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Swift Cookbook

You're reading from   Swift Cookbook Over 60 proven recipes for developing better iOS applications with Swift 5.3

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Product type Paperback
Published in Feb 2021
Publisher Packt
ISBN-13 9781839211195
Length 500 pages
Edition 2nd Edition
Languages
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Authors (3):
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Chris Barker Chris Barker
Author Profile Icon Chris Barker
Chris Barker
Keith D. Moon Keith D. Moon
Author Profile Icon Keith D. Moon
Keith D. Moon
Keith Moon Keith Moon
Author Profile Icon Keith Moon
Keith Moon
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Table of Contents (14) Chapters Close

Preface 1. Swift Building Blocks 2. Mastering the Building Blocks FREE CHAPTER 3. Data Wrangling with Swift Control Flow 4. Generics, Operators, and Nested Types 5. Beyond the Standard Library 6. Building iOS Apps with Swift 7. Swift Playgrounds 8. Server-Side Swift 9. Performance and Responsiveness in Swift 10. SwiftUI and Combine Framework 11. Using CoreML and Vision in Swift 12. About Packt 13. Other Books You May Enjoy

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...

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