I'm trying to build a list where each entry depends on the previous one. Unfoldr seemed like a good idea at the time.
Unfortunately, my values are monadic values (specifically RVars, from the random-fu package). Okay, shouldn't be a problem; I just monadic bind and...
> -- example code
> updateCell :: Bool -> RVar Bool
> updateCell False = return False
> updateCell True = bernoulli (0.9 :: Double)
> sim = sequence $ take 20 $ unfoldr (\x -> Just (x, x >>= updateCell)) (return True)
> runRVar sim DevURandom
[True,True,True,True,True,False,True,False,True,False,False,False,False,False,False,True,True,False,False,False]
That output shouldn't be possible if I'm doing things right... It appears that each cell has an independent history. I'm stumped.
Advice on threading monad input in general and random-fu in specific would be appreciated.
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