Book Image

Mastering Swift 3

Book Image

Mastering Swift 3

Overview of this book

Swift is the definitive language of Apple development today. It’s a vital part of any iOS and OS X developer’s skillset, helping them to build the most impressive and popular apps on the App Store—the sort of apps that are essential to iPhone and iPad users every day. With version 3.0, the Swift team have added new features to improve the development experience—making it easier to get the results you want and customers expect. Inside, you’ll find the key features of Swift 3.0 and quickly learn how to use the newest updates to your development advantage. From Objective-C interoperability to ARC, to closures and concurrency, this advanced Swift guide will develop your expertise and make you more fluent in this vital programming language. We give you in-depth knowledge of some of the most sophisticated elements of Swift development including protocol extensions, error-handling, design patterns, and concurrency, and guide you on how to use and apply them in your own projects. You'll see how even the most challenging design patterns and programming techniques can be used to write cleaner code and to build more performant iOS and OS X applications. By the end of this book, you’ll have a handle on effective design patterns and techniques, which means you’ll soon be writing better iOS and OS X applications with a new level of sophistication and control.
Table of Contents (23 chapters)
Mastering Swift 3
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Free Chapter
1
Taking the First Steps with Swift
2
Learning About Variables, Constants, Strings, and Operators

When not to use generics


One of the things that we should watch out for while using generics is to avoid using them when we should be using protocols. This is, in my opinion, one of the most common misuses of generics in other languages. Let's take a look at an example so that we know what to avoid.

Let's say that we define a protocol called WidgetProtocol, which is as follows:

protocol WidgetProtocol { 
    //Code 
} 

Now, let's say that we want to create a custom type (or function) that will use various implementations of the WidgetProtocol protocol. I have seen a couple of instances where developers have used generics with a type constraint to create custom types as follows:

class MyClass<T: WidgetProtocol> { 
    var myProp: T? 
    func myFunc(myVar: T) { 
        //Code 
    } 
} 

While this is a perfectly valid use of generics, it is recommended that we avoid implementations like this. It is a lot cleaner and easier to read if we use...