-{-# OPTIONS -fno-implicit-prelude #-}
+{-# OPTIONS_GHC -fno-implicit-prelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : Data.Typeable
-- Stability : experimental
-- Portability : portable
--
--- The Typeable class reifies types to some extent by associating type
+-- 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.Generics uses Typeable
+-- equivalence. The module "Data.Dynamic" uses Typeable for an
+-- implementation of dynamics. The module "Data.Generics" uses Typeable
-- and type-safe cast (but not dynamics) to support the \"Scrap your
-- boilerplate\" style of generic programming.
--
+-- Note, only relevant if you use dynamic linking. If you have a program
+-- that is statically linked with Data.Typeable, and then dynamically link
+-- a program that also uses Data.Typeable, you'll get two copies of the module.
+-- That's fine, but behind the scenes, the module uses a mutable variable to
+-- allocate unique Ids to type constructors. So in the situation described,
+-- there'll be two separate Id allocators, which aren't comparable to each other.
+-- This can lead to chaos. (It's a bug that we will fix.) None of
+-- this matters if you aren't using dynamic linking.
+--
-----------------------------------------------------------------------------
module Data.Typeable
-- * Construction of type representations
mkTyCon, -- :: String -> TyCon
- mkAppTy, -- :: TyCon -> [TypeRep] -> TypeRep
+ mkTyConApp, -- :: TyCon -> [TypeRep] -> TypeRep
+ mkAppTy, -- :: TypeRep -> TypeRep -> TypeRep
mkFunTy, -- :: TypeRep -> TypeRep -> TypeRep
- applyTy, -- :: TypeRep -> TypeRep -> Maybe TypeRep
- popStarTy, -- :: TypeRep -> TypeRep -> TypeRep
-- * Observation of type representations
- typerepTyCon, -- :: TypeRep -> TyCon
- typerepArgs, -- :: TypeRep -> [TypeRep]
- tyconString, -- :: TyCon -> String
+ splitTyConApp, -- :: TypeRep -> (TyCon, [TypeRep])
+ funResultTy, -- :: TypeRep -> TypeRep -> Maybe TypeRep
+ typeRepTyCon, -- :: TypeRep -> TyCon
+ typeRepArgs, -- :: TypeRep -> [TypeRep]
+ tyConString, -- :: TyCon -> String
-- * The other Typeable classes
+ -- | /Note:/ The general instances are provided for GHC only.
Typeable1( typeOf1 ), -- :: t a -> TypeRep
Typeable2( typeOf2 ), -- :: t a b -> TypeRep
Typeable3( typeOf3 ), -- :: t a b c -> TypeRep
gcast2, -- :: ... => c (t a b) -> Maybe (c (t' a b))
-- * Default instances
+ -- | /Note:/ These are not needed by GHC, for which these instances
+ -- are generated by general instance declarations.
typeOfDefault, -- :: (Typeable1 t, Typeable a) => t a -> TypeRep
typeOf1Default, -- :: (Typeable2 t, Typeable a) => t a b -> TypeRep
- typeOf2Default, -- :: (Typeable2 t, Typeable a) => t a b c -> TypeRep
- typeOf3Default, -- :: (Typeable2 t, Typeable a) => t a b c d -> TypeRep
- typeOf4Default, -- :: (Typeable2 t, Typeable a) => t a b c d e -> TypeRep
- typeOf5Default, -- :: (Typeable2 t, Typeable a) => t a b c d e f -> TypeRep
- typeOf6Default -- :: (Typeable2 t, Typeable a) => t a b c d e f g -> TypeRep
+ typeOf2Default, -- :: (Typeable3 t, Typeable a) => t a b c -> TypeRep
+ typeOf3Default, -- :: (Typeable4 t, Typeable a) => t a b c d -> TypeRep
+ typeOf4Default, -- :: (Typeable5 t, Typeable a) => t a b c d e -> TypeRep
+ typeOf5Default, -- :: (Typeable6 t, Typeable a) => t a b c d e f -> TypeRep
+ typeOf6Default -- :: (Typeable7 t, Typeable a) => t a b c d e f g -> TypeRep
) where
-
import qualified Data.HashTable as HT
import Data.Maybe
import Data.Either
import GHC.Err
import GHC.Num
import GHC.Float
-import GHC.Real( rem, Ratio )
-import GHC.IOBase
-import GHC.Ptr -- So we can give Typeable instance for Ptr
-import GHC.Stable -- So we can give Typeable instance for StablePtr
+import GHC.Real ( rem, Ratio )
+import GHC.IOBase (IORef,newIORef,unsafePerformIO)
+
+-- These imports are so we can define Typeable instances
+-- It'd be better to give Typeable instances in the modules themselves
+-- but they all have to be compiled before Typeable
+import GHC.IOBase ( IO, MVar, Exception, ArithException, IOException,
+ ArrayException, AsyncException, Handle )
+import GHC.ST ( ST )
+import GHC.STRef ( STRef )
+import GHC.Ptr ( Ptr, FunPtr )
+import GHC.ForeignPtr ( ForeignPtr )
+import GHC.Stable ( StablePtr )
+import GHC.Arr ( Array, STArray )
+
#endif
#ifdef __HUGS__
import Hugs.IO
import Hugs.IORef
import Hugs.IOExts
+ -- For the Typeable instance
+import Hugs.Array ( Array )
+import Hugs.ConcBase ( MVar )
#endif
#ifdef __GLASGOW_HASKELL__
#ifdef __NHC__
import NonStdUnsafeCoerce (unsafeCoerce)
import NHC.IOExtras (IORef,newIORef,readIORef,writeIORef,unsafePerformIO)
-#else
-#include "Typeable.h"
+import IO (Handle)
+import Ratio (Ratio)
+ -- For the Typeable instance
+import NHC.FFI ( Ptr,FunPtr,StablePtr,ForeignPtr )
+import Array ( Array )
#endif
+#include "Typeable.h"
#ifndef __HUGS__
--
-------------------------------------------------------------
-
-- | A concrete representation of a (monomorphic) type. 'TypeRep'
-- supports reasonably efficient equality.
data TypeRep = TypeRep !Key TyCon [TypeRep]
#endif
--
- -- let fTy = mkTyCon "Foo" in show (mkAppTy (mkTyCon ",,")
+ -- let fTy = mkTyCon "Foo" in show (mkTyConApp (mkTyCon ",,")
-- [fTy,fTy,fTy])
--
-- returns "(Foo,Foo,Foo)"
-- sequence of commas, e.g., (mkTyCon ",,,,") returns
-- the 5-tuple tycon.
-
----------------- Construction --------------------
-- | Applies a type constructor to a sequence of types
-mkAppTy :: TyCon -> [TypeRep] -> TypeRep
-mkAppTy tc@(TyCon tc_k _) args
+mkTyConApp :: TyCon -> [TypeRep] -> TypeRep
+mkTyConApp tc@(TyCon tc_k _) args
= TypeRep (appKeys tc_k arg_ks) tc args
where
arg_ks = [k | TypeRep k _ _ <- args]
-
--- | A special case of 'mkAppTy', which applies the function
+-- | A special case of 'mkTyConApp', which applies the function
-- type constructor to a pair of types.
mkFunTy :: TypeRep -> TypeRep -> TypeRep
-mkFunTy f a = mkAppTy funTc [f,a]
+mkFunTy f a = mkTyConApp funTc [f,a]
+-- | Splits a type constructor application
+splitTyConApp :: TypeRep -> (TyCon,[TypeRep])
+splitTyConApp (TypeRep _ tc trs) = (tc,trs)
-- | 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'.
-applyTy :: TypeRep -> TypeRep -> Maybe TypeRep
-applyTy (TypeRep _ tc [t1,t2]) t3
- | tc == funTc && t1 == t3 = Just t2
-applyTy _ _ = Nothing
-
+funResultTy :: TypeRep -> TypeRep -> Maybe TypeRep
+funResultTy trFun trArg
+ = case splitTyConApp trFun of
+ (tc, [t1,t2]) | tc == funTc && t1 == trArg -> Just t2
+ _ -> Nothing
-- | Adds a TypeRep argument to a TypeRep.
-popStarTy :: TypeRep -> TypeRep -> TypeRep
-popStarTy (TypeRep tr_k tc trs) arg_tr
+mkAppTy :: TypeRep -> TypeRep -> TypeRep
+mkAppTy (TypeRep tr_k tc trs) arg_tr
= let (TypeRep arg_k _ _) = arg_tr
in TypeRep (appKey tr_k arg_k) tc (trs++[arg_tr])
-
-- If we enforce the restriction that there is only one
-- @TyCon@ for a type & it is shared among all its uses,
-- we can map them onto Ints very simply. The benefit is,
-> TyCon -- ^ A unique 'TyCon' object
mkTyCon str = TyCon (mkTyConKey str) str
-
-
----------------- Observation ---------------------
-
-- | Observe the type constructor of a type representation
-typerepTyCon :: TypeRep -> TyCon
-typerepTyCon (TypeRep _ tc _) = tc
-
+typeRepTyCon :: TypeRep -> TyCon
+typeRepTyCon (TypeRep _ tc _) = tc
-- | Observe the argument types of a type representation
-typerepArgs :: TypeRep -> [TypeRep]
-typerepArgs (TypeRep _ _ args) = args
-
+typeRepArgs :: TypeRep -> [TypeRep]
+typeRepArgs (TypeRep _ _ args) = args
-- | Observe string encoding of a type representation
-tyconString :: TyCon -> String
-tyconString (TyCon _ str) = str
-
+tyConString :: TyCon -> String
+tyConString (TyCon _ str) = str
----------------- Showing TypeReps --------------------
isTupleTyCon (TyCon _ (',':_)) = True
isTupleTyCon _ = False
-
-- Some (Show.TypeRep) helpers:
showArgs :: Show a => [a] -> ShowS
go (',':xs) (a:as) = showsPrec 10 a . showChar ',' . go xs as
go _ _ = showChar ')'
-
-------------------------------------------------------------
--
-- The Typeable class and friends
--
-------------------------------------------------------------
-
-- | The class 'Typeable' allows a concrete representation of a type to
-- be calculated.
class Typeable a where
-- | For defining a 'Typeable' instance from any 'Typeable1' instance.
typeOfDefault :: (Typeable1 t, Typeable a) => t a -> TypeRep
-typeOfDefault x = typeOf1 x `popStarTy` typeOf (argType x)
+typeOfDefault x = typeOf1 x `mkAppTy` typeOf (argType x)
where
argType :: t a -> a
argType = undefined
-#ifdef __GLASGOW_HASKELL__
--- | One Typeable instance for all Typeable1 instances
-instance (Typeable1 s, Typeable a)
- => Typeable (s a) where
- typeOf = typeOfDefault
-#endif
-
-
-- | Variant for binary type constructors
class Typeable2 t where
typeOf2 :: t a b -> TypeRep
-- | For defining a 'Typeable1' instance from any 'Typeable2' instance.
typeOf1Default :: (Typeable2 t, Typeable a) => t a b -> TypeRep
-typeOf1Default x = typeOf2 x `popStarTy` typeOf (argType x)
+typeOf1Default x = typeOf2 x `mkAppTy` typeOf (argType x)
where
argType :: t a b -> a
argType = undefined
-
-#ifdef __GLASGOW_HASKELL__
--- | One Typeable1 instance for all Typeable2 instances
-instance (Typeable2 s, Typeable a)
- => Typeable1 (s a) where
- typeOf1 = typeOf1Default
-#endif
-
-
-- | Variant for 3-ary type constructors
class Typeable3 t where
typeOf3 :: t a b c -> TypeRep
-- | For defining a 'Typeable2' instance from any 'Typeable3' instance.
typeOf2Default :: (Typeable3 t, Typeable a) => t a b c -> TypeRep
-typeOf2Default x = typeOf3 x `popStarTy` typeOf (argType x)
+typeOf2Default x = typeOf3 x `mkAppTy` typeOf (argType x)
where
argType :: t a b c -> a
argType = undefined
-
-#ifdef __GLASGOW_HASKELL__
--- | One Typeable2 instance for all Typeable3 instances
-instance (Typeable3 s, Typeable a)
- => Typeable2 (s a) where
- typeOf2 = typeOf2Default
-#endif
-
-
-- | Variant for 4-ary type constructors
class Typeable4 t where
typeOf4 :: t a b c d -> TypeRep
-- | For defining a 'Typeable3' instance from any 'Typeable4' instance.
typeOf3Default :: (Typeable4 t, Typeable a) => t a b c d -> TypeRep
-typeOf3Default x = typeOf4 x `popStarTy` typeOf (argType x)
+typeOf3Default x = typeOf4 x `mkAppTy` typeOf (argType x)
where
argType :: t a b c d -> a
argType = undefined
-
-#ifdef __GLASGOW_HASKELL__
--- | One Typeable3 instance for all Typeable4 instances
-instance (Typeable4 s, Typeable a)
- => Typeable3 (s a) where
- typeOf3 = typeOf3Default
-#endif
-
-
-- | Variant for 5-ary type constructors
class Typeable5 t where
typeOf5 :: t a b c d e -> TypeRep
-- | For defining a 'Typeable4' instance from any 'Typeable5' instance.
typeOf4Default :: (Typeable5 t, Typeable a) => t a b c d e -> TypeRep
-typeOf4Default x = typeOf5 x `popStarTy` typeOf (argType x)
+typeOf4Default x = typeOf5 x `mkAppTy` typeOf (argType x)
where
argType :: t a b c d e -> a
argType = undefined
-
-#ifdef __GLASGOW_HASKELL__
--- | One Typeable4 instance for all Typeable5 instances
-instance (Typeable5 s, Typeable a)
- => Typeable4 (s a) where
- typeOf4 = typeOf4Default
-#endif
-
-
-- | Variant for 6-ary type constructors
class Typeable6 t where
typeOf6 :: t a b c d e f -> TypeRep
-- | For defining a 'Typeable5' instance from any 'Typeable6' instance.
typeOf5Default :: (Typeable6 t, Typeable a) => t a b c d e f -> TypeRep
-typeOf5Default x = typeOf6 x `popStarTy` typeOf (argType x)
+typeOf5Default x = typeOf6 x `mkAppTy` typeOf (argType x)
where
argType :: t a b c d e f -> a
argType = undefined
-
-#ifdef __GLASGOW_HASKELL__
--- | One Typeable5 instance for all Typeable6 instances
-instance (Typeable6 s, Typeable a)
- => Typeable5 (s a) where
- typeOf5 = typeOf5Default
-#endif
-
-
-- | Variant for 7-ary type constructors
class Typeable7 t where
typeOf7 :: t a b c d e f g -> TypeRep
-- | For defining a 'Typeable6' instance from any 'Typeable7' instance.
typeOf6Default :: (Typeable7 t, Typeable a) => t a b c d e f g -> TypeRep
-typeOf6Default x = typeOf7 x `popStarTy` typeOf (argType x)
+typeOf6Default x = typeOf7 x `mkAppTy` typeOf (argType x)
where
argType :: t a b c d e f g -> a
argType = undefined
-
#ifdef __GLASGOW_HASKELL__
+-- Given a @Typeable@/n/ instance for an /n/-ary type constructor,
+-- define the instances for partial applications.
+-- Programmers using non-GHC implementations must do this manually
+-- for each type constructor.
+-- (The INSTANCE_TYPEABLE/n/ macros in Typeable.h include this.)
+
+-- | One Typeable instance for all Typeable1 instances
+instance (Typeable1 s, Typeable a)
+ => Typeable (s a) where
+ typeOf = typeOfDefault
+
+-- | One Typeable1 instance for all Typeable2 instances
+instance (Typeable2 s, Typeable a)
+ => Typeable1 (s a) where
+ typeOf1 = typeOf1Default
+
+-- | One Typeable2 instance for all Typeable3 instances
+instance (Typeable3 s, Typeable a)
+ => Typeable2 (s a) where
+ typeOf2 = typeOf2Default
+
+-- | One Typeable3 instance for all Typeable4 instances
+instance (Typeable4 s, Typeable a)
+ => Typeable3 (s a) where
+ typeOf3 = typeOf3Default
+
+-- | One Typeable4 instance for all Typeable5 instances
+instance (Typeable5 s, Typeable a)
+ => Typeable4 (s a) where
+ typeOf4 = typeOf4Default
+
+-- | One Typeable5 instance for all Typeable6 instances
+instance (Typeable6 s, Typeable a)
+ => Typeable5 (s a) where
+ typeOf5 = typeOf5Default
+
-- | One Typeable6 instance for all Typeable7 instances
instance (Typeable7 s, Typeable a)
=> Typeable6 (s a) where
typeOf6 = typeOf6Default
-#endif
-
+#endif /* __GLASGOW_HASKELL__ */
-------------------------------------------------------------
--
then Just $ unsafeCoerce x
else Nothing
-
-- | A flexible variation parameterised in a type constructor
gcast :: (Typeable a, Typeable b) => c a -> Maybe (c b)
gcast x = r
getArg :: c x -> x
getArg = undefined
-
-
-- | Cast for * -> *
gcast1 :: (Typeable1 t, Typeable1 t') => c (t a) -> Maybe (c (t' a))
gcast1 x = r
getArg :: c x -> x
getArg = undefined
-
-- | Cast for * -> * -> *
gcast2 :: (Typeable2 t, Typeable2 t') => c (t a b) -> Maybe (c (t' a b))
gcast2 x = r
getArg :: c x -> x
getArg = undefined
-
-
-------------------------------------------------------------
--
-- Instances of the Typeable classes for Prelude types
--
-------------------------------------------------------------
-#ifndef __NHC__
+INSTANCE_TYPEABLE0((),unitTc,"()")
INSTANCE_TYPEABLE1([],listTc,"[]")
INSTANCE_TYPEABLE1(Maybe,maybeTc,"Maybe")
INSTANCE_TYPEABLE1(Ratio,ratioTc,"Ratio")
INSTANCE_TYPEABLE2(Either,eitherTc,"Either")
INSTANCE_TYPEABLE2((->),funTc,"->")
-INSTANCE_TYPEABLE0((),unitTc,"()")
-INSTANCE_TYPEABLE2((,),pairTc,"(,)")
+INSTANCE_TYPEABLE1(IO,ioTc,"IO")
+
+#if defined(__GLASGOW_HASKELL__) || defined(__HUGS__)
+-- Types defined in GHC.IOBase
+INSTANCE_TYPEABLE1(MVar,mvarTc,"MVar" )
+INSTANCE_TYPEABLE0(Exception,exceptionTc,"Exception")
+INSTANCE_TYPEABLE0(IOException,ioExceptionTc,"IOException")
+INSTANCE_TYPEABLE0(ArithException,arithExceptionTc,"ArithException")
+INSTANCE_TYPEABLE0(ArrayException,arrayExceptionTc,"ArrayException")
+INSTANCE_TYPEABLE0(AsyncException,asyncExceptionTc,"AsyncException")
+#endif
+
+-- Types defined in GHC.Arr
+INSTANCE_TYPEABLE2(Array,arrayTc,"Array")
+
+#ifdef __GLASGOW_HASKELL__
+-- Hugs has these too, but their Typeable<n> instances are defined
+-- elsewhere to keep this module within Haskell 98.
+-- This is important because every invocation of runhugs or ffihugs
+-- uses this module via Data.Dynamic.
+INSTANCE_TYPEABLE2(ST,stTc,"ST")
+INSTANCE_TYPEABLE2(STRef,stRefTc,"STRef")
+INSTANCE_TYPEABLE3(STArray,sTArrayTc,"STArray")
+#endif
+
+#ifndef __NHC__
+INSTANCE_TYPEABLE2((,),pairTc,",")
INSTANCE_TYPEABLE3((,,),tup3Tc,",,")
tup4Tc :: TyCon
tup4Tc = mkTyCon ",,,"
instance Typeable4 (,,,) where
- typeOf4 tu = mkAppTy tup4Tc []
-
+ typeOf4 tu = mkTyConApp tup4Tc []
tup5Tc :: TyCon
tup5Tc = mkTyCon ",,,,"
instance Typeable5 (,,,,) where
- typeOf5 tu = mkAppTy tup5Tc []
-
+ typeOf5 tu = mkTyConApp tup5Tc []
tup6Tc :: TyCon
tup6Tc = mkTyCon ",,,,,"
instance Typeable6 (,,,,,) where
- typeOf6 tu = mkAppTy tup6Tc []
-
+ typeOf6 tu = mkTyConApp tup6Tc []
tup7Tc :: TyCon
-tup7Tc = mkTyCon ",,,,,"
+tup7Tc = mkTyCon ",,,,,,"
instance Typeable7 (,,,,,,) where
- typeOf7 tu = mkAppTy tup7Tc []
+ typeOf7 tu = mkTyConApp tup7Tc []
+#endif /* __NHC__ */
-INSTANCE_TYPEABLE1(IO,ioTc,"System.IO.IO")
-INSTANCE_TYPEABLE1(Ptr,ptrTc,"Foreign.Ptr.Ptr")
-INSTANCE_TYPEABLE1(StablePtr,stableptrTc,"Foreign.StablePtr.StablePtr")
-INSTANCE_TYPEABLE1(IORef,iorefTc,"Data.IORef.IORef")
-#endif /* ! __NHC__ */
+INSTANCE_TYPEABLE1(Ptr,ptrTc,"Ptr")
+INSTANCE_TYPEABLE1(FunPtr,funPtrTc,"FunPtr")
+INSTANCE_TYPEABLE1(ForeignPtr,foreignPtrTc,"ForeignPtr")
+INSTANCE_TYPEABLE1(StablePtr,stablePtrTc,"StablePtr")
+INSTANCE_TYPEABLE1(IORef,iORefTc,"IORef")
-------------------------------------------------------
--
--
-------------------------------------------------------
-#ifndef __NHC__
INSTANCE_TYPEABLE0(Bool,boolTc,"Bool")
INSTANCE_TYPEABLE0(Char,charTc,"Char")
INSTANCE_TYPEABLE0(Float,floatTc,"Float")
INSTANCE_TYPEABLE0(Double,doubleTc,"Double")
INSTANCE_TYPEABLE0(Int,intTc,"Int")
+#ifndef __NHC__
+INSTANCE_TYPEABLE0(Word,wordTc,"Word" )
+#endif
INSTANCE_TYPEABLE0(Integer,integerTc,"Integer")
INSTANCE_TYPEABLE0(Ordering,orderingTc,"Ordering")
INSTANCE_TYPEABLE0(Handle,handleTc,"Handle")
INSTANCE_TYPEABLE0(TyCon,tyconTc,"TyCon")
INSTANCE_TYPEABLE0(TypeRep,typeRepTc,"TypeRep")
-#endif /* !__NHC__ */
#ifdef __GLASGOW_HASKELL__
-INSTANCE_TYPEABLE0(Word,wordTc,"Word" )
+INSTANCE_TYPEABLE0(RealWorld,realWorldTc,"RealWorld")
#endif
---------------------------------------------
hashKP :: KeyPr -> Int32
hashKP (KeyPr (Key k1) (Key k2)) = (HT.hashInt k1 + HT.hashInt k2) `rem` HT.prime
-data Cache = Cache { next_key :: !(IORef Key),
+data Cache = Cache { next_key :: !(IORef Key), -- Not used by GHC (calls genSym instead)
tc_tbl :: !(HT.HashTable String Key),
ap_tbl :: !(HT.HashTable KeyPr Key) }
projects / ghc-base.git / blobdiff