Dynamic replacement. The Swift compiler and runtime are fully embedded throughout Xcode, so your app is constantly being built and run. The design canvas you see isn’t just an approximation of your user interface — it’s your live app. And Xcode can swap edited code directly in your live app with “dynamic replacement”, a new feature in Swift.
Hehe, azért ezt mások is tudják már egy jó ideje, ideje volt felzárkózni :)