Hi, I've been in the past told that mersenne-random was much better than the standard random package. However, System.Random.Mersenne doesn't follow the general API described in System.Random, MTGen is not an instance of RandomGen. But a sample on System.Random.Mersenne.getStdRandom documentation ( http://hackage.haskell.org/packages/archive/mersenne-random/1.0.0.1/doc/html...) indicates this: rollDice :: IO Int rollDice = getMTRandom (randomR (1,6)) It looks like wrong documentation (checking of older versions show that getMTRandom have never lived or been exposed by this module), but suggests MTRandom should be an instance of RandomGen (if I assume well that randomR is that of System.Random). So is it possible to use the fast and efficient mersenne generator with the convenient and general random API?