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

On 14 May 2026, at 06:19, Pascal Costanza (as pc at p-cos dot net) <[email protected]> wrote:
> 
> It's important to keep in mind that the CLOS MOP "specification" in AMOP is not of the same level of quality as the ANS CL specification. It is in places not consistent with ANSI CL, and even not fully consistent with itself. It simply didn't go through the same amount of vetting as ANSI Cl. It is somewhat deceiving how close it looks and feels like the ANSI CL spec, but it is actually "just" a draft. (Of course an extremely good one, nonetheless.)

This is exactly right.  However I would go further and argue that it's a draft of something which is not the right answer to the problem.  Yet it's somehow become set in stone as a thing that must be adhered to.  (I'm not trying to disparage Closer to MOP! Given that the AMOP MOP *has* become set in stone, something like that is valuable.)

I'll be even more radical: CLOS itself also suffers from the same problem to a lesser extent.  Not just because OO isn't the silver bullet people thought it was, but because  CLOS was less vetted than much of the rest of CL (it was dropped in more-or-less wholesale pretty late in the process), and also both contains things which it really shouldn't (what on earth is change-class & its machinery doing there?  Don't answer: I know it is often used in the implementation of CLOS, but that is *not* a reason for it to exist at the user level.) and doesn't contain things that it should (I'd suggest sealing).

No, I don't hate CLOS.

--tim

_______________________________________________
Lisp Hug - the mailing list for LispWorks users
[email protected]
http://www.lispworks.com/support/lisp-hug.html