(*
    Swift's closure
        https://d...content-available-to-author-only...e.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Closures.html
*)


load "Intmap";  (* for Moscow ML *)


val digitNames = foldr
    (fn ((i, s), m) => Intmap.insert (m, i, s))
    (Intmap.empty ())
    [
        (0, "Zero"), (1, "One"), (2, "Two"),   (3, "Three"), (4, "Four"),
        (5, "Five"), (6, "Six"), (7, "Seven"), (8, "Eight"), (9, "Nine")
    ]
val numbers = [16, 58, 510]


val strings = map
    (
        fn number => let
            fun f num output =
                if num <= 0 then
                    output
                else
                    f
                        (num div 10)
                        (Intmap.retrieve (digitNames, num mod 10) ^ output) 
        in
            f number ""
        end
    )
    numbers


fun print_strings xs = (
    (map (fn s => (print (s ^ "\n") ; ())) xs) ;
    ()
)



(****

$ mosml numbers-map.sml
Moscow ML version 2.01 (January 2004)
Enter `quit();' to quit.
[opening file "numbers-map.sml"]
> val it = () : unit
> val digitNames = <intmap> : string intmap
  val numbers = [16, 58, 510] : int list
  val strings = ["OneSix", "FiveEight", "FiveOneZero"] : string list
  val print_strings = fn : string list -> unit
[closing file "numbers-map.sml"]
- print_strings strings;
OneSix
FiveEight
FiveOneZero
> val it = () : unit
-

****)