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@justinmeiners
Created February 28, 2018 01:03
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(define (prime-sieve count)
(let ((marked (make-vector count #f)))
(define (build-list index)
(if (>= index count)
'()
(if (vector-ref marked index)
(build-list (+ index 1))
(cons (+ index 1) (build-list (+ index 1))))))
(define (next-prime index)
(if (>= index count)
marked
(begin
(if (vector-ref marked index)
'done
(mark (+ index 1) (+ index index 1)))
(next-prime (+ index 1)))))
(define (mark stride index)
(if (>= index count)
'ok
(begin
(vector-set! marked index #t)
(mark stride (+ index stride)))))
(begin (next-prime 1) (build-list 1))))
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