[Openmcl-devel] Custom Meta Classes

Gary Byers gb at clozure.com
Fri Jan 16 02:12:57 UTC 2004



On Thu, 15 Jan 2004, Gary Byers wrote:

>
>
> On Thu, 15 Jan 2004, Sven Van Caekenberghe wrote:
>
> > In OpenMCL 0.13.x I could define my own meta classes like this:
>
> i.e., without having to define one or more VALIDATE-SUPERCLASS
> methods which describe which subclass relationships between instances
> of your new metaclass and those of other metaclasses make sense.
>
> >
> > This works in LispWorks 4.3 as well.

Just to beat a dead horse, googling for "validate-superclass"
revealed (among other things):

<http://lispworks.com/reference/lw43/LWUG/html/lwuser-113.htm>

>From your experience and from what I can infer from that page, it
would appear that LW may provide a VALIDATE-SUPERCLASS method
that allows the "other-class, STANDARD-CLASS" case.  That minor
deviation from the MOP might be less confusing to most people,
and could always be overridden by a method whose first parameter
had higher precedence than that default.

(Googling does suggest that this whole issue's confusing to many
people.)




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