5. Swift Data Types, Constants and Variables
If you are new to the Swift programming language then the next few chapters are recommended reading. Although SwiftUI makes the development of apps easier, it will still be necessary to learn Swift programming both to understand SwiftUI and develop fully functional apps.
If, on the other hand, you are familiar with the Swift programming language you can skip the Swift specific chapters that follow (though if you are not familiar with implicit returns from single expressions, opaque return types and property wrappers you should at least read the sections and chapters relating to these features before moving on to the SwiftUI chapters).
Prior to the introduction of iOS 8, the stipulated programming language for the development of iOS applications was Objective-C. When Apple announced iOS 8, however, the company also introduced an alternative to Objective-C in the form of the Swift programming language.
Due entirely to the popularity...