(* open Syntax *)

(* Value *)
type v = VNum of int
       | VFun of (v -> c -> t -> m -> v)

and c = v -> t -> m -> v

and t = TNil | Trail of (v -> t -> m -> v)

(* m cannot be (c * t * h) list, because h uses m and thus would be cyclic *)
and m = MNil | MCons of (c * t * h) * m

and h = v -> c -> t -> c -> t -> m -> v

(* to_string : v -> string *)
let rec to_string value = match value with
    VNum n -> string_of_int n
  | VFun _ -> "<VFun>"

(* Value.print : v -> unit *)
let print exp =
  let str = to_string exp in
  print_string str