[mike_hearn]

You can load code written in different languages into different address spaces, you know. Nothing stops Emacs loading a library written in Rust or indeed Java/Kotlin.

Microsoft didn't go that way and again it feels like maybe JS limitations are the cause. Calling into a native library is tough in JS because there's no standardized FFI (browsers wouldn't allow it) and you're going to end up blocking the one JS thread you've got. Native code is going to expect the host to be able to spin up threads and use them because that's a super reasonable assumption, but one V8 can't meet. So they want everything to look like a web server because that's what JavaScript is intended for. That pushes them down a particular path, but it's definitely worth stepping back and saying ... does this really make the most sense, overall?

[adwn]

> You can load code written in different languages into different address spaces, you know.

That's basically what separate processes are, so what's your point?

> Calling into a native library is tough in JS because there's no standardized FFI

No need for using anything standardized: VS Code brings its own custom browser engine – for better or for worse – so it's not limited to what any Web standards allow or forbid.

> you're going to end up blocking the one JS thread you've got

There are worker threads in JS.

[mike_hearn]

Er, sorry, that was a brainfart. I meant you can load them into the same address space.

JS has workers but they aren't sharing memory, so they aren't really threads.