Re: Specializing slot-value-using-class in OpenMCL

On 2007-05-30, Slava Akhmechet <coffeemug@xxxxxxxxx> wrote:
Pascal Costanza <pc@xxxxxxxxx> writes:
I hope this helps.
Thank you, it helps a lot! I just tried the fix and it works. I
only have one last question. Why are metaclasses are not inherited?

(defclass a ()
(slot)
(:metaclass somemeta))

(defclass b ()
(slot2))

Metaclass of 'b' will be standard-class (which causes problems). I
manually added the metaclass declaration to all relevant class, but
is there a way to simply propagate it from base class?

I'm not Pascal, but did you mean

(defclass b (a)
(slot2)) ;^^^

?

As far as why it's not inherited, I don't know for sure, but it seems
to me that the inheritance of metaclass in the presence of multiple
inheritance would be very complex.

You'd probably do better to write a define-somemeta macro along the
lines of:

(defmacro define-somemeta (name &body body)
`(defclass ,name
,@body
(:metaclass somemeta)))

(untested)

-- Larry

.

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