X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FDataCon.lhs;h=0c6e3c57200d8f94c9e6d1691100b38af8875de3;hp=dbc63552045b56f1d8182c09ea49bcc4e16bfa11;hb=6a05ec5ef5373f61b7f9f5bdc344483417fa801b;hpb=474b582b68ea9289f3da4355da816164138604b0 diff --git a/compiler/basicTypes/DataCon.lhs b/compiler/basicTypes/DataCon.lhs index dbc6355..0c6e3c5 100644 --- a/compiler/basicTypes/DataCon.lhs +++ b/compiler/basicTypes/DataCon.lhs @@ -12,9 +12,10 @@ module DataCon ( dataConRepType, dataConSig, dataConFullSig, dataConName, dataConIdentity, dataConTag, dataConTyCon, dataConUserType, dataConUnivTyVars, dataConExTyVars, dataConAllTyVars, - dataConEqSpec, eqSpecPreds, dataConTheta, dataConStupidTheta, + dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta, dataConStupidTheta, dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy, - dataConInstOrigArgTys, dataConRepArgTys, + dataConInstOrigArgTys, dataConInstOrigDictsAndArgTys, + dataConRepArgTys, dataConFieldLabels, dataConFieldType, dataConStrictMarks, dataConExStricts, dataConSourceArity, dataConRepArity, @@ -43,11 +44,11 @@ import ListSetOps import Util import Maybes import FastString -import PackageConfig import Module import Data.Char import Data.Word +import Data.List ( partition ) \end{code} @@ -86,15 +87,20 @@ differently, as follows. Note [Data Constructor Naming] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Each data constructor C has two, and possibly three, Names associated with it: +Each data constructor C has two, and possibly up to four, Names associated with it: - OccName Name space Used for + OccName Name space Name of --------------------------------------------------------------------------- - * The "source data con" C DataName The DataCon itself - * The "real data con" C VarName Its worker Id - * The "wrapper data con" $WC VarName Wrapper Id (optional) - -Each of these three has a distinct Unique. The "source data con" name + * The "data con itself" C DataName DataCon + * The "worker data con" C VarName Id (the worker) + * The "wrapper data con" $WC VarName Id (the wrapper) + * The "newtype coercion" :CoT TcClsName TyCon + +EVERY data constructor (incl for newtypes) has the former two (the +data con itself, and its worker. But only some data constructors have a +wrapper (see Note [The need for a wrapper]). + +Each of these three has a distinct Unique. The "data con itself" name appears in the output of the renamer, and names the Haskell-source data constructor. The type checker translates it into either the wrapper Id (if it exists) or worker Id (otherwise). @@ -128,6 +134,8 @@ The "wrapper Id", $WC, goes as follows nothing for the wrapper to do. That is, if its defn would be $wC = C +Note [The need for a wrapper] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Why might the wrapper have anything to do? Two reasons: * Unboxing strict fields (with -funbox-strict-fields) @@ -151,6 +159,8 @@ Why might the wrapper have anything to do? Two reasons: The third argument is a coerion [a] :: [a]:=:[a] +INVARIANT: the dictionary constructor for a class + never has a wrapper. A note about the stupid context @@ -224,11 +234,11 @@ data DataCon -- -- *** As declared by the user -- data T a where - -- MkT :: forall x y. (Ord x) => x -> y -> T (x,y) + -- MkT :: forall x y. (x~y,Ord x) => x -> y -> T (x,y) -- *** As represented internally -- data T a where - -- MkT :: forall a. forall x y. (a:=:(x,y), Ord x) => x -> y -> T a + -- MkT :: forall a. forall x y. (a:=:(x,y),x~y,Ord x) => x -> y -> T a -- -- The next six fields express the type of the constructor, in pieces -- e.g. @@ -236,7 +246,8 @@ data DataCon -- dcUnivTyVars = [a] -- dcExTyVars = [x,y] -- dcEqSpec = [a:=:(x,y)] - -- dcTheta = [Ord x] + -- dcEqTheta = [x~y] + -- dcDictTheta = [Ord x] -- dcOrigArgTys = [a,List b] -- dcRepTyCon = T @@ -244,7 +255,7 @@ data DataCon -- Its type is of form -- forall a1..an . t1 -> ... tm -> T a1..an -- No existentials, no coercions, nothing. - -- That is: dcExTyVars = dcEqSpec = dcTheta = [] + -- That is: dcExTyVars = dcEqSpec = dcEqTheta = dcDictTheta = [] -- NB 1: newtypes always have a vanilla data con -- NB 2: a vanilla constructor can still be declared in GADT-style -- syntax, provided its type looks like the above. @@ -272,11 +283,14 @@ data DataCon -- Each equality is of the form (a :=: ty), where 'a' is one of -- the universally quantified type variables - dcTheta :: ThetaType, -- The context of the constructor + -- The next two fields give the type context of the data constructor + -- (aside from the GADT constraints, + -- which are given by the dcExpSpec) -- In GADT form, this is *exactly* what the programmer writes, even if -- the context constrains only universally quantified variables - -- MkT :: forall a. Eq a => a -> T a - -- It may contain user-written equality predicates too + -- MkT :: forall a b. (a ~ b, Ord b) => a -> T a b + dcEqTheta :: ThetaType, -- The *equational* constraints + dcDictTheta :: ThetaType, -- The *type-class and implicit-param* constraints dcStupidTheta :: ThetaType, -- The context of the data type declaration -- data Eq a => T a = ... @@ -460,7 +474,7 @@ mkDataCon name declared_infix -- so the error is detected properly... it's just that asaertions here -- are a little dodgy. - = ASSERT( not (any isEqPred theta) ) + = -- ASSERT( not (any isEqPred theta) ) -- We don't currently allow any equality predicates on -- a data constructor (apart from the GADT ones in eq_spec) con @@ -470,7 +484,8 @@ mkDataCon name declared_infix dcVanilla = is_vanilla, dcInfix = declared_infix, dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcStupidTheta = stupid_theta, dcTheta = theta, + dcStupidTheta = stupid_theta, + dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = orig_arg_tys, dcOrigResTy = orig_res_ty, dcRepTyCon = tycon, dcRepArgTys = rep_arg_tys, @@ -486,9 +501,10 @@ mkDataCon name declared_infix -- The 'arg_stricts' passed to mkDataCon are simply those for the -- source-language arguments. We add extra ones for the -- dictionary arguments right here. - dict_tys = mkPredTys theta - real_arg_tys = dict_tys ++ orig_arg_tys - real_stricts = map mk_dict_strict_mark theta ++ arg_stricts + (eq_theta,dict_theta) = partition isEqPred theta + dict_tys = mkPredTys dict_theta + real_arg_tys = dict_tys ++ orig_arg_tys + real_stricts = map mk_dict_strict_mark dict_theta ++ arg_stricts -- Example -- data instance T (b,c) where @@ -497,6 +513,7 @@ mkDataCon name declared_infix -- The representation tycon looks like this: -- data :R7T b c where -- TI :: forall b1 c1. (b1 ~ c1) => b1 -> :R7T b1 c1 + -- In this case orig_res_ty = T (e,e) orig_res_ty = mkFamilyTyConApp tycon (substTyVars (mkTopTvSubst eq_spec) univ_tvs) -- Representation arguments and demands @@ -506,6 +523,7 @@ mkDataCon name declared_infix tag = assoc "mkDataCon" (tyConDataCons tycon `zip` [fIRST_TAG..]) con ty = mkForAllTys univ_tvs $ mkForAllTys ex_tvs $ mkFunTys (mkPredTys (eqSpecPreds eq_spec)) $ + mkFunTys (mkPredTys eq_theta) $ -- NB: the dict args are already in rep_arg_tys -- because they might be flattened.. -- but the equality predicates are not @@ -515,6 +533,7 @@ mkDataCon name declared_infix eqSpecPreds :: [(TyVar,Type)] -> ThetaType eqSpecPreds spec = [ mkEqPred (mkTyVarTy tv, ty) | (tv,ty) <- spec ] +mk_dict_strict_mark :: PredType -> StrictnessMark mk_dict_strict_mark pred | isStrictPred pred = MarkedStrict | otherwise = NotMarkedStrict \end{code} @@ -548,8 +567,11 @@ dataConAllTyVars (MkData { dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs }) dataConEqSpec :: DataCon -> [(TyVar,Type)] dataConEqSpec = dcEqSpec -dataConTheta :: DataCon -> ThetaType -dataConTheta = dcTheta +dataConEqTheta :: DataCon -> ThetaType +dataConEqTheta = dcEqTheta + +dataConDictTheta :: DataCon -> ThetaType +dataConDictTheta = dcDictTheta dataConWorkId :: DataCon -> Id dataConWorkId dc = case dcIds dc of @@ -585,7 +607,7 @@ dataConStrictMarks = dcStrictMarks dataConExStricts :: DataCon -> [StrictnessMark] -- Strictness of *existential* arguments only -- Usually empty, so we don't bother to cache this -dataConExStricts dc = map mk_dict_strict_mark (dcTheta dc) +dataConExStricts dc = map mk_dict_strict_mark $ dcDictTheta dc dataConSourceArity :: DataCon -> Arity -- Source-level arity of the data constructor @@ -595,6 +617,7 @@ dataConSourceArity dc = length (dcOrigArgTys dc) -- {\em representation} of the data constructor. This may be more than appear -- in the source code; the extra ones are the existentially quantified -- dictionaries +dataConRepArity :: DataCon -> Int dataConRepArity (MkData {dcRepArgTys = arg_tys}) = length arg_tys isNullarySrcDataCon, isNullaryRepDataCon :: DataCon -> Bool @@ -608,14 +631,14 @@ dataConRepStrictness dc = dcRepStrictness dc dataConSig :: DataCon -> ([TyVar], ThetaType, [Type], Type) dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcTheta = theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) - = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ theta, arg_tys, res_ty) + dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) + = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ eq_theta ++ dict_theta, arg_tys, res_ty) dataConFullSig :: DataCon - -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, [Type], Type) + -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, ThetaType, [Type], Type) dataConFullSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcTheta = theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) - = (univ_tvs, ex_tvs, eq_spec, theta, arg_tys, res_ty) + dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) + = (univ_tvs, ex_tvs, eq_spec, eq_theta, dict_theta, arg_tys, res_ty) dataConOrigResTy :: DataCon -> Type dataConOrigResTy dc = dcOrigResTy dc @@ -633,10 +656,11 @@ dataConUserType :: DataCon -> Type -- mentions the family tycon, not the internal one. dataConUserType (MkData { dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcTheta = theta, dcOrigArgTys = arg_tys, + dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty }) = mkForAllTys ((univ_tvs `minusList` map fst eq_spec) ++ ex_tvs) $ - mkFunTys (mkPredTys theta) $ + mkFunTys (mkPredTys eq_theta) $ + mkFunTys (mkPredTys dict_theta) $ mkFunTys arg_tys $ res_ty @@ -671,6 +695,21 @@ dataConInstOrigArgTys dc@(MkData {dcOrigArgTys = arg_tys, map (substTyWith tyvars inst_tys) arg_tys where tyvars = univ_tvs ++ ex_tvs + +dataConInstOrigDictsAndArgTys + :: DataCon -- Works for any DataCon + -> [Type] -- Includes existential tyvar args, but NOT + -- equality constraints or dicts + -> [Type] -- Returns just the instsantiated dicts and *value* arguments +dataConInstOrigDictsAndArgTys dc@(MkData {dcOrigArgTys = arg_tys, + dcDictTheta = dicts, + dcUnivTyVars = univ_tvs, + dcExTyVars = ex_tvs}) inst_tys + = ASSERT2( length tyvars == length inst_tys + , ptext SLIT("dataConInstOrigDictsAndArgTys") <+> ppr dc $$ ppr tyvars $$ ppr inst_tys ) + map (substTyWith tyvars inst_tys) (mkPredTys dicts ++ arg_tys) + where + tyvars = univ_tvs ++ ex_tvs \end{code} These two functions get the real argument types of the constructor, @@ -755,14 +794,16 @@ splitProductType_maybe ty where data_con = ASSERT( not (null (tyConDataCons tycon)) ) head (tyConDataCons tycon) - other -> Nothing + _other -> Nothing +splitProductType :: String -> Type -> (TyCon, [Type], DataCon, [Type]) splitProductType str ty = case splitProductType_maybe ty of Just stuff -> stuff Nothing -> pprPanic (str ++ ": not a product") (pprType ty) +deepSplitProductType_maybe :: Type -> Maybe (TyCon, [Type], DataCon, [Type]) deepSplitProductType_maybe ty = do { (res@(tycon, tycon_args, _, _)) <- splitProductType_maybe ty ; let {result @@ -775,6 +816,7 @@ deepSplitProductType_maybe ty ; result } +deepSplitProductType :: String -> Type -> (TyCon, [Type], DataCon, [Type]) deepSplitProductType str ty = case deepSplitProductType_maybe ty of Just stuff -> stuff