Swift has this weird sort of ecosystem where Apple builds much of the platform in a very secret (most of the roadmap isn't shared), closed-source variant for its own OS. Then it has this open source version, with a very public compiler (roadmap IS shared) that allows cross platform toolchains like this one to exist.

I call it out as weird because take SwiftUI for example, the main excuse Apple engineers gave for why SwiftUI itself is closed-source is because a lot of important code lives inside of UIKit/AppKit. Huh?! Apple being Apple, each revision of SwiftUI is now glued to a singular release of a major revision of the OS. Instead, if Apple decided to built SwiftUI entirely in the open, then the foundational APIs that are closed-source would have to co-exist with the open source versions in order to work.

This is in contrast to Rust, another LLVM language ported to Windows. Every part of Rust is open source and is built to work with open roadmaps and very thoroughly documented standard libraries.

So on the one hand, if you're a fan of Swift, you have yourself a nice hobby language you can play with on the weekend on your gaming PC. On the other, I'm not entirely sure what the point of this effort is for?!

> I'm not entirely sure what the point of this effort is for?!

I'm not quite sure I understand your point. Are you saying Swift has no value outside of SwiftUI? It's a pretty nice general purpose language.

My point is that Apple's weird choices like SwiftUI being tied to internal versions of the standard libraries creates mixed messaging. It's only general purpose enough that on Mac/iOS you get Apple's version of the standard libraries. On other platforms you use an open source version of the standard libraries as the community sees fit to implement the API.

Bugs in Apple's internal variant are tied to OS releases, whereas bugs in the open source variant are tied to someone getting around to fixing it.

If Apple went all in on open source like Rust, or all in on proprietary/closed, then it would have more consistent messaging about what the language is for.

In practice I don't think it's that confusing. You have a large standard library which is available everywhere, and then you have a set of proprietary API's which are only available on Apple platforms.

Is the situation that different from C# and windows API's?

https://github.com/dotnet/roslyn (c#)

https://github.com/dotnet/winforms (UI) https://github.com/dotnet/wpf (UI) https://github.com/dotnet/core (Foundation)

I don't consider the Win32 API itself part of .NET or C# as they've existed long before either.