(require 'rep.test.framework)

;; FIXME better logic (see queues.jl in rep.data.queues):
;; enqueue: append item at back of queue
;; dequeue: take car of queue

(define (make-queue)
  (let ((q '()))
    (define (enqueue x)
      (setq q (cons x q)))
    (define (dequeue)
      (if (null q)
          (error "Empty queue -- dequeue")
        (let ((item (last q)))
          (setq q (nreverse (cdr (nreverse q))))
          item)))
    (define (initialize)
      (setq q '())
      'done)
    (define (dispatch message)
      (cond ((eq message 'enqueue) enqueue)
            ((eq message 'dequeue) (dequeue))
            ((eq message 'initialize) (initialize))
            (t (error "Unknown request -- queue: %s" message))))
    dispatch))

(define (dequeue queue)
  (queue 'dequeue))

(define (enqueue queue value)
  ((queue 'enqueue) value))

(defvar qq (make-queue))
(enqueue qq 3)
(enqueue qq 4)
(assert (= 3 (dequeue qq)))
(assert (= 4 (dequeue qq)))