Re: A MOP minimisation question

You could just use slots with :allocation :class, no?

> On 11 Mar 2026, at 12:07, 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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