Safe Haskell	Safe
Language	Haskell2010

Data.Tuple.Only

Synopsis

Documentation

newtype Only a Source #

The 1-tuple type or single-value "collection".

This type is structurally equivalent to the Identity type, but its intent is more about serving as the anonymous 1-tuple type missing from Haskell for attaching typeclass instances.

Parameter usage example:

encodeSomething (Only (42::Int))

Result usage example:

xs <- decodeSomething
forM_ xs $ \(Only id) -> {- ... -}

Constructors

Only
Fields fromOnly :: a

Instances

Functor Only Source #
Methods fmap :: (a -> b) -> Only a -> Only b # (<$) :: a -> Only b -> Only a #
Eq a => Eq (Only a) Source #
Methods (==) :: Only a -> Only a -> Bool # (/=) :: Only a -> Only a -> Bool #
Data a => Data (Only a) Source #
Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Only a -> c (Only a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Only a) # toConstr :: Only a -> Constr # dataTypeOf :: Only a -> DataType # dataCast1 :: Typeable (* -> ) t => (forall d. Data d => c (t d)) -> Maybe (c (Only a)) # dataCast2 :: Typeable ( -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Only a)) # gmapT :: (forall b. Data b => b -> b) -> Only a -> Only a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Only a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Only a -> r # gmapQ :: (forall d. Data d => d -> u) -> Only a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Only a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Only a -> m (Only a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Only a -> m (Only a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Only a -> m (Only a) #
Ord a => Ord (Only a) Source #
Methods compare :: Only a -> Only a -> Ordering # (<) :: Only a -> Only a -> Bool # (<=) :: Only a -> Only a -> Bool # (>) :: Only a -> Only a -> Bool # (>=) :: Only a -> Only a -> Bool # max :: Only a -> Only a -> Only a # min :: Only a -> Only a -> Only a #
Read a => Read (Only a) Source #
Methods readsPrec :: Int -> ReadS (Only a) # readList :: ReadS [Only a] # readPrec :: ReadPrec (Only a) # readListPrec :: ReadPrec [Only a] #
Show a => Show (Only a) Source #
Methods showsPrec :: Int -> Only a -> ShowS # show :: Only a -> String # showList :: [Only a] -> ShowS #
Generic (Only a) Source #
Associated Types type Rep (Only a) :: * -> * # Methods from :: Only a -> Rep (Only a) x # to :: Rep (Only a) x -> Only a #
NFData a => NFData (Only a) Source #
Methods rnf :: Only a -> () #
type Rep (Only a) Source #
type Rep (Only a) = D1 (MetaData "Only" "Data.Tuple.Only" "Only-0.1-1dkiXHtbc8zGqo2Q6b73I6" True) (C1 (MetaCons "Only" PrefixI True) (S1 (MetaSel (Just Symbol "fromOnly") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a)))