Random

The Random library deals with the common task of pseudo-random number generation. The library makes it possible to generate repeatable results, by starting with a specified initial random number generator; or to get different results on each run by using the system-initialised generator, or by supplying a seed from some other source.

module Random (
RandomGen(next, split),
StdGen, mkStdGen,
Random( random, randomR, 
randoms, randomRs,
randomIO, randomRIO ),
getStdRandom, getStdGen, setStdGen, newStdGen
 ) where
---------------- The RandomGen class ------------------------
class RandomGen g where
 next :: g -> (Int, g)
 split :: g -> (g, g)
---------------- A standard instance of RandomGen -----------
data StdGen = ... -- Abstract
instance RandomGen StdGen where ...
instance Read StdGen where ...
instance Show StdGen where ...
mkStdGen :: Int -> StdGen
---------------- The Random class ---------------------------
class Random a where
 randomR :: RandomGen g => (a, a) -> g -> (a, g)
 random :: RandomGen g => g -> (a, g)
 randomRs :: RandomGen g => (a, a) -> g -> [a]
 randoms :: RandomGen g => g -> [a]
 randomRIO :: (a,a) -> IO a
 randomIO :: IO a
instance Random Int where ...
instance Random Integer where ...
instance Random Float where ...
instance Random Double where ...
instance Random Bool where ...
instance Random Char where ...
---------------- The global random generator ----------------
newStdGen :: IO StdGen
setStdGen :: StdGen -> IO ()
getStdGen :: IO StdGen
getStdRandom :: (StdGen -> (a, StdGen)) -> IO a
The Random