;;;	Copyright (c) 1983 Massachusetts Institute of Technology
;;;
;;;	All rights reserved.  This software is distributed on the
;;;	condition that any improvements or modifications to it are
;;;	returned to the Scheme project at MIT.
;;;
;;;	Permission to copy all or part of this material is granted,
;;;	provided that the copies are not made or distributed for
;;;	resale, the MIT copyright notice appears, and that notice is
;;;	given that copying is by permission of Massachusetts Institute
;;;	of Technology.