2 % (c) The GRASP Project, Glasgow University, 1994-1998
4 \section[TysWiredIn]{Wired-in knowledge about {\em non-primitive} types}
6 This module is about types that can be defined in Haskell, but which
7 must be wired into the compiler nonetheless.
9 This module tracks the ``state interface'' document, ``GHC prelude:
10 types and operations.''
27 falseDataCon, falseDataConId,
52 unitTyCon, unitDataConId, pairTyCon,
53 unboxedSingletonTyCon, unboxedSingletonDataCon,
54 unboxedPairTyCon, unboxedPairDataCon,
58 trueDataCon, trueDataConId,
65 isFFIArgumentTy, -- :: Bool -> Type -> Bool
66 isFFIResultTy, -- :: Type -> Bool
67 isFFIExternalTy, -- :: Type -> Bool
68 isAddrTy, -- :: Type -> Bool
69 isForeignObjTy -- :: Type -> Bool
73 #include "HsVersions.h"
75 import {-# SOURCE #-} MkId( mkDataConId, mkDataConWrapId )
82 import Constants ( mAX_TUPLE_SIZE )
83 import Module ( Module, mkPrelModule )
84 import Name ( mkWiredInTyConName, mkWiredInIdName, mkSrcOccFS, mkWorkerOcc, dataName )
85 import DataCon ( DataCon, StrictnessMark(..), mkDataCon, dataConId )
86 import Var ( TyVar, tyVarKind )
87 import TyCon ( TyCon, AlgTyConFlavour(..), ArgVrcs, tyConDataCons,
88 mkAlgTyCon, mkSynTyCon, mkTupleTyCon, isUnLiftedTyCon
90 import BasicTypes ( Arity, NewOrData(..), RecFlag(..), Boxity(..), isBoxed )
91 import Type ( Type, mkTyConTy, mkTyConApp, mkSigmaTy, mkTyVarTys,
92 mkArrowKinds, boxedTypeKind, unboxedTypeKind,
94 splitTyConApp_maybe, repType,
95 TauType, ClassContext )
96 import PrimRep ( PrimRep(..) )
98 import CmdLineOpts ( opt_GlasgowExts )
100 import Panic ( panic )
103 alpha_tyvar = [alphaTyVar]
105 alpha_beta_tyvars = [alphaTyVar, betaTyVar]
107 pcRecDataTyCon, pcNonRecDataTyCon
108 :: Unique{-TyConKey-} -> Module -> FAST_STRING
109 -> [TyVar] -> ArgVrcs -> [DataCon] -> TyCon
111 pcRecDataTyCon = pcTyCon DataTyCon Recursive
112 pcNonRecDataTyCon = pcTyCon DataTyCon NonRecursive
114 pcTyCon new_or_data is_rec key mod str tyvars argvrcs cons
117 tycon = mkAlgTyCon name kind
127 name = mkWiredInTyConName key mod str tycon
128 kind = mkArrowKinds (map tyVarKind tyvars) boxedTypeKind
130 pcSynTyCon key mod str kind arity tyvars expansion argvrcs -- this fun never used!
133 tycon = mkSynTyCon name kind arity tyvars expansion argvrcs
134 name = mkWiredInTyConName key mod str tycon
136 pcDataCon :: Unique{-DataConKey-} -> Module -> FAST_STRING
137 -> [TyVar] -> ClassContext -> [TauType] -> TyCon -> DataCon
138 -- The unique is the first of two free uniques;
139 -- the first is used for the datacon itself and the worker;
140 -- the second is used for the wrapper.
141 pcDataCon wrap_key mod str tyvars context arg_tys tycon
144 data_con = mkDataCon wrap_name
145 [ NotMarkedStrict | a <- arg_tys ]
146 [ {- no labelled fields -} ]
147 tyvars context [] [] arg_tys tycon work_id wrap_id
149 work_occ = mkWorkerOcc wrap_occ
150 work_key = incrUnique wrap_key
151 work_name = mkWiredInIdName work_key mod work_occ work_id
152 work_id = mkDataConId work_name data_con
154 wrap_occ = mkSrcOccFS dataName str
155 wrap_name = mkWiredInIdName wrap_key mod wrap_occ wrap_id
156 wrap_id = mkDataConWrapId data_con
160 %************************************************************************
162 \subsection[TysWiredIn-tuples]{The tuple types}
164 %************************************************************************
167 tupleTyCon :: Boxity -> Arity -> TyCon
168 tupleTyCon boxity i | i > mAX_TUPLE_SIZE = fst (mk_tuple boxity i) -- Build one specially
169 tupleTyCon Boxed i = fst (boxedTupleArr ! i)
170 tupleTyCon Unboxed i = fst (unboxedTupleArr ! i)
172 tupleCon :: Boxity -> Arity -> DataCon
173 tupleCon boxity i | i > mAX_TUPLE_SIZE = snd (mk_tuple boxity i) -- Build one specially
174 tupleCon Boxed i = snd (boxedTupleArr ! i)
175 tupleCon Unboxed i = snd (unboxedTupleArr ! i)
177 boxedTupleArr, unboxedTupleArr :: Array Int (TyCon,DataCon)
178 boxedTupleArr = array (0,mAX_TUPLE_SIZE) [(i,mk_tuple Boxed i) | i <- [0..mAX_TUPLE_SIZE]]
179 unboxedTupleArr = array (0,mAX_TUPLE_SIZE) [(i,mk_tuple Unboxed i) | i <- [0..mAX_TUPLE_SIZE]]
181 mk_tuple :: Boxity -> Int -> (TyCon,DataCon)
182 mk_tuple boxity arity = (tycon, tuple_con)
184 tycon = mkTupleTyCon tc_name tc_kind arity tyvars tuple_con boxity
185 tc_name = mkWiredInTyConName tc_uniq mod name_str tycon
186 tc_kind = mkArrowKinds (map tyVarKind tyvars) res_kind
187 res_kind | isBoxed boxity = boxedTypeKind
188 | otherwise = unboxedTypeKind
190 tyvars | isBoxed boxity = take arity alphaTyVars
191 | otherwise = take arity openAlphaTyVars
193 tuple_con = pcDataCon dc_uniq mod name_str tyvars [] tyvar_tys tycon
194 tyvar_tys = mkTyVarTys tyvars
195 (mod_name, name_str) = mkTupNameStr boxity arity
196 tc_uniq = mkTupleTyConUnique boxity arity
197 dc_uniq = mkTupleDataConUnique boxity arity
198 mod = mkPrelModule mod_name
200 unitTyCon = tupleTyCon Boxed 0
201 unitDataConId = dataConId (head (tyConDataCons unitTyCon))
203 pairTyCon = tupleTyCon Boxed 2
205 unboxedSingletonTyCon = tupleTyCon Unboxed 1
206 unboxedSingletonDataCon = tupleCon Unboxed 1
208 unboxedPairTyCon = tupleTyCon Unboxed 2
209 unboxedPairDataCon = tupleCon Unboxed 2
212 %************************************************************************
214 \subsection[TysWiredIn-boxed-prim]{The ``boxed primitive'' types (@Char@, @Int@, etc)}
216 %************************************************************************
219 -- The Void type is represented as a data type with no constructors
220 -- It's a built in type (i.e. there's no way to define it in Haskell;
221 -- the nearest would be
223 -- data Void = -- No constructors!
225 -- ) It's boxed; there is only one value of this
226 -- type, namely "void", whose semantics is just bottom.
228 -- Haskell 98 drops the definition of a Void type, so we just 'simulate'
235 charTy = mkTyConTy charTyCon
237 charTyCon = pcNonRecDataTyCon charTyConKey pREL_BASE SLIT("Char") [] [] [charDataCon]
238 charDataCon = pcDataCon charDataConKey pREL_BASE SLIT("C#") [] [] [charPrimTy] charTyCon
240 stringTy = mkListTy charTy -- convenience only
244 intTy = mkTyConTy intTyCon
246 intTyCon = pcNonRecDataTyCon intTyConKey pREL_BASE SLIT("Int") [] [] [intDataCon]
247 intDataCon = pcDataCon intDataConKey pREL_BASE SLIT("I#") [] [] [intPrimTy] intTyCon
249 isIntTy :: Type -> Bool
250 isIntTy = isTyCon intTyConKey
255 wordTy = mkTyConTy wordTyCon
257 wordTyCon = pcNonRecDataTyCon wordTyConKey pREL_ADDR SLIT("Word") [] [] [wordDataCon]
258 wordDataCon = pcDataCon wordDataConKey pREL_ADDR SLIT("W#") [] [] [wordPrimTy] wordTyCon
262 addrTy = mkTyConTy addrTyCon
264 addrTyCon = pcNonRecDataTyCon addrTyConKey pREL_ADDR SLIT("Addr") [] [] [addrDataCon]
265 addrDataCon = pcDataCon addrDataConKey pREL_ADDR SLIT("A#") [] [] [addrPrimTy] addrTyCon
267 isAddrTy :: Type -> Bool
268 isAddrTy = isTyCon addrTyConKey
272 floatTy = mkTyConTy floatTyCon
274 floatTyCon = pcNonRecDataTyCon floatTyConKey pREL_FLOAT SLIT("Float") [] [] [floatDataCon]
275 floatDataCon = pcDataCon floatDataConKey pREL_FLOAT SLIT("F#") [] [] [floatPrimTy] floatTyCon
277 isFloatTy :: Type -> Bool
278 isFloatTy = isTyCon floatTyConKey
282 doubleTy = mkTyConTy doubleTyCon
284 isDoubleTy :: Type -> Bool
285 isDoubleTy = isTyCon doubleTyConKey
287 doubleTyCon = pcNonRecDataTyCon doubleTyConKey pREL_FLOAT SLIT("Double") [] [] [doubleDataCon]
288 doubleDataCon = pcDataCon doubleDataConKey pREL_FLOAT SLIT("D#") [] [] [doublePrimTy] doubleTyCon
293 = pcNonRecDataTyCon stablePtrTyConKey pREL_STABLE SLIT("StablePtr")
294 alpha_tyvar [(True,False)] [stablePtrDataCon]
297 = pcDataCon stablePtrDataConKey pREL_STABLE SLIT("StablePtr")
298 alpha_tyvar [] [mkStablePtrPrimTy alphaTy] stablePtrTyCon
303 = pcNonRecDataTyCon foreignObjTyConKey pREL_IO_BASE SLIT("ForeignObj")
304 [] [] [foreignObjDataCon]
307 = pcDataCon foreignObjDataConKey pREL_IO_BASE SLIT("ForeignObj")
308 [] [] [foreignObjPrimTy] foreignObjTyCon
310 isForeignObjTy :: Type -> Bool
311 isForeignObjTy = isTyCon foreignObjTyConKey
314 %************************************************************************
316 \subsection[TysWiredIn-Integer]{@Integer@ and its related ``pairing'' types}
318 %************************************************************************
320 @Integer@ and its pals are not really primitive. @Integer@ itself, first:
323 integerTy = mkTyConTy integerTyCon
325 integerTyCon = pcNonRecDataTyCon integerTyConKey pREL_NUM SLIT("Integer")
326 [] [] [smallIntegerDataCon, largeIntegerDataCon]
328 smallIntegerDataCon = pcDataCon smallIntegerDataConKey pREL_NUM SLIT("S#")
329 [] [] [intPrimTy] integerTyCon
330 largeIntegerDataCon = pcDataCon largeIntegerDataConKey pREL_NUM SLIT("J#")
331 [] [] [intPrimTy, byteArrayPrimTy] integerTyCon
334 isIntegerTy :: Type -> Bool
335 isIntegerTy = isTyCon integerTyConKey
339 %************************************************************************
341 \subsection[TysWiredIn-ext-type]{External types}
343 %************************************************************************
345 The compiler's foreign function interface supports the passing of a
346 restricted set of types as arguments and results (the restricting factor
350 isFFIArgumentTy :: Bool -> Type -> Bool
351 -- Checks for valid argument type for a 'foreign import'
352 isFFIArgumentTy is_safe ty = checkTyCon (legalOutgoingTyCon is_safe) ty
354 isFFIExternalTy :: Type -> Bool
355 -- Types that are allowed as arguments of a 'foreign export'
356 isFFIExternalTy ty = checkTyCon legalIncomingTyCon ty
358 isFFIResultTy :: Type -> Bool
359 -- Types that are allowed as a result of a 'foreign import' or of a 'foreign export'
360 -- Maybe we should distinguish between import and export, but
361 -- here we just choose the more restrictive 'incoming' predicate
362 -- But we allow () as well
363 isFFIResultTy ty = checkTyCon (\tc -> tc == unitTyCon || legalIncomingTyCon tc) ty
365 checkTyCon :: (TyCon -> Bool) -> Type -> Bool
366 checkTyCon check_tc ty = case splitTyConApp_maybe (repType ty) of
367 Just (tycon, _) -> check_tc tycon
370 isTyCon :: Unique -> Type -> Bool
371 isTyCon uniq ty = checkTyCon (\tc -> uniq == getUnique tc) ty
374 ----------------------------------------------
375 These chaps do the work; they are not exported
376 ----------------------------------------------
379 legalIncomingTyCon :: TyCon -> Bool
380 -- It's illegal to return foreign objects and (mutable)
381 -- bytearrays from a _ccall_ / foreign declaration
382 -- (or be passed them as arguments in foreign exported functions).
383 legalIncomingTyCon tc
384 | getUnique tc `elem` [ foreignObjTyConKey, byteArrayTyConKey, mutableByteArrayTyConKey ]
387 = marshalableTyCon tc
389 legalOutgoingTyCon :: Bool -> TyCon -> Bool
390 -- Checks validity of types going from Haskell -> external world
391 -- The boolean is true for a 'safe' call (when we don't want to
392 -- pass Haskell pointers to the world)
393 legalOutgoingTyCon be_safe tc
394 | be_safe && getUnique tc `elem` [byteArrayTyConKey, mutableByteArrayTyConKey]
397 = marshalableTyCon tc
400 = (opt_GlasgowExts && isUnLiftedTyCon tc)
401 || getUnique tc `elem` [ intTyConKey, int8TyConKey, int16TyConKey, int32TyConKey, int64TyConKey
402 , wordTyConKey, word8TyConKey, word16TyConKey, word32TyConKey, word64TyConKey
403 , floatTyConKey, doubleTyConKey
404 , addrTyConKey, charTyConKey, foreignObjTyConKey
406 , byteArrayTyConKey, mutableByteArrayTyConKey
412 %************************************************************************
414 \subsection[TysWiredIn-Bool]{The @Bool@ type}
416 %************************************************************************
418 An ordinary enumeration type, but deeply wired in. There are no
419 magical operations on @Bool@ (just the regular Prelude code).
421 {\em BEGIN IDLE SPECULATION BY SIMON}
423 This is not the only way to encode @Bool@. A more obvious coding makes
424 @Bool@ just a boxed up version of @Bool#@, like this:
427 data Bool = MkBool Bool#
430 Unfortunately, this doesn't correspond to what the Report says @Bool@
431 looks like! Furthermore, we get slightly less efficient code (I
432 think) with this coding. @gtInt@ would look like this:
435 gtInt :: Int -> Int -> Bool
436 gtInt x y = case x of I# x# ->
438 case (gtIntPrim x# y#) of
442 Notice that the result of the @gtIntPrim@ comparison has to be turned
443 into an integer (here called @b#@), and returned in a @MkBool@ box.
445 The @if@ expression would compile to this:
448 MkBool b# -> case b# of { 1# -> e1; 0# -> e2 }
451 I think this code is a little less efficient than the previous code,
452 but I'm not certain. At all events, corresponding with the Report is
453 important. The interesting thing is that the language is expressive
454 enough to describe more than one alternative; and that a type doesn't
455 necessarily need to be a straightforwardly boxed version of its
456 primitive counterpart.
458 {\em END IDLE SPECULATION BY SIMON}
461 boolTy = mkTyConTy boolTyCon
463 boolTyCon = pcTyCon EnumTyCon NonRecursive boolTyConKey
464 pREL_BASE SLIT("Bool") [] [] [falseDataCon, trueDataCon]
466 falseDataCon = pcDataCon falseDataConKey pREL_BASE SLIT("False") [] [] [] boolTyCon
467 trueDataCon = pcDataCon trueDataConKey pREL_BASE SLIT("True") [] [] [] boolTyCon
469 falseDataConId = dataConId falseDataCon
470 trueDataConId = dataConId trueDataCon
473 %************************************************************************
475 \subsection[TysWiredIn-List]{The @List@ type (incl ``build'' magic)}
477 %************************************************************************
479 Special syntax, deeply wired in, but otherwise an ordinary algebraic
482 data [] a = [] | a : (List a)
484 data (,) a b = (,,) a b
489 mkListTy :: Type -> Type
490 mkListTy ty = mkTyConApp listTyCon [ty]
492 alphaListTy = mkSigmaTy alpha_tyvar [] (mkTyConApp listTyCon alpha_ty)
494 listTyCon = pcRecDataTyCon listTyConKey pREL_BASE SLIT("[]")
495 alpha_tyvar [(True,False)] [nilDataCon, consDataCon]
497 nilDataCon = pcDataCon nilDataConKey pREL_BASE SLIT("[]") alpha_tyvar [] [] listTyCon
498 consDataCon = pcDataCon consDataConKey pREL_BASE SLIT(":")
499 alpha_tyvar [] [alphaTy, mkTyConApp listTyCon alpha_ty] listTyCon
500 -- Interesting: polymorphic recursion would help here.
501 -- We can't use (mkListTy alphaTy) in the defn of consDataCon, else mkListTy
502 -- gets the over-specific type (Type -> Type)
505 %************************************************************************
507 \subsection[TysWiredIn-Tuples]{The @Tuple@ types}
509 %************************************************************************
511 The tuple types are definitely magic, because they form an infinite
516 They have a special family of type constructors, of type @TyCon@
517 These contain the tycon arity, but don't require a Unique.
520 They have a special family of constructors, of type
521 @Id@. Again these contain their arity but don't need a Unique.
524 There should be a magic way of generating the info tables and
525 entry code for all tuples.
527 But at the moment we just compile a Haskell source
528 file\srcloc{lib/prelude/...} containing declarations like:
531 data Tuple2 a b = Tup2 a b
532 data Tuple3 a b c = Tup3 a b c
533 data Tuple4 a b c d = Tup4 a b c d
536 The print-names associated with the magic @Id@s for tuple constructors
537 ``just happen'' to be the same as those generated by these
541 The instance environment should have a magic way to know
542 that each tuple type is an instances of classes @Eq@, @Ix@, @Ord@ and
543 so on. \ToDo{Not implemented yet.}
546 There should also be a way to generate the appropriate code for each
547 of these instances, but (like the info tables and entry code) it is
548 done by enumeration\srcloc{lib/prelude/InTup?.hs}.
552 mkTupleTy :: Boxity -> Int -> [Type] -> Type
553 mkTupleTy boxity arity tys = mkTyConApp (tupleTyCon boxity arity) tys
555 unitTy = mkTupleTy Boxed 0 []