Hi Blake,
I understand the benefits and I'll consider adopting this approach. The :allocation :class was sufficient in this case and I was curious about what to do absent full metaclass/mop implementation.
Regards, Alan
On Wed, Mar 10, 2010 at 5:36 PM, Blake McBride blake@mcbride.name wrote:
Another example is that as you create sub-classes :allocate :class variables don't function like regular instance variables in terms of inheritance. Correctly defined class variables using metaclasses do.
Blake McBride
On Wed, Mar 10, 2010 at 2:12 PM, Alessio Stalla alessiostalla@gmail.com wrote:
On Wed, Mar 10, 2010 at 8:50 PM, Blake McBride blake@mcbride.name wrote:
(slot-value (make-instance 'class1) 'cv2)
creates an instance.
Sure, but (slot-value (mop::class-prototype (find-class 'class1)) 'cv2) does not and still fails with a slot-missing error, which was my point.
He wanted access to a true class variable,
no, he wanted to "access class-allocated slot values" in his own words. This, in the context of CL, can only mean slots with :allocation :class.
stored in the class (class1) that was accessible via a class reference. If that's what he wanted, that's exactly what my code does.
My example code does store cv? in class1, not the meta-class.
It's perfectly fine, but cv? are not class-allocated slots, at least not as the CL standard defines them.
Alessio