Show HN: Fuse – statically typed functional programming language
fuselang.org30 points by the_unproven 3 hours ago
30 points by the_unproven 3 hours ago
Hi HN! I've been working on the fuse programming language, it's a statically typed purely functional language with higher-kinder types and ad-hoc polymorphism. It compiles to the GRIN whole-program optimizer, producing LLVM-generated native code.
Fuse supports ADTs, Generics, Type Methods, Traits, Pattern matching etc. all in a functional style with no mutations.
I’ve been developing the language for 5 years, with code written in Scala. I’ve started coding the language from the base of System F that was implemented as part of the book: Types and Programming Languages (tapl). And then extending with concepts such as Bidirectional Type Checking with Higher-Rank Polymorphism.
I’ve mainly drawn inspiration from Rust, Haskell, Scala and Python (in terms of syntax). It all started because I wanted a language that has Rust-like concepts such as: ADT, Traits, Impl block syntax, etc. but have the pure functional semantics.
I'd would love feedback on the language design and its general usage.
It's nice to see a GRIN backend in the wild! It looks like a tidy little functional language - a small, easily grasped syntax surface and generally clear semantics. That you've got it to the point that it can compile and run proper programs is a great achievement for a solo dev project! The string type in the standard library isn't Unicode-aware, might be worth just noting that. Unicode support can be a big undertaking, but considering whether you'll add it later or not might affect your library design now. I don't really understand why you have an IO monad. The language isn't pure - `.exec()` means any function can perform IO actions no matter its type signature - so what's IO really for? Do `impl` additions export? What happens when two libraries add the same function name with different signatures (or just bodies!) to a type's `impl` ? Is currying automatic? It doesn't seem to be, but, eg, the `sum(x: i32, y: i32)` function theoretically could be called as `sum(5)` to create a closure, but this isn't a documented feature if so. The website's font is using ligatures, not unicode operator symbols - I'd personally find it much clearer to use a non-ligature font to show what's really there, but that's immaterial to the language. First of all thanks for all the feedback and looking into it, appreciate it! Yeah GRIN is a great project, it took a lot of debugging and analysis to make it compile 100% especially with monomorphization involved. I'll look into Unicode support, makes total sense. Didn't scope it in initially. I can fix the site ligatures too, that's a fair remark. > I don't really understand why you have an IO monad. The language isn't pure - `.exec()` means any function can perform IO actions no matter its type signature - so what's IO really for? That's a fair point, I still left a place for `.exec()` to happen as un-handled side-effect. But the preference is with using the IO monad as the stdlib is built around it, with `main() -> IO[i32]` as a type signature. As languages evolves I'm planning to build a runtime around IO execution, and build more constraints for handling strict side-effects. However for this initial stage of the language, I left it as a really simple solution. > Do `impl` additions export? What happens when two libraries add the same function name with different signatures (or just bodies!) to a type's `impl` ? For now the language doesn't support modules (libraries), I'm planning on adding it. At the moment it's a bit of undefined behavior, as overloading would occur with latest `impl` definition. > Is currying automatic? It doesn't seem to be, but, eg, the `sum(x: i32, y: i32)` function theoretically could be called as `sum(5)` to create a closure, but this isn't a documented feature if so. In the type-system it is automatic, and it successfully passes type checker as it's entirely built on top of lambda calculus. But there's an issue with codegen right now. I can def look into it and document it. I wish you took Haskell's syntax as such. Why did you mix rust and possibly other stuff with it?
codebje - an hour ago
the_unproven - 20 minutes ago
qsera - an hour ago