transcendental-lisp/lisp/fruit-counter.lisp

(load "dlambda.lisp")

(defun fruit-counter (initial-count)

  (let ((apple-count initial-count)
        (banana-count initial-count)
        (coconut-count initial-count))

    (eval
      (dlambda

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

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

        (:get-apple ()
          apple-count
        )

        (:set-apple (value)
          (setf apple-count value)
        )

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

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

        (:get-banana ()
          banana-count
        )

        (:set-banana (value)
          (setf banana-count value)
        )

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

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

        (:get-coconut ()
          coconut-count
        )

        (:set-coconut (value)
          (setf coconut-count value)
        )

      )
    )

  )
)

; Create an instance
; 
; usage: 
;   ~ (my-counter :set-apple 23)
;   23
;
(let ((instance (fruit-counter 0)))
  (defun my-counter (&rest args) (apply instance args))
)

; Another way
; 
; usage: 
;   ~ (funcall my-counter2 :set-apple 23)
;   23
;
(setf my-counter2 (fruit-counter 10000))