Re: MOP question for language lawyers: can you specialize on standard-class

Julia gets many things right and some spectacularly wrong.  Structs and
their slot access being one of them, unless you start loading libraries.

MA


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On Tue, May 26, 2026, 10:20 Tim Bradshaw (as tfb at cley dot com) <
[email protected]> wrote:

> On 18 May 2026, at 15:20, [email protected] wrote:
> >
> > Anyway, I don’t like participating in discussions where somebody is
> “exaggerating for effect.” That reminds me too much of the bad days in
> comp.lang.lisp. Feel free to have the final word in our exchange.
>
> I'm sorry, I didn't intentionally exaggerate for effect.
>
> What I am trying to say is this:
>
> Some aspects of CLOS (slot access for one thing) are *significantly*
> slow.  CLOS is about 40 years old, so I think that if it could have been
> made fast it would have been by now.  So I infer that this is because of
> something to do with the design of CLOS.
>
> Julia's object system is not slow, but it is not correct to say it has
> 'solved it' in the sense that we could just use what Julia does in CLOS
> (this is what I thought you meant when you said that), because Julia's
> object system is significantly different to CLOS.
>
> So the interesting question is: what could be done to CLOS to make it
> quick?  And in particular can anything be done *without compromises*?  I
> believe the answer to that is no, it can't: to make slot access quick in
> CLOS you would need to make promises that you will not use various features
> of it.
>
> That's what Dylan did, for instance.
>
> --tim
>
>
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