[Zababa]

Mostly because it has first-class functions and that's about it. Future might be used as a monad, but I'm not sure. Currently it has no ADTs, no pattern matching, Java-like immutability, null safety seems to be a special compiler feature rather than an option type or monad.

Right now it's less functional than Java, about as much as JavaScript (though in JS classes are less idiomatic so maybe it's a bit more functional in practice).

Considering what people are asking to add to the language (https://github.com/dart-lang/language/blob/master/working/05...), I wish people would start with a minimal functional language (Caml/SML without the modules, so functions, pattern matching and ADTs mostly) and then add things from there. It's a strong basis for a language, and people are going to ask for that stuff later anyways.