Sub List

sub_list.sml

(* subList : 'a list -> 'a list list *)
fun subList v = 
  List.foldl
    List.@ 
    [ nil ]
    (
      List.map 
        (
          fn x => (
            fn v =>
              List.map 
                (fn x => List.take (v, x)) 
                (List.tabulate ((List.length v), (fn x => x + 1)))
          ) 
          (List.drop (v, x))
        ) 
        (List.rev(List.tabulate ((List.length v) + 1, (fn x => x))))
    );
 
(* Example*)
val v = [1, 2, 3, 4, 5, 6];
val () = print ((listToString (fn v => listToString Int.toString v) (subList v)) ^ "\n");

val v = ["A", "B", "C", "D", "E"];
val () = print ((listToString (fn v => listToString (fn s => s)  v) (subList v)) ^ "\n");