+let get_status sid = fst (List.assoc sid !session_tbl)
+
+let get_history sid = snd (List.assoc sid !session_tbl)
+
+let set_status sid st =
+ let oldst, hist = List.assoc sid !session_tbl in
+ session_tbl := (sid,(st,hist))::(List.remove_assoc sid !session_tbl)
+
+let set_history sid hist =
+ let st, oldhist = List.assoc sid !session_tbl in
+ session_tbl := (sid,(st,hist))::(List.remove_assoc sid !session_tbl)
+