Generics.Eot

generics-eot tries to be a library for datatype generic programming that is easy to understand. "eot" stands for "eithers of tuples".

A tutorial on how to use generics-eot can be found here: https://generics-eot.readthedocs.io/.

Documentation

class HasEot a where

An instance (HasEot a) allows us to

• convert values of an arbitrary algebraic datatype a to and from a generic representation (Eot a) (see toEot and fromEot).
• extract meta information about the type a (see datatype).

Once an algebraic datatype has an instance for Generic it automatically gets one for HasEot.

Associated Types

type Eot a :: *

Eot is a type level function that maps arbitrary ADTs to isomorphic generic representations. Here's an example:

data Foo = A Int Bool | B String

would be mapped to:

Either (Int, (Bool, ())) (Either (String, ()) Void)

These representations follow these rules:

• The choice between constructors is mapped to right-nested Eithers.
• There's always a so-called end-marker Void. It's an invalid choice (and Void is uninhabited to make sure you don't accidentally create such a value). So e.g. data Foo = A would be mapped to Either () Void, and a type with no constructors is mapped to Void.
• The fields of one constructor are mapped to right-nested tuples.
• Again there's always an end-marker, this time of type (). A constructor with three fields a, b, c is mapped to (a, (b, (c, ()))), one field a is mapped to (a, ()), and no fields are mapped to () (just the end-marker).

These rules (and the end-markers) are necessary to make sure generic functions know exactly which parts of the generic representation are field types and which parts belong to the generic skeleton.

Methods

toEot :: a -> Eot a

Convert a value of type a to its generic representation.

fromEot :: Eot a -> a

Convert a value in a generic representation to a (inverse of toEot).

datatype :: Proxy a -> Datatype

Extract meta information about the ADT.

Instances

(Generic a, ImpliedByGeneric a c f) => HasEot a

Defined in Generics.Eot

Associated Types

type Eot a

Methods

toEot :: a -> Eot a

fromEot :: Eot a -> a

datatype :: Proxy a -> Datatype

data Named (a :: Symbol) field

Constructors

Named field

Instances

Show field => Show (Named a field)

Defined in Generics.Eot.Eot

Methods

showsPrec :: Int -> Named a field -> ShowS

show :: Named a field -> String

showList :: [Named a field] -> ShowS

Meta Information

data Datatype

Type for meta information about ADTs.

Constructors

Datatype

Fields

• datatypeName :: String

  unqualified name of the type

• constructors :: [Constructor]

Instances

Eq Datatype

Defined in Generics.Eot.Datatype

Methods

(==) :: Datatype -> Datatype -> Bool

(/=) :: Datatype -> Datatype -> Bool

Show Datatype

Defined in Generics.Eot.Datatype

Methods

showsPrec :: Int -> Datatype -> ShowS

show :: Datatype -> String

showList :: [Datatype] -> ShowS

data Constructor

Constructors

Constructor

Fields

• constructorName :: String
• fields :: Fields

Instances

Eq Constructor

Defined in Generics.Eot.Datatype

Methods

(==) :: Constructor -> Constructor -> Bool

(/=) :: Constructor -> Constructor -> Bool

Show Constructor

Defined in Generics.Eot.Datatype

Methods

showsPrec :: Int -> Constructor -> ShowS

show :: Constructor -> String

showList :: [Constructor] -> ShowS

data Fields

Type that represents meta information about fields of one constructor.

Constructors

Selectors [String]

Record constructor, containing the list of the selector names.

NoSelectors Int

Constructor with fields, but without selector names. The argument gives the number of fields.

NoFields

Constructor without fields.

Instances

Eq Fields

Defined in Generics.Eot.Datatype

Methods

(==) :: Fields -> Fields -> Bool

(/=) :: Fields -> Fields -> Bool

Show Fields

Defined in Generics.Eot.Datatype

Methods

showsPrec :: Int -> Fields -> ShowS

show :: Fields -> String

showList :: [Fields] -> ShowS

Useful Re-exports

class Generic a

Representable types of kind *. This class is derivable in GHC with the DeriveGeneric flag on.

A Generic instance must satisfy the following laws:

from . to ≡ id
to . from ≡ id

Minimal complete definition

from, to

Instances

Generic Bool

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep Bool :: Type -> Type

Methods

from :: Bool -> Rep Bool x

to :: Rep Bool x -> Bool

Generic Ordering

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep Ordering :: Type -> Type

Methods

from :: Ordering -> Rep Ordering x

to :: Rep Ordering x -> Ordering

Generic ()

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep () :: Type -> Type

Methods

from :: () -> Rep () x

to :: Rep () x -> ()

Generic Void

Since: base-4.8.0.0

Defined in Data.Void

Associated Types

type Rep Void :: Type -> Type

Methods

from :: Void -> Rep Void x

to :: Rep Void x -> Void

Generic Version

Since: base-4.9.0.0

Defined in Data.Version

Associated Types

type Rep Version :: Type -> Type

Methods

from :: Version -> Rep Version x

to :: Rep Version x -> Version

Generic ExitCode

Defined in GHC.IO.Exception

Associated Types

type Rep ExitCode :: Type -> Type

Methods

from :: ExitCode -> Rep ExitCode x

to :: Rep ExitCode x -> ExitCode

Generic Fixity

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep Fixity :: Type -> Type

Methods

from :: Fixity -> Rep Fixity x

to :: Rep Fixity x -> Fixity

Generic Associativity

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep Associativity :: Type -> Type

Methods

from :: Associativity -> Rep Associativity x

to :: Rep Associativity x -> Associativity

Generic SourceUnpackedness

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep SourceUnpackedness :: Type -> Type

Methods

from :: SourceUnpackedness -> Rep SourceUnpackedness x

to :: Rep SourceUnpackedness x -> SourceUnpackedness

Generic SourceStrictness

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep SourceStrictness :: Type -> Type

Methods

from :: SourceStrictness -> Rep SourceStrictness x

to :: Rep SourceStrictness x -> SourceStrictness

Generic DecidedStrictness

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep DecidedStrictness :: Type -> Type

Methods

from :: DecidedStrictness -> Rep DecidedStrictness x

to :: Rep DecidedStrictness x -> DecidedStrictness

Generic [a]

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep [a] :: Type -> Type

Methods

from :: [a] -> Rep [a] x

to :: Rep [a] x -> [a]

Generic (Maybe a)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (Maybe a) :: Type -> Type

Methods

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

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

Generic (Par1 p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep (Par1 p) :: Type -> Type

Methods

from :: Par1 p -> Rep (Par1 p) x

to :: Rep (Par1 p) x -> Par1 p

Generic (Min a)

Since: base-4.9.0.0

Defined in Data.Semigroup

Associated Types

type Rep (Min a) :: Type -> Type

Methods

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

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

Generic (Max a)

Since: base-4.9.0.0

Defined in Data.Semigroup

Associated Types

type Rep (Max a) :: Type -> Type

Methods

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

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

Generic (First a)

Since: base-4.9.0.0

Defined in Data.Semigroup

Associated Types

type Rep (First a) :: Type -> Type

Methods

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

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

Generic (Last a)

Since: base-4.9.0.0

Defined in Data.Semigroup

Associated Types

type Rep (Last a) :: Type -> Type

Methods

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

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

Generic (WrappedMonoid m)

Since: base-4.9.0.0

Defined in Data.Semigroup

Associated Types

type Rep (WrappedMonoid m) :: Type -> Type

Methods

from :: WrappedMonoid m -> Rep (WrappedMonoid m) x

to :: Rep (WrappedMonoid m) x -> WrappedMonoid m

Generic (Option a)

Since: base-4.9.0.0

Defined in Data.Semigroup

Associated Types

type Rep (Option a) :: Type -> Type

Methods

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

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

Generic (Down a)

Since: base-4.12.0.0

Defined in GHC.Generics

Associated Types

type Rep (Down a) :: Type -> Type

Methods

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

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

Generic (NonEmpty a)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (NonEmpty a) :: Type -> Type

Methods

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

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

Generic (Either a b)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (Either a b) :: Type -> Type

Methods

from :: Either a b -> Rep (Either a b) x

to :: Rep (Either a b) x -> Either a b

Generic (V1 p)

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep (V1 p) :: Type -> Type

Methods

from :: V1 p -> Rep (V1 p) x

to :: Rep (V1 p) x -> V1 p

Generic (U1 p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep (U1 p) :: Type -> Type

Methods

from :: U1 p -> Rep (U1 p) x

to :: Rep (U1 p) x -> U1 p

Generic (a, b)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (a, b) :: Type -> Type

Methods

from :: (a, b) -> Rep (a, b) x

to :: Rep (a, b) x -> (a, b)

Generic (Arg a b)

Since: base-4.9.0.0

Defined in Data.Semigroup

Associated Types

type Rep (Arg a b) :: Type -> Type

Methods

from :: Arg a b -> Rep (Arg a b) x

to :: Rep (Arg a b) x -> Arg a b

Generic (Proxy t)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (Proxy t) :: Type -> Type

Methods

from :: Proxy t -> Rep (Proxy t) x

to :: Rep (Proxy t) x -> Proxy t

Generic (Rec1 f p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep (Rec1 f p) :: Type -> Type

Methods

from :: Rec1 f p -> Rep (Rec1 f p) x

to :: Rep (Rec1 f p) x -> Rec1 f p

Generic (URec (Ptr ()) p)

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep (URec (Ptr ()) p) :: Type -> Type

Methods

from :: URec (Ptr ()) p -> Rep (URec (Ptr ()) p) x

to :: Rep (URec (Ptr ()) p) x -> URec (Ptr ()) p

Generic (URec Char p)

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep (URec Char p) :: Type -> Type

Methods

from :: URec Char p -> Rep (URec Char p) x

to :: Rep (URec Char p) x -> URec Char p

Generic (URec Double p)

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep (URec Double p) :: Type -> Type

Methods

from :: URec Double p -> Rep (URec Double p) x

to :: Rep (URec Double p) x -> URec Double p

Generic (URec Float p)

Defined in GHC.Generics

Associated Types

type Rep (URec Float p) :: Type -> Type

Methods

from :: URec Float p -> Rep (URec Float p) x

to :: Rep (URec Float p) x -> URec Float p

Generic (URec Int p)

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep (URec Int p) :: Type -> Type

Methods

from :: URec Int p -> Rep (URec Int p) x

to :: Rep (URec Int p) x -> URec Int p

Generic (URec Word p)

Since: base-4.9.0.0

Defined in GHC.Generics

Associated Types

type Rep (URec Word p) :: Type -> Type

Methods

from :: URec Word p -> Rep (URec Word p) x

to :: Rep (URec Word p) x -> URec Word p

Generic (a, b, c)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (a, b, c) :: Type -> Type

Methods

from :: (a, b, c) -> Rep (a, b, c) x

to :: Rep (a, b, c) x -> (a, b, c)

Generic (K1 i c p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep (K1 i c p) :: Type -> Type

Methods

from :: K1 i c p -> Rep (K1 i c p) x

to :: Rep (K1 i c p) x -> K1 i c p

Generic ((f :+: g) p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep ((f :+: g) p) :: Type -> Type

Methods

from :: (f :+: g) p -> Rep ((f :+: g) p) x

to :: Rep ((f :+: g) p) x -> (f :+: g) p

Generic ((f :*: g) p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep ((f :*: g) p) :: Type -> Type

Methods

from :: (f :*: g) p -> Rep ((f :*: g) p) x

to :: Rep ((f :*: g) p) x -> (f :*: g) p

Generic (a, b, c, d)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (a, b, c, d) :: Type -> Type

Methods

from :: (a, b, c, d) -> Rep (a, b, c, d) x

to :: Rep (a, b, c, d) x -> (a, b, c, d)

Generic (M1 i c f p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep (M1 i c f p) :: Type -> Type

Methods

from :: M1 i c f p -> Rep (M1 i c f p) x

to :: Rep (M1 i c f p) x -> M1 i c f p

Generic ((f :.: g) p)

Since: base-4.7.0.0

Defined in GHC.Generics

Associated Types

type Rep ((f :.: g) p) :: Type -> Type

Methods

from :: (f :.: g) p -> Rep ((f :.: g) p) x

to :: Rep ((f :.: g) p) x -> (f :.: g) p

Generic (a, b, c, d, e)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (a, b, c, d, e) :: Type -> Type

Methods

from :: (a, b, c, d, e) -> Rep (a, b, c, d, e) x

to :: Rep (a, b, c, d, e) x -> (a, b, c, d, e)

Generic (a, b, c, d, e, f)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (a, b, c, d, e, f) :: Type -> Type

Methods

from :: (a, b, c, d, e, f) -> Rep (a, b, c, d, e, f) x

to :: Rep (a, b, c, d, e, f) x -> (a, b, c, d, e, f)

Generic (a, b, c, d, e, f, g)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (a, b, c, d, e, f, g) :: Type -> Type

Methods

from :: (a, b, c, d, e, f, g) -> Rep (a, b, c, d, e, f, g) x

to :: Rep (a, b, c, d, e, f, g) x -> (a, b, c, d, e, f, g)

data Proxy (t :: k)

Proxy is a type that holds no data, but has a phantom parameter of arbitrary type (or even kind). Its use is to provide type information, even though there is no value available of that type (or it may be too costly to create one).

Historically, Proxy :: Proxy a is a safer alternative to the undefined :: a idiom.

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

Proxy can even hold types of higher kinds,

>>> Proxy :: Proxy Either
Proxy

>>> Proxy :: Proxy Functor
Proxy

>>> Proxy :: Proxy complicatedStructure
Proxy

Constructors

Proxy

Instances

Generic1 (Proxy :: k -> Type)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep1 Proxy :: k -> Type

Methods

from1 :: forall (a :: k0). Proxy a -> Rep1 Proxy a

to1 :: forall (a :: k0). Rep1 Proxy a -> Proxy a

Monad (Proxy :: Type -> Type)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

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

(>>) :: Proxy a -> Proxy b -> Proxy b

return :: a -> Proxy a

Functor (Proxy :: Type -> Type)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

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

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

Applicative (Proxy :: Type -> Type)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

pure :: a -> Proxy a

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

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

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

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

Foldable (Proxy :: Type -> Type)

Since: base-4.7.0.0

Defined in Data.Foldable

Methods

fold :: Monoid m => Proxy m -> m

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

foldMap' :: Monoid m => (a -> m) -> Proxy a -> m

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

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

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

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

foldr1 :: (a -> a -> a) -> Proxy a -> a

foldl1 :: (a -> a -> a) -> Proxy a -> a

toList :: Proxy a -> [a]

null :: Proxy a -> Bool

length :: Proxy a -> Int

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

maximum :: Ord a => Proxy a -> a

minimum :: Ord a => Proxy a -> a

sum :: Num a => Proxy a -> a

product :: Num a => Proxy a -> a

Traversable (Proxy :: Type -> Type)

Since: base-4.7.0.0

Defined in Data.Traversable

Methods

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

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

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

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

Alternative (Proxy :: Type -> Type)

Since: base-4.9.0.0

Defined in Data.Proxy

Methods

empty :: Proxy a

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

some :: Proxy a -> Proxy [a]

many :: Proxy a -> Proxy [a]

MonadPlus (Proxy :: Type -> Type)

Since: base-4.9.0.0

Defined in Data.Proxy

Methods

mzero :: Proxy a

mplus :: Proxy a -> Proxy a -> Proxy a

Bounded (Proxy t)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

minBound :: Proxy t

maxBound :: Proxy t

Enum (Proxy s)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

succ :: Proxy s -> Proxy s

pred :: Proxy s -> Proxy s

toEnum :: Int -> Proxy s

fromEnum :: Proxy s -> Int

enumFrom :: Proxy s -> [Proxy s]

enumFromThen :: Proxy s -> Proxy s -> [Proxy s]

enumFromTo :: Proxy s -> Proxy s -> [Proxy s]

enumFromThenTo :: Proxy s -> Proxy s -> Proxy s -> [Proxy s]

Eq (Proxy s)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

(==) :: Proxy s -> Proxy s -> Bool

(/=) :: Proxy s -> Proxy s -> Bool

Ord (Proxy s)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

compare :: Proxy s -> Proxy s -> Ordering

(<) :: Proxy s -> Proxy s -> Bool

(<=) :: Proxy s -> Proxy s -> Bool

(>) :: Proxy s -> Proxy s -> Bool

(>=) :: Proxy s -> Proxy s -> Bool

max :: Proxy s -> Proxy s -> Proxy s

min :: Proxy s -> Proxy s -> Proxy s

Read (Proxy t)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

readsPrec :: Int -> ReadS (Proxy t)

readList :: ReadS [Proxy t]

readPrec :: ReadPrec (Proxy t)

readListPrec :: ReadPrec [Proxy t]

Show (Proxy s)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

showsPrec :: Int -> Proxy s -> ShowS

show :: Proxy s -> String

showList :: [Proxy s] -> ShowS

Ix (Proxy s)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

range :: (Proxy s, Proxy s) -> [Proxy s]

index :: (Proxy s, Proxy s) -> Proxy s -> Int

unsafeIndex :: (Proxy s, Proxy s) -> Proxy s -> Int

inRange :: (Proxy s, Proxy s) -> Proxy s -> Bool

rangeSize :: (Proxy s, Proxy s) -> Int

unsafeRangeSize :: (Proxy s, Proxy s) -> Int

Generic (Proxy t)

Since: base-4.6.0.0

Defined in GHC.Generics

Associated Types

type Rep (Proxy t) :: Type -> Type

Methods

from :: Proxy t -> Rep (Proxy t) x

to :: Rep (Proxy t) x -> Proxy t

Semigroup (Proxy s)

Since: base-4.9.0.0

Defined in Data.Proxy

Methods

(<>) :: Proxy s -> Proxy s -> Proxy s

sconcat :: NonEmpty (Proxy s) -> Proxy s

stimes :: Integral b => b -> Proxy s -> Proxy s

Monoid (Proxy s)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

mempty :: Proxy s

mappend :: Proxy s -> Proxy s -> Proxy s

mconcat :: [Proxy s] -> Proxy s

type Rep1 (Proxy :: k -> Type)

Defined in GHC.Generics

type Rep1 (Proxy :: k -> Type) = D1 ('MetaData "Proxy" "Data.Proxy" "base" 'False) (C1 ('MetaCons "Proxy" 'PrefixI 'False) (U1 :: k -> Type))

type Rep (Proxy t)

Defined in GHC.Generics

type Rep (Proxy t) = D1 ('MetaData "Proxy" "Data.Proxy" "base" 'False) (C1 ('MetaCons "Proxy" 'PrefixI 'False) (U1 :: Type -> Type))

data Void

Uninhabited data type

Since: base-4.8.0.0

Instances

Eq Void

Since: base-4.8.0.0

Defined in Data.Void

Methods

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

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

Data Void

Since: base-4.8.0.0

Defined in 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 t => (forall d. Data d => c (t d)) -> Maybe (c Void)

dataCast2 :: Typeable 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 :: forall r r'. (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

Since: base-4.8.0.0

Defined in Data.Void

Methods

compare :: Void -> Void -> Ordering

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

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

(>) :: Void -> Void -> Bool

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

max :: Void -> Void -> Void

min :: Void -> Void -> Void

Read Void

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

Since: base-4.8.0.0

Defined in Data.Void

Methods

readsPrec :: Int -> ReadS Void

readList :: ReadS [Void]

readPrec :: ReadPrec Void

readListPrec :: ReadPrec [Void]

Show Void

Since: base-4.8.0.0

Defined in Data.Void

Methods

showsPrec :: Int -> Void -> ShowS

show :: Void -> String

showList :: [Void] -> ShowS

Ix Void

Since: base-4.8.0.0

Defined in Data.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

Since: base-4.8.0.0

Defined in Data.Void

Associated Types

type Rep Void :: Type -> Type

Methods

from :: Void -> Rep Void x

to :: Rep Void x -> Void

Semigroup Void

Since: base-4.9.0.0

Defined in Data.Void

Methods

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

sconcat :: NonEmpty Void -> Void

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

Exception Void

Since: base-4.8.0.0

Defined in Data.Void

Methods

toException :: Void -> SomeException

fromException :: SomeException -> Maybe Void

displayException :: Void -> String

type Rep Void

Defined in Data.Void

type Rep Void = D1 ('MetaData "Void" "Data.Void" "base" 'False) (V1 :: Type -> Type)

absurd :: Void -> a

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

>>> let x :: Either Void Int; x = Right 5
>>> :{
case x of
    Right r -> r
    Left l  -> absurd l
:}
5

Since: base-4.8.0.0