Data.Church.Maybe

Documentation

just :: a -> Maybe a

nothing :: Maybe a

newtype Maybe a

Constructors

Maybe

Fields

• unMaybe :: forall r. r -> (a -> r) -> r

Instances

Monad Maybe

Methods

(>>=) :: Maybe a -> (a -> Maybe b) -> Maybe b

(>>) :: Maybe a -> Maybe b -> Maybe b

return :: a -> Maybe a

fail :: String -> Maybe a

Functor Maybe

Methods

fmap :: (a -> b) -> Maybe a -> Maybe b

(<$) :: a -> Maybe b -> Maybe a

MonadFix Maybe

Methods

mfix :: (a -> Maybe a) -> Maybe a

Applicative Maybe

Methods

pure :: a -> Maybe a

(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b

liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c

(*>) :: Maybe a -> Maybe b -> Maybe b

(<*) :: Maybe a -> Maybe b -> Maybe a

Foldable Maybe

Methods

fold :: Monoid m => Maybe m -> m

foldMap :: Monoid m => (a -> m) -> Maybe a -> m

foldr :: (a -> b -> b) -> b -> Maybe a -> b

foldr' :: (a -> b -> b) -> b -> Maybe a -> b

foldl :: (b -> a -> b) -> b -> Maybe a -> b

foldl' :: (b -> a -> b) -> b -> Maybe a -> b

foldr1 :: (a -> a -> a) -> Maybe a -> a

foldl1 :: (a -> a -> a) -> Maybe a -> a

toList :: Maybe a -> [a]

null :: Maybe a -> Bool

length :: Maybe a -> Int

elem :: Eq a => a -> Maybe a -> Bool

maximum :: Ord a => Maybe a -> a

minimum :: Ord a => Maybe a -> a

sum :: Num a => Maybe a -> a

product :: Num a => Maybe a -> a

Traversable Maybe

Methods

traverse :: Applicative f => (a -> f b) -> Maybe a -> f (Maybe b)

sequenceA :: Applicative f => Maybe (f a) -> f (Maybe a)

mapM :: Monad m => (a -> m b) -> Maybe a -> m (Maybe b)

sequence :: Monad m => Maybe (m a) -> m (Maybe a)

MonadZip Maybe

Methods

mzip :: Maybe a -> Maybe b -> Maybe (a, b)

mzipWith :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c

munzip :: Maybe (a, b) -> (Maybe a, Maybe b)

Alternative Maybe

Methods

empty :: Maybe a

(<|>) :: Maybe a -> Maybe a -> Maybe a

some :: Maybe a -> Maybe [a]

many :: Maybe a -> Maybe [a]

MonadPlus Maybe

Methods

mzero :: Maybe a

mplus :: Maybe a -> Maybe a -> Maybe a

NFData1 Maybe

Methods

liftRnf :: (a -> ()) -> Maybe a -> ()

Alt Maybe

Methods

(<!>) :: Maybe a -> Maybe a -> Maybe a

some :: Applicative Maybe => Maybe a -> Maybe [a]

many :: Applicative Maybe => Maybe a -> Maybe [a]

Apply Maybe

Methods

(<.>) :: Maybe (a -> b) -> Maybe a -> Maybe b

(.>) :: Maybe a -> Maybe b -> Maybe b

(<.) :: Maybe a -> Maybe b -> Maybe a

Bind Maybe

Methods

(>>-) :: Maybe a -> (a -> Maybe b) -> Maybe b

join :: Maybe (Maybe a) -> Maybe a

Semigroup a => Semigroup (Maybe a)

Methods

(<>) :: Maybe a -> Maybe a -> Maybe a

sconcat :: NonEmpty (Maybe a) -> Maybe a

stimes :: Integral b => b -> Maybe a -> Maybe a

Semigroup a => Monoid (Maybe a)

Methods

mempty :: Maybe a

mappend :: Maybe a -> Maybe a -> Maybe a

mconcat :: [Maybe a] -> Maybe a

NFData a => NFData (Maybe a)

And NFData1 for GHC >=8.2

Methods

rnf :: Maybe a -> ()

maybe :: b -> (a -> b) -> Maybe a -> b

isNothing :: Maybe a -> Bool

isJust :: Maybe a -> Bool

fromMaybe :: a -> Maybe a -> a

listToMaybe :: [a] -> Maybe a

maybeToList :: Maybe a -> [a]

catMaybes :: [Maybe a] -> [a]

mapMaybe :: (a -> Maybe b) -> [a] -> [b]