non-GHC: add Typeable instance for ForeignPtr
[ghc.git] / libraries / base / Data / Typeable.hs
1 {-# OPTIONS_GHC -XNoImplicitPrelude -XOverlappingInstances -funbox-strict-fields #-}
2
3 -- The -XOverlappingInstances flag allows the user to over-ride
4 -- the instances for Typeable given here. In particular, we provide an instance
5 -- instance ... => Typeable (s a)
6 -- But a user might want to say
7 -- instance ... => Typeable (MyType a b)
8
9 -----------------------------------------------------------------------------
10 -- |
11 -- Module : Data.Typeable
12 -- Copyright : (c) The University of Glasgow, CWI 2001--2004
13 -- License : BSD-style (see the file libraries/base/LICENSE)
14 --
15 -- Maintainer : libraries@haskell.org
16 -- Stability : experimental
17 -- Portability : portable
18 --
19 -- The 'Typeable' class reifies types to some extent by associating type
20 -- representations to types. These type representations can be compared,
21 -- and one can in turn define a type-safe cast operation. To this end,
22 -- an unsafe cast is guarded by a test for type (representation)
23 -- equivalence. The module "Data.Dynamic" uses Typeable for an
24 -- implementation of dynamics. The module "Data.Generics" uses Typeable
25 -- and type-safe cast (but not dynamics) to support the \"Scrap your
26 -- boilerplate\" style of generic programming.
27 --
28 -----------------------------------------------------------------------------
29
30 module Data.Typeable
31 (
32
33 -- * The Typeable class
34 Typeable( typeOf ), -- :: a -> TypeRep
35
36 -- * Type-safe cast
37 cast, -- :: (Typeable a, Typeable b) => a -> Maybe b
38 gcast, -- a generalisation of cast
39
40 -- * Type representations
41 TypeRep, -- abstract, instance of: Eq, Show, Typeable
42 TyCon, -- abstract, instance of: Eq, Show, Typeable
43 showsTypeRep,
44
45 -- * Construction of type representations
46 mkTyCon, -- :: String -> TyCon
47 mkTyConApp, -- :: TyCon -> [TypeRep] -> TypeRep
48 mkAppTy, -- :: TypeRep -> TypeRep -> TypeRep
49 mkFunTy, -- :: TypeRep -> TypeRep -> TypeRep
50
51 -- * Observation of type representations
52 splitTyConApp, -- :: TypeRep -> (TyCon, [TypeRep])
53 funResultTy, -- :: TypeRep -> TypeRep -> Maybe TypeRep
54 typeRepTyCon, -- :: TypeRep -> TyCon
55 typeRepArgs, -- :: TypeRep -> [TypeRep]
56 tyConString, -- :: TyCon -> String
57 typeRepKey, -- :: TypeRep -> IO Int
58
59 -- * The other Typeable classes
60 -- | /Note:/ The general instances are provided for GHC only.
61 Typeable1( typeOf1 ), -- :: t a -> TypeRep
62 Typeable2( typeOf2 ), -- :: t a b -> TypeRep
63 Typeable3( typeOf3 ), -- :: t a b c -> TypeRep
64 Typeable4( typeOf4 ), -- :: t a b c d -> TypeRep
65 Typeable5( typeOf5 ), -- :: t a b c d e -> TypeRep
66 Typeable6( typeOf6 ), -- :: t a b c d e f -> TypeRep
67 Typeable7( typeOf7 ), -- :: t a b c d e f g -> TypeRep
68 gcast1, -- :: ... => c (t a) -> Maybe (c (t' a))
69 gcast2, -- :: ... => c (t a b) -> Maybe (c (t' a b))
70
71 -- * Default instances
72 -- | /Note:/ These are not needed by GHC, for which these instances
73 -- are generated by general instance declarations.
74 typeOfDefault, -- :: (Typeable1 t, Typeable a) => t a -> TypeRep
75 typeOf1Default, -- :: (Typeable2 t, Typeable a) => t a b -> TypeRep
76 typeOf2Default, -- :: (Typeable3 t, Typeable a) => t a b c -> TypeRep
77 typeOf3Default, -- :: (Typeable4 t, Typeable a) => t a b c d -> TypeRep
78 typeOf4Default, -- :: (Typeable5 t, Typeable a) => t a b c d e -> TypeRep
79 typeOf5Default, -- :: (Typeable6 t, Typeable a) => t a b c d e f -> TypeRep
80 typeOf6Default -- :: (Typeable7 t, Typeable a) => t a b c d e f g -> TypeRep
81
82 ) where
83
84 import qualified Data.HashTable as HT
85 import Data.Maybe
86 import Data.Int
87 import Data.Word
88 import Data.List( foldl, intersperse )
89 import Unsafe.Coerce
90
91 #ifdef __GLASGOW_HASKELL__
92 import GHC.Base
93 import GHC.Show (Show(..), ShowS,
94 shows, showString, showChar, showParen)
95 import GHC.Err (undefined)
96 import GHC.Num (Integer, fromInteger, (+))
97 import GHC.Real ( rem, Ratio )
98 import GHC.IOBase (IORef,newIORef,unsafePerformIO)
99
100 -- These imports are so we can define Typeable instances
101 -- It'd be better to give Typeable instances in the modules themselves
102 -- but they all have to be compiled before Typeable
103 import GHC.IOBase ( IOArray, IO, MVar, Handle, block )
104 import GHC.ST ( ST )
105 import GHC.STRef ( STRef )
106 import GHC.Ptr ( Ptr, FunPtr )
107 import GHC.Stable ( StablePtr, newStablePtr, freeStablePtr,
108 deRefStablePtr, castStablePtrToPtr,
109 castPtrToStablePtr )
110 import GHC.Arr ( Array, STArray )
111
112 #endif
113
114 #ifdef __HUGS__
115 import Hugs.Prelude ( Key(..), TypeRep(..), TyCon(..), Ratio,
116 Handle, Ptr, FunPtr, ForeignPtr, StablePtr )
117 import Hugs.IORef ( IORef, newIORef, readIORef, writeIORef )
118 import Hugs.IOExts ( unsafePerformIO )
119 -- For the Typeable instance
120 import Hugs.Array ( Array )
121 import Hugs.IOArray
122 import Hugs.ConcBase ( MVar )
123 #endif
124
125 #ifdef __NHC__
126 import NHC.IOExtras (IOArray,IORef,newIORef,readIORef,writeIORef,unsafePerformIO)
127 import IO (Handle)
128 import Ratio (Ratio)
129 -- For the Typeable instance
130 import NHC.FFI ( Ptr,FunPtr,StablePtr,ForeignPtr )
131 import Array ( Array )
132 #endif
133
134 #include "Typeable.h"
135
136 #ifndef __HUGS__
137
138 -------------------------------------------------------------
139 --
140 -- Type representations
141 --
142 -------------------------------------------------------------
143
144 -- | A concrete representation of a (monomorphic) type. 'TypeRep'
145 -- supports reasonably efficient equality.
146 data TypeRep = TypeRep !Key TyCon [TypeRep]
147
148 -- Compare keys for equality
149 instance Eq TypeRep where
150 (TypeRep k1 _ _) == (TypeRep k2 _ _) = k1 == k2
151
152 -- | An abstract representation of a type constructor. 'TyCon' objects can
153 -- be built using 'mkTyCon'.
154 data TyCon = TyCon !Key String
155
156 instance Eq TyCon where
157 (TyCon t1 _) == (TyCon t2 _) = t1 == t2
158 #endif
159
160 -- | Returns a unique integer associated with a 'TypeRep'. This can
161 -- be used for making a mapping with TypeReps
162 -- as the keys, for example. It is guaranteed that @t1 == t2@ if and only if
163 -- @typeRepKey t1 == typeRepKey t2@.
164 --
165 -- It is in the 'IO' monad because the actual value of the key may
166 -- vary from run to run of the program. You should only rely on
167 -- the equality property, not any actual key value. The relative ordering
168 -- of keys has no meaning either.
169 --
170 typeRepKey :: TypeRep -> IO Int
171 typeRepKey (TypeRep (Key i) _ _) = return i
172
173 --
174 -- let fTy = mkTyCon "Foo" in show (mkTyConApp (mkTyCon ",,")
175 -- [fTy,fTy,fTy])
176 --
177 -- returns "(Foo,Foo,Foo)"
178 --
179 -- The TypeRep Show instance promises to print tuple types
180 -- correctly. Tuple type constructors are specified by a
181 -- sequence of commas, e.g., (mkTyCon ",,,,") returns
182 -- the 5-tuple tycon.
183
184 ----------------- Construction --------------------
185
186 -- | Applies a type constructor to a sequence of types
187 mkTyConApp :: TyCon -> [TypeRep] -> TypeRep
188 mkTyConApp tc@(TyCon tc_k _) args
189 = TypeRep (appKeys tc_k arg_ks) tc args
190 where
191 arg_ks = [k | TypeRep k _ _ <- args]
192
193 -- | A special case of 'mkTyConApp', which applies the function
194 -- type constructor to a pair of types.
195 mkFunTy :: TypeRep -> TypeRep -> TypeRep
196 mkFunTy f a = mkTyConApp funTc [f,a]
197
198 -- | Splits a type constructor application
199 splitTyConApp :: TypeRep -> (TyCon,[TypeRep])
200 splitTyConApp (TypeRep _ tc trs) = (tc,trs)
201
202 -- | Applies a type to a function type. Returns: @'Just' u@ if the
203 -- first argument represents a function of type @t -> u@ and the
204 -- second argument represents a function of type @t@. Otherwise,
205 -- returns 'Nothing'.
206 funResultTy :: TypeRep -> TypeRep -> Maybe TypeRep
207 funResultTy trFun trArg
208 = case splitTyConApp trFun of
209 (tc, [t1,t2]) | tc == funTc && t1 == trArg -> Just t2
210 _ -> Nothing
211
212 -- | Adds a TypeRep argument to a TypeRep.
213 mkAppTy :: TypeRep -> TypeRep -> TypeRep
214 mkAppTy (TypeRep tr_k tc trs) arg_tr
215 = let (TypeRep arg_k _ _) = arg_tr
216 in TypeRep (appKey tr_k arg_k) tc (trs++[arg_tr])
217
218 -- If we enforce the restriction that there is only one
219 -- @TyCon@ for a type & it is shared among all its uses,
220 -- we can map them onto Ints very simply. The benefit is,
221 -- of course, that @TyCon@s can then be compared efficiently.
222
223 -- Provided the implementor of other @Typeable@ instances
224 -- takes care of making all the @TyCon@s CAFs (toplevel constants),
225 -- this will work.
226
227 -- If this constraint does turn out to be a sore thumb, changing
228 -- the Eq instance for TyCons is trivial.
229
230 -- | Builds a 'TyCon' object representing a type constructor. An
231 -- implementation of "Data.Typeable" should ensure that the following holds:
232 --
233 -- > mkTyCon "a" == mkTyCon "a"
234 --
235
236 mkTyCon :: String -- ^ the name of the type constructor (should be unique
237 -- in the program, so it might be wise to use the
238 -- fully qualified name).
239 -> TyCon -- ^ A unique 'TyCon' object
240 mkTyCon str = TyCon (mkTyConKey str) str
241
242 ----------------- Observation ---------------------
243
244 -- | Observe the type constructor of a type representation
245 typeRepTyCon :: TypeRep -> TyCon
246 typeRepTyCon (TypeRep _ tc _) = tc
247
248 -- | Observe the argument types of a type representation
249 typeRepArgs :: TypeRep -> [TypeRep]
250 typeRepArgs (TypeRep _ _ args) = args
251
252 -- | Observe string encoding of a type representation
253 tyConString :: TyCon -> String
254 tyConString (TyCon _ str) = str
255
256 ----------------- Showing TypeReps --------------------
257
258 instance Show TypeRep where
259 showsPrec p (TypeRep _ tycon tys) =
260 case tys of
261 [] -> showsPrec p tycon
262 [x] | tycon == listTc -> showChar '[' . shows x . showChar ']'
263 [a,r] | tycon == funTc -> showParen (p > 8) $
264 showsPrec 9 a .
265 showString " -> " .
266 showsPrec 8 r
267 xs | isTupleTyCon tycon -> showTuple xs
268 | otherwise ->
269 showParen (p > 9) $
270 showsPrec p tycon .
271 showChar ' ' .
272 showArgs tys
273
274 showsTypeRep :: TypeRep -> ShowS
275 showsTypeRep = shows
276
277 instance Show TyCon where
278 showsPrec _ (TyCon _ s) = showString s
279
280 isTupleTyCon :: TyCon -> Bool
281 isTupleTyCon (TyCon _ ('(':',':_)) = True
282 isTupleTyCon _ = False
283
284 -- Some (Show.TypeRep) helpers:
285
286 showArgs :: Show a => [a] -> ShowS
287 showArgs [] = id
288 showArgs [a] = showsPrec 10 a
289 showArgs (a:as) = showsPrec 10 a . showString " " . showArgs as
290
291 showTuple :: [TypeRep] -> ShowS
292 showTuple args = showChar '('
293 . (foldr (.) id $ intersperse (showChar ',')
294 $ map (showsPrec 10) args)
295 . showChar ')'
296
297 -------------------------------------------------------------
298 --
299 -- The Typeable class and friends
300 --
301 -------------------------------------------------------------
302
303 -- | The class 'Typeable' allows a concrete representation of a type to
304 -- be calculated.
305 class Typeable a where
306 typeOf :: a -> TypeRep
307 -- ^ Takes a value of type @a@ and returns a concrete representation
308 -- of that type. The /value/ of the argument should be ignored by
309 -- any instance of 'Typeable', so that it is safe to pass 'undefined' as
310 -- the argument.
311
312 -- | Variant for unary type constructors
313 class Typeable1 t where
314 typeOf1 :: t a -> TypeRep
315
316 -- | For defining a 'Typeable' instance from any 'Typeable1' instance.
317 typeOfDefault :: (Typeable1 t, Typeable a) => t a -> TypeRep
318 typeOfDefault x = typeOf1 x `mkAppTy` typeOf (argType x)
319 where
320 argType :: t a -> a
321 argType = undefined
322
323 -- | Variant for binary type constructors
324 class Typeable2 t where
325 typeOf2 :: t a b -> TypeRep
326
327 -- | For defining a 'Typeable1' instance from any 'Typeable2' instance.
328 typeOf1Default :: (Typeable2 t, Typeable a) => t a b -> TypeRep
329 typeOf1Default x = typeOf2 x `mkAppTy` typeOf (argType x)
330 where
331 argType :: t a b -> a
332 argType = undefined
333
334 -- | Variant for 3-ary type constructors
335 class Typeable3 t where
336 typeOf3 :: t a b c -> TypeRep
337
338 -- | For defining a 'Typeable2' instance from any 'Typeable3' instance.
339 typeOf2Default :: (Typeable3 t, Typeable a) => t a b c -> TypeRep
340 typeOf2Default x = typeOf3 x `mkAppTy` typeOf (argType x)
341 where
342 argType :: t a b c -> a
343 argType = undefined
344
345 -- | Variant for 4-ary type constructors
346 class Typeable4 t where
347 typeOf4 :: t a b c d -> TypeRep
348
349 -- | For defining a 'Typeable3' instance from any 'Typeable4' instance.
350 typeOf3Default :: (Typeable4 t, Typeable a) => t a b c d -> TypeRep
351 typeOf3Default x = typeOf4 x `mkAppTy` typeOf (argType x)
352 where
353 argType :: t a b c d -> a
354 argType = undefined
355
356 -- | Variant for 5-ary type constructors
357 class Typeable5 t where
358 typeOf5 :: t a b c d e -> TypeRep
359
360 -- | For defining a 'Typeable4' instance from any 'Typeable5' instance.
361 typeOf4Default :: (Typeable5 t, Typeable a) => t a b c d e -> TypeRep
362 typeOf4Default x = typeOf5 x `mkAppTy` typeOf (argType x)
363 where
364 argType :: t a b c d e -> a
365 argType = undefined
366
367 -- | Variant for 6-ary type constructors
368 class Typeable6 t where
369 typeOf6 :: t a b c d e f -> TypeRep
370
371 -- | For defining a 'Typeable5' instance from any 'Typeable6' instance.
372 typeOf5Default :: (Typeable6 t, Typeable a) => t a b c d e f -> TypeRep
373 typeOf5Default x = typeOf6 x `mkAppTy` typeOf (argType x)
374 where
375 argType :: t a b c d e f -> a
376 argType = undefined
377
378 -- | Variant for 7-ary type constructors
379 class Typeable7 t where
380 typeOf7 :: t a b c d e f g -> TypeRep
381
382 -- | For defining a 'Typeable6' instance from any 'Typeable7' instance.
383 typeOf6Default :: (Typeable7 t, Typeable a) => t a b c d e f g -> TypeRep
384 typeOf6Default x = typeOf7 x `mkAppTy` typeOf (argType x)
385 where
386 argType :: t a b c d e f g -> a
387 argType = undefined
388
389 #ifdef __GLASGOW_HASKELL__
390 -- Given a @Typeable@/n/ instance for an /n/-ary type constructor,
391 -- define the instances for partial applications.
392 -- Programmers using non-GHC implementations must do this manually
393 -- for each type constructor.
394 -- (The INSTANCE_TYPEABLE/n/ macros in Typeable.h include this.)
395
396 -- | One Typeable instance for all Typeable1 instances
397 instance (Typeable1 s, Typeable a)
398 => Typeable (s a) where
399 typeOf = typeOfDefault
400
401 -- | One Typeable1 instance for all Typeable2 instances
402 instance (Typeable2 s, Typeable a)
403 => Typeable1 (s a) where
404 typeOf1 = typeOf1Default
405
406 -- | One Typeable2 instance for all Typeable3 instances
407 instance (Typeable3 s, Typeable a)
408 => Typeable2 (s a) where
409 typeOf2 = typeOf2Default
410
411 -- | One Typeable3 instance for all Typeable4 instances
412 instance (Typeable4 s, Typeable a)
413 => Typeable3 (s a) where
414 typeOf3 = typeOf3Default
415
416 -- | One Typeable4 instance for all Typeable5 instances
417 instance (Typeable5 s, Typeable a)
418 => Typeable4 (s a) where
419 typeOf4 = typeOf4Default
420
421 -- | One Typeable5 instance for all Typeable6 instances
422 instance (Typeable6 s, Typeable a)
423 => Typeable5 (s a) where
424 typeOf5 = typeOf5Default
425
426 -- | One Typeable6 instance for all Typeable7 instances
427 instance (Typeable7 s, Typeable a)
428 => Typeable6 (s a) where
429 typeOf6 = typeOf6Default
430
431 #endif /* __GLASGOW_HASKELL__ */
432
433 -------------------------------------------------------------
434 --
435 -- Type-safe cast
436 --
437 -------------------------------------------------------------
438
439 -- | The type-safe cast operation
440 cast :: (Typeable a, Typeable b) => a -> Maybe b
441 cast x = r
442 where
443 r = if typeOf x == typeOf (fromJust r)
444 then Just $ unsafeCoerce x
445 else Nothing
446
447 -- | A flexible variation parameterised in a type constructor
448 gcast :: (Typeable a, Typeable b) => c a -> Maybe (c b)
449 gcast x = r
450 where
451 r = if typeOf (getArg x) == typeOf (getArg (fromJust r))
452 then Just $ unsafeCoerce x
453 else Nothing
454 getArg :: c x -> x
455 getArg = undefined
456
457 -- | Cast for * -> *
458 gcast1 :: (Typeable1 t, Typeable1 t') => c (t a) -> Maybe (c (t' a))
459 gcast1 x = r
460 where
461 r = if typeOf1 (getArg x) == typeOf1 (getArg (fromJust r))
462 then Just $ unsafeCoerce x
463 else Nothing
464 getArg :: c x -> x
465 getArg = undefined
466
467 -- | Cast for * -> * -> *
468 gcast2 :: (Typeable2 t, Typeable2 t') => c (t a b) -> Maybe (c (t' a b))
469 gcast2 x = r
470 where
471 r = if typeOf2 (getArg x) == typeOf2 (getArg (fromJust r))
472 then Just $ unsafeCoerce x
473 else Nothing
474 getArg :: c x -> x
475 getArg = undefined
476
477 -------------------------------------------------------------
478 --
479 -- Instances of the Typeable classes for Prelude types
480 --
481 -------------------------------------------------------------
482
483 INSTANCE_TYPEABLE0((),unitTc,"()")
484 INSTANCE_TYPEABLE1([],listTc,"[]")
485 INSTANCE_TYPEABLE1(Maybe,maybeTc,"Maybe")
486 INSTANCE_TYPEABLE1(Ratio,ratioTc,"Ratio")
487 INSTANCE_TYPEABLE2((->),funTc,"->")
488 INSTANCE_TYPEABLE1(IO,ioTc,"IO")
489
490 #if defined(__GLASGOW_HASKELL__) || defined(__HUGS__)
491 -- Types defined in GHC.IOBase
492 INSTANCE_TYPEABLE1(MVar,mvarTc,"MVar" )
493 #endif
494
495 INSTANCE_TYPEABLE2(Array,arrayTc,"Array")
496 INSTANCE_TYPEABLE2(IOArray,iOArrayTc,"IOArray")
497
498 #ifdef __GLASGOW_HASKELL__
499 -- Hugs has these too, but their Typeable<n> instances are defined
500 -- elsewhere to keep this module within Haskell 98.
501 -- This is important because every invocation of runhugs or ffihugs
502 -- uses this module via Data.Dynamic.
503 INSTANCE_TYPEABLE2(ST,stTc,"ST")
504 INSTANCE_TYPEABLE2(STRef,stRefTc,"STRef")
505 INSTANCE_TYPEABLE3(STArray,sTArrayTc,"STArray")
506 #endif
507
508 #ifndef __NHC__
509 INSTANCE_TYPEABLE2((,),pairTc,"(,)")
510 INSTANCE_TYPEABLE3((,,),tup3Tc,"(,,)")
511
512 tup4Tc :: TyCon
513 tup4Tc = mkTyCon "(,,,)"
514
515 instance Typeable4 (,,,) where
516 typeOf4 _ = mkTyConApp tup4Tc []
517
518 tup5Tc :: TyCon
519 tup5Tc = mkTyCon "(,,,,)"
520
521 instance Typeable5 (,,,,) where
522 typeOf5 _ = mkTyConApp tup5Tc []
523
524 tup6Tc :: TyCon
525 tup6Tc = mkTyCon "(,,,,,)"
526
527 instance Typeable6 (,,,,,) where
528 typeOf6 _ = mkTyConApp tup6Tc []
529
530 tup7Tc :: TyCon
531 tup7Tc = mkTyCon "(,,,,,,)"
532
533 instance Typeable7 (,,,,,,) where
534 typeOf7 _ = mkTyConApp tup7Tc []
535 #endif /* __NHC__ */
536
537 INSTANCE_TYPEABLE1(Ptr,ptrTc,"Ptr")
538 INSTANCE_TYPEABLE1(FunPtr,funPtrTc,"FunPtr")
539 #ifndef __GLASGOW_HASKELL__
540 INSTANCE_TYPEABLE1(ForeignPtr,foreignPtrTc,"ForeignPtr")
541 #endif
542 INSTANCE_TYPEABLE1(StablePtr,stablePtrTc,"StablePtr")
543 INSTANCE_TYPEABLE1(IORef,iORefTc,"IORef")
544
545 -------------------------------------------------------
546 --
547 -- Generate Typeable instances for standard datatypes
548 --
549 -------------------------------------------------------
550
551 INSTANCE_TYPEABLE0(Bool,boolTc,"Bool")
552 INSTANCE_TYPEABLE0(Char,charTc,"Char")
553 INSTANCE_TYPEABLE0(Float,floatTc,"Float")
554 INSTANCE_TYPEABLE0(Double,doubleTc,"Double")
555 INSTANCE_TYPEABLE0(Int,intTc,"Int")
556 #ifndef __NHC__
557 INSTANCE_TYPEABLE0(Word,wordTc,"Word" )
558 #endif
559 INSTANCE_TYPEABLE0(Integer,integerTc,"Integer")
560 INSTANCE_TYPEABLE0(Ordering,orderingTc,"Ordering")
561 INSTANCE_TYPEABLE0(Handle,handleTc,"Handle")
562
563 INSTANCE_TYPEABLE0(Int8,int8Tc,"Int8")
564 INSTANCE_TYPEABLE0(Int16,int16Tc,"Int16")
565 INSTANCE_TYPEABLE0(Int32,int32Tc,"Int32")
566 INSTANCE_TYPEABLE0(Int64,int64Tc,"Int64")
567
568 INSTANCE_TYPEABLE0(Word8,word8Tc,"Word8" )
569 INSTANCE_TYPEABLE0(Word16,word16Tc,"Word16")
570 INSTANCE_TYPEABLE0(Word32,word32Tc,"Word32")
571 INSTANCE_TYPEABLE0(Word64,word64Tc,"Word64")
572
573 INSTANCE_TYPEABLE0(TyCon,tyconTc,"TyCon")
574 INSTANCE_TYPEABLE0(TypeRep,typeRepTc,"TypeRep")
575
576 #ifdef __GLASGOW_HASKELL__
577 INSTANCE_TYPEABLE0(RealWorld,realWorldTc,"RealWorld")
578 #endif
579
580 ---------------------------------------------
581 --
582 -- Internals
583 --
584 ---------------------------------------------
585
586 #ifndef __HUGS__
587 newtype Key = Key Int deriving( Eq )
588 #endif
589
590 data KeyPr = KeyPr !Key !Key deriving( Eq )
591
592 hashKP :: KeyPr -> Int32
593 hashKP (KeyPr (Key k1) (Key k2)) = (HT.hashInt k1 + HT.hashInt k2) `rem` HT.prime
594
595 data Cache = Cache { next_key :: !(IORef Key), -- Not used by GHC (calls genSym instead)
596 tc_tbl :: !(HT.HashTable String Key),
597 ap_tbl :: !(HT.HashTable KeyPr Key) }
598
599 {-# NOINLINE cache #-}
600 #ifdef __GLASGOW_HASKELL__
601 foreign import ccall unsafe "RtsTypeable.h getOrSetTypeableStore"
602 getOrSetTypeableStore :: Ptr a -> IO (Ptr a)
603 #endif
604
605 cache :: Cache
606 cache = unsafePerformIO $ do
607 empty_tc_tbl <- HT.new (==) HT.hashString
608 empty_ap_tbl <- HT.new (==) hashKP
609 key_loc <- newIORef (Key 1)
610 let ret = Cache { next_key = key_loc,
611 tc_tbl = empty_tc_tbl,
612 ap_tbl = empty_ap_tbl }
613 #ifdef __GLASGOW_HASKELL__
614 block $ do
615 stable_ref <- newStablePtr ret
616 let ref = castStablePtrToPtr stable_ref
617 ref2 <- getOrSetTypeableStore ref
618 if ref==ref2
619 then deRefStablePtr stable_ref
620 else do
621 freeStablePtr stable_ref
622 deRefStablePtr
623 (castPtrToStablePtr ref2)
624 #else
625 return ret
626 #endif
627
628 newKey :: IORef Key -> IO Key
629 #ifdef __GLASGOW_HASKELL__
630 newKey _ = do i <- genSym; return (Key i)
631 #else
632 newKey kloc = do { k@(Key i) <- readIORef kloc ;
633 writeIORef kloc (Key (i+1)) ;
634 return k }
635 #endif
636
637 #ifdef __GLASGOW_HASKELL__
638 foreign import ccall unsafe "genSymZh"
639 genSym :: IO Int
640 #endif
641
642 mkTyConKey :: String -> Key
643 mkTyConKey str
644 = unsafePerformIO $ do
645 let Cache {next_key = kloc, tc_tbl = tbl} = cache
646 mb_k <- HT.lookup tbl str
647 case mb_k of
648 Just k -> return k
649 Nothing -> do { k <- newKey kloc ;
650 HT.insert tbl str k ;
651 return k }
652
653 appKey :: Key -> Key -> Key
654 appKey k1 k2
655 = unsafePerformIO $ do
656 let Cache {next_key = kloc, ap_tbl = tbl} = cache
657 mb_k <- HT.lookup tbl kpr
658 case mb_k of
659 Just k -> return k
660 Nothing -> do { k <- newKey kloc ;
661 HT.insert tbl kpr k ;
662 return k }
663 where
664 kpr = KeyPr k1 k2
665
666 appKeys :: Key -> [Key] -> Key
667 appKeys k ks = foldl appKey k ks