How to use MonadRandom?

Question

Can someone provide \"for-dummies\" example of how to use `MonadRandom\'?

Currently I have code that does stuff like passing around the generator variable, all the w

Answer 1

Basically all the extra g parameters can just be dropped. You then get random numbers using the functions from Control.Monad.Random (such as getRandomR). Here is your example (I added some args to make it compile):

import Control.Monad.Random

main = do
    g <- getStdGen
    let r = evalRand (myFunc 1 2 3) g :: Double
    -- or use runRand if you want to do more random stuff:
    -- let (r,g') = runRand (myFunc 1 2 3) g :: (Double,StdGen)
    putStrLn $ "Result is : " ++ show r

--my complicated func
myFunc x y z = afunc x y z
afunc x y z = bfunc x y
bfunc x y = cfunc x
cfunc x = do
    ret <- getRandomR (0.0,1.0)
    return ret