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 Arity(..), NewOrData(..),
14 isFunTyCon, isPrimTyCon, isBoxedTyCon,
15 isDataTyCon, isSynTyCon,
31 tyConArity, synTyConArity,
39 CHK_Ubiq() -- debugging consistency check
41 import TyLoop ( Type(..), GenType,
44 mkTupleCon, dataConSig,
48 import TyVar ( GenTyVar, alphaTyVars, alphaTyVar, betaTyVar )
49 import Usage ( GenUsage, Usage(..) )
50 import Kind ( Kind, mkBoxedTypeKind, mkArrowKind, resultKind, argKind )
51 import PrelMods ( pRELUDE_BUILTIN )
54 import Name ( Name, RdrName(..), appendRdr, nameUnique,
55 mkTupleTyConName, mkFunTyConName
57 import Unique ( Unique, funTyConKey, mkTupleTyConUnique )
58 import Pretty ( Pretty(..), PrettyRep )
59 import PprStyle ( PprStyle )
60 import SrcLoc ( SrcLoc, mkBuiltinSrcLoc )
61 import Util ( panic, panic#, nOfThem, isIn, Ord3(..) )
68 = FunTyCon -- Kind = Type -> Type -> Type
70 | DataTyCon Unique{-TyConKey-}
74 [(Class,Type)] -- Its context
75 [Id] -- Its data constructors, with fully polymorphic types
76 [Class] -- Classes which have derived instances
79 | TupleTyCon Unique -- cached
80 Name -- again, we could do without this, but
81 -- it makes life somewhat easier
82 Arity -- just a special case of DataTyCon
83 -- Kind = BoxedTypeKind
84 -- -> ... (n times) ...
88 | PrimTyCon -- Primitive types; cannot be defined in Haskell
89 Unique -- Always unboxed; hence never represented by a closure
90 Name -- Often represented by a bit-pattern for the thing
91 Kind -- itself (eg Int#), but sometimes by a pointer to
93 | SpecTyCon -- A specialised TyCon; eg (Arr# Int#), or (List Int#)
95 [Maybe Type] -- Specialising types
97 -- OLD STUFF ABOUT Array types. Use SpecTyCon instead
98 -- ([PrimRep] -> PrimRep) -- a heap-allocated object (eg ArrInt#).
99 -- The primitive types Arr# and StablePtr# have
100 -- parameters (hence arity /= 0); but the rest don't.
101 -- Only arrays use the list in a non-trivial way.
102 -- Length of that list must == arity.
109 [TyVar] -- Argument type variables
110 Type -- Right-hand side, mentioning these type vars.
111 -- Acts as a template for the expansion when
112 -- the tycon is applied to some types.
115 = NewType -- "newtype Blah ..."
116 | DataType -- "data Blah ..."
120 mkFunTyCon = FunTyCon
121 mkSpecTyCon = SpecTyCon
124 = TupleTyCon u n arity
126 n = mkTupleTyConName arity
130 = DataTyCon (nameUnique name) name
132 = PrimTyCon (nameUnique name) name
134 = SynTyCon (nameUnique name) name
136 isFunTyCon FunTyCon = True
139 isPrimTyCon (PrimTyCon _ _ _) = True
140 isPrimTyCon _ = False
142 -- At present there are no unboxed non-primitive types, so
143 -- isBoxedTyCon is just the negation of isPrimTyCon.
144 isBoxedTyCon = not . isPrimTyCon
146 -- isDataTyCon returns False for @newtype@.
147 -- Not sure about this decision yet.
148 isDataTyCon (DataTyCon _ _ _ _ _ _ _ DataType) = True
149 isDataTyCon other = False
151 isSynTyCon (SynTyCon _ _ _ _ _ _) = True
156 -- Special cases to avoid reconstructing lots of kinds
157 kind1 = mkBoxedTypeKind `mkArrowKind` mkBoxedTypeKind
158 kind2 = mkBoxedTypeKind `mkArrowKind` kind1
160 tyConKind :: TyCon -> Kind
161 tyConKind FunTyCon = kind2
162 tyConKind (DataTyCon _ _ kind _ _ _ _ _) = kind
163 tyConKind (PrimTyCon _ _ kind) = kind
165 tyConKind (SpecTyCon tc tys)
166 = spec (tyConKind tc) tys
169 spec kind (Just _ : tys) = spec (resultKind kind) tys
170 spec kind (Nothing : tys) =
171 argKind kind `mkArrowKind` spec (resultKind kind) tys
173 tyConKind (TupleTyCon _ _ n)
176 mkArrow 0 = mkBoxedTypeKind
179 mkArrow n = mkBoxedTypeKind `mkArrowKind` mkArrow (n-1)
183 tyConUnique :: TyCon -> Unique
184 tyConUnique FunTyCon = funTyConKey
185 tyConUnique (DataTyCon uniq _ _ _ _ _ _ _) = uniq
186 tyConUnique (TupleTyCon uniq _ _) = uniq
187 tyConUnique (PrimTyCon uniq _ _) = uniq
188 tyConUnique (SynTyCon uniq _ _ _ _ _) = uniq
189 tyConUnique (SpecTyCon _ _ ) = panic "tyConUnique:SpecTyCon"
191 tyConArity :: TyCon -> Arity
192 tyConArity FunTyCon = 2
193 tyConArity (DataTyCon _ _ _ tvs _ _ _ _) = length tvs
194 tyConArity (TupleTyCon _ _ arity) = arity
195 tyConArity (PrimTyCon _ _ _) = 0 -- ??
196 tyConArity (SpecTyCon _ _) = 0
197 tyConArity (SynTyCon _ _ _ arity _ _) = arity
199 synTyConArity :: TyCon -> Maybe Arity -- Nothing <=> not a syn tycon
200 synTyConArity (SynTyCon _ _ _ arity _ _) = Just arity
201 synTyConArity _ = Nothing
205 tyConTyVars :: TyCon -> [TyVar]
206 tyConTyVars FunTyCon = [alphaTyVar,betaTyVar]
207 tyConTyVars (DataTyCon _ _ _ tvs _ _ _ _) = tvs
208 tyConTyVars (TupleTyCon _ _ arity) = take arity alphaTyVars
209 tyConTyVars (SynTyCon _ _ _ _ tvs _) = tvs
210 tyConTyVars (PrimTyCon _ _ _) = panic "tyConTyVars:PrimTyCon"
211 tyConTyVars (SpecTyCon _ _ ) = panic "tyConTyVars:SpecTyCon"
215 tyConDataCons :: TyCon -> [Id]
216 tyConFamilySize :: TyCon -> Int
218 tyConDataCons (DataTyCon _ _ _ _ _ data_cons _ _) = data_cons
219 tyConDataCons (TupleTyCon _ _ a) = [mkTupleCon a]
220 tyConDataCons other = []
221 -- You may think this last equation should fail,
222 -- but it's quite convenient to return no constructors for
223 -- a synonym; see for example the call in TcTyClsDecls.
225 tyConFamilySize (DataTyCon _ _ _ _ _ data_cons _ _) = length data_cons
226 tyConFamilySize (TupleTyCon _ _ _) = 1
230 tyConDerivings :: TyCon -> [Class]
231 tyConDerivings (DataTyCon _ _ _ _ _ _ derivs _) = derivs
232 tyConDerivings other = []
236 getSynTyConDefn :: TyCon -> ([TyVar], Type)
237 getSynTyConDefn (SynTyCon _ _ _ _ tyvars ty) = (tyvars,ty)
241 maybeTyConSingleCon :: TyCon -> Maybe Id
243 maybeTyConSingleCon (TupleTyCon _ _ arity) = Just (mkTupleCon arity)
244 maybeTyConSingleCon (DataTyCon _ _ _ _ _ [c] _ _) = Just c
245 maybeTyConSingleCon (DataTyCon _ _ _ _ _ _ _ _) = Nothing
246 maybeTyConSingleCon (PrimTyCon _ _ _) = Nothing
247 maybeTyConSingleCon (SpecTyCon tc tys) = panic "maybeTyConSingleCon:SpecTyCon"
248 -- requires DataCons of TyCon
250 isEnumerationTyCon (TupleTyCon _ _ arity)
252 isEnumerationTyCon (DataTyCon _ _ _ _ _ data_cons _ _)
253 = not (null data_cons) && all is_nullary data_cons
255 is_nullary con = case (dataConSig con) of { (_,_, arg_tys, _) ->
259 @derivedFor@ reports if we have an {\em obviously}-derived instance
260 for the given class/tycon. Of course, you might be deriving something
261 because it a superclass of some other obviously-derived class --- this
262 function doesn't deal with that.
264 ToDo: what about derivings for specialised tycons !!!
267 derivedFor :: Class -> TyCon -> Bool
268 derivedFor clas (DataTyCon _ _ _ _ _ _ derivs _) = isIn "derivedFor" clas derivs
269 derivedFor clas something_weird = False
272 %************************************************************************
274 \subsection[TyCon-instances]{Instance declarations for @TyCon@}
276 %************************************************************************
278 @TyCon@s are compared by comparing their @Unique@s.
280 The strictness analyser needs @Ord@. It is a lexicographic order with
281 the property @(a<=b) || (b<=a)@.
284 instance Ord3 TyCon where
285 cmp FunTyCon FunTyCon = EQ_
286 cmp (DataTyCon a _ _ _ _ _ _ _) (DataTyCon b _ _ _ _ _ _ _) = a `cmp` b
287 cmp (SynTyCon a _ _ _ _ _) (SynTyCon b _ _ _ _ _) = a `cmp` b
288 cmp (TupleTyCon _ _ a) (TupleTyCon _ _ b) = a `cmp` b
289 cmp (PrimTyCon a _ _) (PrimTyCon b _ _) = a `cmp` b
290 cmp (SpecTyCon tc1 mtys1) (SpecTyCon tc2 mtys2)
291 = panic# "cmp on SpecTyCons" -- case (tc1 `cmp` tc2) of { EQ_ -> mtys1 `cmp` mtys2; xxx -> xxx }
293 -- now we *know* the tags are different, so...
295 | tag1 _LT_ tag2 = LT_
298 tag1 = tag_TyCon other_1
299 tag2 = tag_TyCon other_2
300 tag_TyCon FunTyCon = ILIT(1)
301 tag_TyCon (DataTyCon _ _ _ _ _ _ _ _) = ILIT(2)
302 tag_TyCon (TupleTyCon _ _ _) = ILIT(3)
303 tag_TyCon (PrimTyCon _ _ _) = ILIT(4)
304 tag_TyCon (SpecTyCon _ _) = ILIT(5)
306 instance Eq TyCon where
307 a == b = case (a `cmp` b) of { EQ_ -> True; _ -> False }
308 a /= b = case (a `cmp` b) of { EQ_ -> False; _ -> True }
310 instance Ord TyCon where
311 a <= b = case (a `cmp` b) of { LT_ -> True; EQ_ -> True; GT__ -> False }
312 a < b = case (a `cmp` b) of { LT_ -> True; EQ_ -> False; GT__ -> False }
313 a >= b = case (a `cmp` b) of { LT_ -> False; EQ_ -> True; GT__ -> True }
314 a > b = case (a `cmp` b) of { LT_ -> False; EQ_ -> False; GT__ -> True }
315 _tagCmp a b = case (a `cmp` b) of { LT_ -> _LT; EQ_ -> _EQ; GT__ -> _GT }
317 instance Uniquable TyCon where
318 uniqueOf (DataTyCon u _ _ _ _ _ _ _) = u
319 uniqueOf (PrimTyCon u _ _) = u
320 uniqueOf (SynTyCon u _ _ _ _ _) = u
321 uniqueOf tc@(SpecTyCon _ _) = panic "uniqueOf:SpecTyCon"
322 uniqueOf tc = uniqueOf (getName tc)
326 instance NamedThing TyCon where
327 getName (DataTyCon _ n _ _ _ _ _ _) = n
328 getName (PrimTyCon _ n _) = n
329 getName (SpecTyCon tc _) = getName tc
330 getName (SynTyCon _ n _ _ _ _) = n
331 getName FunTyCon = mkFunTyConName
332 getName (TupleTyCon _ n _) = n
333 getName tc = panic "TyCon.getName"
336 getName (SpecTyCon tc tys) = let (m,n) = getOrigName tc in
337 (m, n _APPEND_ specMaybeTysSuffix tys)
338 getName other_tc = getOrigName (expectJust "tycon1" (getName other_tc))
339 getName other = Nothing