Comment by flohofwoe

Here's something similar by Garrett Bass:

https://github.com/garettbass/oc

...I also experimented a bit with parsing macOS system headers via clang-ast-dump and then code-generating C and Zig bindings but that didn't get far:

https://github.com/floooh/objc-ast-experiments

...with a bit of effort and maybe using libclang instead of clang-ast-dump that's definitely feasible though.

I guess a similar approach is used by the official C++ bindings for Metal:

https://developer.apple.com/metal/cpp/

...also shameless plug: the sokol headers allow to write simple macOS applications (just a Metal canvas in a window) in various non-Apple languages (currently C, C++, Zig, Rust, Odin, Nim):

https://github.com/floooh/sokol

...I'm cheating though and use ObjC under the hood to talk to Cocoa and Metal ;)