🚀 go-pugleaf

   Date: 	Wed, 17 Apr 1991 15:06:02 PDT
   From: Kevin Gallagher <Gallagher@gilgamesh.cs.umass.edu>


       From: Gregor Kiczales <Gregor@parc.xerox.com>  (via barmar@think.com)
       Date: Mon, 15 Apr 1991 09:37:22 -0700

       The MOP spec does not require SLOT-VALUE to work on structures.  This
       requirement was dropped in the final version because some people were
       concerned that it interfered with efficient structure implementations.

   I am very disappointed to see this.  For several *years* the standard
   answer to the question ``How do I access an arbitrary slot in a structure
   instance?'' has been ``Use SLOT-VALUE (when CLOS is available).''  This
   question is asked almost monthly on the various lisp mailing lists and
   newsgroups.

   Providing this capability does not prevent efficient structure
   implementations.  All that is required is to maintain declarative
   information about the implemenation of the structure.

I agree with you, but some vendors were concerned that it would cause
performance problems.

At this point, the best route is for customer requests to cause vendors
to provide this functionality.  As I said before, the MOP document makes
it clear how to provide the functionality, it just doesn't specify it.
So, there is an open hole waiting for vendors to fill.