gistfile1.ml

module Int = struct 
  type t = int 
  let compare : int -> int -> int = compare 
end

module M = Map.Make(Int)
  type +'a elt
  type 'a map = 'a elt M.t

  let addA (x : 'a) (m : [> `A of 'a] map) =
    M.add (Obj.magic `A) (Obj.magic x) m

  let addB (x : 'a) (m : [> `B of 'a] map) =
    M.add (Obj.magic `B) (Obj.magic x) m

  let getA (m : [> `A of 'a] map) : 'a =
    Obj.magic (M.find (Obj.magic `A) m)

  let getB (m : [> `B of 'a] map) : 'a =
    Obj.magic (M.find (Obj.magic `B) m)