fixed_array.ml

module Fixed_array (P : sig
  val length : int
end) : sig
  type 'a t
  val length : 'a t -> int
  val make : 'a -> 'a t
  val get : 'a t -> int -> 'a
  val set : 'a t -> int -> 'a -> unit
end = struct
  type 'a t = 'a array
  let length _ = P.length
  let make x = Array.make P.length x
  let get = Array.get
  let set = Array.set
end

module Array_2 = Fixed_array (struct
  let length = 2
end)
module Array_3 = Fixed_array (struct
  let length = 3
end)

let f (arr : int Array_3.t) = Array_3.set arr 2 3

let arr = Array_2.make 0
let () = f arr