Safe Haskell	Safe
Language	Haskell2010

Data.Tuple.Only

Synopsis

newtype Only a = Only {
- fromOnly :: a
}

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

Instances details

Functor Only Source #

Instance details

Defined in Data.Tuple.Only

Methods

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

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

NFData a => NFData (Only a) Source #

Instance details

Defined in Data.Tuple.Only

Methods

rnf :: Only a -> ()

Data a => Data (Only a) Source #

Instance details

Defined in Data.Tuple.Only

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 :: forall r r'. (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)

Generic (Only a) Source #

Instance details

Defined in Data.Tuple.Only

Associated Types

type Rep (Only a)
Instance details Defined in Data.Tuple.Only type Rep (Only a) = D1 ('MetaData "Only" "Data.Tuple.Only" "Only-0.1-AQAgoqcWSEz8RLl3wD9zjM" 'True) (C1 ('MetaCons "Only" 'PrefixI 'True) (S1 ('MetaSel ('Just "fromOnly") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

Methods

from :: Only a -> Rep (Only a) x

to :: Rep (Only a) x -> Only a

Read a => Read (Only a) Source #

Instance details

Defined in Data.Tuple.Only

Methods

readsPrec :: Int -> ReadS (Only a)

readList :: ReadS [Only a]

readPrec :: ReadPrec (Only a)

readListPrec :: ReadPrec [Only a]

Show a => Show (Only a) Source #

Instance details

Defined in Data.Tuple.Only

Methods

showsPrec :: Int -> Only a -> ShowS

show :: Only a -> String

showList :: [Only a] -> ShowS

Eq a => Eq (Only a) Source #

Instance details

Defined in Data.Tuple.Only

Methods

(==) :: Only a -> Only a -> Bool

(/=) :: Only a -> Only a -> Bool

Ord a => Ord (Only a) Source #

Instance details

Defined in Data.Tuple.Only

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

type Rep (Only a) Source #

Instance details

Defined in Data.Tuple.Only

type Rep (Only a) = D1 ('MetaData "Only" "Data.Tuple.Only" "Only-0.1-AQAgoqcWSEz8RLl3wD9zjM" 'True) (C1 ('MetaCons "Only" 'PrefixI 'True) (S1 ('MetaSel ('Just "fromOnly") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))