state_monad.hs

import Control.Monad.State.Strict
import System.Random

main = do
    print "hello world"
    print $ evalState (genPrimes 100) [2]

isPrime :: Int -> [Int] -> Bool
isPrime n primes = all (\p -> mod n p /= 0) primes

getNextPrime :: [Int] -> Int
getNextPrime primes = head $ take 1 $ filter (\n -> isPrime n primes) $ [(head primes)..]

genPrime :: State [Int] Int
genPrime = state (\primes -> (\next_p -> (head primes, (next_p:primes))) $ getNextPrime primes)

genPrimes :: Int -> State [Int] [Int]
genPrimes n = replicateM n genPrime