What is on the cutting edge of programming language design and research?

ColorForth has a very interesting idea that I think deserves more attention, that of adding markup to source code that directly sets a few mode bits (comment, literal, immediate). Often we do a lot of things that clutter up source code, like doc strings, that really could be separate layers.

Metamine was an experimental system that combined declarative as well as the normal imperative code. You had a "magical equals" that kept the left side updated as the conditions on the right changed (like a formula in excel). It allowed for some very interesting things. It got pulled from the internet, though.

https://github.com/Microsoft/BosqueLanguage

I'm not super familiar but it looked cool when I read about it a few years ago

Also, differentiable programming is interesting and getting lots of attention (jax, zygote, enzyme, kornia etc). I don't know if there is a "killer app" outside just training neural networks yet, but it's worth watching and e.g. kornia is doing some cools stuff

pldi is coming up, watch the proceedings! https://pldi22.sigplan.org/

in my mind the work on extending our reach into quantum computing models is the only “cutting edge” stuff happening right now.

the is one of the most mature areas of computer science, there isn’t a whole lot of cutting happening imo, the blade is plenty sharp.

For me it’s DSLs that have clear use cases.

Memory management also may be fertile ground.

WASM!