On 12/6/07, Ryan Ingram <[EMAIL PROTECTED]> wrote: > > On 12/6/07, Luke Palmer <[EMAIL PROTECTED]> wrote: > > > > I have actually seen this pattern a lot recently. Recently I have > > started using a function: > > > > mergeMaybes :: (a -> a -> a) -> Maybe a -> Maybe a -> Maybe a > > mergeMaybes f Nothing y = y > > mergeMaybes f x Nothing = x > > mergeMaybes f (Just x) (Just y) = Just (f x y) > > > mergeMaybes = liftM2 -- from Control.Monad >
Oh wait, not quite. Didn't realize you were returning the intermediate values in the "not nothing" case. mergeMaybes f x y = liftM2 f `mplus` x `mplus` y
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