X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FTypeable.hs;h=69ed9a010f826ce7dc3b04aab39b23e7538fa98c;hb=7aaade59f10b1c79686c7a36a7bb8af883d01644;hp=7e4a5185bd66e22d4cf8af2c4634365631b0663c;hpb=ed5427e38b5dc7543ae0fbb1252f9a65061dee7f;p=ghc-base.git diff --git a/Data/Typeable.hs b/Data/Typeable.hs index 7e4a518..69ed9a0 100644 --- a/Data/Typeable.hs +++ b/Data/Typeable.hs @@ -18,6 +18,15 @@ -- 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 @@ -36,17 +45,19 @@ 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 @@ -55,11 +66,21 @@ module Data.Typeable Typeable6( typeOf6 ), -- :: t a b c d e f -> TypeRep Typeable7( typeOf7 ), -- :: t a b c d e f g -> TypeRep gcast1, -- :: ... => c (t a) -> Maybe (c (t' a)) - gcast2 -- :: ... => c (t a b) -> Maybe (c (t' a b)) + 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, -- :: (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 @@ -94,10 +115,13 @@ unsafeCoerce = unsafeCoerce# #ifdef __NHC__ import NonStdUnsafeCoerce (unsafeCoerce) import NHC.IOExtras (IORef,newIORef,readIORef,writeIORef,unsafePerformIO) +import IO (Handle) +import Ratio (Ratio) +import NHC.FFI (Ptr,StablePtr) #else -#include "Typeable.h" #endif +#include "Typeable.h" #ifndef __HUGS__ @@ -107,7 +131,6 @@ import NHC.IOExtras (IORef,newIORef,readIORef,writeIORef,unsafePerformIO) -- ------------------------------------------------------------- - -- | A concrete representation of a (monomorphic) type. 'TypeRep' -- supports reasonably efficient equality. data TypeRep = TypeRep !Key TyCon [TypeRep] @@ -126,7 +149,7 @@ instance Eq TyCon where #endif -- - -- let fTy = mkTyCon "Foo" in show (mkAppTy (mkTyCon ",,") + -- let fTy = mkTyCon "Foo" in show (mkTyConApp (mkTyCon ",,") -- [fTy,fTy,fTy]) -- -- returns "(Foo,Foo,Foo)" @@ -136,45 +159,40 @@ instance Eq TyCon where -- 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] - --- The function type constructor -funTc :: TyCon -funTc = mkTyCon "->" - - --- | 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, @@ -199,25 +217,19 @@ mkTyCon :: String -- ^ the name of the type constructor (should be unique -> 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 -------------------- @@ -244,7 +256,6 @@ isTupleTyCon :: TyCon -> Bool isTupleTyCon (TyCon _ (',':_)) = True isTupleTyCon _ = False - -- Some (Show.TypeRep) helpers: showArgs :: Show a => [a] -> ShowS @@ -260,14 +271,12 @@ showTuple (TyCon _ str) args = showChar '(' . go str args 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 @@ -277,137 +286,126 @@ class Typeable a where -- any instance of 'Typeable', so that it is safe to pass 'undefined' as -- the argument. --- HACK HACK HACK -#ifdef __HUGS__ -#define INSTANCE_TYPEABLE1x(tycon,tcname,str) \ -instance Typeable a => Typeable (tycon a) where { \ - typeOf x = mkAppTy tcname [typeOf ((undefined :: tycon a -> a) x) ] } -#define INSTANCE_TYPEABLE2x(tycon,tcname,str) \ -instance (Typeable a, Typeable b) => Typeable (tycon a b) where { \ - typeOf x = mkAppTy tcname [typeOf ((undefined :: tycon a b -> a) x), \ - typeOf ((undefined :: tycon a b -> b) x)] } - -INSTANCE_TYPEABLE1x(Ratio,ratioTc,"Ratio") -INSTANCE_TYPEABLE2x(Either,eitherTc,"Either") -INSTANCE_TYPEABLE1(IO,ioTc,"IO") -INSTANCE_TYPEABLE1x(Maybe,maybeTc,"Maybe") -INSTANCE_TYPEABLE1(Ptr,ptrTc,"Ptr") -INSTANCE_TYPEABLE1(StablePtr,stablePtrTc,"StablePtr") -INSTANCE_TYPEABLE1(IORef,ioRefTc,"IORef") -#endif - -- | Variant for unary type constructors class Typeable1 t where typeOf1 :: t a -> TypeRep - -#ifndef __HUGS__ --- | One Typeable instance for all Typeable1 instances -instance (Typeable1 s, Typeable a) - => Typeable (s a) where - typeOf x = typeOf1 x `popStarTy` typeOf (argType x) - where - argType :: t x -> x - argType = undefined -#endif - +-- | For defining a 'Typeable' instance from any 'Typeable1' instance. +typeOfDefault :: (Typeable1 t, Typeable a) => t a -> TypeRep +typeOfDefault x = typeOf1 x `mkAppTy` typeOf (argType x) + where + argType :: t a -> a + argType = undefined -- | Variant for binary type constructors class Typeable2 t where typeOf2 :: t a b -> TypeRep - -#ifndef __HUGS__ --- | One Typeable1 instance for all Typeable2 instances -instance (Typeable2 s, Typeable a) - => Typeable1 (s a) where - typeOf1 x = typeOf2 x `popStarTy` typeOf (argType x) - where - argType :: t x y -> x - argType = undefined -#endif - +-- | For defining a 'Typeable1' instance from any 'Typeable2' instance. +typeOf1Default :: (Typeable2 t, Typeable a) => t a b -> TypeRep +typeOf1Default x = typeOf2 x `mkAppTy` typeOf (argType x) + where + argType :: t a b -> a + argType = undefined -- | Variant for 3-ary type constructors class Typeable3 t where typeOf3 :: t a b c -> TypeRep - -#ifndef __HUGS__ --- | One Typeable2 instance for all Typeable3 instances -instance (Typeable3 s, Typeable a) - => Typeable2 (s a) where - typeOf2 x = typeOf3 x `popStarTy` typeOf (argType x) - where - argType :: t x y z -> x - argType = undefined -#endif - +-- | For defining a 'Typeable2' instance from any 'Typeable3' instance. +typeOf2Default :: (Typeable3 t, Typeable a) => t a b c -> TypeRep +typeOf2Default x = typeOf3 x `mkAppTy` typeOf (argType x) + where + argType :: t a b c -> a + argType = undefined -- | Variant for 4-ary type constructors class Typeable4 t where typeOf4 :: t a b c d -> TypeRep - -#ifndef __HUGS__ --- | One Typeable3 instance for all Typeable4 instances -instance (Typeable4 s, Typeable a) - => Typeable3 (s a) where - typeOf3 x = typeOf4 x `popStarTy` typeOf (argType x) - where - argType :: t x y z z' -> x - argType = undefined -#endif - +-- | For defining a 'Typeable3' instance from any 'Typeable4' instance. +typeOf3Default :: (Typeable4 t, Typeable a) => t a b c d -> TypeRep +typeOf3Default x = typeOf4 x `mkAppTy` typeOf (argType x) + where + argType :: t a b c d -> a + argType = undefined -- | Variant for 5-ary type constructors class Typeable5 t where typeOf5 :: t a b c d e -> TypeRep - -#ifndef __HUGS__ --- | One Typeable4 instance for all Typeable5 instances -instance (Typeable5 s, Typeable a) - => Typeable4 (s a) where - typeOf4 x = typeOf5 x `popStarTy` typeOf (argType x) - where - argType :: t x y z z' z'' -> x - argType = undefined -#endif - +-- | 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 `mkAppTy` typeOf (argType x) + where + argType :: t a b c d e -> a + argType = undefined -- | Variant for 6-ary type constructors class Typeable6 t where typeOf6 :: t a b c d e f -> TypeRep - -#ifndef __HUGS__ --- | One Typeable5 instance for all Typeable6 instances -instance (Typeable6 s, Typeable a) - => Typeable5 (s a) where - typeOf5 x = typeOf6 x `popStarTy` typeOf (argType x) - where - argType :: t x y z z' z'' z''' -> x - argType = undefined -#endif - +-- | 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 `mkAppTy` typeOf (argType x) + where + argType :: t a b c d e f -> a + argType = undefined -- | 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 `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 -#ifndef __HUGS__ -- | One Typeable6 instance for all Typeable7 instances instance (Typeable7 s, Typeable a) => Typeable6 (s a) where - typeOf6 x = typeOf7 x `popStarTy` typeOf (argType x) - where - argType :: t x y z z' z'' z''' z'''' -> x - argType = undefined -#endif - + typeOf6 = typeOf6Default +#endif /* __GLASGOW_HASKELL__ */ ------------------------------------------------------------- -- @@ -423,7 +421,6 @@ cast x = r 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 @@ -434,8 +431,6 @@ 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 @@ -446,7 +441,6 @@ 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 @@ -457,133 +451,51 @@ gcast2 x = r getArg :: c x -> x getArg = undefined - - ------------------------------------------------------------- -- -- Instances of the Typeable classes for Prelude types -- ------------------------------------------------------------- -unitTc :: TyCon -unitTc = mkTyCon "()" - -instance Typeable () where - typeOf _ = mkAppTy unitTc [] - - -tup3Tc :: TyCon -tup3Tc = mkTyCon ",," - -instance Typeable3 (,,) where - typeOf3 tu = mkAppTy tup3Tc [] - +INSTANCE_TYPEABLE1([],listTc,"[]") +INSTANCE_TYPEABLE1(Maybe,maybeTc,"Maybe") +INSTANCE_TYPEABLE1(Ratio,ratioTc,"Ratio") +INSTANCE_TYPEABLE2(Either,eitherTc,"Either") +INSTANCE_TYPEABLE2((->),funTc,"->") +INSTANCE_TYPEABLE1(IO,ioTc,"IO") +INSTANCE_TYPEABLE0((),unitTc,"()") +#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 ",,,,," instance Typeable7 (,,,,,,) where - typeOf7 tu = mkAppTy tup7Tc [] - - -listTc :: TyCon -listTc = mkTyCon "[]" - --- | Instance for lists -instance Typeable1 [] where - typeOf1 _ = mkAppTy listTc [] - - -maybeTc :: TyCon -maybeTc = mkTyCon "Maybe" - --- | Instance for maybes -instance Typeable1 Maybe where - typeOf1 _ = mkAppTy maybeTc [] - - -ratioTc :: TyCon -ratioTc = mkTyCon "Ratio" - --- | Instance for ratios -instance Typeable1 Ratio where - typeOf1 _ = mkAppTy ratioTc [] - - -pairTc :: TyCon -pairTc = mkTyCon "(,)" - --- | Instance for products -instance Typeable2 (,) where - typeOf2 _ = mkAppTy pairTc [] - - -eitherTc :: TyCon -eitherTc = mkTyCon "Either" - --- | Instance for sums -instance Typeable2 Either where - typeOf2 _ = mkAppTy eitherTc [] - - --- | Instance for functions -instance Typeable2 (->) where - typeOf2 _ = mkAppTy funTc [] - - -#ifdef __GLASGOW_HASKELL__ - -ioTc :: TyCon -ioTc = mkTyCon "GHC.IOBase.IO" - -instance Typeable1 IO where - typeOf1 _ = mkAppTy ioTc [] - - -ptrTc :: TyCon -ptrTc = mkTyCon "GHC.Ptr.Ptr" - -instance Typeable1 Ptr where - typeOf1 _ = mkAppTy ptrTc [] - - -stableptrTc :: TyCon -stableptrTc = mkTyCon "GHC.Stable.StablePtr" - -instance Typeable1 StablePtr where - typeOf1 _ = mkAppTy stableptrTc [] - - -iorefTc :: TyCon -iorefTc = mkTyCon "GHC.IOBase.IORef" - -instance Typeable1 IORef where - typeOf1 _ = mkAppTy iorefTc [] - -#endif - + typeOf7 tu = mkTyConApp tup7Tc [] +#endif /* __NHC__ */ +INSTANCE_TYPEABLE1(Ptr,ptrTc,"Ptr") +INSTANCE_TYPEABLE1(StablePtr,stableptrTc,"StablePtr") +INSTANCE_TYPEABLE1(IORef,iorefTc,"IORef") ------------------------------------------------------- -- @@ -591,7 +503,6 @@ instance Typeable1 IORef where -- ------------------------------------------------------- -#ifndef __NHC__ INSTANCE_TYPEABLE0(Bool,boolTc,"Bool") INSTANCE_TYPEABLE0(Char,charTc,"Char") INSTANCE_TYPEABLE0(Float,floatTc,"Float") @@ -613,14 +524,11 @@ INSTANCE_TYPEABLE0(Word64,word64Tc,"Word64") INSTANCE_TYPEABLE0(TyCon,tyconTc,"TyCon") INSTANCE_TYPEABLE0(TypeRep,typeRepTc,"TypeRep") -#endif #ifdef __GLASGOW_HASKELL__ INSTANCE_TYPEABLE0(Word,wordTc,"Word" ) #endif - - --------------------------------------------- -- -- Internals