]> You need to use a type alias: # type ('a, 'b) func = 'a -> 'b;; type ('a, 'b) func = 'a -> 'b # let castro a = (fun _ -> a : ('a,'b) func);; val castro : 'a -> ('b, 'a) func = <fun> This is also how the compiler decides the arity of C functions from "external" declarations, that is, it "counts the arrows" without unfolding type aliases. On Sun, Oct 11, 2009 at 11:46 PM, Gilles Pirio <gilles.ocaml@googlemail.com> wrote: > Hey Damien > > Sure, I fully understand that both types are equivalent given the rules > governing the application operator. My point was more on the usability side, > as the type display is primarily intended at helping the programmer to > quickly figure out type mismatch. So I'd think having a display allowing to > quickly distinguish between the noe and castro functions below would be a > good thing, especially for beginners. I've been using ocaml for a few years > now, and I have to say that it's not a major issue any more - just wanted to > give some feedback about this. > > Thanks > Gilles > > > # let noe a b = a;; > val noe : 'a -> 'b -> 'a = <fun> > # let castro a = fun _ -> a;; > val castro : 'a -> 'b -> 'a = <fun> >