Safe Haskell	Safe
Language	Haskell2010

Typeable

Contents

Optics

Synopsis

class Typeable (a :: k)
cast :: (Typeable a, Typeable b) => a -> Maybe b
eqT :: (Typeable a, Typeable b) => Maybe (a :~: b)
gcast :: (Typeable a, Typeable b) => c a -> Maybe (c b)
gcast1 :: (Typeable t, Typeable t') => c (t a) -> Maybe (c (t' a))
gcast2 :: (Typeable t, Typeable t') => c (t a b) -> Maybe (c (t' a b))
data TypeRep (a :: k) :: forall k. k -> *
typeRep :: Typeable a => TypeRep a
typeOf :: Typeable a => a -> TypeRep a
withTypeable :: TypeRep a -> (Typeable a -> r) -> r
pattern App :: forall k2 (t :: k2). () => forall k1 (a :: k1 -> k2) (b :: k1). t ~ a b => TypeRep a -> TypeRep b -> TypeRep t
pattern Con :: forall k (a :: k). () => IsApplication a ~ "" => TyCon -> TypeRep a
pattern Con' :: forall k (a :: k). () => IsApplication a ~ "" => TyCon -> [SomeTypeRep] -> TypeRep a
pattern Fun :: forall k (fun :: k). () => forall (r1 :: RuntimeRep) (r2 :: RuntimeRep) (arg :: TYPE r1) (res :: TYPE r2). (k ~ Type, fun ~~ (arg -> res)) => TypeRep arg -> TypeRep res -> TypeRep fun
typeRepTyCon :: TypeRep a -> TyCon
rnfTypeRep :: TypeRep a -> ()
eqTypeRep :: TypeRep a -> TypeRep b -> Maybe (a :~~: b)
typeRepKind :: TypeRep a -> TypeRep k
splitApps :: TypeRep a -> (TyCon, [SomeTypeRep])
data SomeTypeRep where
- SomeTypeRep :: SomeTypeRep
someTypeRep :: Typeable a => proxy a -> SomeTypeRep
someTypeRepTyCon :: SomeTypeRep -> TyCon
rnfSomeTypeRep :: SomeTypeRep -> ()
data TyCon
tyConPackage :: TyCon -> String
tyConModule :: TyCon -> String
tyConName :: TyCon -> String
rnfTyCon :: TyCon -> ()
data Module
moduleName :: Module -> String
modulePackage :: Module -> String
rnfModule :: Module -> ()
_cast :: (Typeable s, Typeable a) => Traversal' s a
_gcast :: (Typeable s, Typeable a) => Traversal' (c s) (c a)

Documentation

class Typeable (a :: k) #

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

Minimal complete definition

typeRep#

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

The type-safe cast operation

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

Extract a witness of equality of two types

Since: base-4.7.0.0

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

A flexible variation parameterised in a type constructor

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

Cast over k1 -> k2

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

Cast over k1 -> k2 -> k3

data TypeRep (a :: k) :: forall k. k -> * #

A concrete representation of a (monomorphic) type. TypeRep supports reasonably efficient equality.

Instances

TestEquality (TypeRep :: k -> *)
Instance details Defined in Data.Typeable.Internal Methods testEquality :: TypeRep a -> TypeRep b -> Maybe (a :~: b) #
Eq (TypeRep a)	Since: base-2.1
Instance details Defined in Data.Typeable.Internal Methods (==) :: TypeRep a -> TypeRep a -> Bool # (/=) :: TypeRep a -> TypeRep a -> Bool #
Ord (TypeRep a)	Since: base-4.4.0.0
Instance details Defined in Data.Typeable.Internal Methods compare :: TypeRep a -> TypeRep a -> Ordering # (<) :: TypeRep a -> TypeRep a -> Bool # (<=) :: TypeRep a -> TypeRep a -> Bool # (>) :: TypeRep a -> TypeRep a -> Bool # (>=) :: TypeRep a -> TypeRep a -> Bool # max :: TypeRep a -> TypeRep a -> TypeRep a # min :: TypeRep a -> TypeRep a -> TypeRep a #
Show (TypeRep a)
Instance details Defined in Data.Typeable.Internal Methods showsPrec :: Int -> TypeRep a -> ShowS # show :: TypeRep a -> String # showList :: [TypeRep a] -> ShowS #
Hashable (TypeRep a)
Instance details Defined in Data.Hashable.Class Methods hashWithSalt :: Int -> TypeRep a -> Int # hash :: TypeRep a -> Int #
Typeable a => Serialise (TypeRep a)	Since: serialise-0.2.0.0
Instance details Defined in Codec.Serialise.Class Methods encode :: TypeRep a -> Encoding # decode :: Decoder s (TypeRep a) # encodeList :: [TypeRep a] -> Encoding # decodeList :: Decoder s [TypeRep a] #

typeRep :: Typeable a => TypeRep a #

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

withTypeable :: TypeRep a -> (Typeable a -> r) -> r #

Use a TypeRep as Typeable evidence.

pattern App :: forall k2 (t :: k2). () => forall k1 (a :: k1 -> k2) (b :: k1). t ~ a b => TypeRep a -> TypeRep b -> TypeRep t #

A type application.

For instance,

typeRep @(Maybe Int) === App (typeRep @Maybe) (typeRep @Int)

Note that this will also match a function type,

typeRep @(Int# -> Char)
  ===
App (App arrow (typeRep @Int#)) (typeRep @Char)

where arrow :: TypeRep ((->) :: TYPE IntRep -> Type -> Type).

pattern Con :: forall k (a :: k). () => IsApplication a ~ "" => TyCon -> TypeRep a #

Pattern match on a type constructor

pattern Con' :: forall k (a :: k). () => IsApplication a ~ "" => TyCon -> [SomeTypeRep] -> TypeRep a #

Pattern match on a type constructor including its instantiated kind variables.

For instance,

App (Con' proxyTyCon ks) intRep = typeRep @(Proxy @Int)

will bring into scope,

proxyTyCon :: TyCon
ks         == [someTypeRep Type] :: [SomeTypeRep]
intRep     == typeRep Int

pattern Fun :: forall k (fun :: k). () => forall (r1 :: RuntimeRep) (r2 :: RuntimeRep) (arg :: TYPE r1) (res :: TYPE r2). (k ~ Type, fun ~~ (arg -> res)) => TypeRep arg -> TypeRep res -> TypeRep fun #

The function type constructor.

For instance,

typeRep @(Int -> Char) === Fun (typeRep @Int) (typeRep @Char)

typeRepTyCon :: TypeRep a -> TyCon #

Observe the type constructor of a type representation

rnfTypeRep :: TypeRep a -> () #

Helper to fully evaluate TypeRep for use as NFData(rnf) implementation

Since: base-4.8.0.0

eqTypeRep :: TypeRep a -> TypeRep b -> Maybe (a :~~: b) #

Type equality

Since: base-4.10

typeRepKind :: TypeRep a -> TypeRep k #

Observe the kind of a type.

splitApps :: TypeRep a -> (TyCon, [SomeTypeRep]) #

data SomeTypeRep where #

A non-indexed type representation.

Constructors

SomeTypeRep :: SomeTypeRep

Instances

Eq SomeTypeRep
Instance details Defined in Data.Typeable.Internal Methods (==) :: SomeTypeRep -> SomeTypeRep -> Bool # (/=) :: SomeTypeRep -> SomeTypeRep -> Bool #
Ord SomeTypeRep
Instance details Defined in Data.Typeable.Internal Methods compare :: SomeTypeRep -> SomeTypeRep -> Ordering # (<) :: SomeTypeRep -> SomeTypeRep -> Bool # (<=) :: SomeTypeRep -> SomeTypeRep -> Bool # (>) :: SomeTypeRep -> SomeTypeRep -> Bool # (>=) :: SomeTypeRep -> SomeTypeRep -> Bool # max :: SomeTypeRep -> SomeTypeRep -> SomeTypeRep # min :: SomeTypeRep -> SomeTypeRep -> SomeTypeRep #
Show SomeTypeRep	Since: base-4.10.0.0
Instance details Defined in Data.Typeable.Internal Methods showsPrec :: Int -> SomeTypeRep -> ShowS # show :: SomeTypeRep -> String # showList :: [SomeTypeRep] -> ShowS #
Hashable SomeTypeRep
Instance details Defined in Data.Hashable.Class Methods hashWithSalt :: Int -> SomeTypeRep -> Int # hash :: SomeTypeRep -> Int #
NFData TypeRep	NOTE: Only defined for `base-4.8.0.0` and later Since: deepseq-1.4.0.0
Instance details Defined in Control.DeepSeq Methods rnf :: TypeRep -> () #
Serialise SomeTypeRep	Since: serialise-0.2.0.0
Instance details Defined in Codec.Serialise.Class Methods encode :: SomeTypeRep -> Encoding # decode :: Decoder s SomeTypeRep # encodeList :: [SomeTypeRep] -> Encoding # decodeList :: Decoder s [SomeTypeRep] #

someTypeRep :: Typeable a => proxy a -> SomeTypeRep #

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

Since: base-4.7.0.0

someTypeRepTyCon :: SomeTypeRep -> TyCon #

Observe the type constructor of a quantified type representation.

rnfSomeTypeRep :: SomeTypeRep -> () #

Helper to fully evaluate SomeTypeRep for use as NFData(rnf) implementation

Since: base-4.10.0.0

data TyCon #

Instances

Eq TyCon
Instance details Defined in GHC.Classes Methods (==) :: TyCon -> TyCon -> Bool # (/=) :: TyCon -> TyCon -> Bool #
Ord TyCon
Instance details Defined in GHC.Classes Methods compare :: TyCon -> TyCon -> Ordering # (<) :: TyCon -> TyCon -> Bool # (<=) :: TyCon -> TyCon -> Bool # (>) :: TyCon -> TyCon -> Bool # (>=) :: TyCon -> TyCon -> Bool # max :: TyCon -> TyCon -> TyCon # min :: TyCon -> TyCon -> TyCon #
Show TyCon	Since: base-2.1
Instance details Defined in GHC.Show Methods showsPrec :: Int -> TyCon -> ShowS # show :: TyCon -> String # showList :: [TyCon] -> ShowS #
NFData TyCon	NOTE: Only defined for `base-4.8.0.0` and later Since: deepseq-1.4.0.0
Instance details Defined in Control.DeepSeq Methods rnf :: TyCon -> () #
Serialise TyCon	Since: serialise-0.2.0.0
Instance details Defined in Codec.Serialise.Class Methods encode :: TyCon -> Encoding # decode :: Decoder s TyCon # encodeList :: [TyCon] -> Encoding # decodeList :: Decoder s [TyCon] #

tyConPackage :: TyCon -> String #

tyConModule :: TyCon -> String #

tyConName :: TyCon -> String #

rnfTyCon :: TyCon -> () #

data Module #

Instances

Eq Module
Instance details Defined in GHC.Classes Methods (==) :: Module -> Module -> Bool # (/=) :: Module -> Module -> Bool #
Show Module	Since: base-4.9.0.0
Instance details Defined in GHC.Show Methods showsPrec :: Int -> Module -> ShowS # show :: Module -> String # showList :: [Module] -> ShowS #

moduleName :: Module -> String #

modulePackage :: Module -> String #

rnfModule :: Module -> () #

Helper to fully evaluate TyCon for use as NFData(rnf) implementation

Since: base-4.8.0.0

Optics

_cast :: (Typeable s, Typeable a) => Traversal' s a #

A Traversal' for working with a cast of a Typeable value.

_gcast :: (Typeable s, Typeable a) => Traversal' (c s) (c a) #

A Traversal' for working with a gcast of a Typeable value.