(* Copyright (C) 1990, Digital Equipment Corporation.         *)
(* All rights reserved.                                       *)
(* See the file COPYRIGHT for a full description.             *)

(* Last modified on Wed Mar 21 00:02:50 1990 by muller        *)


INTERFACE Property;

(* A Property.Set is a set of non-nil traced references, all of different 
   types.  *) 

TYPE
  Set <: ROOT;

PROCEDURE New(): Set;
(* Return a new empty property set. *)

PROCEDURE Put(ps: Set; ref: REFANY);
(* Add ref to ps, replacing any existing reference of the same type 
   as ref.  This is a checked runtime error if ref is NIL. *)

PROCEDURE Get(ps: Set; tc: INTEGER): REFANY;
(* Return the element of ps with typecode tc, or return NIL if no 
   such element exists. *)

PROCEDURE Remove(ps: Set; tc: INTEGER);
(* Remove the element of ps with typecode tc, if one exists. *)

END Property.