Book Image

Mastering Swift 2

By : Jon Hoffman
Book Image

Mastering Swift 2

By: Jon Hoffman

Overview of this book

<p><span id="description" class="sugar_field">At their Worldwide Developer’s conference (WWDC) in 2015, Apple announced Swift 2, a major update to the innovative programming language they first unveiled to the world the year before. Swift 2 features exciting enhancements to the original iteration of Swift, acting, as Apple put it themselves as “a successor to the C and Objective-C languages.” – This book demonstrates how to get the most from these new features, and gives you the skills and knowledge you need to develop dynamic iOS and OS X applications.<br /> </span></p> <p><span id="description" class="sugar_field">Learn how to harness the newest features of Swift 2 todevelop advanced applications on a wide range of platforms with this cutting-edge development guide. Exploring and demonstrating how to tackle advanced topics such as Objective-C interoperability, ARC, closures, and concurrency, you’ll develop your Swift expertise and become even more fluent in this vital and innovative language. With examples that demonstrate how to put the concepts into practice, and design patterns and best practices, you’ll be writing better iOS and OSX applications in with a new level of sophistication and control.</span></p>
Table of Contents (24 chapters)
Mastering Swift 2
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
Index

Type casting with protocols


Type casting is a way to check the type of the instance and/or to treat the instance as a specified type. In Swift, we use the is keyword to check if an instance is a specific type and the as keyword to treat the instance as a specific type.

To start with, let's see how we would check the instance type using the is keyword. The following example shows how would we do this:

for person in people {
  if person is SwiftProgrammer {
     print("\(person.firstName) is a Swift Programmer")
}
}

In this example, we use the if conditional statement to check whether each element in the people array is an instance of the SwiftProgrammer type and if so, we print that the person is a Swift programmer to the console. While this is a good method to check whether we have an instance of a specific class or struct, it is not very efficient if we wanted to check for multiple types. It is a lot more efficient to use the switch statement, as shown in the next example, if we want to check...