Migrating from Swift 3 to Swift 4

This book aims to build on your current iOS development knowledge in Swift and gradually increase your Swift skills to master Reactive programming concepts in Swift. This book will guide you through the concepts while working with real-world apps and projects to give you a better understanding of RxSwift and related APIs.

Swift, as a programming language, has evolved many times over the years since its launch in 2014, and like any software update, we developers have to keep ourselves updated as well. We will start this book by giving you a hands-on update about what's new in Swift and how you can seamlessly migrate from your Swift 3 code to the latest Swift 4 syntax. You will then learn about Swift 4's new features and enhancements—from improvements in language syntax to the new protocols and APIs.

We will start with compatible Xcode IDE and how you can set up the environment required to work with the latest Swift release, some prerequisites before starting to migrate to the latest version, premigration preparation, things to do once the migration is complete, special cases, and other related stuff as we go through this chapter.

Unlike previous Swift releases, this release provides source compatibility with Swift 3 while working toward ABI stability. The main topics that will be covered in this chapter are as listed:

• Setting up the Swift 4 environment
• Changes/improvements to Swift
• Additions to Swift
• Migrating to Swift 4