The only reason I could think of was being able to compile to JS, but other than that Rust seems to be a superior choice for all the use cases I could have used practically used OCaml for.
Unless the project absolutely couldn't tolerate GC, why would I choose a low level language like Rust over a high level language like Ocaml?
Rust is a low level systems language, where you care about memory. You may not be malloc’ing, but you’re borrowing.
Conversely OCaml is an interpreted functional language. It has a much richer and more concise syntax than rust.
You can’t define operators in rust. That means no ‘|>’, no parser combinators. I doubt I’ll ever write a parser in a non-ML language, after my experiences with FParsec.
Rust can’t do partial application properly. I can’t compose functions in rust.
Don’t get me wrong though - Rust is a fantastic language and miles ahead of similar languages in terms of functional features. The only popular C-like language that’s catching up is C#, but discriminated unions aren’t due until next autumn.
Rust is better for manipulating a computer, OCaml is better for math-ey things such as parsers.
You should try OCaml, even if you don’t use it you’ll learn about programming from it.
Correction: OCaml is not an interpreted language. OCaml programmes are compiled down to native code (or bytecode, or Javascript).
In fact I would argue that rust is much more suited to write low level things like operating systems and unikernels than ocaml. Having said that mirage is very cool. It is a unikernel and it has garbage collection. So it’s easy to write robust and secure services! Yeah anything written in rust will probably be faster but then unless you’re a mega company and have mega size deployments this should not really matter to you. Mirage should serve your needs well if you need unikernels
2. Compilation times