Bringing Swift to Windows
Porting Swift to Windows is not about simply porting the compiler, but rather ensuring that the full ecosystem is available on the platform. This includes the compiler, the standard library, and the core libraries (dispatch, Foundation, XCTest). These libraries are part of what enables developers to write powerful applications with ease and without having to worry about many of the details of the underlying system. There are many technical details in the story of bringing Swift to a usable state on Windows, and if you are interested in them, I would recommend checking out my talk on the topic from the LLVM Developer Conference.
With these core libraries and the flexible interoperability of Swift with C, it is possible to develop applications on Windows purely in Swift while taking advantage of the existing corpus of libraries on the Windows platforms.😱