X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypes%2FTypeRep.lhs;h=7bb863a210e37841c77a8b7be7a6dac00985a439;hb=9d7da331989abcd1844e9d03b8d1e4163796fa85;hp=5c04c9ce9d44bf78ed01fe960ec11308f6a430a5;hpb=9f0923372607a5fe646a89266b8961faf61421b9;p=ghc-hetmet.git diff --git a/ghc/compiler/types/TypeRep.lhs b/ghc/compiler/types/TypeRep.lhs index 5c04c9c..7bb863a 100644 --- a/ghc/compiler/types/TypeRep.lhs +++ b/ghc/compiler/types/TypeRep.lhs @@ -10,22 +10,18 @@ module TypeRep ( PredType(..), -- to friends Kind, ThetaType, -- Synonyms - TyVarSubst, - - superKind, superBoxity, -- KX and BX respectively - liftedBoxity, unliftedBoxity, -- :: BX - openKindCon, -- :: KX - typeCon, -- :: BX -> KX - liftedTypeKind, unliftedTypeKind, openTypeKind, -- :: KX - isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind, - mkArrowKind, mkArrowKinds, -- :: KX -> KX -> KX funTyCon, -- Pretty-printing - pprKind, pprParendKind, - pprType, pprParendType, - pprPred, pprTheta, pprThetaArrow, pprClassPred + pprType, pprParendType, pprTyThingCategory, + pprPred, pprTheta, pprThetaArrow, pprClassPred, + + -- Re-export fromKind + liftedTypeKind, unliftedTypeKind, openTypeKind, + isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind, + mkArrowKind, mkArrowKinds, + pprKind, pprParendKind ) where #include "HsVersions.h" @@ -33,23 +29,17 @@ module TypeRep ( import {-# SOURCE #-} DataCon( DataCon, dataConName ) -- friends: -import Var ( Id, TyVar, tyVarKind ) -import VarEnv ( TyVarEnv ) +import Kind +import Var ( Var, Id, TyVar, tyVarKind ) import VarSet ( TyVarSet ) -import Name ( Name, NamedThing(..), mkWiredInName, mkInternalName ) -import OccName ( mkOccFS, mkKindOccFS, tcName ) +import Name ( Name, NamedThing(..), BuiltInSyntax(..), mkWiredInName ) +import OccName ( mkOccNameFS, tcName, parenSymOcc ) import BasicTypes ( IPName, tupleParens ) -import TyCon ( TyCon, KindCon, mkFunTyCon, mkKindCon, mkSuperKindCon, isNewTyCon, - tyConArity, tupleTyConBoxity, isTupleTyCon, tyConName ) +import TyCon ( TyCon, mkFunTyCon, tyConArity, tupleTyConBoxity, isTupleTyCon, isRecursiveTyCon, isNewTyCon ) import Class ( Class ) -- others -import PrelNames ( gHC_PRIM, kindConKey, boxityConKey, liftedConKey, - unliftedConKey, typeConKey, anyBoxConKey, - funTyConKey, listTyConKey, parrTyConKey, - hasKey - ) -import SrcLoc ( noSrcLoc ) +import PrelNames ( gHC_PRIM, funTyConKey, listTyConKey, parrTyConKey, hasKey ) import Outputable \end{code} @@ -124,7 +114,7 @@ Similarly splitForAllTys and splitFunTys can get into a loop. Solution: -* Newtypes are always represented using NewTcApp, never as TyConApp. +* Newtypes are always represented using TyConApp. * For non-recursive newtypes, P, treat P just like a type synonym after type-checking is done; i.e. it's opaque during type checking (functions @@ -154,35 +144,23 @@ to cut all loops. The other members of the loop may be marked 'non-recursive'. \begin{code} -type SuperKind = Type -type Kind = Type - -type TyVarSubst = TyVarEnv Type - data Type - = TyVarTy TyVar + = TyVarTy TyVar | AppTy Type -- Function is *not* a TyConApp - Type + Type -- It must be another AppTy, or TyVarTy + -- (or NoteTy of these) - | TyConApp -- Application of a TyCon - TyCon -- *Invariant* saturated appliations of FunTyCon and + | TyConApp -- Application of a TyCon, including newtypes *and* synonyms + TyCon -- *Invariant* saturated appliations of FunTyCon and -- synonyms have their own constructors, below. + -- However, *unsaturated* FunTyCons do appear as TyConApps. + -- [Type] -- Might not be saturated. - - | NewTcApp -- Application of a NewType TyCon. All newtype applications - TyCon -- show up like this until they are fed through newTypeRep, - -- which returns - -- * an ordinary TyConApp for non-saturated, - -- or recursive newtypes - -- - -- * the representation type of the newtype for satuarted, - -- non-recursive ones - -- [But the result of a call to newTypeRep is always consumed - -- immediately; it never lives on in another type. So in any - -- type, newtypes are always represented with NewTcApp.] - [Type] -- Might not be saturated. + -- Even type synonyms are not necessarily saturated; + -- for example unsaturated type synonyms can appear as the + -- RHS of a type synonym. | FunTy -- Special case of TyConApp: TyConApp FunTyCon [t1,t2] Type @@ -199,12 +177,7 @@ data Type TyNote Type -- The expanded version -data TyNote - = FTVNote TyVarSet -- The free type variables of the noted expression - - | SynNote Type -- Used for type synonyms - -- The Type is always a TyConApp, and is the un-expanded form. - -- The type to which the note is attached is the expanded form. +data TyNote = FTVNote TyVarSet -- The free type variables of the noted expression \end{code} ------------------------------------- @@ -250,129 +223,6 @@ represented by evidence (a dictionary, for example, of type (predRepTy p). %************************************************************************ %* * -\subsection{Kinds} -%* * -%************************************************************************ - -Kinds -~~~~~ -kind :: KX = kind -> kind - - | Type liftedness -- (Type *) is printed as just * - -- (Type #) is printed as just # - - | OpenKind -- Can be lifted or unlifted - -- Printed '?' - - | kv -- A kind variable; *only* happens during kind checking - -boxity :: BX = * -- Lifted - | # -- Unlifted - | bv -- A boxity variable; *only* happens during kind checking - -There's a little subtyping at the kind level: - forall b. Type b <: OpenKind - -That is, a type of kind (Type b) is OK in a context requiring an OpenKind - -OpenKind, written '?', is used as the kind for certain type variables, -in two situations: - -1. The universally quantified type variable(s) for special built-in - things like error :: forall (a::?). String -> a. - Here, the 'a' can be instantiated to a lifted or unlifted type. - -2. Kind '?' is also used when the typechecker needs to create a fresh - type variable, one that may very well later be unified with a type. - For example, suppose f::a, and we see an application (f x). Then a - must be a function type, so we unify a with (b->c). But what kind - are b and c? They can be lifted or unlifted types, or indeed type schemes, - so we give them kind '?'. - - When the type checker generalises over a bunch of type variables, it - makes any that still have kind '?' into kind '*'. So kind '?' is never - present in an inferred type. - - ------------------------------------------- -Define KX, the type of a kind - BX, the type of a boxity - -\begin{code} -superKindName = kindQual FSLIT("KX") kindConKey -superBoxityName = kindQual FSLIT("BX") boxityConKey -liftedConName = kindQual FSLIT("*") liftedConKey -unliftedConName = kindQual FSLIT("#") unliftedConKey -openKindConName = kindQual FSLIT("?") anyBoxConKey -typeConName = kindQual FSLIT("Type") typeConKey - -kindQual str uq = mkInternalName uq (mkKindOccFS tcName str) noSrcLoc - -- Kinds are not z-encoded in interface file, hence mkKindOccFS - -- And they don't come from any particular module; indeed we always - -- want to print them unqualified. Hence the InternalName. -\end{code} - -\begin{code} -superKind :: SuperKind -- KX, the type of all kinds -superKind = TyConApp (mkSuperKindCon superKindName) [] - -superBoxity :: SuperKind -- BX, the type of all boxities -superBoxity = TyConApp (mkSuperKindCon superBoxityName) [] -\end{code} - ------------------------------------------- -Define boxities: @*@ and @#@ - -\begin{code} -liftedBoxity, unliftedBoxity :: Kind -- :: BX -liftedBoxity = TyConApp liftedBoxityCon [] -unliftedBoxity = TyConApp unliftedBoxityCon [] - -liftedBoxityCon = mkKindCon liftedConName superBoxity -unliftedBoxityCon = mkKindCon unliftedConName superBoxity -\end{code} - ------------------------------------------- -Define kinds: Type, Type *, Type #, OpenKind - -\begin{code} -typeCon :: KindCon -- :: BX -> KX -typeCon = mkKindCon typeConName (superBoxity `FunTy` superKind) - -liftedTypeKind, unliftedTypeKind, openTypeKind :: Kind -- Of superkind superKind - -liftedTypeKind = TyConApp typeCon [liftedBoxity] -unliftedTypeKind = TyConApp typeCon [unliftedBoxity] - -openKindCon = mkKindCon openKindConName superKind -openTypeKind = TyConApp openKindCon [] -\end{code} - -\begin{code} -isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind :: Kind -> Bool -isLiftedTypeKind (TyConApp tc [TyConApp bc []]) = tyConName tc == typeConName && - tyConName bc == liftedConName -isUnliftedTypeKind (TyConApp tc [TyConApp bc []]) = tyConName tc == typeConName && - tyConName bc == unliftedConName -isOpenTypeKind (TyConApp tc []) = tyConName tc == openKindConName - -isSuperKind (TyConApp tc []) = tyConName tc == superKindName -\end{code} - ------------------------------------------- -Define arrow kinds - -\begin{code} -mkArrowKind :: Kind -> Kind -> Kind -mkArrowKind k1 k2 = k1 `FunTy` k2 - -mkArrowKinds :: [Kind] -> Kind -> Kind -mkArrowKinds arg_kinds result_kind = foldr mkArrowKind result_kind arg_kinds -\end{code} - - -%************************************************************************ -%* * TyThing %* * %************************************************************************ @@ -388,10 +238,13 @@ data TyThing = AnId Id | AClass Class instance Outputable TyThing where - ppr (AnId id) = ptext SLIT("AnId") <+> ppr id - ppr (ATyCon tc) = ptext SLIT("ATyCon") <+> ppr tc - ppr (AClass cl) = ptext SLIT("AClass") <+> ppr cl - ppr (ADataCon dc) = ptext SLIT("ADataCon") <+> ppr (dataConName dc) + ppr thing = pprTyThingCategory thing <+> quotes (ppr (getName thing)) + +pprTyThingCategory :: TyThing -> SDoc +pprTyThingCategory (ATyCon _) = ptext SLIT("Type constructor") +pprTyThingCategory (AClass _) = ptext SLIT("Class") +pprTyThingCategory (AnId _) = ptext SLIT("Identifier") +pprTyThingCategory (ADataCon _) = ptext SLIT("Data constructor") instance NamedThing TyThing where -- Can't put this with the type getName (AnId id) = getName id -- decl, because the DataCon instance @@ -410,8 +263,8 @@ instance NamedThing TyThing where -- Can't put this with the type We define a few wired-in type constructors here to avoid module knots \begin{code} -funTyCon = mkFunTyCon funTyConName (mkArrowKinds [liftedTypeKind, liftedTypeKind] liftedTypeKind) - -- You might think that (->) should have type (? -> ? -> *), and you'd be right +funTyCon = mkFunTyCon funTyConName (mkArrowKinds [argTypeKind, openTypeKind] liftedTypeKind) + -- You might think that (->) should have type (?? -> ? -> *), and you'd be right -- But if we do that we get kind errors when saying -- instance Control.Arrow (->) -- becuase the expected kind is (*->*->*). The trouble is that the @@ -420,10 +273,11 @@ funTyCon = mkFunTyCon funTyConName (mkArrowKinds [liftedTypeKind, liftedTypeKind -- a prefix way, thus: (->) Int# Int#. And this is unusual. funTyConName = mkWiredInName gHC_PRIM - (mkOccFS tcName FSLIT("(->)")) + (mkOccNameFS tcName FSLIT("(->)")) funTyConKey Nothing -- No parent object (ATyCon funTyCon) -- Relevant TyCon + BuiltInSyntax \end{code} @@ -455,17 +309,13 @@ pprType ty = ppr_type TopPrec ty pprParendType ty = ppr_type TyConPrec ty ------------------ -pprKind, pprParendKind :: Kind -> SDoc -pprKind k = ppr_kind TopPrec k -pprParendKind k = ppr_kind TyConPrec k - ------------------- pprPred :: PredType -> SDoc pprPred (ClassP cls tys) = pprClassPred cls tys pprPred (IParam ip ty) = ppr ip <> dcolon <> pprType ty pprClassPred :: Class -> [Type] -> SDoc -pprClassPred clas tys = ppr clas <+> sep (map pprParendType tys) +pprClassPred clas tys = parenSymOcc (getOccName clas) (ppr clas) + <+> sep (map pprParendType tys) pprTheta :: ThetaType -> SDoc pprTheta theta = parens (sep (punctuate comma (map pprPred theta))) @@ -489,18 +339,17 @@ instance Outputable name => OutputableBndr (IPName name) where -- OK, here's the main printer ppr_type :: Prec -> Type -> SDoc -ppr_type p (TyVarTy tv) = ppr tv -ppr_type p (PredTy pred) = braces (ppr pred) -ppr_type p (NoteTy (SynNote ty1) ty2) = ppr_type p ty1 -ppr_type p (NoteTy other ty2) = ppr_type p ty2 - -ppr_type p (TyConApp tc tys) = ppr_tc_app p tc tys -ppr_type p (NewTcApp tc tys) = ifPprDebug (ptext SLIT("")) <> - ppr_tc_app p tc tys +ppr_type p (TyVarTy tv) = ppr tv +ppr_type p (PredTy pred) = braces (ppr pred) +ppr_type p (NoteTy other ty2) = ppr_type p ty2 +ppr_type p (TyConApp tc tys) = ppr_tc_app p tc tys ppr_type p (AppTy t1 t2) = maybeParen p TyConPrec $ pprType t1 <+> ppr_type TyConPrec t2 +ppr_type p ty@(ForAllTy _ _) = ppr_forall_type p ty +ppr_type p ty@(FunTy (PredTy _) _) = ppr_forall_type p ty + ppr_type p (FunTy ty1 ty2) = -- We don't want to lose synonyms, so we mustn't use splitFunTys here. maybeParen p FunPrec $ @@ -509,7 +358,8 @@ ppr_type p (FunTy ty1 ty2) ppr_fun_tail (FunTy ty1 ty2) = (arrow <+> ppr_type FunPrec ty1) : ppr_fun_tail ty2 ppr_fun_tail other_ty = [arrow <+> pprType other_ty] -ppr_type p ty@(ForAllTy _ _) +ppr_forall_type :: Prec -> Type -> SDoc +ppr_forall_type p ty = maybeParen p FunPrec $ sep [pprForAll tvs, pprThetaArrow ctxt, pprType tau] where @@ -517,14 +367,18 @@ ppr_type p ty@(ForAllTy _ _) (ctxt, tau) = split2 [] rho split1 tvs (ForAllTy tv ty) = split1 (tv:tvs) ty + split1 tvs (NoteTy _ ty) = split1 tvs ty split1 tvs ty = (reverse tvs, ty) - split2 ps (PredTy p `FunTy` ty) = split2 (p:ps) ty - split2 ps ty = (reverse ps, ty) + split2 ps (NoteTy _ arg -- Rather a disgusting case + `FunTy` res) = split2 ps (arg `FunTy` res) + split2 ps (PredTy p `FunTy` ty) = split2 (p:ps) ty + split2 ps (NoteTy _ ty) = split2 ps ty + split2 ps ty = (reverse ps, ty) ppr_tc_app :: Prec -> TyCon -> [Type] -> SDoc ppr_tc_app p tc [] - = ppr tc + = ppr_tc tc ppr_tc_app p tc [ty] | tc `hasKey` listTyConKey = brackets (pprType ty) | tc `hasKey` parrTyConKey = ptext SLIT("[:") <> pprType ty <> ptext SLIT(":]") @@ -533,26 +387,23 @@ ppr_tc_app p tc tys = tupleParens (tupleTyConBoxity tc) (sep (punctuate comma (map pprType tys))) | otherwise = maybeParen p TyConPrec $ - ppr tc <+> sep (map (ppr_type TyConPrec) tys) + ppr_tc tc <+> sep (map (ppr_type TyConPrec) tys) + +ppr_tc :: TyCon -> SDoc +ppr_tc tc = parenSymOcc (getOccName tc) (pp_nt_debug <> ppr tc) + where + pp_nt_debug | isNewTyCon tc = ifPprDebug (if isRecursiveTyCon tc + then ptext SLIT("") + else ptext SLIT("")) + | otherwise = empty ------------------- +pprForAll [] = empty pprForAll tvs = ptext SLIT("forall") <+> sep (map pprTvBndr tvs) <> dot pprTvBndr tv | isLiftedTypeKind kind = ppr tv | otherwise = parens (ppr tv <+> dcolon <+> pprKind kind) where kind = tyVarKind tv - - -------------------- -ppr_kind :: Prec -> Kind -> SDoc -ppr_kind p k - | isOpenTypeKind k = ptext SLIT("?") - | isLiftedTypeKind k = ptext SLIT("*") - | isUnliftedTypeKind k = ptext SLIT("#") -ppr_kind p (TyVarTy tv) = ppr tv -ppr_kind p (FunTy k1 k2) = maybeParen p FunPrec $ - sep [ ppr_kind FunPrec k1, arrow <+> pprKind k2] -ppr_kind p other = ptext SLIT("STRANGE KIND:") <+> ppr_type p other \end{code}