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, NamedThing(getName) )
57 import Unique ( Unique, funTyConKey )
58 import UniqFM ( Uniquable(..) )
60 import PrimRep ( PrimRep(..) )
61 import PrelMods ( gHC__, pREL_TUP, pREL_BASE )
62 import Lex ( mkTupNameStr )
63 import SrcLoc ( SrcLoc, mkBuiltinSrcLoc )
64 import Util ( nOfThem, isIn, Ord3(..), panic, panic#, assertPanic )
75 = FunTyCon -- Kind = Type -> Type -> Type
77 | DataTyCon Unique{-TyConKey-}
81 [(Class,Type)] -- Its context
82 [Id{-DataCon-}] -- Its data constructors, with fully polymorphic types
83 -- This list can be empty, when we import a data type abstractly,
84 -- either (a) the interface is hand-written and doesn't give
85 -- the constructors, or
86 -- (b) in a quest for fast compilation we don't import
88 [Class] -- Classes which have derived instances
91 | TupleTyCon Unique -- cached
92 Name -- again, we could do without this, but
93 -- it makes life somewhat easier
94 Arity -- just a special case of DataTyCon
95 -- Kind = BoxedTypeKind
96 -- -> ... (n times) ...
100 | PrimTyCon -- Primitive types; cannot be defined in Haskell
101 Unique -- Always unboxed; hence never represented by a closure
102 Name -- Often represented by a bit-pattern for the thing
103 Kind -- itself (eg Int#), but sometimes by a pointer to
106 | SpecTyCon -- A specialised TyCon; eg (Arr# Int#), or (List Int#)
108 [Maybe Type] -- Specialising types
110 -- OLD STUFF ABOUT Array types. Use SpecTyCon instead
111 -- ([PrimRep] -> PrimRep) -- a heap-allocated object (eg ArrInt#).
112 -- The primitive types Arr# and StablePtr# have
113 -- parameters (hence arity /= 0); but the rest don't.
114 -- Only arrays use the list in a non-trivial way.
115 -- Length of that list must == arity.
122 [TyVar] -- Argument type variables
123 Type -- Right-hand side, mentioning these type vars.
124 -- Acts as a template for the expansion when
125 -- the tycon is applied to some types.
128 = NewType -- "newtype Blah ..."
129 | DataType -- "data Blah ..."
133 mkFunTyCon = FunTyCon
134 mkFunTyConName = mkWiredInTyConName funTyConKey gHC__ SLIT("->") FunTyCon
136 mkSpecTyCon = SpecTyCon
137 mkTupleTyCon = TupleTyCon
139 mkDataTyCon name = DataTyCon (nameUnique name) name
140 mkPrimTyCon name = PrimTyCon (nameUnique name) name
141 mkSynTyCon name = SynTyCon (nameUnique name) name
143 isFunTyCon FunTyCon = True
146 isPrimTyCon (PrimTyCon _ _ _ _) = True
147 isPrimTyCon _ = False
149 -- At present there are no unboxed non-primitive types, so
150 -- isBoxedTyCon is just the negation of isPrimTyCon.
151 isBoxedTyCon = not . isPrimTyCon
153 -- isDataTyCon returns False for @newtype@.
154 -- Not sure about this decision yet.
155 isDataTyCon (DataTyCon _ _ _ _ _ _ _ DataType) = True
156 isDataTyCon (TupleTyCon _ _ _) = True
157 isDataTyCon other = False
159 maybeNewTyCon :: TyCon -> Maybe ([TyVar], Type) -- Returns representation type info
160 maybeNewTyCon (DataTyCon _ _ _ _ _ (con:null_cons) _ NewType)
161 = ASSERT( null null_cons && null null_tys)
162 Just (tyvars, rep_ty)
164 (tyvars, theta, tau) = splitSigmaTy (idType con)
165 (rep_ty:null_tys, res_ty) = splitFunTy tau
167 maybeNewTyCon other = Nothing
169 isNewTyCon (DataTyCon _ _ _ _ _ _ _ NewType) = True
170 isNewTyCon other = False
172 isSynTyCon (SynTyCon _ _ _ _ _ _) = True
177 -- Special cases to avoid reconstructing lots of kinds
178 kind1 = mkBoxedTypeKind `mkArrowKind` mkBoxedTypeKind
179 kind2 = mkBoxedTypeKind `mkArrowKind` kind1
181 tyConKind :: TyCon -> Kind
182 tyConKind FunTyCon = kind2
183 tyConKind (DataTyCon _ _ kind _ _ _ _ _) = kind
184 tyConKind (PrimTyCon _ _ kind _) = kind
185 tyConKind (SynTyCon _ _ k _ _ _) = k
187 tyConKind (TupleTyCon _ _ n)
190 mkArrow 0 = mkBoxedTypeKind
193 mkArrow n = mkBoxedTypeKind `mkArrowKind` mkArrow (n-1)
195 tyConKind (SpecTyCon tc tys)
196 = spec (tyConKind tc) tys
199 spec kind (Just _ : tys) = spec (resultKind kind) tys
200 spec kind (Nothing : tys) =
201 argKind kind `mkArrowKind` spec (resultKind kind) tys
205 tyConUnique :: TyCon -> Unique
206 tyConUnique FunTyCon = funTyConKey
207 tyConUnique (DataTyCon uniq _ _ _ _ _ _ _) = uniq
208 tyConUnique (TupleTyCon uniq _ _) = uniq
209 tyConUnique (PrimTyCon uniq _ _ _) = uniq
210 tyConUnique (SynTyCon uniq _ _ _ _ _) = uniq
211 tyConUnique (SpecTyCon _ _ ) = panic "tyConUnique:SpecTyCon"
213 synTyConArity :: TyCon -> Maybe Arity -- Nothing <=> not a syn tycon
214 synTyConArity (SynTyCon _ _ _ arity _ _) = Just arity
215 synTyConArity _ = Nothing
219 tyConTyVars :: TyCon -> [TyVar]
220 tyConTyVars FunTyCon = [alphaTyVar,betaTyVar]
221 tyConTyVars (DataTyCon _ _ _ tvs _ _ _ _) = tvs
222 tyConTyVars (TupleTyCon _ _ arity) = take arity alphaTyVars
223 tyConTyVars (SynTyCon _ _ _ _ tvs _) = tvs
225 tyConTyVars (PrimTyCon _ _ _ _) = panic "tyConTyVars:PrimTyCon"
226 tyConTyVars (SpecTyCon _ _ ) = panic "tyConTyVars:SpecTyCon"
231 tyConDataCons :: TyCon -> [Id]
232 tyConFamilySize :: TyCon -> Int
234 tyConDataCons (DataTyCon _ _ _ _ _ data_cons _ _) = data_cons
235 tyConDataCons (TupleTyCon _ _ a) = [tupleCon a]
236 tyConDataCons other = []
237 -- You may think this last equation should fail,
238 -- but it's quite convenient to return no constructors for
239 -- a synonym; see for example the call in TcTyClsDecls.
241 tyConFamilySize (DataTyCon _ _ _ _ _ data_cons _ _) = length data_cons
242 tyConFamilySize (TupleTyCon _ _ _) = 1
244 --tyConFamilySize other = pprPanic "tyConFamilySize:" (pprTyCon PprDebug other)
247 tyConPrimRep :: TyCon -> PrimRep
248 tyConPrimRep (PrimTyCon _ _ _ rep) = rep
249 tyConPrimRep _ = PtrRep
253 tyConDerivings :: TyCon -> [Class]
254 tyConDerivings (DataTyCon _ _ _ _ _ _ derivs _) = derivs
255 tyConDerivings other = []
259 tyConTheta :: TyCon -> [(Class,Type)]
260 tyConTheta (DataTyCon _ _ _ _ theta _ _ _) = theta
261 tyConTheta (TupleTyCon _ _ _) = []
262 -- should ask about anything else
266 getSynTyConDefn :: TyCon -> ([TyVar], Type)
267 getSynTyConDefn (SynTyCon _ _ _ _ tyvars ty) = (tyvars,ty)
271 maybeTyConSingleCon :: TyCon -> Maybe Id
273 maybeTyConSingleCon (TupleTyCon _ _ arity) = Just (tupleCon arity)
274 maybeTyConSingleCon (DataTyCon _ _ _ _ _ [c] _ _) = Just c
275 maybeTyConSingleCon (DataTyCon _ _ _ _ _ _ _ _) = Nothing
276 maybeTyConSingleCon (PrimTyCon _ _ _ _) = Nothing
277 maybeTyConSingleCon (SpecTyCon tc tys) = panic "maybeTyConSingleCon:SpecTyCon"
278 -- requires DataCons of TyCon
280 isEnumerationTyCon (TupleTyCon _ _ arity)
282 isEnumerationTyCon (DataTyCon _ _ _ _ _ data_cons _ _)
283 = not (null data_cons) && all isNullaryDataCon data_cons
286 isTupleTyCon (TupleTyCon _ _ arity) = arity >= 2 -- treat "0-tuple" specially
287 isTupleTyCon (SpecTyCon tc tys) = isTupleTyCon tc
288 isTupleTyCon other = False
293 @derivedFor@ reports if we have an {\em obviously}-derived instance
294 for the given class/tycon. Of course, you might be deriving something
295 because it a superclass of some other obviously-derived class --- this
296 function doesn't deal with that.
298 ToDo: what about derivings for specialised tycons !!!
301 derivedFor :: Class -> TyCon -> Bool
302 derivedFor clas (DataTyCon _ _ _ _ _ _ derivs _) = isIn "derivedFor" clas derivs
303 derivedFor clas something_weird = False
306 %************************************************************************
308 \subsection[TyCon-instances]{Instance declarations for @TyCon@}
310 %************************************************************************
312 @TyCon@s are compared by comparing their @Unique@s.
314 The strictness analyser needs @Ord@. It is a lexicographic order with
315 the property @(a<=b) || (b<=a)@.
318 instance Ord3 TyCon where
319 cmp tc1 tc2 = uniqueOf tc1 `cmp` uniqueOf tc2
321 instance Eq TyCon where
322 a == b = case (a `cmp` b) of { EQ_ -> True; _ -> False }
323 a /= b = case (a `cmp` b) of { EQ_ -> False; _ -> True }
325 instance Ord TyCon where
326 a <= b = case (a `cmp` b) of { LT_ -> True; EQ_ -> True; GT__ -> False }
327 a < b = case (a `cmp` b) of { LT_ -> True; EQ_ -> False; GT__ -> False }
328 a >= b = case (a `cmp` b) of { LT_ -> False; EQ_ -> True; GT__ -> True }
329 a > b = case (a `cmp` b) of { LT_ -> False; EQ_ -> False; GT__ -> True }
330 _tagCmp a b = case (a `cmp` b) of { LT_ -> _LT; EQ_ -> _EQ; GT__ -> _GT }
332 instance Uniquable TyCon where
333 uniqueOf (DataTyCon u _ _ _ _ _ _ _) = u
334 uniqueOf (TupleTyCon u _ _) = u
335 uniqueOf (PrimTyCon u _ _ _) = u
336 uniqueOf (SynTyCon u _ _ _ _ _) = u
337 uniqueOf tc@(SpecTyCon _ _) = panic "uniqueOf:SpecTyCon"
338 uniqueOf tc = uniqueOf (getName tc)
342 instance NamedThing TyCon where
343 getName (DataTyCon _ n _ _ _ _ _ _) = n
344 getName (PrimTyCon _ n _ _) = n
345 getName (SpecTyCon tc _) = getName tc
346 getName (SynTyCon _ n _ _ _ _) = n
347 getName FunTyCon = mkFunTyConName
348 getName (TupleTyCon _ n _) = n
349 getName tc = panic "TyCon.getName"
352 getName (SpecTyCon tc tys) = let (OrigName m n) = origName "????" tc in
353 (m, n _APPEND_ specMaybeTysSuffix tys)
354 getName other_tc = moduleNamePair (expectJust "tycon1" (getName other_tc))
355 getName other = Nothing