Swift was designed for writing apps on the mac platforms, primarily on iOS, and although somewhat debatable as a replacement for Objective-C due to it's quirks. If you want proof of that, just read between the lines in the original documentation.

Not to mention, many of the features that were called out originally are direct responses to issues with Objective-C: Optionals, Typed containers, Generics, modules, real first class functions instead of just blocks, final classes, let, etc.