commons/oseth.ml

   1 open Common
   2
   3 open Oset
   4
   5 (* !!take care!!: this class does side effect, not a pure oassoc *)
   6 class ['a] oseth xs   =
   7 object(o)
   8   inherit ['a] oset
   9
  10   val data = Hashtbl.create 100
  11
  12   (* if put [] then no segfault, if [11] then segfault *)
  13   method toset = Obj.magic data
  14
  15   method empty = {< data = Hashtbl.create 100 >}
  16   method add k =
  17     Hashtbl.add data k true;
  18     o
  19
  20   method iter f = Hashtbl.iter (fun k v -> f k) data
  21   method view = raise Todo
  22
  23   method del k =
  24     Hashtbl.remove data k;
  25     o
  26   method mem k =
  27     try (ignore(Hashtbl.find data k); true)
  28     with Not_found -> false
  29
  30   method null =
  31     try (Hashtbl.iter (fun k v -> raise ReturnExn) data; false)
  32     with ReturnExn -> true
  33
  34 (* TODO    method length *)
  35
  36   method union s =
  37     let v = Hashtbl.create 100 in
  38     o#iter (fun k -> Hashtbl.add v k true);
  39     s#iter (fun k -> Hashtbl.add v k true);
  40     {< data = v >}
  41   method inter s =
  42     let v = Hashtbl.create 100 in
  43     o#iter (fun k -> if s#mem k then Hashtbl.add v k true);
  44     {< data = v >}
  45   method minus s =
  46     let v = Hashtbl.create 100 in
  47     o#iter (fun k -> if not(s#mem k) then Hashtbl.add v k true);
  48     {< data = v >}
  49
  50   (* override default  *)
  51   method getone =
  52     let x = ref None in
  53     try (
  54       Hashtbl.iter (fun k _ -> x := Some k; raise ReturnExn) data;
  55       raise Not_found
  56     )
  57     with ReturnExn -> some !x
  58
  59
  60 end
  61
  62