Book Image

Swift Cookbook. - Second Edition

By : Keith Moon, Chris Barker
Book Image

Swift Cookbook. - Second Edition

By: Keith Moon, Chris Barker

Overview of this book

Swift is an exciting, multi-platform, general-purpose programming language, and with this book, you'll explore the features of its latest version, Swift 5.3. The book begins with an introduction to the basic building blocks of Swift 5.3, its syntax, and the functionalities of Swift constructs. You’ll then discover how Swift Playgrounds provide an ideal platform to write, execute, and debug your Swift code. As you advance through the chapters, the book will show you how to bundle variables into tuples or sets, order your data with an array, store key-value pairs with dictionaries, and use property observers. You’ll also get to grips with the decision-making and control structures in Swift, examine advanced features such as generics and operators, and explore functionalities outside of the standard library. Once you’ve learned how to build iOS applications using UIKit, you'll find out how to use Swift for server-side programming, run Swift on Linux, and investigate Vapor. Finally, you'll discover some of the newest features of Swift 5.3 using SwiftUI and Combine to build adaptive and reactive applications, and find out how to use Swift to build and integrate machine learning models along with Apple’s Vision Framework. By the end of this Swift book, you'll have discovered solutions to boost your productivity while developing code using Swift 5.3.
Table of Contents (14 chapters)
12
About Packt

Value and reference semantics

We saw back in Chapter 1, Swift Building Blocks, that certain Swift types behave differently from others, specifically regarding ownership and the mutation of properties. We even defined this difference, saying that classes are reference types, while structs and enums are value types. In this recipe, we will examine why these types behave differently and the performance implications this entails.

Let's create the model for an app that allows a user to schedule events that they do every day and reminds them when these events should occur.

Getting ready

We need to decide how we will model our daily event. The key to this decision is whether we want our event to have reference semantics or value semantics. We discussed the differences between the two in Chapter 1, Swift Building Blocks, but let's re-examine the differences.

Value types are simple data structures that you can think of as just bundles of data. Swift makes these types more useful by allowing...