set.ml

open Format

let pp_ls f ppf ls =
  let rec loop ppf = function
    | [] -> ()
    | [x] -> fprintf ppf "%a@?" f x
    | x::xs -> fprintf ppf "%a, %a" f x loop xs
  in
  fprintf ppf "{%a}@?" loop ls
let pp_i ppf i = fprintf ppf "%d@?" i

module N = struct
  module IntSet = Set.Make(
    struct
      let compare = Pervasives.compare
      type t = int
    end )
  include IntSet
  let of_list l = List.fold_left (fun s e -> add e s) empty l
  let pp ppf s = pp_ls pp_i ppf (elements s)
  let powerset s =
    let rec ps = function
    | [] -> [[]]
    | h::t -> List.fold_right (fun t xs -> (h::t)::t::xs) (ps t) []
    in ps(elements s)
  let pp_l ppf ls = pp_ls pp_i ppf ls
  let pp_ss ppf ss = pp_ls pp_l ppf ss
end

let a = N.of_list [1;2;3]
let b = N.of_list [3;4;5;6]

let _ =
  fprintf std_formatter "a = %a@." N.pp a;
  fprintf std_formatter "a = %a@." N.pp a;
  fprintf std_formatter "b = %a@." N.pp b;
  fprintf std_formatter "a ∪ b = %a 和集合@." N.pp (N.union a b);
  fprintf std_formatter "a ∩ b = %a 積集合@." N.pp (N.inter a b);
  fprintf std_formatter "a \\ b = %a 差集合@." N.pp (N.diff a b);
  fprintf std_formatter "|a| = %d aの大きさ@." (N.cardinal a);
  fprintf std_formatter "|a ∪ b| = %d aの大きさ@." (N.cardinal (N.union a b));
  fprintf std_formatter "aの冪集合 %a@." N.pp_ss (N.powerset a);