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  • Book Overview & Buying Mastering Swift 5.3
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Mastering Swift 5.3

Mastering Swift 5.3

By : Jon Hoffman
3.7 (15)
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Mastering Swift 5.3

Mastering Swift 5.3

3.7 (15)
By: Jon Hoffman

Overview of this book

Over the years, Mastering Swift has proven itself among developers as a popular choice for an in-depth and practical guide to the Swift programming language. This sixth edition comes with the latest features, an overall revision to align with Swift 5.3, and two new chapters on building swift from source and advanced operators. From the basics of the language to popular features such as concurrency, generics, and memory management, this in-depth guide will help you develop your expertise and mastery of the language. As you progress, you will gain practical insights into some of the most sophisticated elements in Swift development, including protocol extensions, error handling, and closures. The book will also show you how to use and apply them in your own projects. In later chapters, you will understand how to use the power of protocol-oriented programming to write flexible and easier-to-manage code in Swift. Finally, you will learn how to add the copy-on-write feature to your custom value types, along with understanding how to avoid memory management issues caused by strong reference cycles. By the end of this Swift book, you will have mastered the Swift 5.3 language and developed the skills you need to effectively use its features to build robust applications.
Table of Contents (23 chapters)
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21
Other Books You May Enjoy
22
Index

Generic subscripts

Prior to Swift 4, if we wanted to use generics with a subscript, we had to define the subscript at the class or structure level. This forced us to make generic methods when it felt like we should be using subscripts. Starting with Swift 4, we can create generic subscripts, where either the subscript's return type or its parameters may be generic. Let's look at how we can create a generic subscript. In this first example, we will create a subscript that will accept one generic parameter:

subscript<T: Hashable>(item: T) -> Int { 
    return item.hashValue
}

When we create a generic subscript, we define the placeholder type after the subscript keyword. In the previous example, we define the T placeholder type and use a type constraint to ensure that the type conforms to the Hashable protocol. This will allow us to pass in an instance of any type that conforms to the Hashable protocol.

As we mentioned at the start of this section, we...

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