Many of these developers had never used Objective-C before, and that was the first challenge Apple threw at them. They are now recognized as iOS developers. This event started another revolution in software development, and a new breed of developer was born. The intention, instead, is for you to abstract this special method into what you actually want this to look like in Swift.In 2008 Apple announced and released the iPhone SDK 2.0.

In fact, if you try to implement this example you'll notice that while you can use it, it will not show in code completion at all. The reason for this is precisely to indicate that this method shouldn't be used as-is. In the case of methods, this special way will be that the method's name will be prefixed by two underscores ( _): let instance = SRM圜lass._sharedInstance() To customize how it'll be translated, let's add the attribute to the Objective-C definition: SRM圜lass : NSObject + (instancetype)sharedInstance NS_REFINED_FOR_SWIFT mentioned, using this attribute won't stop the method from being migrated to Swift - but it'll be done in a special way. Here's an example of a singleton in Objective-C: SRM圜lass : NSObject + (instancetype)sharedInstance default this will be converted to a sharedInstance() method in Swift, but in Swift standards, this would look better as a computed property instead. When added to an Objective-C API, the compiler will still port it, but it will do so in the shape of a special hidden method that you can use to redefine it as something else. The NS_REFINED_FOR_SWIFT attribute can be added to Objective-C methods to indicate that you want to have full control on how this API is translated to Swift. Fortunately, the compiler provides you a way to completely customize how Objective-C APIs end up in Swift. The compiler isn't that smart, so by default you'll end up with methods even if they are better defined as something else in Swift: M圜lass.sharedInstance() // would work better in Swift as `M圜lass.shared`!Īdditionally, the automatic API translation doesn't consider Swift-only features like default arguments and generics in methods, which are really good tools for developing APIs in Swift. However, what if you want that Objective-C API to become something completely different? One example of a common architectural difference between the languages is the usage of methods versus properties - most things in Objective-C are methods, while Swift will advise you to use computed properties for things that are computed but yet don't involve actually processing data. While I'm not a fan of how the naming can end up sometimes, there are attributes that you can use to finetune the final result, like NS_SWIFT_NAME(customName) to use a customized name or NS_SWIFT_NOTHROW to disable the error pointer -> throws conversion.

Swift code in objective c