-{-# OPTIONS_GHC -fno-implicit-prelude #-}
+{-# OPTIONS_GHC -fno-implicit-prelude -fallow-overlapping-instances #-}
+
+-- The -fallow-overlapping-instances flag allows the user to over-ride
+-- the instances for Typeable given here. In particular, we provide an instance
+-- instance ... => Typeable (s a)
+-- But a user might want to say
+-- instance ... => Typeable (MyType a b)
+
-----------------------------------------------------------------------------
-- |
-- Module : Data.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
typeRepTyCon, -- :: TypeRep -> TyCon
typeRepArgs, -- :: TypeRep -> [TypeRep]
tyConString, -- :: TyCon -> String
+ typeRepKey, -- :: TypeRep -> IO Int
-- * The other Typeable classes
-- | /Note:/ The general instances are provided for GHC only.
import GHC.Err
import GHC.Num
import GHC.Float
-import GHC.Real( rem, Ratio )
-import GHC.IOBase
-import GHC.ST -- So we can give Typeable instance for ST
-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, newStablePtr, freeStablePtr,
+ deRefStablePtr, castStablePtrToPtr,
+ castPtrToStablePtr )
+import GHC.Exception ( block )
+import GHC.Arr ( Array, STArray )
+
#endif
#ifdef __HUGS__
-import Hugs.Prelude
-import Hugs.IO
-import Hugs.IORef
-import Hugs.IOExts
+import Hugs.Prelude ( Key(..), TypeRep(..), TyCon(..), Ratio,
+ Exception, ArithException, IOException,
+ ArrayException, AsyncException, Handle,
+ Ptr, FunPtr, ForeignPtr, StablePtr )
+import Hugs.IORef ( IORef, newIORef, readIORef, writeIORef )
+import Hugs.IOExts ( unsafePerformIO, unsafeCoerce )
+ -- For the Typeable instance
+import Hugs.Array ( Array )
+import Hugs.ConcBase ( MVar )
#endif
#ifdef __GLASGOW_HASKELL__
import NHC.IOExtras (IORef,newIORef,readIORef,writeIORef,unsafePerformIO)
import IO (Handle)
import Ratio (Ratio)
-import NHC.FFI (Ptr,StablePtr)
-#else
+ -- For the Typeable instance
+import NHC.FFI ( Ptr,FunPtr,StablePtr,ForeignPtr )
+import Array ( Array )
#endif
#include "Typeable.h"
instance Eq TyCon where
(TyCon t1 _) == (TyCon t2 _) = t1 == t2
-
#endif
+-- | Returns a unique integer associated with a 'TypeRep'. This can
+-- be used for making a mapping ('Data.IntMap.IntMap') with TypeReps
+-- as the keys, for example. It is guaranteed that @t1 == t2@ if and only if
+-- @typeRepKey t1 == typeRepKey t2@.
+--
+-- It is in the 'IO' monad because the actual value of the key may
+-- vary from run to run of the program. You should only rely on
+-- the equality property, not any actual key value. The relative ordering
+-- of keys has no meaning either.
+--
+typeRepKey :: TypeRep -> IO Int
+typeRepKey (TypeRep (Key i) _ _) = return i
+
--
-- let fTy = mkTyCon "Foo" in show (mkTyConApp (mkTyCon ",,")
-- [fTy,fTy,fTy])
--
-------------------------------------------------------------
+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_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
-INSTANCE_TYPEABLE0((),unitTc,"()")
+
#ifndef __NHC__
INSTANCE_TYPEABLE2((,),pairTc,",")
INSTANCE_TYPEABLE3((,,),tup3Tc,",,")
instance Typeable7 (,,,,,,) where
typeOf7 tu = mkTyConApp tup7Tc []
-
#endif /* __NHC__ */
+
INSTANCE_TYPEABLE1(Ptr,ptrTc,"Ptr")
-INSTANCE_TYPEABLE1(StablePtr,stableptrTc,"StablePtr")
-INSTANCE_TYPEABLE1(IORef,iorefTc,"IORef")
+INSTANCE_TYPEABLE1(FunPtr,funPtrTc,"FunPtr")
+INSTANCE_TYPEABLE1(ForeignPtr,foreignPtrTc,"ForeignPtr")
+INSTANCE_TYPEABLE1(StablePtr,stablePtrTc,"StablePtr")
+INSTANCE_TYPEABLE1(IORef,iORefTc,"IORef")
-------------------------------------------------------
--
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")
#ifdef __GLASGOW_HASKELL__
INSTANCE_TYPEABLE0(RealWorld,realWorldTc,"RealWorld")
-INSTANCE_TYPEABLE0(Word,wordTc,"Word" )
-INSTANCE_TYPEABLE1(MVar,mvarTc,"MVar" )
#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) }
{-# NOINLINE cache #-}
+#ifdef __GLASGOW_HASKELL__
+foreign import ccall unsafe "RtsTypeable.h getOrSetTypeableStore"
+ getOrSetTypeableStore :: Ptr a -> IO (Ptr a)
+#endif
+
cache :: Cache
cache = unsafePerformIO $ do
empty_tc_tbl <- HT.new (==) HT.hashString
empty_ap_tbl <- HT.new (==) hashKP
key_loc <- newIORef (Key 1)
- return (Cache { next_key = key_loc,
- tc_tbl = empty_tc_tbl,
- ap_tbl = empty_ap_tbl })
+ let ret = Cache { next_key = key_loc,
+ tc_tbl = empty_tc_tbl,
+ ap_tbl = empty_ap_tbl }
+#ifdef __GLASGOW_HASKELL__
+ block $ do
+ stable_ref <- newStablePtr ret
+ let ref = castStablePtrToPtr stable_ref
+ ref2 <- getOrSetTypeableStore ref
+ if ref==ref2
+ then deRefStablePtr stable_ref
+ else do
+ freeStablePtr stable_ref
+ deRefStablePtr
+ (castPtrToStablePtr ref2)
+#else
+ return ret
+#endif
newKey :: IORef Key -> IO Key
#ifdef __GLASGOW_HASKELL__
#endif
#ifdef __GLASGOW_HASKELL__
--- In GHC we use the RTS's genSym function to get a new unique,
--- because in GHCi we might have two copies of the Data.Typeable
--- library running (one in the compiler and one in the running
--- program), and we need to make sure they don't share any keys.
---
--- This is really a hack. A better solution would be to centralise the
--- whole mutable state used by this module, i.e. both hashtables. But
--- the current solution solves the immediate problem, which is that
--- dynamics generated in one world with one type were erroneously
--- being recognised by the other world as having a different type.
foreign import ccall unsafe "genSymZh"
genSym :: IO Int
#endif
projects / haskell-directory.git / blobdiff