X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FDataCon.lhs;h=8f09078055cfbc818363e3f008f17ddcf6a515c1;hp=1b354c65ddcf1c44098557a7001e288e477b05a9;hb=d436c70d43fb905c63220040168295e473f4b90a;hpb=5e5310b3cb4f78e30cc7b90879eb016e97c214cb diff --git a/compiler/basicTypes/DataCon.lhs b/compiler/basicTypes/DataCon.lhs index 1b354c6..8f09078 100644 --- a/compiler/basicTypes/DataCon.lhs +++ b/compiler/basicTypes/DataCon.lhs @@ -15,9 +15,11 @@ module DataCon ( -- ** Type deconstruction dataConRepType, dataConSig, dataConFullSig, - dataConName, dataConIdentity, dataConTag, dataConTyCon, dataConUserType, + dataConName, dataConIdentity, dataConTag, dataConTyCon, + dataConOrigTyCon, dataConUserType, dataConUnivTyVars, dataConExTyVars, dataConAllTyVars, - dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta, dataConStupidTheta, + dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta, + dataConStupidTheta, dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy, dataConInstOrigArgTys, dataConRepArgTys, dataConFieldLabels, dataConFieldType, @@ -49,7 +51,6 @@ import Outputable import Unique import ListSetOps import Util -import Maybes import FastString import Module @@ -96,12 +97,12 @@ Note [Data Constructor Naming] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Each data constructor C has two, and possibly up to four, Names associated with it: - OccName Name space Name of - --------------------------------------------------------------------------- - * 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 + OccName Name space Name of Notes + --------------------------------------------------------------------------- + The "data con itself" C DataName DataCon In dom( GlobalRdrEnv ) + 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 @@ -269,8 +270,9 @@ data DataCon -- syntax, provided its type looks like the above. -- The declaration format is held in the TyCon (algTcGadtSyntax) - dcUnivTyVars :: [TyVar], -- Universally-quantified type vars + dcUnivTyVars :: [TyVar], -- Universally-quantified type vars [a,b,c] -- INVARIANT: length matches arity of the dcRepTyCon + --- result type of (rep) data con is exactly (T a b c) dcExTyVars :: [TyVar], -- Existentially-quantified type vars -- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE TYVARS @@ -317,7 +319,7 @@ data DataCon dcOrigArgTys :: [Type], -- Original argument types -- (before unboxing and flattening of strict fields) - dcOrigResTy :: Type, -- Original result type + dcOrigResTy :: Type, -- Original result type, as seen by the user -- NB: for a data instance, the original user result type may -- differ from the DataCon's representation TyCon. Example -- data instance T [a] where MkT :: a -> T [a] @@ -466,14 +468,17 @@ instance Show DataCon where mkDataCon :: Name -> Bool -- ^ Is the constructor declared infix? -> [StrictnessMark] -- ^ Strictness annotations written in the source file - -> [FieldLabel] -- ^ Field labels for the constructor, if it is a record, otherwise empty + -> [FieldLabel] -- ^ Field labels for the constructor, if it is a record, + -- otherwise empty -> [TyVar] -- ^ Universally quantified type variables -> [TyVar] -- ^ Existentially quantified type variables -> [(TyVar,Type)] -- ^ GADT equalities -> ThetaType -- ^ Theta-type occuring before the arguments proper - -> [Type] -- ^ Argument types - -> TyCon -- ^ Type constructor we are for - -> ThetaType -- ^ The "stupid theta", context of the data declaration e.g. @data Eq a => T a ...@ + -> [Type] -- ^ Original argument types + -> Type -- ^ Original result type + -> TyCon -- ^ Representation type constructor + -> ThetaType -- ^ The "stupid theta", context of the data declaration + -- e.g. @data Eq a => T a ...@ -> DataConIds -- ^ The Ids of the actual builder functions -> DataCon -- Can get the tag from the TyCon @@ -483,7 +488,7 @@ mkDataCon name declared_infix fields univ_tvs ex_tvs eq_spec theta - orig_arg_tys tycon + orig_arg_tys orig_res_ty rep_tycon stupid_theta ids -- Warning: mkDataCon is not a good place to check invariants. -- If the programmer writes the wrong result type in the decl, thus: @@ -506,7 +511,7 @@ mkDataCon name declared_infix dcStupidTheta = stupid_theta, dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = orig_arg_tys, dcOrigResTy = orig_res_ty, - dcRepTyCon = tycon, + dcRepTyCon = rep_tycon, dcRepArgTys = rep_arg_tys, dcStrictMarks = arg_stricts, dcRepStrictness = rep_arg_stricts, @@ -525,21 +530,11 @@ mkDataCon name declared_infix 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 - -- TI :: forall e. e -> T (e,e) - -- - -- 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 -- To do: eliminate duplication with MkId (rep_arg_stricts, rep_arg_tys) = computeRep real_stricts real_arg_tys - tag = assoc "mkDataCon" (tyConDataCons tycon `zip` [fIRST_TAG..]) con + tag = assoc "mkDataCon" (tyConDataCons rep_tycon `zip` [fIRST_TAG..]) con ty = mkForAllTys univ_tvs $ mkForAllTys ex_tvs $ mkFunTys (mkPredTys (eqSpecPreds eq_spec)) $ mkFunTys (mkPredTys eq_theta) $ @@ -547,7 +542,7 @@ mkDataCon name declared_infix -- because they might be flattened.. -- but the equality predicates are not mkFunTys rep_arg_tys $ - mkTyConApp tycon (mkTyVarTys univ_tvs) + mkTyConApp rep_tycon (mkTyVarTys univ_tvs) eqSpecPreds :: [(TyVar,Type)] -> ThetaType eqSpecPreds spec = [ mkEqPred (mkTyVarTy tv, ty) | (tv,ty) <- spec ] @@ -570,6 +565,14 @@ dataConTag = dcTag dataConTyCon :: DataCon -> TyCon dataConTyCon = dcRepTyCon +-- | The original type constructor used in the definition of this data +-- constructor. In case of a data family instance, that will be the family +-- type constructor. +dataConOrigTyCon :: DataCon -> TyCon +dataConOrigTyCon dc + | Just (tc, _) <- tyConFamInst_maybe (dcRepTyCon dc) = tc + | otherwise = dcRepTyCon dc + -- | The representation type of the data constructor, i.e. the sort -- type that will represent values of this type at runtime dataConRepType :: DataCon -> Type @@ -642,8 +645,10 @@ dataConFieldLabels = dcFields -- | Extract the type for any given labelled field of the 'DataCon' dataConFieldType :: DataCon -> FieldLabel -> Type -dataConFieldType con label = expectJust "unexpected label" $ - lookup label (dcFields con `zip` dcOrigArgTys con) +dataConFieldType con label + = case lookup label (dcFields con `zip` dcOrigArgTys con) of + Just ty -> ty + Nothing -> pprPanic "dataConFieldType" (ppr con <+> ppr label) -- | The strictness markings decided on by the compiler. Does not include those for -- existential dictionaries. The list is in one-to-one correspondence with the arity of the 'DataCon' @@ -690,7 +695,8 @@ dataConRepStrictness dc = dcRepStrictness dc -- 4) The /original/ result type of the 'DataCon' dataConSig :: DataCon -> ([TyVar], ThetaType, [Type], Type) dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, dcOrigResTy = 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) -- | The \"full signature\" of the 'DataCon' returns, in order: @@ -703,13 +709,15 @@ dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_ -- -- 4) The result of 'dataConDictTheta' -- --- 5) The original argument types to the 'DataCon' (i.e. before any change of the representation of the type) +-- 5) The original argument types to the 'DataCon' (i.e. before +-- any change of the representation of the type) -- -- 6) The original result type of the 'DataCon' dataConFullSig :: DataCon -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, ThetaType, [Type], Type) dataConFullSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, dcOrigResTy = 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 @@ -729,7 +737,7 @@ dataConUserType :: DataCon -> Type -- -- rather than: -- --- > T :: forall a c. forall b. (c=[a]) => a -> b -> T c +-- > T :: forall a c. forall b. (c~[a]) => a -> b -> T c -- -- NB: If the constructor is part of a data instance, the result type -- mentions the family tycon, not the internal one.