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.''
16 boolTy, boolTyCon, boolTyCon_RDR, boolTyConName,
17 trueDataCon, trueDataConId, true_RDR,
18 falseDataCon, falseDataConId, false_RDR,
20 charTyCon, charDataCon, charTyCon_RDR,
21 charTy, stringTy, charTyConName,
24 doubleTyCon, doubleDataCon, doubleTy, doubleTyConName,
26 floatTyCon, floatDataCon, floatTy, floatTyConName,
28 intTyCon, intDataCon, intTyCon_RDR, intDataCon_RDR, intTyConName,
31 listTyCon, nilDataCon, consDataCon,
32 listTyCon_RDR, consDataCon_RDR, listTyConName,
38 unitTyCon, unitDataCon, unitDataConId, pairTyCon,
39 unboxedSingletonTyCon, unboxedSingletonDataCon,
40 unboxedPairTyCon, unboxedPairDataCon,
47 parrTyCon, parrFakeCon, isPArrTyCon, isPArrFakeCon,
48 parrTyCon_RDR, parrTyConName
51 #include "HsVersions.h"
53 import {-# SOURCE #-} MkId( mkDataConIds )
60 import Constants ( mAX_TUPLE_SIZE )
61 import Module ( Module )
62 import RdrName ( nameRdrName )
63 import Name ( Name, BuiltInSyntax(..), nameUnique, nameOccName,
64 nameModule, mkWiredInName )
65 import OccName ( mkOccNameFS, tcName, dataName, mkTupleOcc,
67 import DataCon ( DataCon, mkDataCon, dataConWorkId, dataConSourceArity )
68 import Var ( TyVar, tyVarKind )
69 import TyCon ( TyCon, AlgTyConRhs(DataTyCon), tyConDataCons,
70 mkTupleTyCon, mkAlgTyCon, tyConName,
71 AlgTyConParent(NoParentTyCon) )
73 import BasicTypes ( Arity, RecFlag(..), Boxity(..), isBoxed,
76 import Type ( Type, mkTyConTy, mkTyConApp, mkTyVarTy, mkTyVarTys,
78 import Coercion ( unsafeCoercionTyCon, symCoercionTyCon,
79 transCoercionTyCon, leftCoercionTyCon,
80 rightCoercionTyCon, instCoercionTyCon )
81 import TypeRep ( mkArrowKinds, liftedTypeKind, ubxTupleKind )
82 import Unique ( incrUnique, mkTupleTyConUnique,
83 mkTupleDataConUnique, mkPArrDataConUnique )
88 alpha_tyvar = [alphaTyVar]
93 %************************************************************************
95 \subsection{Wired in type constructors}
97 %************************************************************************
99 If you change which things are wired in, make sure you change their
100 names in PrelNames, so they use wTcQual, wDataQual, etc
103 wiredInTyCons :: [TyCon] -- Excludes tuples
104 -- This list is used only to define PrelInfo.wiredInThings
106 -- It does not need to include kind constructors, because
107 -- all that wiredInThings does is to initialise the Name table,
108 -- and kind constructors don't appear in source code.
110 wiredInTyCons = [ unitTyCon -- Not treated like other tuples, because
111 -- it's defined in GHC.Base, and there's only
112 -- one of it. We put it in wiredInTyCons so
113 -- that it'll pre-populate the name cache, so
114 -- the special case in lookupOrigNameCache
115 -- doesn't need to look out for it
123 , unsafeCoercionTyCon
133 mkWiredInTyConName :: BuiltInSyntax -> Module -> FastString -> Unique -> TyCon -> Name
134 mkWiredInTyConName built_in mod fs uniq tycon
135 = mkWiredInName mod (mkOccNameFS tcName fs) uniq
136 Nothing -- No parent object
137 (ATyCon tycon) -- Relevant TyCon
140 mkWiredInDataConName :: BuiltInSyntax -> Module -> FastString -> Unique -> DataCon -> Name -> Name
141 mkWiredInDataConName built_in mod fs uniq datacon parent
142 = mkWiredInName mod (mkOccNameFS dataName fs) uniq
143 (Just parent) -- Name of parent TyCon
144 (ADataCon datacon) -- Relevant DataCon
147 charTyConName = mkWiredInTyConName UserSyntax gHC_BASE FSLIT("Char") charTyConKey charTyCon
148 charDataConName = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("C#") charDataConKey charDataCon charTyConName
149 intTyConName = mkWiredInTyConName UserSyntax gHC_BASE FSLIT("Int") intTyConKey intTyCon
150 intDataConName = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("I#") intDataConKey intDataCon intTyConName
152 boolTyConName = mkWiredInTyConName UserSyntax gHC_BASE FSLIT("Bool") boolTyConKey boolTyCon
153 falseDataConName = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("False") falseDataConKey falseDataCon boolTyConName
154 trueDataConName = mkWiredInDataConName UserSyntax gHC_BASE FSLIT("True") trueDataConKey trueDataCon boolTyConName
155 listTyConName = mkWiredInTyConName BuiltInSyntax gHC_BASE FSLIT("[]") listTyConKey listTyCon
156 nilDataConName = mkWiredInDataConName BuiltInSyntax gHC_BASE FSLIT("[]") nilDataConKey nilDataCon listTyConName
157 consDataConName = mkWiredInDataConName BuiltInSyntax gHC_BASE FSLIT(":") consDataConKey consDataCon listTyConName
159 floatTyConName = mkWiredInTyConName UserSyntax gHC_FLOAT FSLIT("Float") floatTyConKey floatTyCon
160 floatDataConName = mkWiredInDataConName UserSyntax gHC_FLOAT FSLIT("F#") floatDataConKey floatDataCon floatTyConName
161 doubleTyConName = mkWiredInTyConName UserSyntax gHC_FLOAT FSLIT("Double") doubleTyConKey doubleTyCon
162 doubleDataConName = mkWiredInDataConName UserSyntax gHC_FLOAT FSLIT("D#") doubleDataConKey doubleDataCon doubleTyConName
164 parrTyConName = mkWiredInTyConName BuiltInSyntax gHC_PARR FSLIT("[::]") parrTyConKey parrTyCon
165 parrDataConName = mkWiredInDataConName UserSyntax gHC_PARR FSLIT("PArr") parrDataConKey parrDataCon parrTyConName
167 boolTyCon_RDR = nameRdrName boolTyConName
168 false_RDR = nameRdrName falseDataConName
169 true_RDR = nameRdrName trueDataConName
170 intTyCon_RDR = nameRdrName intTyConName
171 charTyCon_RDR = nameRdrName charTyConName
172 intDataCon_RDR = nameRdrName intDataConName
173 listTyCon_RDR = nameRdrName listTyConName
174 consDataCon_RDR = nameRdrName consDataConName
175 parrTyCon_RDR = nameRdrName parrTyConName
177 tySuperKindTyCon_RDR = nameRdrName tySuperKindTyConName
178 coSuperKindTyCon_RDR = nameRdrName coSuperKindTyConName
179 liftedTypeKindTyCon_RDR = nameRdrName liftedTypeKindTyConName
180 openTypeKindTyCon_RDR = nameRdrName openTypeKindTyConName
181 unliftedTypeKindTyCon_RDR = nameRdrName unliftedTypeKindTyConName
182 ubxTupleKindTyCon_RDR = nameRdrName ubxTupleKindTyConName
183 argTypeKindTyCon_RDR = nameRdrName argTypeKindTyConName
184 funKindTyCon_RDR = nameRdrName funKindTyConName
189 %************************************************************************
191 \subsection{mkWiredInTyCon}
193 %************************************************************************
196 pcNonRecDataTyCon = pcTyCon False NonRecursive
197 pcRecDataTyCon = pcTyCon False Recursive
199 pcTyCon is_enum is_rec name tyvars cons
202 tycon = mkAlgTyCon name
203 (mkArrowKinds (map tyVarKind tyvars) liftedTypeKind)
205 [] -- No stupid theta
206 (DataTyCon cons is_enum)
207 [] -- No record selectors
210 True -- All the wired-in tycons have generics
211 False -- Not in GADT syntax
213 pcDataCon :: Name -> [TyVar] -> [Type] -> TyCon -> DataCon
214 pcDataCon = pcDataConWithFixity False
216 pcDataConWithFixity :: Bool -> Name -> [TyVar] -> [Type] -> TyCon -> DataCon
217 -- The Name should be in the DataName name space; it's the name
218 -- of the DataCon itself.
220 -- The unique is the first of two free uniques;
221 -- the first is used for the datacon itself,
222 -- the second is used for the "worker name"
224 pcDataConWithFixity declared_infix dc_name tyvars arg_tys tycon
227 data_con = mkDataCon dc_name declared_infix
228 (map (const NotMarkedStrict) arg_tys)
229 [] -- No labelled fields
231 [] -- No existential type variables
232 [] -- No equality spec
235 Nothing -- not a data instance
236 [] -- No stupid theta
237 (mkDataConIds bogus_wrap_name wrk_name data_con)
240 mod = nameModule dc_name
241 wrk_occ = mkDataConWorkerOcc (nameOccName dc_name)
242 wrk_key = incrUnique (nameUnique dc_name)
243 wrk_name = mkWiredInName mod wrk_occ wrk_key
244 (Just (tyConName tycon))
245 (AnId (dataConWorkId data_con)) UserSyntax
246 bogus_wrap_name = pprPanic "Wired-in data wrapper id" (ppr dc_name)
247 -- Wired-in types are too simple to need wrappers
251 %************************************************************************
253 \subsection[TysWiredIn-tuples]{The tuple types}
255 %************************************************************************
258 tupleTyCon :: Boxity -> Arity -> TyCon
259 tupleTyCon boxity i | i > mAX_TUPLE_SIZE = fst (mk_tuple boxity i) -- Build one specially
260 tupleTyCon Boxed i = fst (boxedTupleArr ! i)
261 tupleTyCon Unboxed i = fst (unboxedTupleArr ! i)
263 tupleCon :: Boxity -> Arity -> DataCon
264 tupleCon boxity i | i > mAX_TUPLE_SIZE = snd (mk_tuple boxity i) -- Build one specially
265 tupleCon Boxed i = snd (boxedTupleArr ! i)
266 tupleCon Unboxed i = snd (unboxedTupleArr ! i)
268 boxedTupleArr, unboxedTupleArr :: Array Int (TyCon,DataCon)
269 boxedTupleArr = listArray (0,mAX_TUPLE_SIZE) [mk_tuple Boxed i | i <- [0..mAX_TUPLE_SIZE]]
270 unboxedTupleArr = listArray (0,mAX_TUPLE_SIZE) [mk_tuple Unboxed i | i <- [0..mAX_TUPLE_SIZE]]
272 mk_tuple :: Boxity -> Int -> (TyCon,DataCon)
273 mk_tuple boxity arity = (tycon, tuple_con)
275 tycon = mkTupleTyCon tc_name tc_kind arity tyvars tuple_con boxity gen_info
276 mod = mkTupleModule boxity arity
277 tc_name = mkWiredInName mod (mkTupleOcc tcName boxity arity) tc_uniq
278 Nothing (ATyCon tycon) BuiltInSyntax
279 tc_kind = mkArrowKinds (map tyVarKind tyvars) res_kind
280 res_kind | isBoxed boxity = liftedTypeKind
281 | otherwise = ubxTupleKind
283 tyvars | isBoxed boxity = take arity alphaTyVars
284 | otherwise = take arity openAlphaTyVars
286 tuple_con = pcDataCon dc_name tyvars tyvar_tys tycon
287 tyvar_tys = mkTyVarTys tyvars
288 dc_name = mkWiredInName mod (mkTupleOcc dataName boxity arity) dc_uniq
289 (Just tc_name) (ADataCon tuple_con) BuiltInSyntax
290 tc_uniq = mkTupleTyConUnique boxity arity
291 dc_uniq = mkTupleDataConUnique boxity arity
292 gen_info = True -- Tuples all have generics..
293 -- hmm: that's a *lot* of code
295 unitTyCon = tupleTyCon Boxed 0
296 unitDataCon = head (tyConDataCons unitTyCon)
297 unitDataConId = dataConWorkId unitDataCon
299 pairTyCon = tupleTyCon Boxed 2
301 unboxedSingletonTyCon = tupleTyCon Unboxed 1
302 unboxedSingletonDataCon = tupleCon Unboxed 1
304 unboxedPairTyCon = tupleTyCon Unboxed 2
305 unboxedPairDataCon = tupleCon Unboxed 2
308 %************************************************************************
310 \subsection[TysWiredIn-boxed-prim]{The ``boxed primitive'' types (@Char@, @Int@, etc)}
312 %************************************************************************
315 -- The Void type is represented as a data type with no constructors
316 -- It's a built in type (i.e. there's no way to define it in Haskell;
317 -- the nearest would be
319 -- data Void = -- No constructors!
321 -- ) It's lifted; there is only one value of this
322 -- type, namely "void", whose semantics is just bottom.
324 -- Haskell 98 drops the definition of a Void type, so we just 'simulate'
331 charTy = mkTyConTy charTyCon
333 charTyCon = pcNonRecDataTyCon charTyConName [] [charDataCon]
334 charDataCon = pcDataCon charDataConName [] [charPrimTy] charTyCon
336 stringTy = mkListTy charTy -- convenience only
340 intTy = mkTyConTy intTyCon
342 intTyCon = pcNonRecDataTyCon intTyConName [] [intDataCon]
343 intDataCon = pcDataCon intDataConName [] [intPrimTy] intTyCon
347 floatTy = mkTyConTy floatTyCon
349 floatTyCon = pcNonRecDataTyCon floatTyConName [] [floatDataCon]
350 floatDataCon = pcDataCon floatDataConName [] [floatPrimTy] floatTyCon
354 doubleTy = mkTyConTy doubleTyCon
356 doubleTyCon = pcNonRecDataTyCon doubleTyConName [] [doubleDataCon]
357 doubleDataCon = pcDataCon doubleDataConName [] [doublePrimTy] doubleTyCon
361 %************************************************************************
363 \subsection[TysWiredIn-Bool]{The @Bool@ type}
365 %************************************************************************
367 An ordinary enumeration type, but deeply wired in. There are no
368 magical operations on @Bool@ (just the regular Prelude code).
370 {\em BEGIN IDLE SPECULATION BY SIMON}
372 This is not the only way to encode @Bool@. A more obvious coding makes
373 @Bool@ just a boxed up version of @Bool#@, like this:
376 data Bool = MkBool Bool#
379 Unfortunately, this doesn't correspond to what the Report says @Bool@
380 looks like! Furthermore, we get slightly less efficient code (I
381 think) with this coding. @gtInt@ would look like this:
384 gtInt :: Int -> Int -> Bool
385 gtInt x y = case x of I# x# ->
387 case (gtIntPrim x# y#) of
391 Notice that the result of the @gtIntPrim@ comparison has to be turned
392 into an integer (here called @b#@), and returned in a @MkBool@ box.
394 The @if@ expression would compile to this:
397 MkBool b# -> case b# of { 1# -> e1; 0# -> e2 }
400 I think this code is a little less efficient than the previous code,
401 but I'm not certain. At all events, corresponding with the Report is
402 important. The interesting thing is that the language is expressive
403 enough to describe more than one alternative; and that a type doesn't
404 necessarily need to be a straightforwardly boxed version of its
405 primitive counterpart.
407 {\em END IDLE SPECULATION BY SIMON}
410 boolTy = mkTyConTy boolTyCon
412 boolTyCon = pcTyCon True NonRecursive boolTyConName
413 [] [falseDataCon, trueDataCon]
415 falseDataCon = pcDataCon falseDataConName [] [] boolTyCon
416 trueDataCon = pcDataCon trueDataConName [] [] boolTyCon
418 falseDataConId = dataConWorkId falseDataCon
419 trueDataConId = dataConWorkId trueDataCon
422 %************************************************************************
424 \subsection[TysWiredIn-List]{The @List@ type (incl ``build'' magic)}
426 %************************************************************************
428 Special syntax, deeply wired in, but otherwise an ordinary algebraic
431 data [] a = [] | a : (List a)
433 data (,) a b = (,,) a b
438 mkListTy :: Type -> Type
439 mkListTy ty = mkTyConApp listTyCon [ty]
441 listTyCon = pcRecDataTyCon listTyConName alpha_tyvar [nilDataCon, consDataCon]
443 nilDataCon = pcDataCon nilDataConName alpha_tyvar [] listTyCon
444 consDataCon = pcDataConWithFixity True {- Declared infix -}
446 alpha_tyvar [alphaTy, mkTyConApp listTyCon alpha_ty] listTyCon
447 -- Interesting: polymorphic recursion would help here.
448 -- We can't use (mkListTy alphaTy) in the defn of consDataCon, else mkListTy
449 -- gets the over-specific type (Type -> Type)
452 %************************************************************************
454 \subsection[TysWiredIn-Tuples]{The @Tuple@ types}
456 %************************************************************************
458 The tuple types are definitely magic, because they form an infinite
463 They have a special family of type constructors, of type @TyCon@
464 These contain the tycon arity, but don't require a Unique.
467 They have a special family of constructors, of type
468 @Id@. Again these contain their arity but don't need a Unique.
471 There should be a magic way of generating the info tables and
472 entry code for all tuples.
474 But at the moment we just compile a Haskell source
475 file\srcloc{lib/prelude/...} containing declarations like:
478 data Tuple2 a b = Tup2 a b
479 data Tuple3 a b c = Tup3 a b c
480 data Tuple4 a b c d = Tup4 a b c d
483 The print-names associated with the magic @Id@s for tuple constructors
484 ``just happen'' to be the same as those generated by these
488 The instance environment should have a magic way to know
489 that each tuple type is an instances of classes @Eq@, @Ix@, @Ord@ and
490 so on. \ToDo{Not implemented yet.}
493 There should also be a way to generate the appropriate code for each
494 of these instances, but (like the info tables and entry code) it is
495 done by enumeration\srcloc{lib/prelude/InTup?.hs}.
499 mkTupleTy :: Boxity -> Int -> [Type] -> Type
500 mkTupleTy boxity arity tys = mkTyConApp (tupleTyCon boxity arity) tys
502 unitTy = mkTupleTy Boxed 0 []
505 %************************************************************************
507 \subsection[TysWiredIn-PArr]{The @[::]@ type}
509 %************************************************************************
511 Special syntax for parallel arrays needs some wired in definitions.
514 -- construct a type representing the application of the parallel array
517 mkPArrTy :: Type -> Type
518 mkPArrTy ty = mkTyConApp parrTyCon [ty]
520 -- represents the type constructor of parallel arrays
522 -- * this must match the definition in `PrelPArr'
524 -- NB: Although the constructor is given here, it will not be accessible in
525 -- user code as it is not in the environment of any compiled module except
529 parrTyCon = pcNonRecDataTyCon parrTyConName alpha_tyvar [parrDataCon]
531 parrDataCon :: DataCon
532 parrDataCon = pcDataCon
534 alpha_tyvar -- forall'ed type variables
535 [intPrimTy, -- 1st argument: Int#
536 mkTyConApp -- 2nd argument: Array# a
541 -- check whether a type constructor is the constructor for parallel arrays
543 isPArrTyCon :: TyCon -> Bool
544 isPArrTyCon tc = tyConName tc == parrTyConName
546 -- fake array constructors
548 -- * these constructors are never really used to represent array values;
549 -- however, they are very convenient during desugaring (and, in particular,
550 -- in the pattern matching compiler) to treat array pattern just like
551 -- yet another constructor pattern
553 parrFakeCon :: Arity -> DataCon
554 parrFakeCon i | i > mAX_TUPLE_SIZE = mkPArrFakeCon i -- build one specially
555 parrFakeCon i = parrFakeConArr!i
557 -- pre-defined set of constructors
559 parrFakeConArr :: Array Int DataCon
560 parrFakeConArr = array (0, mAX_TUPLE_SIZE) [(i, mkPArrFakeCon i)
561 | i <- [0..mAX_TUPLE_SIZE]]
563 -- build a fake parallel array constructor for the given arity
565 mkPArrFakeCon :: Int -> DataCon
566 mkPArrFakeCon arity = data_con
568 data_con = pcDataCon name [tyvar] tyvarTys parrTyCon
569 tyvar = head alphaTyVars
570 tyvarTys = replicate arity $ mkTyVarTy tyvar
571 nameStr = mkFastString ("MkPArr" ++ show arity)
572 name = mkWiredInName gHC_PARR (mkOccNameFS dataName nameStr) uniq
573 Nothing (ADataCon data_con) UserSyntax
574 uniq = mkPArrDataConUnique arity
576 -- checks whether a data constructor is a fake constructor for parallel arrays
578 isPArrFakeCon :: DataCon -> Bool
579 isPArrFakeCon dcon = dcon == parrFakeCon (dataConSourceArity dcon)