;; Lazy Prime Numbers
(module lazy-prime-numbers

  (lazy-prime-numbers)

  (import chicken scheme)
  (use lazy-seq)

  (define (prime? n)
    (let loop ((d 2))
     (cond
       ((< n (fx* d d)) #t)
       ((zero? (fxmod n d)) #f)
       (else (loop (add1 d))))))

  (define lazy-prime-numbers
    (lazy-filter prime? (lazy-numbers start: 2)))
)

;; SRFI-127 Prime Numbers
(module lseq-prime-numbers

  (lseq-prime-numbers)

  (import chicken scheme)
  (use srfi-121 srfi-127)

  (define (prime? n)
    (let loop ((d 2))
     (cond
       ((< n (fx* d d)) #t)
       ((zero? (fxmod n d)) #f)
       (else (loop (add1 d))))))

  (define lseq-prime-numbers
    (lseq-filter prime? (generator->lseq
                          (make-range-generator 2))))
)

;;; THE BENCHMARK
(use srfi-41 streams-math lazy-seq srfi-127)
(import lazy-prime-numbers lseq-prime-numbers)

(newline)
(print* "first run")
(newline)

(print* "srfi-41: ")
(time (print (stream-car (stream-drop 1000 prime-numbers-stream))))

(newline)
(print* "lazy-seq: ")
(time (print (lazy-head (lazy-drop 1000 lazy-prime-numbers))))

(newline)
(print* "srfi-121: ")
(time (print (lseq-car (lseq-drop lseq-prime-numbers 1000))))

(newline)
(print* "second run")
(newline)

(print* "srfi-41: ")
(time (print (stream-car (stream-drop 1000 prime-numbers-stream))))

(newline)
(print* "lazy-seq: ")
(time (print (lazy-head (lazy-drop 1000 lazy-prime-numbers))))

(newline)
(print* "srfi-121: ")
(time (print (lseq-car (lseq-drop lseq-prime-numbers 1000))))