module CPS where 

sieve :: [Int] -> [Int]
sieve (x:xs) = filter (\ y -> y `mod` x /= 0) xs

primes :: [Int]
primes = map head (iterate sieve [2..])

elem' n [] = False
elem' n (x:xs) = if n<x then False
                 else if n==x then True
                 else elem' n xs


isprime :: Int -> Bool
isprime n = elem' n primes


prodprimes n = if n==1 then 1
               else if isprime n then n*prodprimes(n-1)
                                 else prodprimes(n-1)


isprime' n c = c (isprime n)

prodprimes' n c = if n==1 then c 1
                  else isprime' n (\ b ->
                       if b then prodprimes' (n-1) (\ p -> c (n*p))
                            else prodprimes' (n-1) c)