Testing one, two, three... Is this thing on?
AMOP sayeth about CLASS-PROTOTYPE: "Wheter the instance is initialized or not is not specified."
(defclass foo () ((bar :initarg :bar :initform (error "required initarg missing"))))
;; or equivalent behaviour by default-initargs or initialization ;; methods
Classes such as the above can then lead to problems: it would be legal for an implementation to signal the "required ... missing" error for
(class-prototype (find-class 'foo))
Tightening the spec to guarantee that no user-supplied initialization code (including initforms, default-initargs, and initialization methods) will be executed by CLASS-PROTOTYPE would solve this, but at that point it would seem both simpler and cleaner to specify an uninitialized instance.
That in turn could be relaxed to allow returning an instance previously created by user code, but I've the feeling that this could create problems, since it would make it unnecessarily hard for the user to control the lifetime of his instances, leading to unnecessary garbage being retained -- and the gain for allowing such seems rather small as well.
Cheers,
-- Nikodemus "Not as clumsy or random as a C++ or Java. An elegant weapon for a more civilized time."