Book Image

Learning Swift Second Edition - Second Edition

By : Andrew J Wagner
Book Image

Learning Swift Second Edition - Second Edition

By: Andrew J Wagner

Overview of this book

Swift is Apple’s new programming language and the future of iOS and OS X app development. It is a high-performance language that feels like a modern scripting language. On the surface, Swift is easy to jump into, but it has complex underpinnings that are critical to becoming proficient at turning an idea into reality. This book is an approachable, step-by-step introduction into programming with Swift for everyone. It begins by giving you an overview of the key features through practical examples and progresses to more advanced topics that help differentiate the proficient developers from the mediocre ones. It covers important concepts such as Variables, Optionals, Closures, Generics, and Memory Management. Mixed in with those concepts, it also helps you learn the art of programming such as maintainability, useful design patterns, and resources to further your knowledge. This all culminates in writing a basic iOS app that will get you well on your way to turning your own app ideas into reality.
Table of Contents (19 chapters)
Learning Swift Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Enumerations


So far, we have covered two of the three types of classification in Swift: structure and class. The third classification is called enumeration. Enumerations are used to define a group of related values for an instance. For example, if we want values to represent one of the three primary colors, an enumeration is a great tool.

Basic declaration

An enumeration is made up of cases much like a switch and uses the keyword enum instead of struct or class. An enumeration for primary colors should look like this:

enum PrimaryColor {
    case Red
    case Green
    case Blue
}

You can then define a variable with this type and assign it one of the cases:

var color = PrimaryColor.Green

Note that, to use one of the values, we must use the name of the type followed by a dot (.) and then the specific case. If the type of the variable can be inferred, you can even leave out the enumeration name and just start with a dot:

var color = PrimaryColor.Green
color = .Red

During the assignment to .Red, the...