Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!LUCID.COM!jonl
From: jonl@LUCID.COM (Jon L White)
Newsgroups: comp.lang.clos
Subject: Persistent Objects
Message-ID: <9101142148.AA14994@kolyma>
Date: 14 Jan 91 21:48:54 GMT
References: <1991Jan13.183134.17914@athena.mit.edu>
Sender: welch@tut.cis.ohio-state.edu
Distribution: inet
Organization: CommonLoops
Lines: 33

re: Persistent Objects in CLOS . . .
    . . . and I've reached a point where I find it necessary to
    write some methods to save the state of CLOS objects (i.e. - class
    metaobjects as well as instances) to a file, so they can be restored at
    a later time...

This is probably not the same issue as "persistence" in general --
for that you might want to look at the last two OOPSLA proceedings
at papers by Andraes Paepcke of HP Labs on PCLOS.

Your immediate need sounds like a "fasdmping" facility would suffice
("fasdmp" is Lisp Machine terminology).  CLtL/II page 659 presents a
function MAKE-LOAD-FORM invented for just this purpose.

I don't suppose that any commercial CLOS in the field right now
actually has that implemented, since it was added rather late in the
X3J13 game.  Lucid's 4.1 image has it working now, but I'm unable to
make any guesses as to when this might be publicly available.

As a temporary "stop-gap", I prepared for my own use a kludge that
somewhat simulates in 4.0 and earlier releases the LOAD-TIME-VALUE
facililty of CLtL/II page 680; at least one person was able to
write some "reconstructor" functons for PCL and CLOS objects using
this kludge.  It's not a product or supported item, but if you are
using Lucid and really stuck, give me a call privately.  If you
are using Franz, I would suspect that one of the Franzoids should
be able to prepare a similar kludge for their system too.


-- JonL --

P.S.  I see your email return address is different in the two msgs;
      are you really a bellcore person, or an MIT "athena" student?