2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
4 \section[TyCon]{The @TyCon@ datatype}
7 #include "HsVersions.h"
10 TyCon(..), -- NB: some pals need to see representation
12 SYN_IE(Arity), NewOrData(..),
14 isFunTyCon, isPrimTyCon, isBoxedTyCon,
15 isDataTyCon, isSynTyCon, isNewTyCon, maybeNewTyCon,
41 CHK_Ubiq() -- debugging consistency check
43 IMPORT_DELOOPER(TyLoop) ( SYN_IE(Type), GenType,
44 SYN_IE(Class), GenClass,
46 splitSigmaTy, splitFunTy,
47 tupleCon, isNullaryDataCon, idType
48 --LATER: specMaybeTysSuffix
51 import TyVar ( GenTyVar, alphaTyVars, alphaTyVar, betaTyVar, SYN_IE(TyVar) )
52 import Usage ( GenUsage, SYN_IE(Usage) )
53 import Kind ( Kind, mkBoxedTypeKind, mkArrowKind, resultKind, argKind )
56 import Name ( Name, nameUnique, mkWiredInTyConName )
57 import Unique ( Unique, funTyConKey )
58 import Pretty ( SYN_IE(Pretty), PrettyRep )
59 import PrimRep ( PrimRep(..) )
60 import PrelMods ( gHC__, pREL_TUP, pREL_BASE )
61 import Lex ( mkTupNameStr )
62 import SrcLoc ( SrcLoc, mkBuiltinSrcLoc )
63 import Util ( nOfThem, isIn, Ord3(..), panic, panic#, assertPanic )
74 = FunTyCon -- Kind = Type -> Type -> Type
76 | DataTyCon Unique{-TyConKey-}
80 [(Class,Type)] -- Its context
81 [Id] -- Its data constructors, with fully polymorphic types
82 [Class] -- Classes which have derived instances
85 | TupleTyCon Unique -- cached
86 Name -- again, we could do without this, but
87 -- it makes life somewhat easier
88 Arity -- just a special case of DataTyCon
89 -- Kind = BoxedTypeKind
90 -- -> ... (n times) ...
94 | PrimTyCon -- Primitive types; cannot be defined in Haskell
95 Unique -- Always unboxed; hence never represented by a closure
96 Name -- Often represented by a bit-pattern for the thing
97 Kind -- itself (eg Int#), but sometimes by a pointer to
100 | SpecTyCon -- A specialised TyCon; eg (Arr# Int#), or (List Int#)
102 [Maybe Type] -- Specialising types
104 -- OLD STUFF ABOUT Array types. Use SpecTyCon instead
105 -- ([PrimRep] -> PrimRep) -- a heap-allocated object (eg ArrInt#).
106 -- The primitive types Arr# and StablePtr# have
107 -- parameters (hence arity /= 0); but the rest don't.
108 -- Only arrays use the list in a non-trivial way.
109 -- Length of that list must == arity.
116 [TyVar] -- Argument type variables
117 Type -- Right-hand side, mentioning these type vars.
118 -- Acts as a template for the expansion when
119 -- the tycon is applied to some types.
122 = NewType -- "newtype Blah ..."
123 | DataType -- "data Blah ..."
127 mkFunTyCon = FunTyCon
128 mkFunTyConName = mkWiredInTyConName funTyConKey gHC__ SLIT("->") FunTyCon
130 mkSpecTyCon = SpecTyCon
131 mkTupleTyCon = TupleTyCon
133 mkDataTyCon name = DataTyCon (nameUnique name) name
134 mkPrimTyCon name = PrimTyCon (nameUnique name) name
135 mkSynTyCon name = SynTyCon (nameUnique name) name
137 isFunTyCon FunTyCon = True
140 isPrimTyCon (PrimTyCon _ _ _ _) = True
141 isPrimTyCon _ = False
143 -- At present there are no unboxed non-primitive types, so
144 -- isBoxedTyCon is just the negation of isPrimTyCon.
145 isBoxedTyCon = not . isPrimTyCon
147 -- isDataTyCon returns False for @newtype@.
148 -- Not sure about this decision yet.
149 isDataTyCon (DataTyCon _ _ _ _ _ _ _ DataType) = True
150 isDataTyCon (TupleTyCon _ _ _) = True
151 isDataTyCon other = False
153 maybeNewTyCon :: TyCon -> Maybe ([TyVar], Type) -- Returns representation type info
154 maybeNewTyCon (DataTyCon _ _ _ _ _ (con:null_cons) _ NewType)
155 = ASSERT( null null_cons && null null_tys)
156 Just (tyvars, rep_ty)
158 (tyvars, theta, tau) = splitSigmaTy (idType con)
159 (rep_ty:null_tys, res_ty) = splitFunTy tau
161 maybeNewTyCon other = Nothing
163 isNewTyCon (DataTyCon _ _ _ _ _ _ _ NewType) = True
164 isNewTyCon other = False
166 isSynTyCon (SynTyCon _ _ _ _ _ _) = True
171 -- Special cases to avoid reconstructing lots of kinds
172 kind1 = mkBoxedTypeKind `mkArrowKind` mkBoxedTypeKind
173 kind2 = mkBoxedTypeKind `mkArrowKind` kind1
175 tyConKind :: TyCon -> Kind
176 tyConKind FunTyCon = kind2
177 tyConKind (DataTyCon _ _ kind _ _ _ _ _) = kind
178 tyConKind (PrimTyCon _ _ kind _) = kind
179 tyConKind (SynTyCon _ _ k _ _ _) = k
181 tyConKind (TupleTyCon _ _ n)
184 mkArrow 0 = mkBoxedTypeKind
187 mkArrow n = mkBoxedTypeKind `mkArrowKind` mkArrow (n-1)
189 tyConKind (SpecTyCon tc tys)
190 = spec (tyConKind tc) tys
193 spec kind (Just _ : tys) = spec (resultKind kind) tys
194 spec kind (Nothing : tys) =
195 argKind kind `mkArrowKind` spec (resultKind kind) tys
199 tyConUnique :: TyCon -> Unique
200 tyConUnique FunTyCon = funTyConKey
201 tyConUnique (DataTyCon uniq _ _ _ _ _ _ _) = uniq
202 tyConUnique (TupleTyCon uniq _ _) = uniq
203 tyConUnique (PrimTyCon uniq _ _ _) = uniq
204 tyConUnique (SynTyCon uniq _ _ _ _ _) = uniq
205 tyConUnique (SpecTyCon _ _ ) = panic "tyConUnique:SpecTyCon"
207 synTyConArity :: TyCon -> Maybe Arity -- Nothing <=> not a syn tycon
208 synTyConArity (SynTyCon _ _ _ arity _ _) = Just arity
209 synTyConArity _ = Nothing
213 tyConTyVars :: TyCon -> [TyVar]
214 tyConTyVars FunTyCon = [alphaTyVar,betaTyVar]
215 tyConTyVars (DataTyCon _ _ _ tvs _ _ _ _) = tvs
216 tyConTyVars (TupleTyCon _ _ arity) = take arity alphaTyVars
217 tyConTyVars (SynTyCon _ _ _ _ tvs _) = tvs
219 tyConTyVars (PrimTyCon _ _ _ _) = panic "tyConTyVars:PrimTyCon"
220 tyConTyVars (SpecTyCon _ _ ) = panic "tyConTyVars:SpecTyCon"
225 tyConDataCons :: TyCon -> [Id]
226 tyConFamilySize :: TyCon -> Int
228 tyConDataCons (DataTyCon _ _ _ _ _ data_cons _ _) = data_cons
229 tyConDataCons (TupleTyCon _ _ a) = [tupleCon a]
230 tyConDataCons other = []
231 -- You may think this last equation should fail,
232 -- but it's quite convenient to return no constructors for
233 -- a synonym; see for example the call in TcTyClsDecls.
235 tyConFamilySize (DataTyCon _ _ _ _ _ data_cons _ _) = length data_cons
236 tyConFamilySize (TupleTyCon _ _ _) = 1
238 --tyConFamilySize other = pprPanic "tyConFamilySize:" (pprTyCon PprDebug other)
241 tyConPrimRep :: TyCon -> PrimRep
242 tyConPrimRep (PrimTyCon _ _ _ rep) = rep
243 tyConPrimRep _ = PtrRep
247 tyConDerivings :: TyCon -> [Class]
248 tyConDerivings (DataTyCon _ _ _ _ _ _ derivs _) = derivs
249 tyConDerivings other = []
253 tyConTheta :: TyCon -> [(Class,Type)]
254 tyConTheta (DataTyCon _ _ _ _ theta _ _ _) = theta
255 tyConTheta (TupleTyCon _ _ _) = []
256 -- should ask about anything else
260 getSynTyConDefn :: TyCon -> ([TyVar], Type)
261 getSynTyConDefn (SynTyCon _ _ _ _ tyvars ty) = (tyvars,ty)
265 maybeTyConSingleCon :: TyCon -> Maybe Id
267 maybeTyConSingleCon (TupleTyCon _ _ arity) = Just (tupleCon arity)
268 maybeTyConSingleCon (DataTyCon _ _ _ _ _ [c] _ _) = Just c
269 maybeTyConSingleCon (DataTyCon _ _ _ _ _ _ _ _) = Nothing
270 maybeTyConSingleCon (PrimTyCon _ _ _ _) = Nothing
271 maybeTyConSingleCon (SpecTyCon tc tys) = panic "maybeTyConSingleCon:SpecTyCon"
272 -- requires DataCons of TyCon
274 isEnumerationTyCon (TupleTyCon _ _ arity)
276 isEnumerationTyCon (DataTyCon _ _ _ _ _ data_cons _ _)
277 = not (null data_cons) && all isNullaryDataCon data_cons
280 @derivedFor@ reports if we have an {\em obviously}-derived instance
281 for the given class/tycon. Of course, you might be deriving something
282 because it a superclass of some other obviously-derived class --- this
283 function doesn't deal with that.
285 ToDo: what about derivings for specialised tycons !!!
288 derivedFor :: Class -> TyCon -> Bool
289 derivedFor clas (DataTyCon _ _ _ _ _ _ derivs _) = isIn "derivedFor" clas derivs
290 derivedFor clas something_weird = False
293 %************************************************************************
295 \subsection[TyCon-instances]{Instance declarations for @TyCon@}
297 %************************************************************************
299 @TyCon@s are compared by comparing their @Unique@s.
301 The strictness analyser needs @Ord@. It is a lexicographic order with
302 the property @(a<=b) || (b<=a)@.
305 instance Ord3 TyCon where
306 cmp tc1 tc2 = uniqueOf tc1 `cmp` uniqueOf tc2
308 instance Eq TyCon where
309 a == b = case (a `cmp` b) of { EQ_ -> True; _ -> False }
310 a /= b = case (a `cmp` b) of { EQ_ -> False; _ -> True }
312 instance Ord TyCon where
313 a <= b = case (a `cmp` b) of { LT_ -> True; EQ_ -> True; GT__ -> False }
314 a < b = case (a `cmp` b) of { LT_ -> True; EQ_ -> False; GT__ -> False }
315 a >= b = case (a `cmp` b) of { LT_ -> False; EQ_ -> True; GT__ -> True }
316 a > b = case (a `cmp` b) of { LT_ -> False; EQ_ -> False; GT__ -> True }
317 _tagCmp a b = case (a `cmp` b) of { LT_ -> _LT; EQ_ -> _EQ; GT__ -> _GT }
319 instance Uniquable TyCon where
320 uniqueOf (DataTyCon u _ _ _ _ _ _ _) = u
321 uniqueOf (TupleTyCon u _ _) = u
322 uniqueOf (PrimTyCon u _ _ _) = u
323 uniqueOf (SynTyCon u _ _ _ _ _) = u
324 uniqueOf tc@(SpecTyCon _ _) = panic "uniqueOf:SpecTyCon"
325 uniqueOf tc = uniqueOf (getName tc)
329 instance NamedThing TyCon where
330 getName (DataTyCon _ n _ _ _ _ _ _) = n
331 getName (PrimTyCon _ n _ _) = n
332 getName (SpecTyCon tc _) = getName tc
333 getName (SynTyCon _ n _ _ _ _) = n
334 getName FunTyCon = mkFunTyConName
335 getName (TupleTyCon _ n _) = n
336 getName tc = panic "TyCon.getName"
339 getName (SpecTyCon tc tys) = let (OrigName m n) = origName "????" tc in
340 (m, n _APPEND_ specMaybeTysSuffix tys)
341 getName other_tc = moduleNamePair (expectJust "tycon1" (getName other_tc))
342 getName other = Nothing