Re: Ensuring class x is a superclass of class y

http://metamodular.com/CLOS-MOP/compute-class-precedence-list.html says 
that you should be able to call COMPUTE-CLASS-PRECEDENCE-LIST yourself 
if the class is not 
http://metamodular.com/CLOS-MOP/class-finalized-p.html 
CLASS-FINALIZED-P.

W dniu 2026-03-21 11:09, Tim Bradshaw (as tfb at tfeb dot org) 
napisał(a):

> This is a general CL question (although it's MOPpy and I need the 
> answer to work in LW).
> 
> I have a metaclass, soa-class, which has some additional behaviour from 
> standard-class.  There is a class, soa, which is an soa-class, but 
> whose direct superclass is standard-object.  soa needs to be a 
> superclass of any soa-class, except itself.
> 
> What I currently do is have methods on validate-superclass which will 
> succeed if both classes are soa-classes, but will succeed if the 
> superclass is a standard-class and the subclass is an soa-class only if 
> the subclass is named soa.
> 
> This achieves what I want, but it also does something much stronger: if 
> an soa-class has superclasses x, y, ... z then *all* of these must be 
> soa-classes.  So I can't use mixin classes which are not themselves 
> soa-classes.  That's stronger than I need or want.
> 
> What is the appropriate way to ensure that, in the above case, at least 
> one of x, y ... z is an soa-class?  Is the superclass argument to 
> validate-superclass finalized enough that I can check its precedence 
> list?
> 
> --tim
> 
> (Sigh.  Every time I use the CLOS MOP I realise how lucky we are they 
> didn't try to standardise it as part of CL: the language never would 
> have been standardised if they had.  It's just made of jelly, and 
> language standards made of jelly are not a good idea.  Although they 
> can be nutritious.)
> 
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