(load "dlambda.lisp")

(defun counter (initial-count)
  (let ((count initial-count)
        (print-prefix nil)
        (this nil))

    (setf print-prefix "Counter")

    (setf this
      (eval
        (dlambda

          (:inc ()
            (setf count (+ count 1))
          )

          (:inc-3 ()
            (funcall this :inc)
            (funcall this :inc)
            (funcall this :inc)
          )

          (:dec ()
            (setf count (- count 1))
          )

          (:dec-3 ()
            (funcall this :dec)
            (funcall this :dec)
            (funcall this :dec)
          )

          (:get ()
            count
          )

          (:set (value)
            (setf count value)
          )

          (t ()
            (cons print-prefix count)
          )

        )
      )
    )

  )
)

; Create an instance
; 
; usage: 
;   ~ (my-counter :inc-3)
;   3
;
(let ((instance (counter 0)))
  (defun my-counter (&rest args) (apply instance args))
)

; Another way
; 
; usage: 
;   ~ (funcall my-counter2 :dec-3)
;   997
;
(setf my-counter2 (counter 10000))