set/src/SetList.ig

 Copyright (C) 1992, Digital Equipment Corporation                         
 All rights reserved.                                                      
 See the file COPYRIGHT for a full description.                            
 Last modified on Mon Jul 25 11:53:25 PDT 1994 by detlefs                  
      modified on Tue Feb 11 20:48:45 PST 1992 by muller                   


 SetList is a generic interface defining sets of Elem.T's,
   implemented as linked lists.  This implementations is appropriate
   only for small sets.



GENERIC INTERFACE SetList(ElemSet);

 WHERE Elem.T is a REF type and contains 



      PROCEDURE Equal(e1, e2: Elem.T): BOOLEAN;


   ElemSet = Set(Elem).


   Equal must be an equivalence relation.


   Equal may be declared with a parameter mode of either VALUE or
   READONLY, but not VAR.


TYPE
  Public = ElemSet.T OBJECT METHODS
    init(): T;
  END;
  T <: Public;
  Iterator <: ElemSet.Iterator;

 If s is an object of type SetDefault.T, the expression



      NEW(SetDef.T).init()


   creates a new, empty set.


   The call s.toRefList() returns a RefList.T whose elements
   include an element from each of the equivalence classes in
   set(s), and no other elements. 



END SetList.