Re: [Haskell-cafe] Random pattern generation with list comprehensions

On Sunday, December 14, 2014 5:22:14 PM UTC-6, Michael Jones wrote:

The alternative might be to make a State Monad where the State is a tuple with each item holding the state for each generator.

There is a common technique of using `split` and `randoms` (or `randomsR`) to create a pure list of random values which you might find helpful. Here is an example: {-# LANGUAGE ParallelListComp #-} import System.Random main = do g <- newStdGen let (g1,g2) = split g letters = randomRs ('a','z') g1 numbers = randomRs (15,35) g2 :: [Int] pairs = [ (a,n) | (a,n) <- zip letters numbers ] pairs2 = [ (a,n) | a <- letters | n <- numbers ] print $ take 10 pairs print $ take 10 pairs2 -- produces the same list of pairs