This is amazing. I've been wanting to do this for ages (even tried a few times and failed a few times). Great to see this.

It is crazy how much work comes out of Bruno Oliveira’s research groups.

Another cool online thing that exists is CP, a language with disjoint intersection and union types:

https://github.com/yzyzsun/CP-next

  printNum = trait implements ExpSig<Eval => Print> {

  trait ExpSig[F[_]]
  object printNum extends ExpSig[[A] =>> Eval[A] => Print]

huh funny how python's doing the job of modeling type systems when it barely enforces types itself. but makes sense the more u poke around. didn't have to fight any compiler layer or deal with noise. could just build the inference logic raw, decide how types get unified, how ctx gets stored, all that. no annotations or weird conversions. the language just stepped aside so i could focus. actually helped my brain map the theory better ngl