Swift is out, and we can see that this will replace Objective-C in iOS development sooner or later. However, how should you migrate your Objective-C app? Is it necessary to rewrite everything all over again?

Of course, you don't have to rewrite a whole application in Swift from scratch; you can gradually migrate it. Imagine a 4-year app developed by 10 developers, it would take a long time to get this rewritten.

Actually, you've already seen that some of the code we used in this book has some kind of "old Objective-C fashion". The reason is that not even Apple computers could migrate the whole Objective-C code into Swift.

This chapter will help you migrate from Objective-C to Swift step by step.