PolyML? It's an interesting puzzle, I'm not sure if it's because ML users and implementers are primarily interested in some other problem and they implement M

PolyML? It's an interesting puzzle, I'm not sure if it's because ML users and implementers are primarily interested in some other problem and they implement ML as a tool to work on it or if the wars about extending semantics are rooted somewhere else. On the upside, it seems like a new implementation crops up every few years. Caml and ocaml are definitely the most popular and the largest communities though.