catMaybes :: [Maybe a] -> [a]
fromJust :: GHC.Stack.Types.HasCallStack => 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]
type Maybe :: * -> *
data Maybe a = Nothing | Just a
type T :: *
data T = A Int | B Float
f :: Double -> Double
g :: Double -> Double
h :: Integral a => a -> a
f :: Double -> Double