; Start this script with `csi -:D` to observe heap resizing

(use lazy-seq)

; Remove this when in lazy-seq {{{

(define (lazy-reductions kons knil . streams)
  (letrec ((s (lazy-seq
                (cons knil
                      (apply lazy-map kons s streams)))))
    s))

; (define (lazy-reductions kons init seq)
;     (if (lazy-null? seq)
;             lazy-null
;                   (lazy-seq
;                             (let ((next (kons (lazy-head seq) init)))
;                                         (cons next (lazy-reductions kons next (lazy-tail seq)))))))

; }}}

(define (time-stream)
  (define last (current-milliseconds))
  (lazy-seq (cons 0
                  (lazy-repeatedly
                    (lambda ()
                      (let* ((now (current-milliseconds))
                             (dt (- now last)))
                        (set! last now)
                        dt))))))

(define (make-clock time)
  (lazy-reductions + 0 time))

(define (render coords)
  (void coords))

(define (complex-stream time)
  (lazy-map (cut * 2 <>) (make-clock time)))


; This seems to leak:

(lazy-each
  render
  (complex-stream
      (time-stream)))


; This doesn't:

#;(lazy-each
  render
  (lazy-map
    (cut * 2 <>)
    (make-clock
      (time-stream))))