Haskell の乱数でごにょごにょ

Rand2.hs

module Rand2 where

-- stack install random
-- stack install list-t
-- stack exec ghci

import Control.Monad.IO.Class ( liftIO )
import ListT                  ( ListT, toList, cons, take )
import System.Random          ( Random(randomIO) )

t3 :: ListT IO Int
t3 = do
  x <- liftIO (randomIO :: IO Int)
  cons x t3

-- IO [Int] の乱数が得られるところがポイント 
output :: IO ()
output = do
  li <- toList $ ListT.take 10 t3
  print li

{-
*Rand2> output
[7616927328998369033,6970782903781268443,-1509938769401207081,-2789264750098693865,-6524417077297424569,8403979199680420436,-3097298192134792937,-2736699795503652525,-4754186463647322678,5658901448509988002]
-}