Copyright	(c) The University of Glasgow CWI 2001--2004
License	BSD-style (see the file libraries/base/LICENSE)
Maintainer	libraries@haskell.org
Stability	experimental
Portability	portable
Safe Haskell	Trustworthy
Language	Haskell2010

Data.Typeable

Contents

The Typeable class
Propositional equality
Type-safe cast
Generalized casts for higher-order kinds
A canonical proxy type
Type representations
Observing type representations
Type constructors
For backwards compatibility

Description

The Typeable class reifies types to some extent by associating type representations to types. These type representations can be compared, and one can in turn define a type-safe cast operation. To this end, an unsafe cast is guarded by a test for type (representation) equivalence. The module Data.Dynamic uses Typeable for an implementation of dynamics. The module Data.Data uses Typeable and type-safe cast (but not dynamics) to support the "Scrap your boilerplate" style of generic programming.

Compatibility Notes

Since GHC 8.2, GHC has supported type-indexed type representations. Data.Typeable provides type representations which are qualified over this index, providing an interface very similar to the Typeable notion seen in previous releases. For the type-indexed interface, see Type.Reflection.

Since GHC 7.8, Typeable is poly-kinded. The changes required for this might break some old programs involving Typeable. More details on this, including how to fix your code, can be found on the PolyTypeable wiki page

Synopsis

class Typeable (a :: k)
typeOf :: forall a. Typeable a => a -> TypeRep
typeRep :: forall proxy a. Typeable a => proxy a -> TypeRep
data a :~: b where
- Refl :: a :~: a
data (a :: k1) :~~: (b :: k2) where
- HRefl :: a :~~: a
cast :: forall a b. (Typeable a, Typeable b) => a -> Maybe b
eqT :: forall a b. (Typeable a, Typeable b) => Maybe (a :~: b)
gcast :: forall a b c. (Typeable a, Typeable b) => c a -> Maybe (c b)
gcast1 :: forall c t t' a. (Typeable t, Typeable t') => c (t a) -> Maybe (c (t' a))
gcast2 :: forall c t t' a b. (Typeable t, Typeable t') => c (t a b) -> Maybe (c (t' a b))
data Proxy t = Proxy
type TypeRep = SomeTypeRep
rnfTypeRep :: TypeRep -> ()
showsTypeRep :: TypeRep -> ShowS
mkFunTy :: TypeRep -> TypeRep -> TypeRep
funResultTy :: TypeRep -> TypeRep -> Maybe TypeRep
splitTyConApp :: TypeRep -> (TyCon, [TypeRep])
typeRepArgs :: TypeRep -> [TypeRep]
typeRepTyCon :: TypeRep -> TyCon
typeRepFingerprint :: TypeRep -> Fingerprint
data TyCon
tyConPackage :: TyCon -> String
tyConModule :: TyCon -> String
tyConName :: TyCon -> String
rnfTyCon :: TyCon -> ()
tyConFingerprint :: TyCon -> Fingerprint
typeOf1 :: forall t (a :: Type). Typeable t => t a -> TypeRep
typeOf2 :: forall t (a :: Type) (b :: Type). Typeable t => t a b -> TypeRep
typeOf3 :: forall t (a :: Type) (b :: Type) (c :: Type). Typeable t => t a b c -> TypeRep
typeOf4 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type). Typeable t => t a b c d -> TypeRep
typeOf5 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type) (e :: Type). Typeable t => t a b c d e -> TypeRep
typeOf6 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type) (e :: Type) (f :: Type). Typeable t => t a b c d e f -> TypeRep
typeOf7 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type) (e :: Type) (f :: Type) (g :: Type). Typeable t => t a b c d e f g -> TypeRep

The Typeable class

class Typeable (a :: k) #

The class Typeable allows a concrete representation of a type to be calculated.

Minimal complete definition

typeRep#

typeOf :: forall a. Typeable a => a -> TypeRep #

Observe a type representation for the type of a value.

typeRep :: forall proxy a. Typeable a => proxy a -> TypeRep #

Takes a value of type a and returns a concrete representation of that type.

Since: base-4.7.0.0

Propositional equality

data a :~: b where infix 4 #

Propositional equality. If a :~: b is inhabited by some terminating value, then the type a is the same as the type b. To use this equality in practice, pattern-match on the a :~: b to get out the Refl constructor; in the body of the pattern-match, the compiler knows that a ~ b.

Since: base-4.7.0.0

Constructors

Refl :: a :~: a

Instances

Category ((:~:) :: k -> k -> Type) #	Since: base-4.7.0.0
Instance details Defined in Control.Category Methods id :: a :~: a # (.) :: (b :~: c) -> (a :~: b) -> a :~: c #
TestEquality ((:~:) a :: k -> Type) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Equality Methods testEquality :: (a :~: a0) -> (a :~: b) -> Maybe (a0 :~: b) #
TestCoercion ((:~:) a :: k -> Type) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Coercion Methods testCoercion :: (a :~: a0) -> (a :~: b) -> Maybe (Coercion a0 b) #
a ~ b => Bounded (a :~: b) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Equality Methods minBound :: a :~: b # maxBound :: a :~: b #
a ~ b => Enum (a :~: b) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Equality Methods succ :: (a :~: b) -> a :~: b # pred :: (a :~: b) -> a :~: b # toEnum :: Int -> a :~: b # fromEnum :: (a :~: b) -> Int # enumFrom :: (a :~: b) -> [a :~: b] # enumFromThen :: (a :~: b) -> (a :~: b) -> [a :~: b] # enumFromTo :: (a :~: b) -> (a :~: b) -> [a :~: b] # enumFromThenTo :: (a :~: b) -> (a :~: b) -> (a :~: b) -> [a :~: b] #
Eq (a :~: b) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Equality Methods (==) :: (a :~: b) -> (a :~: b) -> Bool Source # (/=) :: (a :~: b) -> (a :~: b) -> Bool Source #
(a ~ b, Data a) => Data (a :~: b) #	Since: base-4.7.0.0
Instance details Defined in Data.Data Methods gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> (a :~: b) -> c (a :~: b) # gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (a :~: b) # toConstr :: (a :~: b) -> Constr # dataTypeOf :: (a :~: b) -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (a :~: b)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (a :~: b)) # gmapT :: (forall b0. Data b0 => b0 -> b0) -> (a :~: b) -> a :~: b # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> (a :~: b) -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> (a :~: b) -> r # gmapQ :: (forall d. Data d => d -> u) -> (a :~: b) -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> (a :~: b) -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> (a :~: b) -> m (a :~: b) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> (a :~: b) -> m (a :~: b) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> (a :~: b) -> m (a :~: b) #
Ord (a :~: b) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Equality Methods compare :: (a :~: b) -> (a :~: b) -> Ordering Source # (<) :: (a :~: b) -> (a :~: b) -> Bool Source # (<=) :: (a :~: b) -> (a :~: b) -> Bool Source # (>) :: (a :~: b) -> (a :~: b) -> Bool Source # (>=) :: (a :~: b) -> (a :~: b) -> Bool Source # max :: (a :~: b) -> (a :~: b) -> a :~: b Source # min :: (a :~: b) -> (a :~: b) -> a :~: b Source #
a ~ b => Read (a :~: b) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Equality Methods readsPrec :: Int -> ReadS (a :~: b) # readList :: ReadS [a :~: b] # readPrec :: ReadPrec (a :~: b) # readListPrec :: ReadPrec [a :~: b] #
Show (a :~: b) #	Since: base-4.7.0.0
Instance details Defined in Data.Type.Equality Methods showsPrec :: Int -> (a :~: b) -> ShowS # show :: (a :~: b) -> String # showList :: [a :~: b] -> ShowS #

data (a :: k1) :~~: (b :: k2) where infix 4 #

Kind heterogeneous propositional equality. Like :~:, a :~~: b is inhabited by a terminating value if and only if a is the same type as b.

Since: base-4.10.0.0

Constructors

HRefl :: a :~~: a

Instances

Category ((:~~:) :: k -> k -> Type) #	Since: base-4.10.0.0
Instance details Defined in Control.Category Methods id :: a :~~: a # (.) :: (b :~~: c) -> (a :~~: b) -> a :~~: c #
TestEquality ((:~~:) a :: k -> Type) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Equality Methods testEquality :: (a :~~: a0) -> (a :~~: b) -> Maybe (a0 :~: b) #
TestCoercion ((:~~:) a :: k -> Type) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Coercion Methods testCoercion :: (a :~~: a0) -> (a :~~: b) -> Maybe (Coercion a0 b) #
a ~~ b => Bounded (a :~~: b) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Equality Methods minBound :: a :~~: b # maxBound :: a :~~: b #
a ~~ b => Enum (a :~~: b) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Equality Methods succ :: (a :~~: b) -> a :~~: b # pred :: (a :~~: b) -> a :~~: b # toEnum :: Int -> a :~~: b # fromEnum :: (a :~~: b) -> Int # enumFrom :: (a :~~: b) -> [a :~~: b] # enumFromThen :: (a :~~: b) -> (a :~~: b) -> [a :~~: b] # enumFromTo :: (a :~~: b) -> (a :~~: b) -> [a :~~: b] # enumFromThenTo :: (a :~~: b) -> (a :~~: b) -> (a :~~: b) -> [a :~~: b] #
Eq (a :~~: b) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Equality Methods (==) :: (a :~~: b) -> (a :~~: b) -> Bool Source # (/=) :: (a :~~: b) -> (a :~~: b) -> Bool Source #
(Typeable i, Typeable j, Typeable a, Typeable b, a ~~ b) => Data (a :~~: b) #	Since: base-4.10.0.0
Instance details Defined in Data.Data Methods gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> (a :~~: b) -> c (a :~~: b) # gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (a :~~: b) # toConstr :: (a :~~: b) -> Constr # dataTypeOf :: (a :~~: b) -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (a :~~: b)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (a :~~: b)) # gmapT :: (forall b0. Data b0 => b0 -> b0) -> (a :~~: b) -> a :~~: b # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> (a :~~: b) -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> (a :~~: b) -> r # gmapQ :: (forall d. Data d => d -> u) -> (a :~~: b) -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> (a :~~: b) -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> (a :~~: b) -> m (a :~~: b) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> (a :~~: b) -> m (a :~~: b) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> (a :~~: b) -> m (a :~~: b) #
Ord (a :~~: b) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Equality Methods compare :: (a :~~: b) -> (a :~~: b) -> Ordering Source # (<) :: (a :~~: b) -> (a :~~: b) -> Bool Source # (<=) :: (a :~~: b) -> (a :~~: b) -> Bool Source # (>) :: (a :~~: b) -> (a :~~: b) -> Bool Source # (>=) :: (a :~~: b) -> (a :~~: b) -> Bool Source # max :: (a :~~: b) -> (a :~~: b) -> a :~~: b Source # min :: (a :~~: b) -> (a :~~: b) -> a :~~: b Source #
a ~~ b => Read (a :~~: b) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Equality Methods readsPrec :: Int -> ReadS (a :~~: b) # readList :: ReadS [a :~~: b] # readPrec :: ReadPrec (a :~~: b) # readListPrec :: ReadPrec [a :~~: b] #
Show (a :~~: b) #	Since: base-4.10.0.0
Instance details Defined in Data.Type.Equality Methods showsPrec :: Int -> (a :~~: b) -> ShowS # show :: (a :~~: b) -> String # showList :: [a :~~: b] -> ShowS #

Type-safe cast

cast :: forall a b. (Typeable a, Typeable b) => a -> Maybe b #

The type-safe cast operation

eqT :: forall a b. (Typeable a, Typeable b) => Maybe (a :~: b) #

Extract a witness of equality of two types

Since: base-4.7.0.0

gcast :: forall a b c. (Typeable a, Typeable b) => c a -> Maybe (c b) #

A flexible variation parameterised in a type constructor

Generalized casts for higher-order kinds

gcast1 :: forall c t t' a. (Typeable t, Typeable t') => c (t a) -> Maybe (c (t' a)) #

Cast over k1 -> k2

gcast2 :: forall c t t' a b. (Typeable t, Typeable t') => c (t a b) -> Maybe (c (t' a b)) #

Cast over k1 -> k2 -> k3

A canonical proxy type

data Proxy t #

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) #
Instance details Defined in GHC.Generics Associated Types type Rep1 Proxy :: k -> Type # Methods from1 :: Proxy a -> Rep1 Proxy a # to1 :: Rep1 Proxy a -> Proxy a #
Monad (Proxy :: Type -> Type) #	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods (>>=) :: Proxy a -> (a -> Proxy b) -> Proxy b # (>>) :: Proxy a -> Proxy b -> Proxy b # return :: a -> Proxy a # fail :: String -> Proxy a #
Functor (Proxy :: Type -> Type) #	Since: base-4.7.0.0
Instance details 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
Instance details 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
Instance details Defined in Data.Foldable Methods fold :: Monoid m => Proxy m -> 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
Instance details 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) #
MonadPlus (Proxy :: Type -> Type) #	Since: base-4.9.0.0
Instance details Defined in Data.Proxy Methods mzero :: Proxy a # mplus :: Proxy a -> Proxy a -> Proxy a #
Alternative (Proxy :: Type -> Type) #	Since: base-4.9.0.0
Instance details Defined in Data.Proxy Methods empty :: Proxy a # (<\|>) :: Proxy a -> Proxy a -> Proxy a # some :: Proxy a -> Proxy [a] # many :: Proxy a -> Proxy [a] #
MonadZip (Proxy :: Type -> Type) #	Since: base-4.9.0.0
Instance details Defined in Control.Monad.Zip Methods mzip :: Proxy a -> Proxy b -> Proxy (a, b) # mzipWith :: (a -> b -> c) -> Proxy a -> Proxy b -> Proxy c # munzip :: Proxy (a, b) -> (Proxy a, Proxy b) #
Show1 (Proxy :: Type -> Type) #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Proxy a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Proxy a] -> ShowS #
Read1 (Proxy :: Type -> Type) #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Proxy a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Proxy a] # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Proxy a) # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Proxy a] #
Ord1 (Proxy :: Type -> Type) #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> Proxy a -> Proxy b -> Ordering #
Eq1 (Proxy :: Type -> Type) #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> Proxy a -> Proxy b -> Bool #
Contravariant (Proxy :: Type -> Type) #
Instance details Defined in Data.Functor.Contravariant Methods contramap :: (a -> b) -> Proxy b -> Proxy a # (>$) :: b -> Proxy b -> Proxy a #
Bounded (Proxy t) #	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods minBound :: Proxy t # maxBound :: Proxy t #
Enum (Proxy s) #	Since: base-4.7.0.0
Instance details 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
Instance details Defined in Data.Proxy Methods (==) :: Proxy s -> Proxy s -> Bool Source # (/=) :: Proxy s -> Proxy s -> Bool Source #
Data t => Data (Proxy t) #	Since: base-4.7.0.0
Instance details Defined in Data.Data Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Proxy t -> c (Proxy t) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Proxy t) # toConstr :: Proxy t -> Constr # dataTypeOf :: Proxy t -> DataType # dataCast1 :: Typeable t0 => (forall d. Data d => c (t0 d)) -> Maybe (c (Proxy t)) # dataCast2 :: Typeable t0 => (forall d e. (Data d, Data e) => c (t0 d e)) -> Maybe (c (Proxy t)) # gmapT :: (forall b. Data b => b -> b) -> Proxy t -> Proxy t # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Proxy t -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Proxy t -> r # gmapQ :: (forall d. Data d => d -> u) -> Proxy t -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Proxy t -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Proxy t -> m (Proxy t) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Proxy t -> m (Proxy t) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Proxy t -> m (Proxy t) #
Ord (Proxy s) #	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods compare :: Proxy s -> Proxy s -> Ordering Source # (<) :: Proxy s -> Proxy s -> Bool Source # (<=) :: Proxy s -> Proxy s -> Bool Source # (>) :: Proxy s -> Proxy s -> Bool Source # (>=) :: Proxy s -> Proxy s -> Bool Source # max :: Proxy s -> Proxy s -> Proxy s Source # min :: Proxy s -> Proxy s -> Proxy s Source #
Read (Proxy t) #	Since: base-4.7.0.0
Instance details 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
Instance details 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
Instance details 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) #
Instance details 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
Instance details 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
Instance details 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) #	Since: base-4.6.0.0
Instance details 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) #	Since: base-4.6.0.0
Instance details Defined in GHC.Generics type Rep (Proxy t) = D1 (MetaData "Proxy" "Data.Proxy" "base" False) (C1 (MetaCons "Proxy" PrefixI False) (U1 :: Type -> Type))

Type representations

type TypeRep = SomeTypeRep #

A quantified type representation.

rnfTypeRep :: TypeRep -> () #

Force a TypeRep to normal form.

showsTypeRep :: TypeRep -> ShowS #

Show a type representation

mkFunTy :: TypeRep -> TypeRep -> TypeRep #

Build a function type.

Observing type representations

funResultTy :: TypeRep -> TypeRep -> Maybe TypeRep #

Applies a type to a function type. Returns: Just u if the first argument represents a function of type t -> u and the second argument represents a function of type t. Otherwise, returns Nothing.

splitTyConApp :: TypeRep -> (TyCon, [TypeRep]) #

Splits a type constructor application. Note that if the type constructor is polymorphic, this will not return the kinds that were used.

typeRepArgs :: TypeRep -> [TypeRep] #

Observe the argument types of a type representation

typeRepTyCon :: TypeRep -> TyCon #

Observe the type constructor of a quantified type representation.

typeRepFingerprint :: TypeRep -> Fingerprint #

Takes a value of type a and returns a concrete representation of that type.

Since: base-4.7.0.0

Type constructors

data TyCon Source #

Instances

Eq TyCon
Instance details Defined in GHC.Classes Methods (==) :: TyCon -> TyCon -> Bool Source # (/=) :: TyCon -> TyCon -> Bool Source #
Ord TyCon
Instance details Defined in GHC.Classes Methods compare :: TyCon -> TyCon -> Ordering Source # (<) :: TyCon -> TyCon -> Bool Source # (<=) :: TyCon -> TyCon -> Bool Source # (>) :: TyCon -> TyCon -> Bool Source # (>=) :: TyCon -> TyCon -> Bool Source # max :: TyCon -> TyCon -> TyCon Source # min :: TyCon -> TyCon -> TyCon Source #
Show TyCon #	Since: base-2.1
Instance details Defined in GHC.Show Methods showsPrec :: Int -> TyCon -> ShowS # show :: TyCon -> String # showList :: [TyCon] -> ShowS #

tyConPackage :: TyCon -> String #

tyConModule :: TyCon -> String #

tyConName :: TyCon -> String #

rnfTyCon :: TyCon -> () #

tyConFingerprint :: TyCon -> Fingerprint #

For backwards compatibility

typeOf1 :: forall t (a :: Type). Typeable t => t a -> TypeRep #

typeOf2 :: forall t (a :: Type) (b :: Type). Typeable t => t a b -> TypeRep #

typeOf3 :: forall t (a :: Type) (b :: Type) (c :: Type). Typeable t => t a b c -> TypeRep #

typeOf4 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type). Typeable t => t a b c d -> TypeRep #

typeOf5 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type) (e :: Type). Typeable t => t a b c d e -> TypeRep #

typeOf6 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type) (e :: Type) (f :: Type). Typeable t => t a b c d e f -> TypeRep #

typeOf7 :: forall t (a :: Type) (b :: Type) (c :: Type) (d :: Type) (e :: Type) (f :: Type) (g :: Type). Typeable t => t a b c d e f g -> TypeRep #