On 1/26/07, Brandon S. Allbery KF8NH <allbery@ece.cmu.edu> wrote:

On Jan 25, 2007, at 9:15 , John Ky wrote:

> Is there a built-in function that already does this?
>
> foo :: (a -> b) -> Maybe a -> Maybe b
> foo f m
>   | isNothing m = Nothing
>   | otherwise = Just (f (fromJust m))

Nothing specific to Maybe, because the more general liftM (over
monads) or fmap (over functors) already does it.

--
brandon s. allbery    [linux,solaris,freebsd,perl]     allbery@kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH