Source file oseth.ml

open Common

open Oset

(* !!take care!!: this class does side effect, not a pure oassoc *)
class ['a] oseth xs   = 
object(o)
  inherit ['a] oset

  val data = Hashtbl.create 100
    
  (* if put [] then no segfault, if [11] then segfault *)
  method toset = Obj.magic data 

  method empty = {< data = Hashtbl.create 100 >}
  method add k = 
    Hashtbl.add data k true; 
    o
      
  method iter f = Hashtbl.iter (fun k v -> f k) data
  method view = raise Todo
    
  method del k = 
    Hashtbl.remove data k; 
    o
  method mem k = 
    try (ignore(Hashtbl.find data k); true) 
    with Not_found -> false

  method null = 
    try (Hashtbl.iter (fun k v -> raise Common2.ReturnExn) data; false) 
    with Common2.ReturnExn -> true

(* TODO    method length *)

  method union s = 
    let v = Hashtbl.create 100 in 
    o#iter (fun k -> Hashtbl.add v k true);
    s#iter (fun k -> Hashtbl.add v k true);
    {< data = v >}
  method inter s = 
    let v = Hashtbl.create 100 in 
    o#iter (fun k -> if s#mem k then Hashtbl.add v k true);
    {< data = v >}
  method minus s = 
    let v = Hashtbl.create 100 in 
    o#iter (fun k -> if not(s#mem k) then Hashtbl.add v k true);
    {< data = v >}

  (* override default  *)
  method getone = 
    let x = ref None in
    try (
      Hashtbl.iter (fun k _ -> x := Some k; raise Common2.ReturnExn) data; 
      raise Not_found
    ) 
    with Common2.ReturnExn -> Common2.some !x
      
      
end