Gallagher John - Swift Programming: The Big Nerd Ranch Guide

Apples Worldwide Developers Conference is an annual landmark event for its developer community. It is a big deal every year, but 2014 was particularly special because Apple introduced Swift, an entirely new language for the development of iOS and OS X (now called macOS) applications.

As a relatively new language, Swift represents a fairly dramatic shift for macOS and iOS developers. More experienced iOS developers have something new to learn, and new developers cannot rely on a venerable community for tried and true answers and patterns. Naturally, this shift creates some uncertainty.

But this is also an exciting time to be a macOS and iOS developer. There is a lot to learn in a new language, and this is especially true for Swift. The language has evolved quite a bit since its beta release in the summer of 2014, and it continues to evolve.

We are all at the forefront of this languages development. As new features are added to Swift, its users can collaboratively determine its best practices. You can directly contribute to this conversation, and your work with this book will start you on your way to becoming a contributing member of the Swift community.

If you have experience using Objective-C to develop for Apple platforms, you may be wondering why Apple released a new language. After all, developers had been producing high-quality apps for OS X and iOS for years. Apple had a few things in mind.

First, Objective-C is an older language. And while this is not always a problem, it leads to some difficulty in this case. The syntax of Objective-C was solidified prior to the rise of prominent scripting languages in the 1990s that popularized more streamlined and elegant syntax (e.g., JavaScript, Python, PHP, Ruby, and others). This makes Objective-C feel strange to most developers when they get started, so its syntax can be an impediment to developer productivity. Additionally, as an older language, Objective-C is missing many advancements developers in modern languages currently enjoy.

Also, Swift aims to be safe. Objective-C did not aim to be unsafe, but things have changed quite a bit since Objective-C was released in the 1980s. For example, the Swift compiler aims to minimize undefined behavior, which is intended to save the developer time debugging code that failed during the runtime of an application.

Another goal of Swift is to be a suitable replacement for the C family of languages (C, C++, and Objective-C). That means Swift has to be fast. Indeed, Swifts performance is comparable to these languages in most cases.

Swift gives you safety and performance all in a clean, modern syntax. The language is quite expressive; developers can write code that feels natural. This feature makes Swift a joy to write and easy to read, which makes it great for collaborating on larger projects.

Last, Apple wants Swift to be a general purpose programming language. This desire was reflected by the decision to open source Swift in December 2015. Open sourcing the language not only invites developer involvement to help the language progress, but also makes it easier for developers to port the language to other systems beyond macOS and iOS. Apple hopes that developers will use Swift to write apps for a variety of mobile and desktop platforms and to develop back-end web applications as well. Swift is intended to become a mainstream programming language that is the best solution for writing a variety of applications on a variety of systems.