[armedbear-devel] class-prototype

[Blake McBride]

On Wed, Mar 10, 2010 at 1:39 PM, Alessio Stalla <alessiostalla at gmail.com> wrote:
> On Wed, Mar 10, 2010 at 8:32 PM, Blake McBride <blake at mcbride.name> wrote:
>> Here is how to do it in SBCL.  cv? represent class variables.  iv?
>> represent instance variables.  Both associated to the "class1" class.
>>
>> (defclass meta-class1 (standard-class)
>>  (cv1 cv2 cv3)
>>  (:metaclass standard-class))
>>
>> (defmethod sb-mop:validate-superclass ((class meta-class1) (superclass
>> standard-class)) t)
>>
>> (defclass class1 (standard-object)
>>  (iv1 iv2 iv3)
>>  (:metaclass meta-class1))
>>
>> (setf (slot-value (find-class 'class1) 'cv2) 'hello)
>>
>> (slot-value (find-class 'class1) 'cv2)
>
> That's a different thing. (slot-value (make-instance 'class1) 'cv2)
> ==> missing slot, i.e. you're not defining class-allocated slots as
> specified by the CL standard. I'm not saying your approach is wrong,
> but probably it's not what the OP asked.

(slot-value (make-instance 'class1) 'cv2)

creates an instance.  He wanted access to a true class variable,
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.

Blake McBride