-- testing ghci multiline commands :{ .. :}
-- via stdin
(1,2,3)
data Maybe a = Nothing | Just a
catMaybes :: [Maybe a] -> [a]
fromJust :: Maybe a -> a
fromMaybe :: a -> Maybe a -> a
isJust :: Maybe a -> Bool
isNothing :: Maybe a -> Bool
listToMaybe :: [a] -> Maybe a
mapMaybe :: (a -> Maybe b) -> [a] -> [b]
maybe :: b -> (a -> b) -> Maybe a -> b
maybeToList :: Maybe a -> [a]
-- via readFile
(True,False)
id :: a -> a