slime/bin/test.slime

(defun make-vector (x y z)
  (let ((local-x x)
        (local-y y)
        (local-z z)
        (defun (macro (@name @params :rest @body)
                      (eval (pair 'define-upwards (pair @name (pair (pair 'lambda (pair @params @body)) nil)))))))

    (defun set-x (new-x) (mutate local-x new-x))
    (defun set-y (new-y) (mutate local-y new-y))
    (defun set-z (new-z) (mutate local-z new-z))

    (defun dispatch (message)
      (if (= message ::get-x)
          local-x
        (if (= message ::set-x)
            set-x
          nil)))

    (break)
    dispatch))

(define v (make-vector 1 2 3))

(print (v ::get-x))
((v ::set-x) 19)
(print (v ::get-x))

(read " ")