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, isNewTyCon,
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 )
53 import Name ( Name, RdrName(..), appendRdr, nameUnique,
54 mkTupleTyConName, mkFunTyConName
56 import Unique ( Unique, funTyConKey, mkTupleTyConUnique )
57 import PrelInfo ( intDataCon, charDataCon )
58 import Pretty ( Pretty(..), PrettyRep )
59 import PprStyle ( PprStyle )
60 import SrcLoc ( SrcLoc, mkBuiltinSrcLoc )
61 import Unique ( intDataConKey, charDataConKey )
62 import Util ( panic, panic#, nOfThem, isIn, Ord3(..) )
69 = FunTyCon -- Kind = Type -> Type -> Type
71 | DataTyCon Unique{-TyConKey-}
75 [(Class,Type)] -- Its context
76 [Id] -- Its data constructors, with fully polymorphic types
77 [Class] -- Classes which have derived instances
80 | TupleTyCon Unique -- cached
81 Name -- again, we could do without this, but
82 -- it makes life somewhat easier
83 Arity -- just a special case of DataTyCon
84 -- Kind = BoxedTypeKind
85 -- -> ... (n times) ...
89 | PrimTyCon -- Primitive types; cannot be defined in Haskell
90 Unique -- Always unboxed; hence never represented by a closure
91 Name -- Often represented by a bit-pattern for the thing
92 Kind -- itself (eg Int#), but sometimes by a pointer to
94 | SpecTyCon -- A specialised TyCon; eg (Arr# Int#), or (List Int#)
96 [Maybe Type] -- Specialising types
98 -- OLD STUFF ABOUT Array types. Use SpecTyCon instead
99 -- ([PrimRep] -> PrimRep) -- a heap-allocated object (eg ArrInt#).
100 -- The primitive types Arr# and StablePtr# have
101 -- parameters (hence arity /= 0); but the rest don't.
102 -- Only arrays use the list in a non-trivial way.
103 -- Length of that list must == arity.
110 [TyVar] -- Argument type variables
111 Type -- Right-hand side, mentioning these type vars.
112 -- Acts as a template for the expansion when
113 -- the tycon is applied to some types.
116 = NewType -- "newtype Blah ..."
117 | DataType -- "data Blah ..."
121 mkFunTyCon = FunTyCon
122 mkSpecTyCon = SpecTyCon
125 = TupleTyCon u n arity
127 n = mkTupleTyConName arity
131 = DataTyCon (nameUnique name) name
133 = PrimTyCon (nameUnique name) name
135 = 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 isNewTyCon (DataTyCon _ _ _ _ _ _ _ NewType) = True
154 isNewTyCon other = False
156 isSynTyCon (SynTyCon _ _ _ _ _ _) = True
161 -- Special cases to avoid reconstructing lots of kinds
162 kind1 = mkBoxedTypeKind `mkArrowKind` mkBoxedTypeKind
163 kind2 = mkBoxedTypeKind `mkArrowKind` kind1
165 tyConKind :: TyCon -> Kind
166 tyConKind FunTyCon = kind2
167 tyConKind (DataTyCon _ _ kind _ _ _ _ _) = kind
168 tyConKind (PrimTyCon _ _ kind) = kind
169 tyConKind (SynTyCon _ _ k _ _ _) = k
171 tyConKind (TupleTyCon _ _ n)
174 mkArrow 0 = mkBoxedTypeKind
177 mkArrow n = mkBoxedTypeKind `mkArrowKind` mkArrow (n-1)
179 tyConKind (SpecTyCon tc tys)
180 = spec (tyConKind tc) tys
183 spec kind (Just _ : tys) = spec (resultKind kind) tys
184 spec kind (Nothing : tys) =
185 argKind kind `mkArrowKind` spec (resultKind kind) tys
189 tyConUnique :: TyCon -> Unique
190 tyConUnique FunTyCon = funTyConKey
191 tyConUnique (DataTyCon uniq _ _ _ _ _ _ _) = uniq
192 tyConUnique (TupleTyCon uniq _ _) = uniq
193 tyConUnique (PrimTyCon uniq _ _) = uniq
194 tyConUnique (SynTyCon uniq _ _ _ _ _) = uniq
195 tyConUnique (SpecTyCon _ _ ) = panic "tyConUnique:SpecTyCon"
197 tyConArity :: TyCon -> Arity
198 tyConArity FunTyCon = 2
199 tyConArity (DataTyCon _ _ _ tvs _ _ _ _) = length tvs
200 tyConArity (TupleTyCon _ _ arity) = arity
201 tyConArity (PrimTyCon _ _ _) = 0 -- ??
202 tyConArity (SpecTyCon _ _) = 0
203 tyConArity (SynTyCon _ _ _ arity _ _) = arity
205 synTyConArity :: TyCon -> Maybe Arity -- Nothing <=> not a syn tycon
206 synTyConArity (SynTyCon _ _ _ arity _ _) = Just arity
207 synTyConArity _ = Nothing
211 tyConTyVars :: TyCon -> [TyVar]
212 tyConTyVars FunTyCon = [alphaTyVar,betaTyVar]
213 tyConTyVars (DataTyCon _ _ _ tvs _ _ _ _) = tvs
214 tyConTyVars (TupleTyCon _ _ arity) = take arity alphaTyVars
215 tyConTyVars (SynTyCon _ _ _ _ tvs _) = tvs
216 tyConTyVars (PrimTyCon _ _ _) = panic "tyConTyVars:PrimTyCon"
217 tyConTyVars (SpecTyCon _ _ ) = panic "tyConTyVars:SpecTyCon"
221 tyConDataCons :: TyCon -> [Id]
222 tyConFamilySize :: TyCon -> Int
224 tyConDataCons (DataTyCon _ _ _ _ _ data_cons _ _) = data_cons
225 tyConDataCons (TupleTyCon _ _ a) = [mkTupleCon a]
226 tyConDataCons other = []
227 -- You may think this last equation should fail,
228 -- but it's quite convenient to return no constructors for
229 -- a synonym; see for example the call in TcTyClsDecls.
231 tyConFamilySize (DataTyCon _ _ _ _ _ data_cons _ _) = length data_cons
232 tyConFamilySize (TupleTyCon _ _ _) = 1
236 tyConDerivings :: TyCon -> [Class]
237 tyConDerivings (DataTyCon _ _ _ _ _ _ derivs _) = derivs
238 tyConDerivings other = []
242 getSynTyConDefn :: TyCon -> ([TyVar], Type)
243 getSynTyConDefn (SynTyCon _ _ _ _ tyvars ty) = (tyvars,ty)
247 maybeTyConSingleCon :: TyCon -> Maybe Id
249 maybeTyConSingleCon (TupleTyCon _ _ arity) = Just (mkTupleCon arity)
250 maybeTyConSingleCon (DataTyCon _ _ _ _ _ [c] _ _) = Just c
251 maybeTyConSingleCon (DataTyCon _ _ _ _ _ _ _ _) = Nothing
252 maybeTyConSingleCon (PrimTyCon _ _ _) = Nothing
253 maybeTyConSingleCon (SpecTyCon tc tys) = panic "maybeTyConSingleCon:SpecTyCon"
254 -- requires DataCons of TyCon
256 isEnumerationTyCon (TupleTyCon _ _ arity)
258 isEnumerationTyCon (DataTyCon _ _ _ _ _ data_cons _ _)
259 = not (null data_cons) && all is_nullary data_cons
261 is_nullary con = case (dataConSig con) of { (_,_, arg_tys, _) ->
265 @derivedFor@ reports if we have an {\em obviously}-derived instance
266 for the given class/tycon. Of course, you might be deriving something
267 because it a superclass of some other obviously-derived class --- this
268 function doesn't deal with that.
270 ToDo: what about derivings for specialised tycons !!!
273 derivedFor :: Class -> TyCon -> Bool
274 derivedFor clas (DataTyCon _ _ _ _ _ _ derivs _) = isIn "derivedFor" clas derivs
275 derivedFor clas something_weird = False
278 %************************************************************************
280 \subsection[TyCon-instances]{Instance declarations for @TyCon@}
282 %************************************************************************
284 @TyCon@s are compared by comparing their @Unique@s.
286 The strictness analyser needs @Ord@. It is a lexicographic order with
287 the property @(a<=b) || (b<=a)@.
290 instance Ord3 TyCon where
291 cmp FunTyCon FunTyCon = EQ_
292 cmp (DataTyCon a _ _ _ _ _ _ _) (DataTyCon b _ _ _ _ _ _ _) = a `cmp` b
293 cmp (SynTyCon a _ _ _ _ _) (SynTyCon b _ _ _ _ _) = a `cmp` b
294 cmp (TupleTyCon _ _ a) (TupleTyCon _ _ b) = a `cmp` b
295 cmp (PrimTyCon a _ _) (PrimTyCon b _ _) = a `cmp` b
296 cmp (SpecTyCon tc1 mtys1) (SpecTyCon tc2 mtys2)
297 = panic# "cmp on SpecTyCons" -- case (tc1 `cmp` tc2) of { EQ_ -> mtys1 `cmp` mtys2; xxx -> xxx }
299 -- now we *know* the tags are different, so...
301 | tag1 _LT_ tag2 = LT_
304 tag1 = tag_TyCon other_1
305 tag2 = tag_TyCon other_2
307 tag_TyCon FunTyCon = ILIT(1)
308 tag_TyCon (DataTyCon _ _ _ _ _ _ _ _) = ILIT(2)
309 tag_TyCon (TupleTyCon _ _ _) = ILIT(3)
310 tag_TyCon (PrimTyCon _ _ _) = ILIT(4)
311 tag_TyCon (SpecTyCon _ _) = ILIT(5)
312 tag_TyCon (SynTyCon _ _ _ _ _ _) = ILIT(6)
314 instance Eq TyCon where
315 a == b = case (a `cmp` b) of { EQ_ -> True; _ -> False }
316 a /= b = case (a `cmp` b) of { EQ_ -> False; _ -> True }
318 instance Ord TyCon where
319 a <= b = case (a `cmp` b) of { LT_ -> True; EQ_ -> True; GT__ -> False }
320 a < b = case (a `cmp` b) of { LT_ -> True; EQ_ -> False; GT__ -> False }
321 a >= b = case (a `cmp` b) of { LT_ -> False; EQ_ -> True; GT__ -> True }
322 a > b = case (a `cmp` b) of { LT_ -> False; EQ_ -> False; GT__ -> True }
323 _tagCmp a b = case (a `cmp` b) of { LT_ -> _LT; EQ_ -> _EQ; GT__ -> _GT }
325 instance Uniquable TyCon where
326 uniqueOf (DataTyCon u _ _ _ _ _ _ _) = u
327 uniqueOf (TupleTyCon u _ _) = u
328 uniqueOf (PrimTyCon u _ _) = u
329 uniqueOf (SynTyCon u _ _ _ _ _) = u
330 uniqueOf tc@(SpecTyCon _ _) = panic "uniqueOf:SpecTyCon"
331 uniqueOf tc = uniqueOf (getName tc)
335 instance NamedThing TyCon where
336 getName (DataTyCon _ n _ _ _ _ _ _) = n
337 getName (PrimTyCon _ n _) = n
338 getName (SpecTyCon tc _) = getName tc
339 getName (SynTyCon _ n _ _ _ _) = n
340 getName FunTyCon = mkFunTyConName
341 getName (TupleTyCon _ n _) = n
342 getName tc = panic "TyCon.getName"
345 getName (SpecTyCon tc tys) = let (m,n) = moduleNamePair tc in
346 (m, n _APPEND_ specMaybeTysSuffix tys)
347 getName other_tc = moduleNamePair (expectJust "tycon1" (getName other_tc))
348 getName other = Nothing