Given a class definition, is it possible to define one slot in terms of another, similar to how I would do it with let*?
For example, I would like to be able to do something like this (which obviously doesn't work):
(defclass foo ()
((x :initform 1 :accessor x)
(y :initform (+ 1 x) :accessor y)))
In DEFCLASS slot descriptions one can't refer to slots.
A typical way is to write an :after method for initialize-instance:
(defclass foo ()
((x :initform 1 :accessor foo-x)
(y :accessor foo-y)))
(defmethod initialize-instance :after ((object foo) &rest args)
(with-slots (x y) object
(setf y (1+ x))))
CL-USER 44 > (make-instance 'foo)
#<FOO 81B0161EEB>
CL-USER 45 > (describe *)
#<FOO 81B0161EEB> is a FOO
X 1
Y 2