hgmp-0.1.1: examples/primes.hs

{-# LANGUAGE ForeignFunctionInterface #-}
module Main (main) where

import Foreign.Ptr (Ptr(..))
import Numeric.GMP.Types (MPZ)
import Numeric.GMP.Utils (withInInteger, withOutInteger_)
import Numeric.GMP.Raw.Safe (mpz_nextprime)
import System.Environment (getArgs)
import System.IO.Unsafe (unsafePerformIO)

nextPrimeIO :: Integer -> IO Integer
nextPrimeIO n = do
  withOutInteger_ $ \rop ->
    withInInteger n $ \op ->
      mpz_nextprime rop op

nextPrime :: Integer -> Integer
nextPrime n = unsafePerformIO $ nextPrimeIO n

primes :: Integer -> [Integer]
primes = drop 1 . iterate nextPrime

main :: IO ()
main = do
  [sn] <- getArgs
  n <- readIO sn
  mapM_ print . take 10 . primes $ n