Book Image

Mastering Swift 5.3 - Sixth Edition

By : Jon Hoffman
Book Image

Mastering Swift 5.3 - Sixth Edition

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)
21
Other Books You May Enjoy
22
Index

Using a single-parameter function

The syntax that's used to define a function in Swift is very flexible. This flexibility makes it easy for us to define simple C-style functions, or more complex functions with local and external parameter names, which we will see later in this chapter. Let's look at some examples of how to define functions. The following example accepts one parameter and does not return any value to the code that called it:

func sayHello(name: String) ->    Void { 
    let retString = "Hello " + name
    print(retString)
}

In the preceding example, we defined a function named sayHello() that accepted one parameter, named name. Inside the function, we printed out a greeting to the person. Once the code within the function is executed, the function exits, and control is returned to the code that called it. Rather than printing out the greeting, we could return it to the code that called it by adding a return type, as follows:

func...