Play audio slide show -- Keyboard shortcut: 'x'  Back to slide -- Keyboard shortcut: 'u'              Annotated program -- Keyboard shortcut: 't'      sieve.scm - All the functions necessary to use the Sieve of Eratosthenes.Lecture 5 - slide 26 : 26
Program 1

(define (sieve stream)
     (head stream)
         (lambda (x) (not (divisible? x (head stream))))
         (tail stream)))))

(define (divisible? x y)
  (= (remainder x y) 0))

(define (filter-stream p lst)
  (cond ((empty-stream? lst) the-empty-stream)
        ((p (head lst)) (cons-stream (head lst) (filter-stream p (tail lst))))
        (else (filter-stream p (tail lst)))))

(define (integers-starting-from n)
 (cons-stream n 
  (integers-starting-from (+ n 1))))

(define primes (sieve (integers-starting-from 2)))