Re: A MOP minimisation question

On Wed, Mar 11, 2026 at 2:25 PM Pascal Bourguignon (as informatimago at
gmail dot com) <[email protected]> wrote:

>
> 1- using symbol-plist (get and (setf get) are perfectly good options. They
> seem deprecated because there are more sophisticated mechanisms provided
> nowadays in Common Lisp, but this old mechanism is simple, efficient,
> cheap, and works well (thanks to packages to avoid name collisions in keys).
>

I ranted about this 😏 but I did forget p-lists.

https://within-parens.blogspot.com/2024/03/a-rant-about-r-and-python-and-anything.html

Cheers

MA









>
>
>
>
> On 11 Mar 2026, at 12:05, Tim Bradshaw (as tfb at cley dot com) <
> [email protected]> wrote:
>
> As I mentioned in other messages a while ago, I wrote a
> trivial/special-purpose thing which does a limited version of SoA.  I'm now
> slowly writing a more general one which is inevitably suffering from
> serious second-system syndrome.
>
> One of the things it needs to do is maintain information at the class
> level: things like the layout of the arrays and how slots map onto them,
> and so on.
>
> Now bear in mind that once, long ago, I was fairly knowledgeable about the
> AMOP MOP, but for at least a decade I've barely used CLOS at all (I think
> I've had the classic 'object systems aren't all that' moment).
>
> What I do now is to have a metaclass which has some extra slots and so on.
>
> But an earlier version didn't do that: it just stored the class-level data
> in properties on the class name.
>
> If we assume that classes always have names (which is a restriction I am
> more than happy with) is there really *any* good reason not to do this and
> thus rely less on MOP features (I still need some small ones).  Performance
> is not a good reason: these things are never used when that matters since
> their entire purpose is to enable the system to compile things away.
>
> I realise this is an ideological question: assume I would rather minimise
> my code's exposure to the MOP even if using it is The Right Thing.
>
> --tim
>
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