linux, and is gaining ground is a systems programming language, as well as on the server. Swift for Windows is even in the works. You can build everything from mobile apps, to games, to web apps, to frameworks and beyond. Lets get started!

Swift is a language for everything

Swift has evolved fast.

From humble begins with Swift 1, all the way through to today, with Swift 5.x. Each major Swift update has added new language features, as well as deprecating certain syntax elements. Since its announcement and release in 2014, Swift has been one of the fastest growing, and most popular, languages in programming language history.

Swift has been placed in the top 10 programming languages for the past few years, and continues to grow in popularity, amount of projects using Swift, and userbase. Swift skills are also in high-demand, so dont forget to add it your rsum when youre finished with this book.

Swift originally started as a language solely for Apples platformsiOS, macOS, tvOS, watchOSbut has grown and expanded its possibilities since it was open sourced in 2015.

The swift evolution of Swift

How youre going to write Swift

Every programming language needs a tool for you to program in and use to run the code youre writing. Basically, you cant do much with Swift without running some Swift code.

So, hows that done? Well be using an app developed by Apple called Playgrounds!

Playgrounds are just like (collections of) big old-fashioned text files, where it also turns out you can run each and every line written through the Swift compiler, and see the result.

Much of the Swift youll be writing via this book will involve Playgrounds.

Note

But not all of it. Well explain more, a bit later.

Working with Swift in Playgrounds involves three stages:

Its easier, and better, to learn Swift in a Playground.

By working in a Playground now, you dont have to worry about all the boilerplate code that comes with building an app, as well as compiling and running your code into an app, testing it on an iOS device simulator, testing it on a physical iOS device, and troubleshooting your code for the slight differences between all the various pieces of iOS and iPadOS hardware.

A Playground lets you focus on the Swift code, and not worry about any of the other things that come with building an app (or writing a website backend, or doing data science, or any of the other things you might want to do with Swift). Thats why we start in Playgrounds.

It removes all the distractions.

Its not lesser in any way, and its real, actual Swift code, and lets you work up to building apps and more, using Swift.

Note

If youre here because you want to write iOS apps (thats awesome, by the way!) then please stick with us through the Playgrounds. It really is the best way to learn.

The path youll be taking

Getting Playgrounds

Swift Playgrounds is an app thats available for macOS and iPad OS. You use the Playgrounds app to write, run, and tweak your Swift code.