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From: jonl@LUCID.COM (Jon L White)
Newsgroups: comp.lang.clos
Subject: accessing clos objects
Message-ID: <9102140033.AA23240@kolyma>
Date: 14 Feb 91 00:33:48 GMT
References: <2875458505-365193@Gilgamesh>
Sender: welch@tut.cis.ohio-state.edu
Distribution: inet
Organization: CommonLoops
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re: Note that in this example the INSTANCES slot will be shared by all
    subclasses of ENUMERATION-MIXIN, and so will contain all instances of
    all subclasses.  In the context of this discussion this is probably not
    what is desired.  More likely, you would like (CLASS-INSTANCES <some-x>)
    to return a list of all instances of class X and only instances of class
    X. . . .


Good point.  In fact, there is even a bit of terminological confusion
about what "instance" means.   I _think_ that amongst some subset of
of CLOS'ers, we've agreed to use "direct instance" to mean what you
are referring to here; to use "indirect instance" to mean "direct
instance of a subclass" (or, ocasionally "derived instance", following
the C++ inspired terms of "base class" and "derived class"); and to
admit that an unqualified "instance" is ambiguous in that different
sectors of the community use it differently.

So, independently of the design issues you bring up, _I_ would expect to
see the slot named INSTANCES pointing to the union of all direct and
derived instances, and to see the slot named DIRECT-INSTANCES used for
the more immediate set.  Incidentally, I note that Skip Egdorf did
follow this nomenclature in his recent mesages wherein he presesented
the generic function CLASS-DIRECT-INSTANCES.


One more thing -- sigh -- it seems that the mailer has lost my copy
of the message I sent out:

    > Date: Tue, 12 Feb 91 14:48:41 PST
    > From: Jon L White <jonl@lucid.COM>

You don't suppose you could forward me a copy?



-- JonL --