Lisp Array Setter Syntax

Not the most inituituve in the world

(defmethod (setf setter-name) (value (self  class-type) x y z)
  (setf (row-major-aref (array-of self) (* x ... blah... ))))

(setf (setter-name self) x-index y-index z-index value)

The thing to remember is that the value always comes first.