"ML-derived languages like OCaml are "mostly pure". They allow side-effects through things like references and arrays, but by and large most of the code you'll write will be pure functional because they encourage this thinking. Haskell, another functional language, is pure functional. OCaml is therefore more practical because writing impure functions is sometimes useful."
https://ocaml.org/docs/functional-programming
> My complaint is that V claims to be pure...
"V is not a purely functional language however." (from V documentation)
https://github.com/vlang/v/blob/master/doc/docs.md#pure-func...