[polymathist]

Ply looks really cool! I can certainly understand the appeal of that kind of approach in terms of simplicity, stability, and better interop.

Local types are an edge case I'll need to spend more time working on. The type-checker won't have any problems; the real question is how to generate the appropriate Go code. One solution might be to move the local type into a higher scope during code-generation. Another might be inlining the relevant generic types in the same scope as the local type. Finally, the best solution might just be to say this sort of thing isn't allowed and the compiler will return an error.

Imports aren't supported right now, but it's one of the most important things I need to work on next. It'll be pretty tricky, but I'm confident I can find a solution.

The fortunate thing about the approach I'm using with Fo is that I have complete control over the parser, type-checker, and code-generator. At the cost of having significantly more complexity, I have the flexibility to tackle these sorts of edge cases without relying solely on existing tooling.