When I write an Ocaml function to recursively compose the same function n times, I did this:
let rec compose f n =
(fun x -> if n = 1 then f x else ((compose f (n-1))) (f x));;
It gives the type
val compose : ('a -> 'a) -> int -> 'a -> 'a = <fun>
what is the difference between type
('a -> 'a) -> int -> 'a -> 'a
and type
('a -> 'a) -> int -> ('a -> 'a)
?
How would a similar compose function look with the latter type?
There is no difference between them. But sometimes authors of libraries use parens to denote, that the computation is actually staged, so that it is better to apply it partially, so that you can get a more efficient function, rather then applying it every time. But from the type system perspective this functions are exactly the same, since -> type operator associates to the right.