+;;; somewhat akin to DEFAULT-INITARGS (SLOT-CLASS T T), but just
+;;; collecting the defaulted initargs for the call.
+(defun ctor-default-initkeys (supplied-initargs class-default-initargs)
+ (loop for (key nil) in class-default-initargs
+ when (eq (getf supplied-initargs key '.not-there.) '.not-there.)
+ collect key))