"Robert L. Read" <[EMAIL PROTECTED]> writes:
> The contract is that make-instance should only be called once for a
> given object?
FWIW, I wrote a CLOS->SQL layer a few years ago, and I do agreed
with this assessment (that MAKE-INSTANCE should only get called once),
so my protocol ended up with these two extra methods:
(defgeneric customize-persistent-instance (instance &rest initargs &key
&allow-other-keys)
(:documentation "Used to customize an instance when it is created. This takes
the place of the normal initialize-instance :after method.
This will be called both when the objects is being created
for the first time and being re-selected.
Subclasses should define :after methods as required.")
(:method (instance &rest initargs &key &allow-other-keys) t))
(defgeneric customize-new-persistent-instance (instance &rest initargs &key
&allow-other-keys)
(:documentation "Used to customize an instance when it is newly
created by the application. The object HAS
been commited to the database.")
(:method (instance &rest initargs &key &allow-other-keys) t))
In my mind, when you get an instance via a SELECT, you're not
calling MAKE-INSTANCE, you're doing a hash table lookup to
find an object stored persistently in some imaginary infinitely
large lisp image.
YMMV, of course.
--ap
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