On Wed, Oct 7, 2009 at 2:59 PM, Michael Mossey
My thread about randomness got hijacked so I need to restate my remaining question here. Is it acceptable to write pure routines that use but do not return generators, and then call several of them from an IO monad with a generator obtained by several calls to newStdGen?
It's gross. What if you don't want IO as part of this computation? If you have a random generator that supports splitting (something rather hard to do from what I understand), I prefer not to return the new generator but instead to split it. So, using your shuffle:
shuffle :: RandomGen g => g -> [a] -> [a] shuffle = ...
foo :: RandomGen g => [a] -> [a] -> g -> ([a],[a]) foo xs ys gen = let (gen1, gen2) = split gen in (shuffle gen1 xs, shuffle gen2 ys) Luke