Originally, I was going to use D, but its current WASM guideline is buried under a lot of Discord threads, all while people are lazy to touch the wiki. I need to test stuff with WASM (use for scripting in applications, not browsers).
Please NO RUST!!! While I see why functional programming is useful (I even use wasmtime as my WASM engine, which is developed in Rust), but is horribly counterproductive for game development, especially if it’s opt out like in Rust.
EDIT: In the meanwhile, I’ve found AssemblyScript, which seems to be good for my usecase.
Fundamentally it’s a language oriented around blocks of statements rather than composition of expressions. Additionally, it takes a different approach to the mutation problem than FP languages: where FP seeks to make most things pure and push mutation and side effects to the edges of the program, Rust uses its type system to make such mutation and side effects more sane. It’s an entirely different philosophy when it comes to programming. I don’t think either approach is necessarily better, mind you, just a different set of tradeoffs.
I’m a professional Haskell developer and am very much immersed in FP. When I read Rust code, I have to completely shift my thinking to something much more imperative. Whereas if I read, say, Ocaml, the difference is mostly syntactic. This isn’t a slight, mind you. I quite like Rust. But it’s a very different paradigm.
I made this mistake for ages because Haskell is so popular and it’s functional and pure, but it’s not actually a requirement for functional languages to be pure. OCaml isn’t.
I agree Rust code has a different feel to OCaml code but that’s because it makes some things easier (e.g. mutation, vectors). You still could write Rust as if it was OCaml (except for the lack of currying), it’s just that nobody does that because it sucks.
I think we’re probably agreeing, it’s just that “functional programming” is extremely poorly defined and we’re interrupting it differently. You’re thinking “a language where people write enormous nested expressions and over-use recursive functions and linked lists” and I’m thinking “a language that supports lots of features common in the FP paradigm: first class functions, pattern matching, expression based not statement based, iterators/map/filter/reduce, currying, tagged unions/sum types, etc.”
I didn’t say that FP languages have to necessarily be pure, just that FP languages tackle the problem of mutation by arranging programs such that most things are typically pure and side effects typically happen at the periphery (logging is probably the one exception, though). This is true even in FP languages that allow arbitrary side effects in functions, it’s just not enforced by a compiler.
That’s the entire point, though. It’s all about what the language emphasizes and makes easy to do. If it’s unnatural to write a functional program in Rust and no one does it, then it’s not really reasonable to call it a functional language. Writing functional programs is not idiomatic Rust, and that’s okay.