base-4.9.0.0: Basic libraries

Copyright(C) 2008-2014 Edward Kmett
LicenseBSD-style (see the file libraries/base/LICENSE)
MaintainerEdward Kmett <ekmett@gmail.com>
Stabilityprovisional
Portabilityportable
Safe HaskellSafe
LanguageHaskell2010

Data.Void

Description

A logically uninhabited data type, used to indicate that a given term should not exist.

Since: 4.8.0.0

Synopsis

Documentation

data Void

Uninhabited data type

Since: 4.8.0.0

Instances

Eq Void 

Methods

(==) :: Void -> Void -> Bool Source

(/=) :: Void -> Void -> Bool Source

Data Void 

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Void -> c Void

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Void

toConstr :: Void -> Constr

dataTypeOf :: Void -> DataType

dataCast1 :: Typeable (TYPE Lifted -> TYPE Lifted) t => (forall d. Data d => c (t d)) -> Maybe (c Void)

dataCast2 :: Typeable (TYPE Lifted -> TYPE Lifted -> TYPE Lifted) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Void)

gmapT :: (forall b. Data b => b -> b) -> Void -> Void

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Void -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Void -> r

gmapQ :: (forall d. Data d => d -> u) -> Void -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Void -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Void -> m Void

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Void -> m Void

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Void -> m Void

Ord Void 
Read Void

Reading a Void value is always a parse error, considering Void as a data type with no constructors.

Show Void 

Methods

showsPrec :: Int -> Void -> ShowS

show :: Void -> String

showList :: [Void] -> ShowS

Ix Void 

Methods

range :: (Void, Void) -> [Void]

index :: (Void, Void) -> Void -> Int

unsafeIndex :: (Void, Void) -> Void -> Int

inRange :: (Void, Void) -> Void -> Bool

rangeSize :: (Void, Void) -> Int

unsafeRangeSize :: (Void, Void) -> Int

Generic Void 

Associated Types

type Rep Void :: * -> *

Methods

from :: Void -> Rep Void x

to :: Rep Void x -> Void

Semigroup Void 

Methods

(<>) :: Void -> Void -> Void

sconcat :: NonEmpty Void -> Void

stimes :: Integral b => b -> Void -> Void

Exception Void 
type Rep Void = D1 (MetaData "Void" "Data.Void" "base" False) V1 

absurd :: Void -> a

Since Void values logically don't exist, this witnesses the logical reasoning tool of "ex falso quodlibet".

Since: 4.8.0.0

vacuous :: Functor f => f Void -> f a

If Void is uninhabited then any Functor that holds only values of type Void is holding no values.

Since: 4.8.0.0