Swift is strictly less complicated than objective-c for implementing Cocoa apps. It can be used to do more complex things if you want to do functional programm

Swift is strictly less complicated than objective-c for implementing Cocoa apps. It can be used to do more complex things if you want to do functional programming, but to do the same things in the same way, it is less complicated. The weakest point is the lack of examples and documentation. The lack of Linux and windows versions is irrelevant. Although there are open-source implementations of Objective-C, there is no open-source equivalent of Cocoa, so the experience is barely transferable. You certainly will end up learning a lot about objective-c in order to work with Cocoa, but learning Objective-C first will be a waste of time, since once you know Swift, you will barely ever touch Objective-C.