In CLOS, instance remorphing considered useless in practice?
jean.claude.beaudoin at gmail.com
Wed Dec 9 08:09:54 UTC 2020
I had you and ASDF somewhat in mind when I wrote the original post.
On Tue, Dec 8, 2020 at 3:23 PM Faré <fahree at gmail.com> wrote:
> I once used update-instance-for-redefined-class in ASDF, when I was
> trying to make a smooth upgrade from ASDF 1 to ASDF 2. The problem I
> found is that proper support for class redefinition requires the
> cooperation not only of the underlying object system, but also of all
> the parts of the implementation. It also requires more deterministic
> guarantees on what code gets inlined and what code doesn't get
Inlining, what a can or worms!
> In ASDF 3, I threw the towel, and decided I could never get the OTHER
> parts of the system to cooperate (aka ASDF extensions for me, but also
> all the extensions to all existing programs being redefined), so I
> stopped using update-instance-for-redefined-class and instead went for
> deleting/overwriting/resetting functions, generic functions, and, in
> extreme cases, packages.
I followed from somewhat afar your "acharnement" in that area, with some
bewilderment I'd say.
> I would love to see languages with better support for redefinition.
> Like unison, or darklang. Unhappily,
> update-instance-for-redefined-class, while very cool, is *not enough*.
My point is that it is already too much.
> But in relatively small systems that are long-running, with everyone
> cooperating, like they had in the 1980s, it was probably sufficient.
> And it is a marvelous tool. If you control the entire application and
> want images to survive code evolution.
In the late 1980s, all the Lisp Machines I touched were running ZetaLisp
with Flavors as OO extension.
And we were dropping CLTL1 version of Common Lisp on top of them before our
So, no CLOS. That came later...
> —♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics•
> Taxonomy is the death of science — A. N. Whitehead
BTW, I just received the latest book by Denis Robert titled "LARRY ET MOI,
comment BLACKROCK nous aime, nous surveille et nous détruit" and I dropped
it on my pile of books to read soon. Thought you'd be amused to know,
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