[npn]

It's kinda working right now, with some missing features like exceptions raising and catching, block closures, c-library binding (only libc works IIRC).

You can follow the activity here: https://github.com/crystal-lang/crystal/pull/10910

I was pleasantly surprised myself that the interpreter actually already somewhat worked, as you can see in the demo: https://www.youtube.com/watch?v=een_W1YEICw&list=PLe1-A91ZPT...

The creator also claimed that the interpreter only need a few more months to finish.