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.OldTypeable

Contents

The Typeable class
Type-safe cast
Type representations
Construction of type representations
Observation of type representations
The other Typeable classes
Default instances

Description

Deprecated: Use Data.Typeable instead

This module defines the old, kind-monomorphic Typeable class. It is now deprecated; users are recommended to use the kind-polymorphic Data.Typeable module instead.

Since: 4.7.0.0

Synopsis

The Typeable class

class Typeable a where Source

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

Methods

typeOf :: a -> TypeRep Source

Takes a value of type a and returns a concrete representation of that type. The value of the argument should be ignored by any instance of Typeable, so that it is safe to pass undefined as the argument.

Instances

Typeable Bool
Typeable Char
Typeable Double
Typeable Float
Typeable Int
Typeable Int8
Typeable Int16
Typeable Int32
Typeable Int64
Typeable Integer
Typeable Ordering
Typeable RealWorld
Typeable Word
Typeable Word8
Typeable Word16
Typeable Word32
Typeable Word64
Typeable ()
Typeable TyCon
Typeable TypeRep
(Typeable1 s, Typeable a) => Typeable (s a)	One Typeable instance for all Typeable1 instances

Type-safe cast

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

The type-safe cast operation

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

A flexible variation parameterised in a type constructor

Type representations

data TypeRep Source

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

Instances

Eq TypeRep
Ord TypeRep
Show TypeRep
Typeable TypeRep

showsTypeRep :: TypeRep -> ShowS Source

data TyCon Source

An abstract representation of a type constructor. TyCon objects can be built using mkTyCon.

Instances

Eq TyCon
Ord TyCon
Show TyCon
Typeable TyCon

tyConString :: TyCon -> String Source

Observe string encoding of a type representation

tyConPackage :: TyCon -> String Source

tyConModule :: TyCon -> String Source

tyConName :: TyCon -> String Source

Construction of type representations

mkTyCon Source

Arguments

:: String	unique string
-> TyCon	A unique `TyCon` object

Backwards-compatible API

mkTyCon3 Source

Arguments

:: String	package name
-> String	module name
-> String	the name of the type constructor
-> TyCon	A unique `TyCon` object

Builds a TyCon object representing a type constructor. An implementation of Data.Typeable should ensure that the following holds:

 A==A' ^ B==B' ^ C==C' ==> mkTyCon A B C == mkTyCon A' B' C'

mkTyConApp :: TyCon -> [TypeRep] -> TypeRep Source

Applies a type constructor to a sequence of types

mkAppTy :: TypeRep -> TypeRep -> TypeRep Source

Adds a TypeRep argument to a TypeRep.

mkFunTy :: TypeRep -> TypeRep -> TypeRep Source

A special case of mkTyConApp, which applies the function type constructor to a pair of types.

Observation of type representations

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

Splits a type constructor application

funResultTy :: TypeRep -> TypeRep -> Maybe TypeRep Source

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.

typeRepTyCon :: TypeRep -> TyCon Source

Observe the type constructor of a type representation

typeRepArgs :: TypeRep -> [TypeRep] Source

Observe the argument types of a type representation

typeRepKey :: TypeRep -> IO TypeRepKey Source

(DEPRECATED) Returns a unique key associated with a TypeRep. This function is deprecated because TypeRep itself is now an instance of Ord, so mappings can be made directly with TypeRep as the key.

data TypeRepKey Source

Instances

Eq TypeRepKey
Ord TypeRepKey

The other Typeable classes

Note: The general instances are provided for GHC only.

class Typeable1 t where Source

Variant for unary type constructors

Methods

typeOf1 :: t a -> TypeRep Source

Instances

Typeable1 []
Typeable1 Ratio
Typeable1 StablePtr
Typeable1 IO
Typeable1 Ptr
Typeable1 FunPtr
Typeable1 Maybe
Typeable1 IORef
Typeable1 MVar
(Typeable2 s, Typeable a) => Typeable1 (s a)	One Typeable1 instance for all Typeable2 instances

class Typeable2 t where Source

Variant for binary type constructors

Methods

typeOf2 :: t a b -> TypeRep Source

Instances

Typeable2 (->)
Typeable2 (,)
Typeable2 ST
Typeable2 STRef
(Typeable3 s, Typeable a) => Typeable2 (s a)	One Typeable2 instance for all Typeable3 instances

class Typeable3 t where Source

Variant for 3-ary type constructors

Methods

typeOf3 :: t a b c -> TypeRep Source

Instances

Typeable3 (,,)
(Typeable4 s, Typeable a) => Typeable3 (s a)	One Typeable3 instance for all Typeable4 instances

class Typeable4 t where Source

Variant for 4-ary type constructors

Methods

typeOf4 :: t a b c d -> TypeRep Source

Instances

Typeable4 (,,,)
(Typeable5 s, Typeable a) => Typeable4 (s a)	One Typeable4 instance for all Typeable5 instances

class Typeable5 t where Source

Variant for 5-ary type constructors

Methods

typeOf5 :: t a b c d e -> TypeRep Source

Instances

Typeable5 (,,,,)
(Typeable6 s, Typeable a) => Typeable5 (s a)	One Typeable5 instance for all Typeable6 instances

class Typeable6 t where Source

Variant for 6-ary type constructors

Methods

typeOf6 :: t a b c d e f -> TypeRep Source

Instances

Typeable6 (,,,,,)
(Typeable7 s, Typeable a) => Typeable6 (s a)	One Typeable6 instance for all Typeable7 instances

class Typeable7 t where Source

Variant for 7-ary type constructors

Methods

typeOf7 :: t a b c d e f g -> TypeRep Source

Instances

Typeable7 (,,,,,,)

gcast1 :: (Typeable1 t, Typeable1 t') => c (t a) -> Maybe (c (t' a)) Source

Cast for * -> *

gcast2 :: (Typeable2 t, Typeable2 t') => c (t a b) -> Maybe (c (t' a b)) Source

Cast for * -> * -> *

Default instances

Note: These are not needed by GHC, for which these instances are generated by general instance declarations.

typeOfDefault :: forall t a. (Typeable1 t, Typeable a) => t a -> TypeRep Source

For defining a Typeable instance from any Typeable1 instance.

typeOf1Default :: forall t a b. (Typeable2 t, Typeable a) => t a b -> TypeRep Source

For defining a Typeable1 instance from any Typeable2 instance.

typeOf2Default :: forall t a b c. (Typeable3 t, Typeable a) => t a b c -> TypeRep Source

For defining a Typeable2 instance from any Typeable3 instance.

typeOf3Default :: forall t a b c d. (Typeable4 t, Typeable a) => t a b c d -> TypeRep Source

For defining a Typeable3 instance from any Typeable4 instance.

typeOf4Default :: forall t a b c d e. (Typeable5 t, Typeable a) => t a b c d e -> TypeRep Source

For defining a Typeable4 instance from any Typeable5 instance.

typeOf5Default :: forall t a b c d e f. (Typeable6 t, Typeable a) => t a b c d e f -> TypeRep Source

For defining a Typeable5 instance from any Typeable6 instance.

typeOf6Default :: forall t a b c d e f g. (Typeable7 t, Typeable a) => t a b c d e f g -> TypeRep Source

For defining a Typeable6 instance from any Typeable7 instance.