From that page, it looks like Scala-C interop is decent, but that's a far cry from C++/Rust interop. For C++ at least, you more or less need to write a pure-C wrapper API to call from Scala, since it doesn't handle C++ types.

Interesting, I guess I understood that wrong. Looks like no "easy" interop, but it's there if you really need it and don't mind the extra work.

I've been playing with this and trying to convert a ~20 line helper script that I use at work (and would really like to benefit from no JVM warmup time), and I've already run into missing core library functions like parallel collections and regexes.

This thing will be really great when it's ready, but it's not even close yet.

You would need the same for Rust as well.

Rust's FFI is the same as C.

I'm not sure what exactly you mean by that, but what I was trying to say is that you can't expose Rust directly, you need to expose a C ABI. Which is totally doable, but is not just "drop in Rust code and it works."

> languages that can expose APIs via C ABI

That's what I thought.. another C-based FFI. Better than nothing, I suppose.