On 12/6/07, Luke Palmer <lrpalmer@gmail.com > 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