Module functors were an SML feature - not really in the original 'ML' language. I would put Haskell in the ML family, and it doesn't have module functors. Rust

Module functors were an SML feature - not really in the original 'ML' language. I would put Haskell in the ML family, and it doesn't have module functors. Rust has type inference, and a core type syntax and semantics that is heavily inspired by it.