It's not great. However, I heard something hopeful in the latest episode of the Swift Unwrapped podcast. It was mentioned how the person working on the Windows build has recently been employed by Apple.

https://spec.fm/podcasts/swift-unwrapped/316012

Saleem has joined the Swift core team, but as far as I know he’s not employed by Apple.

From what I’ve seen, Windows APIs are in C++, and Swift doesn’t really offer any C++ interop. You’d have to wrap everything in C functions first.

Plus, Windows isn’t an officially supported platform for the Swift compiler.

I wouldn’t hold my breath.

Modern Windows APIs are COM not C++.

Any COM aware language should be able to call them without any issue.

Naturally the first issue is to treat Windows as tier 1 OS to start with.

Most core Windows APIs are C APIs, the only stuff that requires C++ AFAIK are things like ATL and MFC which are just (very thick) wrappers..

This ignores all the new UWP API's which are the basis for modern Windows applications and will work on all future versions of windows. C++ is the preferred language here:

https://docs.microsoft.com/en-us/windows/uwp/cpp-and-winrt-a...

Only the classical API.

Since Vista, the plan has been doing in COM what was thought out for Longhorn with .NET.

As such, all new APIs introduced since Vista are mostly COM libraries, and now UWP, which is an improved version of COM, after its hard rebirth with WinRT and UA.