I’m always glad to see new work on tools, and amplifications to our capabilities of any sort.

I played with Smalltalk, and later Pharo, a bit, but it was years ago. As I recall the editor was always aware of the state of the system. And I think it was at a level beyond what any current IDE can do. While I do not remember if it allowed you to enter invalid code, it was definitely an interesting approach.

So I will be following Eyg for sure.