🚀 go-pugleaf

In article <23063@venera.isi.edu> tar@ISI.EDU (Thomas A. Russ) writes:

   I was wondering what the best way to set a slot with allocation :class
   is.  In particular, I wonder if there is any way to do this portably
   without creating an instance of the class.

   Initially I thought that using the CLASS-PROTOTYPE from the MOP would
   be a good solution, but the documentation indicates that setting slots
   on the prototype is a no-no.

   Currently I just make an instance, set the slot and then throw the
   instance away.  This just strikes me as wasteful.

   Any better ideas?

If you want to set a slot given the class but without an instance,
perhaps what you really want is a class slot -- ie, a new metaclass
with an additional slot.

   (defclass my-class (standard-class)
     ((new-slot :initform ...
                :accessor my-class-new-slot)))

Then your application classes specify my-class as their metaclass:

   (defclass app-object ()
     (...)
     :metaclass my-class)

It depends on the semantics of the slot in question.

-- Harley Davis

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