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From: konstan@elmer-fudd.berkeley.edu (Joe Konstan)
Newsgroups: comp.lang.clos
Subject: How to get class slots with an instance at each class
Message-ID: <41558@ucbvax.BERKELEY.EDU>
Date: 2 Apr 91 23:07:05 GMT
Sender: nobody@ucbvax.BERKELEY.EDU
Reply-To: konstan@elmer-fudd.berkeley.edu (Joe Konstan)
Organization: Picasso Research Group, UC Berkeley CS Division
Lines: 25

Is there an easy way to accomplish the following:

(Assume I have a typical inheritance tree as follows:

	A
       / \
      Aa  Ab             etc.
     /  \   \
   Aa1  Aa2 Ab1


I want to define a slot named "default" that is a class slot for all of these
classes but has a separate value in each class.  In other words, I want 
(defclass A ()
 ((default :allocation :class :initform 10 ...)
  ...))

but also want each subclass to have its own slot named default that can 
be changed separately.

I know this can be done by adding a new slot definition in the defclass for
each subclass, but this is undesirable (for several reasons).  Is there an
alternative?

Joe Konstan