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,
37 isEnumerationTyCon, isTupleTyCon,
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 -- This list can be empty, when we import a data type abstractly,
83 -- either (a) the interface is hand-written and doesn't give
84 -- the constructors, or
85 -- (b) in a quest for fast compilation we don't import
87 [Class] -- Classes which have derived instances
90 | TupleTyCon Unique -- cached
91 Name -- again, we could do without this, but
92 -- it makes life somewhat easier
93 Arity -- just a special case of DataTyCon
94 -- Kind = BoxedTypeKind
95 -- -> ... (n times) ...
99 | PrimTyCon -- Primitive types; cannot be defined in Haskell
100 Unique -- Always unboxed; hence never represented by a closure
101 Name -- Often represented by a bit-pattern for the thing
102 Kind -- itself (eg Int#), but sometimes by a pointer to
105 | SpecTyCon -- A specialised TyCon; eg (Arr# Int#), or (List Int#)
107 [Maybe Type] -- Specialising types
109 -- OLD STUFF ABOUT Array types. Use SpecTyCon instead
110 -- ([PrimRep] -> PrimRep) -- a heap-allocated object (eg ArrInt#).
111 -- The primitive types Arr# and StablePtr# have
112 -- parameters (hence arity /= 0); but the rest don't.
113 -- Only arrays use the list in a non-trivial way.
114 -- Length of that list must == arity.
121 [TyVar] -- Argument type variables
122 Type -- Right-hand side, mentioning these type vars.
123 -- Acts as a template for the expansion when
124 -- the tycon is applied to some types.
127 = NewType -- "newtype Blah ..."
128 | DataType -- "data Blah ..."
132 mkFunTyCon = FunTyCon
133 mkFunTyConName = mkWiredInTyConName funTyConKey gHC__ SLIT("->") FunTyCon
135 mkSpecTyCon = SpecTyCon
136 mkTupleTyCon = TupleTyCon
138 mkDataTyCon name = DataTyCon (nameUnique name) name
139 mkPrimTyCon name = PrimTyCon (nameUnique name) name
140 mkSynTyCon name = SynTyCon (nameUnique name) name
142 isFunTyCon FunTyCon = True
145 isPrimTyCon (PrimTyCon _ _ _ _) = True
146 isPrimTyCon _ = False
148 -- At present there are no unboxed non-primitive types, so
149 -- isBoxedTyCon is just the negation of isPrimTyCon.
150 isBoxedTyCon = not . isPrimTyCon
152 -- isDataTyCon returns False for @newtype@.
153 -- Not sure about this decision yet.
154 isDataTyCon (DataTyCon _ _ _ _ _ _ _ DataType) = True
155 isDataTyCon (TupleTyCon _ _ _) = True
156 isDataTyCon other = False
158 maybeNewTyCon :: TyCon -> Maybe ([TyVar], Type) -- Returns representation type info
159 maybeNewTyCon (DataTyCon _ _ _ _ _ (con:null_cons) _ NewType)
160 = ASSERT( null null_cons && null null_tys)
161 Just (tyvars, rep_ty)
163 (tyvars, theta, tau) = splitSigmaTy (idType con)
164 (rep_ty:null_tys, res_ty) = splitFunTy tau
166 maybeNewTyCon other = Nothing
168 isNewTyCon (DataTyCon _ _ _ _ _ _ _ NewType) = True
169 isNewTyCon other = False
171 isSynTyCon (SynTyCon _ _ _ _ _ _) = True
176 -- Special cases to avoid reconstructing lots of kinds
177 kind1 = mkBoxedTypeKind `mkArrowKind` mkBoxedTypeKind
178 kind2 = mkBoxedTypeKind `mkArrowKind` kind1
180 tyConKind :: TyCon -> Kind
181 tyConKind FunTyCon = kind2
182 tyConKind (DataTyCon _ _ kind _ _ _ _ _) = kind
183 tyConKind (PrimTyCon _ _ kind _) = kind
184 tyConKind (SynTyCon _ _ k _ _ _) = k
186 tyConKind (TupleTyCon _ _ n)
189 mkArrow 0 = mkBoxedTypeKind
192 mkArrow n = mkBoxedTypeKind `mkArrowKind` mkArrow (n-1)
194 tyConKind (SpecTyCon tc tys)
195 = spec (tyConKind tc) tys
198 spec kind (Just _ : tys) = spec (resultKind kind) tys
199 spec kind (Nothing : tys) =
200 argKind kind `mkArrowKind` spec (resultKind kind) tys
204 tyConUnique :: TyCon -> Unique
205 tyConUnique FunTyCon = funTyConKey
206 tyConUnique (DataTyCon uniq _ _ _ _ _ _ _) = uniq
207 tyConUnique (TupleTyCon uniq _ _) = uniq
208 tyConUnique (PrimTyCon uniq _ _ _) = uniq
209 tyConUnique (SynTyCon uniq _ _ _ _ _) = uniq
210 tyConUnique (SpecTyCon _ _ ) = panic "tyConUnique:SpecTyCon"
212 synTyConArity :: TyCon -> Maybe Arity -- Nothing <=> not a syn tycon
213 synTyConArity (SynTyCon _ _ _ arity _ _) = Just arity
214 synTyConArity _ = Nothing
218 tyConTyVars :: TyCon -> [TyVar]
219 tyConTyVars FunTyCon = [alphaTyVar,betaTyVar]
220 tyConTyVars (DataTyCon _ _ _ tvs _ _ _ _) = tvs
221 tyConTyVars (TupleTyCon _ _ arity) = take arity alphaTyVars
222 tyConTyVars (SynTyCon _ _ _ _ tvs _) = tvs
224 tyConTyVars (PrimTyCon _ _ _ _) = panic "tyConTyVars:PrimTyCon"
225 tyConTyVars (SpecTyCon _ _ ) = panic "tyConTyVars:SpecTyCon"
230 tyConDataCons :: TyCon -> [Id]
231 tyConFamilySize :: TyCon -> Int
233 tyConDataCons (DataTyCon _ _ _ _ _ data_cons _ _) = data_cons
234 tyConDataCons (TupleTyCon _ _ a) = [tupleCon a]
235 tyConDataCons other = []
236 -- You may think this last equation should fail,
237 -- but it's quite convenient to return no constructors for
238 -- a synonym; see for example the call in TcTyClsDecls.
240 tyConFamilySize (DataTyCon _ _ _ _ _ data_cons _ _) = length data_cons
241 tyConFamilySize (TupleTyCon _ _ _) = 1
243 --tyConFamilySize other = pprPanic "tyConFamilySize:" (pprTyCon PprDebug other)
246 tyConPrimRep :: TyCon -> PrimRep
247 tyConPrimRep (PrimTyCon _ _ _ rep) = rep
248 tyConPrimRep _ = PtrRep
252 tyConDerivings :: TyCon -> [Class]
253 tyConDerivings (DataTyCon _ _ _ _ _ _ derivs _) = derivs
254 tyConDerivings other = []
258 tyConTheta :: TyCon -> [(Class,Type)]
259 tyConTheta (DataTyCon _ _ _ _ theta _ _ _) = theta
260 tyConTheta (TupleTyCon _ _ _) = []
261 -- should ask about anything else
265 getSynTyConDefn :: TyCon -> ([TyVar], Type)
266 getSynTyConDefn (SynTyCon _ _ _ _ tyvars ty) = (tyvars,ty)
270 maybeTyConSingleCon :: TyCon -> Maybe Id
272 maybeTyConSingleCon (TupleTyCon _ _ arity) = Just (tupleCon arity)
273 maybeTyConSingleCon (DataTyCon _ _ _ _ _ [c] _ _) = Just c
274 maybeTyConSingleCon (DataTyCon _ _ _ _ _ _ _ _) = Nothing
275 maybeTyConSingleCon (PrimTyCon _ _ _ _) = Nothing
276 maybeTyConSingleCon (SpecTyCon tc tys) = panic "maybeTyConSingleCon:SpecTyCon"
277 -- requires DataCons of TyCon
279 isEnumerationTyCon (TupleTyCon _ _ arity)
281 isEnumerationTyCon (DataTyCon _ _ _ _ _ data_cons _ _)
282 = not (null data_cons) && all isNullaryDataCon data_cons
285 isTupleTyCon (TupleTyCon _ _ arity) = arity >= 2 -- treat "0-tuple" specially
286 isTupleTyCon (SpecTyCon tc tys) = isTupleTyCon tc
287 isTupleTyCon other = False
292 @derivedFor@ reports if we have an {\em obviously}-derived instance
293 for the given class/tycon. Of course, you might be deriving something
294 because it a superclass of some other obviously-derived class --- this
295 function doesn't deal with that.
297 ToDo: what about derivings for specialised tycons !!!
300 derivedFor :: Class -> TyCon -> Bool
301 derivedFor clas (DataTyCon _ _ _ _ _ _ derivs _) = isIn "derivedFor" clas derivs
302 derivedFor clas something_weird = False
305 %************************************************************************
307 \subsection[TyCon-instances]{Instance declarations for @TyCon@}
309 %************************************************************************
311 @TyCon@s are compared by comparing their @Unique@s.
313 The strictness analyser needs @Ord@. It is a lexicographic order with
314 the property @(a<=b) || (b<=a)@.
317 instance Ord3 TyCon where
318 cmp tc1 tc2 = uniqueOf tc1 `cmp` uniqueOf tc2
320 instance Eq TyCon where
321 a == b = case (a `cmp` b) of { EQ_ -> True; _ -> False }
322 a /= b = case (a `cmp` b) of { EQ_ -> False; _ -> True }
324 instance Ord TyCon where
325 a <= b = case (a `cmp` b) of { LT_ -> True; EQ_ -> True; GT__ -> False }
326 a < b = case (a `cmp` b) of { LT_ -> True; EQ_ -> False; GT__ -> False }
327 a >= b = case (a `cmp` b) of { LT_ -> False; EQ_ -> True; GT__ -> True }
328 a > b = case (a `cmp` b) of { LT_ -> False; EQ_ -> False; GT__ -> True }
329 _tagCmp a b = case (a `cmp` b) of { LT_ -> _LT; EQ_ -> _EQ; GT__ -> _GT }
331 instance Uniquable TyCon where
332 uniqueOf (DataTyCon u _ _ _ _ _ _ _) = u
333 uniqueOf (TupleTyCon u _ _) = u
334 uniqueOf (PrimTyCon u _ _ _) = u
335 uniqueOf (SynTyCon u _ _ _ _ _) = u
336 uniqueOf tc@(SpecTyCon _ _) = panic "uniqueOf:SpecTyCon"
337 uniqueOf tc = uniqueOf (getName tc)
341 instance NamedThing TyCon where
342 getName (DataTyCon _ n _ _ _ _ _ _) = n
343 getName (PrimTyCon _ n _ _) = n
344 getName (SpecTyCon tc _) = getName tc
345 getName (SynTyCon _ n _ _ _ _) = n
346 getName FunTyCon = mkFunTyConName
347 getName (TupleTyCon _ n _) = n
348 getName tc = panic "TyCon.getName"
351 getName (SpecTyCon tc tys) = let (OrigName m n) = origName "????" tc in
352 (m, n _APPEND_ specMaybeTysSuffix tys)
353 getName other_tc = moduleNamePair (expectJust "tycon1" (getName other_tc))
354 getName other = Nothing