throwaway720348

Ah you're right, I forgot about OCaml's ass-tier multicore support. Rust is definitely better there.

You can use a language like OCaml without allocating and still capture huge benefits over C++, like a decent type system, ADTs, and better abstractions than templates (modules in OCaml's case).

Rust type's system has a similar power level to OCaml's but without modules (which are used heavily at JS) and with linear types/lifetimes. Rust would probably be a good fit for JS, but of course it takes a lot to overcome the momentum of 20 years of using primarily one language.

I think you are ascribing too much thought to Jane Street's decision to use OCaml. I think it was a good choice, on balance, but from what I heard/read when I worked there it was mostly just circumstantial.

The people who work at jane street are generally super talented, but they also mostly work on generic not-especially-interesting software problems.

Source: Former jane street employee, also worked at two FAANGs before that, so I think I have some basis for comparison