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From: gunderson@aiag.enet.dec.com
Newsgroups: comp.lang.lisp
Subject: Re: Prototype methods in CLOS?
Keywords: CLOS, LOOPS
Message-ID: <15344@shlump.nac.dec.com>
Date: 13 Sep 90 15:26:27 GMT
References: <63236@bu.edu.bu.edu>
Sender: newsdaemon@shlump.nac.dec.com
Reply-To: gunderson@aiag.enet.dec.com ()
Organization: Digital Equipment Corporation
Lines: 22

>Does CLOS support sending messages to classes in the way LOOPS (on the
>Xerox 1108) used to (using the prototype syntax)? Otherwise, I have to
>create an instance to evaluate a method for that class... is that
>right?

CLOS supports computational reflection.   Ordinary CLOS classes are thus
instances of a metaclass.  When "defclass" is used, the metaclass
defaults to "standard-class". Thus, a generic function specialized on 
standard-class will apply to the instances of this metaclass.  These 
instances are the classes defined with defclass.   A useful terminology 
refers to the ordinary CLOS classes as 1st-level instances of the metaclass
and the instances of an ordinary CLOS class as 2nd-level instances of
the metaclass.  The term "2nd level instance" was first used in

Graube, Nicolas, "Metaclass Compatibility." Proceedings of the 1989 Object 
Oriented Programming: System Languages, and Applications Conference 
(OOPSLA-89), pp. 305-315, 1989.

In our own work here at DEC, we extended the terminology 
with "1st level instance".

Alan Gunderson