Created
February 27, 2012 06:57
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A poor man's monad
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| (>>?) :: (Ord a, Num a) => Maybe a -> (a -> Maybe b) -> Maybe b | |
| Nothing >>? _ = Nothing | |
| Just v >>? f = if v > 0 then f v else Nothing | |
| decr :: Int -> Maybe Int | |
| decr a = Just (a - 1) | |
| ex1 = (Just 1) >>? decr >>? decr >>? decr | |
| ex2 = (Just 10) >>? decr >>? decr >>? decr |
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