"Russell O'Connor" <[EMAIL PROTECTED]> writes:
> [To: [EMAIL PROTECTED]]
>
> Is there a nicer way of writing the following sort of code?
>
> case (number g) of
> Just n -> Just (show n)
> Nothing ->
> case (fraction g) of
> Just n -> Just (show n)
> Nothing ->
> case (nimber g) of
> Just n -> Just ("*"++(show n))
> Nothing -> Nothing
what about?
listToMaybe $ mapMaybe (\ (f, format) -> fmap format (f g)) l
where l = [ (number, show), (fraction, show), (nimber, (\ n -> "*" ++ show n)) ]
or:
if_just (number g) show $
if_just (fraction g) show $
if_just (nimber g) (\ n -> "*" ++ show n) Nothing
using:
if_just (Just e) f _ = Just(f e)
if_just Nothing _ f = f
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