As a Scala user I think the MLs have a leg up on Scala wrt to a & b. Scala can be quite concise but we do have to be explicit with type signatures, and that on

As a Scala user I think the MLs have a leg up on Scala wrt to a & b. Scala can be quite concise but we do have to be explicit with type signatures, and that only increases as we go up the abstraction ladder. A strict Haskell with a decent module system, or a modern SML that borrows some nice-to-haves from Haskell and Scala would be my ideal language.