Expectations and Technical Requirements

The technical requirements for iOS development are pretty simple: the latest version of Xcode, and a macOS computer that can run it. As of May 2017, that means Xcode 8.3 or later, and a Mac running macOS 10.12 (Sierra).

All code in this book uses the Swift programming language. Swift is a performant, practical language that Apple clearly intends to be the future of all development for its platforms. When it was open sourced in late 2015, the About Swift page declared:

The goal of the Swift project is to create the best available language for uses ranging from systems programming, to mobile and desktop apps, scaling up to cloud services. Most importantly, Swift is designed to make writing and maintaining correct programs easier for the developer.

On the same page, it says that Swift “is intended as a replacement for C-based languages (C, C++, and Objective-C).” That’s not an unreasonable goal! Swift is a neat language that cleans out a lot of cruft from C and Objective-C, while also drawing inspiration from functional programming languages like Haskell.

We’re sure you’ll be able to pick it up quickly, provided you’re a proficient programmer in at least one object-oriented language. That can be one of the many curly-brace descendants of C (C++, C#, or Java), or an OO scripting language like Ruby or Python. While we touch on Swift’s appropriateness for functional programming, the iOS frameworks are largely OO in nature, so most of the functionality provided by Apple comes in the form of classes and objects.