Subject: Re: Need Help !!. (common-lisp CLOS)
From: rpw3@rigden.engr.sgi.com (Rob Warnock)
Date: 8 Jul 2002 20:58:38 GMT
Newsgroups: comp.lang.lisp
Message-ID: <agcudu$7475a$1@fido.engr.sgi.com>
Kenny Tilton  <ktilton@nyc.rr.com> wrote:
+---------------
| Sekkat Samir wrote:
| > AFAIK CLOS do not keep book of all created instances of a specific
| > class.
| 
| Welll, it must because make-instances-obsolete has to call
| update-instance-for-redefined-class on each instance.
+---------------

Actually, I don't think it does. CLOS (quite deliberately!) allows
lazy updating of instances when a class changes, so that a given
instance doesn't have to be updated until the next time it's accessed,
whereupon *it* could check to see if its parent class had changed and
then (and only then) perform the update. But that doesn't require a
collection of instances, only back-pointers from instances to classes
(which are required anyway).


-Rob

-----
Rob Warnock, 30-3-510		<rpw3@sgi.com>
SGI Network Engineering		<http://www.rpw3.org/>
1600 Amphitheatre Pkwy.		Phone: 650-933-1673
Mountain View, CA  94043	PP-ASEL-IA

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