length.ml

let rec compare_lengths l1 l2 =
  match l1, l2 with
  | [], [] -> 0
  | [], _ -> -1
  | _, [] -> 1
  | _ :: l1, _ :: l2 -> compare_lengths l1 l2

let rec compare_length_with l n =
  match l with
  | [] ->
    if n = 0 then 0 else
      if n > 0 then -1 else 1
  | _ :: l ->
    if n <= 0 then 1 else
      compare_length_with l (n-1)


module List = struct
  type 'a t = 'a list

  module Length = struct
    type t = 
      | Of_list: 'a list -> t 
      | Of_int: int -> t

    let of_list list = Of_list list
    let of_int int = Of_int int

    let to_int = function
      | Of_list l -> List.length l
      | Of_int n -> n

    let compare t1 t2 =
      match t1, t2 with
      | Of_list l1, Of_list l2 -> compare_lengths l1 l2
      | Of_list l, Of_int n -> compare_length_with l n
      | Of_int n, Of_list l -> -1 * compare_length_with l n
      | Of_int n, Of_int m -> compare n m
  end


  let length = Length.of_list
end



List.length nom_ev > List.length quote_ev

Length.(of_list nom_ev > of_list quote_ev)

List.compare_lengths nom_ev quote_ev = -1