Data update

Task/Variadic-function/OCaml/variadic-function-5.ml

@@ -0,0 +1,13 @@
+type ('f,'g) t =
+  | Z : ('f,'f) t
+  | S : 'a -> (('a -> 'f), ('f,'g) t -> 'g) t
+
+let rec apply: type f g. f -> (f,g) t -> g =
+  fun k t -> match t with
+  | Z -> k (* type g = f *)
+  | S x -> apply (k x) (* type g = (f,g) t -> g *)
+
+let (!) x = S x (* prefix *)
+
+(* top level *)
+# apply List.map !(fun x -> x+1) ![1;2;3] Z