X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FhsSyn%2FHsTypes.lhs;h=f1343a39ef9aa5e7621b1eb176a34b8751afedc9;hb=28a464a75e14cece5db40f2765a29348273ff2d2;hp=3f7237ec38d6969fd1e5e8ba730766662dcb2654;hpb=7e602b0a11e567fcb035d1afd34015aebcf9a577;p=ghc-hetmet.git diff --git a/ghc/compiler/hsSyn/HsTypes.lhs b/ghc/compiler/hsSyn/HsTypes.lhs index 3f7237e..f1343a3 100644 --- a/ghc/compiler/hsSyn/HsTypes.lhs +++ b/ghc/compiler/hsSyn/HsTypes.lhs @@ -3,222 +3,368 @@ % \section[HsTypes]{Abstract syntax: user-defined types} -If compiled without \tr{#define COMPILING_GHC}, you get -(part of) a Haskell-abstract-syntax library. With it, -you get part of GHC. - \begin{code} module HsTypes ( - HsType(..), HsTyVar(..), - Context, ClassAssertion - - , mkHsForAllTy - , getTyVarName, replaceTyVarName - , pprParendHsType - , pprForAll, pprContext, pprClassAssertion - , cmpHsType, cmpHsTypes, cmpContext + HsType(..), LHsType, + HsTyVarBndr(..), LHsTyVarBndr, + HsExplicitForAll(..), + HsContext, LHsContext, + HsPred(..), LHsPred, + + LBangType, BangType, HsBang(..), + getBangType, getBangStrictness, + + mkExplicitHsForAllTy, mkImplicitHsForAllTy, + hsTyVarName, hsTyVarNames, replaceTyVarName, + hsLTyVarName, hsLTyVarNames, hsLTyVarLocName, hsLTyVarLocNames, + splitHsInstDeclTy, splitHsFunType, + + -- Type place holder + PostTcType, placeHolderType, + + -- Printing + pprParendHsType, pprHsForAll, pprHsContext, ppr_hs_context, pprHsTyVarBndr ) where #include "HsVersions.h" -import Type ( Kind ) -import PprType ( {- instance Outputable Kind -} ) +import {-# SOURCE #-} HsExpr ( HsSplice, pprSplice ) + +import Type ( Type ) +import Kind ( {- instance Outputable Kind -}, Kind, + pprParendKind, pprKind, isLiftedTypeKind ) +import BasicTypes ( IPName, Boxity, tupleParens ) +import SrcLoc ( Located(..), unLoc, noSrcSpan ) +import StaticFlags ( opt_PprStyle_Debug ) import Outputable -import Util ( thenCmp, cmpList ) \end{code} + +%************************************************************************ +%* * +\subsection{Annotating the syntax} +%* * +%************************************************************************ + +\begin{code} +type PostTcType = Type -- Used for slots in the abstract syntax + -- where we want to keep slot for a type + -- to be added by the type checker...but + -- before typechecking it's just bogus + +placeHolderType :: PostTcType -- Used before typechecking +placeHolderType = panic "Evaluated the place holder for a PostTcType" +\end{code} + +%************************************************************************ +%* * +\subsection{Bang annotations} +%* * +%************************************************************************ + +\begin{code} +type LBangType name = Located (BangType name) +type BangType name = HsType name -- Bangs are in the HsType data type + +data HsBang = HsNoBang -- Only used as a return value for getBangStrictness, + -- never appears on a HsBangTy + | HsStrict -- ! + | HsUnbox -- {-# UNPACK #-} ! (GHC extension, meaning "unbox") + +instance Outputable HsBang where + ppr (HsNoBang) = empty + ppr (HsStrict) = char '!' + ppr (HsUnbox) = ptext SLIT("!!") + +getBangType :: LHsType a -> LHsType a +getBangType (L _ (HsBangTy _ ty)) = ty +getBangType ty = ty + +getBangStrictness :: LHsType a -> HsBang +getBangStrictness (L _ (HsBangTy s _)) = s +getBangStrictness _ = HsNoBang +\end{code} + + +%************************************************************************ +%* * +\subsection{Data types} +%* * +%************************************************************************ + This is the syntax for types as seen in type signatures. \begin{code} -type Context name = [ClassAssertion name] +type LHsContext name = Located (HsContext name) + +type HsContext name = [LHsPred name] + +type LHsPred name = Located (HsPred name) + +data HsPred name = HsClassP name [LHsType name] + | HsIParam (IPName name) (LHsType name) -type ClassAssertion name = (name, [HsType name]) - -- The type is usually a type variable, but it - -- doesn't have to be when reading interface files +type LHsType name = Located (HsType name) data HsType name - = HsForAllTy [HsTyVar name] - (Context name) - (HsType name) + = HsForAllTy HsExplicitForAll -- Renamer leaves this flag unchanged, to record the way + -- the user wrote it originally, so that the printer can + -- print it as the user wrote it + [LHsTyVarBndr name] -- With ImplicitForAll, this is the empty list + -- until the renamer fills in the variables + (LHsContext name) + (LHsType name) - | MonoTyVar name -- Type variable + | HsTyVar name -- Type variable or type constructor - | MonoTyApp (HsType name) - (HsType name) + | HsBangTy HsBang (LHsType name) -- Bang-style type annotations - | MonoFunTy (HsType name) -- function type - (HsType name) + | HsAppTy (LHsType name) + (LHsType name) - | MonoListTy (HsType name) -- Element type + | HsFunTy (LHsType name) -- function type + (LHsType name) - | MonoTupleTy [HsType name] -- Element types (length gives arity) - Bool -- boxed? + | HsListTy (LHsType name) -- Element type - -- these next two are only used in unfoldings in interfaces - | MonoDictTy name -- Class - [HsType name] + | HsPArrTy (LHsType name) -- Elem. type of parallel array: [:t:] -mkHsForAllTy [] [] ty = ty -mkHsForAllTy tvs ctxt ty = HsForAllTy tvs ctxt ty + | HsTupleTy Boxity + [LHsType name] -- Element types (length gives arity) -data HsTyVar name - = UserTyVar name - | IfaceTyVar name Kind - -- *** NOTA BENE *** A "monotype" in a pragma can have - -- for-alls in it, (mostly to do with dictionaries). These - -- must be explicitly Kinded. + | HsOpTy (LHsType name) (Located name) (LHsType name) -getTyVarName (UserTyVar n) = n -getTyVarName (IfaceTyVar n _) = n + | HsParTy (LHsType name) + -- Parenthesis preserved for the precedence re-arrangement in RnTypes + -- It's important that a * (b + c) doesn't get rearranged to (a*b) + c! + -- + -- However, NB that toHsType doesn't add HsParTys (in an effort to keep + -- interface files smaller), so when printing a HsType we may need to + -- add parens. -replaceTyVarName :: HsTyVar name1 -> name2 -> HsTyVar name2 -replaceTyVarName (UserTyVar n) n' = UserTyVar n' -replaceTyVarName (IfaceTyVar n k) n' = IfaceTyVar n' k -\end{code} + | HsNumTy Integer -- Generics only + | HsPredTy (HsPred name) -- Only used in the type of an instance + -- declaration, eg. Eq [a] -> Eq a + -- ^^^^ + -- HsPredTy + -- Note no need for location info on the + -- enclosed HsPred; the one on the type will do -%************************************************************************ -%* * -\subsection{Pretty printing} -%* * -%************************************************************************ + | HsKindSig (LHsType name) -- (ty :: kind) + Kind -- A type with a kind signature -\begin{code} + | HsSpliceTy (HsSplice name) -instance (Outputable name) => Outputable (HsType name) where - ppr ty = pprHsType ty +data HsExplicitForAll = Explicit | Implicit -instance (Outputable name) => Outputable (HsTyVar name) where - ppr (UserTyVar name) = ppr name - ppr (IfaceTyVar name kind) = hsep [ppr name, dcolon, ppr kind] +----------------------- +-- Combine adjacent for-alls. +-- The following awkward situation can happen otherwise: +-- f :: forall a. ((Num a) => Int) +-- might generate HsForAll (Just [a]) [] (HsForAll Nothing [Num a] t) +-- Then a isn't discovered as ambiguous, and we abstract the AbsBinds wrt [] +-- but the export list abstracts f wrt [a]. Disaster. +-- +-- A valid type must have one for-all at the top of the type, or of the fn arg types -pprForAll [] = empty -pprForAll tvs = ptext SLIT("forall") <+> interppSP tvs <> ptext SLIT(".") +mkImplicitHsForAllTy ctxt ty = mkHsForAllTy Implicit [] ctxt ty +mkExplicitHsForAllTy tvs ctxt ty = mkHsForAllTy Explicit tvs ctxt ty -pprContext :: (Outputable name) => Context name -> SDoc -pprContext [] = empty -pprContext context = parens (hsep (punctuate comma (map pprClassAssertion context))) <+> ptext SLIT("=>") +mkHsForAllTy :: HsExplicitForAll -> [LHsTyVarBndr name] -> LHsContext name -> LHsType name -> HsType name +-- Smart constructor for HsForAllTy +mkHsForAllTy exp tvs (L _ []) ty = mk_forall_ty exp tvs ty +mkHsForAllTy exp tvs ctxt ty = HsForAllTy exp tvs ctxt ty -pprClassAssertion :: (Outputable name) => ClassAssertion name -> SDoc -pprClassAssertion (clas, tys) - = ppr clas <+> hsep (map pprParendHsType tys) -\end{code} +-- mk_forall_ty makes a pure for-all type (no context) +mk_forall_ty exp tvs (L _ (HsParTy ty)) = mk_forall_ty exp tvs ty +mk_forall_ty exp1 tvs1 (L _ (HsForAllTy exp2 tvs2 ctxt ty)) = mkHsForAllTy (exp1 `plus` exp2) (tvs1 ++ tvs2) ctxt ty +mk_forall_ty exp tvs ty = HsForAllTy exp tvs (L noSrcSpan []) ty + -- Even if tvs is empty, we still make a HsForAll! + -- In the Implicit case, this signals the place to do implicit quantification + -- In the Explicit case, it prevents implicit quantification + -- (see the sigtype production in Parser.y.pp) + -- so that (forall. ty) isn't implicitly quantified -\begin{code} -pREC_TOP = (0 :: Int) -pREC_FUN = (1 :: Int) -pREC_CON = (2 :: Int) +Implicit `plus` Implicit = Implicit +exp1 `plus` exp2 = Explicit -maybeParen :: Bool -> SDoc -> SDoc -maybeParen True p = parens p -maybeParen False p = p - --- printing works more-or-less as for Types +type LHsTyVarBndr name = Located (HsTyVarBndr name) -pprHsType, pprParendHsType :: (Outputable name) => HsType name -> SDoc +data HsTyVarBndr name + = UserTyVar name + | KindedTyVar name Kind + -- *** NOTA BENE *** A "monotype" in a pragma can have + -- for-alls in it, (mostly to do with dictionaries). These + -- must be explicitly Kinded. -pprHsType ty = ppr_mono_ty pREC_TOP ty -pprParendHsType ty = ppr_mono_ty pREC_CON ty +hsTyVarName :: HsTyVarBndr name -> name +hsTyVarName (UserTyVar n) = n +hsTyVarName (KindedTyVar n _) = n -ppr_mono_ty ctxt_prec (HsForAllTy tvs ctxt ty) - = maybeParen (ctxt_prec >= pREC_FUN) $ - sep [pprForAll tvs, pprContext ctxt, pprHsType ty] +hsLTyVarName :: LHsTyVarBndr name -> name +hsLTyVarName = hsTyVarName . unLoc -ppr_mono_ty ctxt_prec (MonoTyVar name) - = ppr name +hsTyVarNames :: [HsTyVarBndr name] -> [name] +hsTyVarNames tvs = map hsTyVarName tvs -ppr_mono_ty ctxt_prec (MonoFunTy ty1 ty2) - = let p1 = ppr_mono_ty pREC_FUN ty1 - p2 = ppr_mono_ty pREC_TOP ty2 - in - maybeParen (ctxt_prec >= pREC_FUN) - (sep [p1, (<>) (ptext SLIT("-> ")) p2]) +hsLTyVarNames :: [LHsTyVarBndr name] -> [name] +hsLTyVarNames = map hsLTyVarName -ppr_mono_ty ctxt_prec (MonoTupleTy tys True) - = parens (sep (punctuate comma (map ppr tys))) -ppr_mono_ty ctxt_prec (MonoTupleTy tys False) - = ptext SLIT("(#") <> sep (punctuate comma (map ppr tys)) <> ptext SLIT("#)") +hsLTyVarLocName :: LHsTyVarBndr name -> Located name +hsLTyVarLocName = fmap hsTyVarName -ppr_mono_ty ctxt_prec (MonoListTy ty) - = brackets (ppr_mono_ty pREC_TOP ty) +hsLTyVarLocNames :: [LHsTyVarBndr name] -> [Located name] +hsLTyVarLocNames = map hsLTyVarLocName + +replaceTyVarName :: HsTyVarBndr name1 -> name2 -> HsTyVarBndr name2 +replaceTyVarName (UserTyVar n) n' = UserTyVar n' +replaceTyVarName (KindedTyVar n k) n' = KindedTyVar n' k +\end{code} -ppr_mono_ty ctxt_prec (MonoTyApp fun_ty arg_ty) - = maybeParen (ctxt_prec >= pREC_CON) - (hsep [ppr_mono_ty pREC_FUN fun_ty, ppr_mono_ty pREC_CON arg_ty]) -ppr_mono_ty ctxt_prec (MonoDictTy clas tys) - = ppr clas <+> hsep (map (ppr_mono_ty pREC_CON) tys) +\begin{code} +splitHsInstDeclTy + :: OutputableBndr name + => HsType name + -> ([LHsTyVarBndr name], HsContext name, name, [LHsType name]) + -- Split up an instance decl type, returning the pieces + +splitHsInstDeclTy inst_ty + = case inst_ty of + HsParTy (L _ ty) -> splitHsInstDeclTy ty + HsForAllTy _ tvs cxt (L _ ty) -> split_tau tvs (unLoc cxt) ty + other -> split_tau [] [] other + -- The type vars should have been computed by now, even if they were implicit + where + split_tau tvs cxt (HsPredTy (HsClassP cls tys)) = (tvs, cxt, cls, tys) + split_tau tvs cxt (HsParTy (L _ ty)) = split_tau tvs cxt ty + +-- Splits HsType into the (init, last) parts +-- Breaks up any parens in the result type: +-- splitHsFunType (a -> (b -> c)) = ([a,b], c) +splitHsFunType :: LHsType name -> ([LHsType name], LHsType name) +splitHsFunType (L l (HsFunTy x y)) = (x:args, res) + where + (args, res) = splitHsFunType y +splitHsFunType (L _ (HsParTy ty)) = splitHsFunType ty +splitHsFunType other = ([], other) \end{code} %************************************************************************ %* * -\subsection{Comparison} +\subsection{Pretty printing} %* * %************************************************************************ -We do define a specialised equality for these \tr{*Type} types; used -in checking interfaces. Most any other use is likely to be {\em -wrong}, so be careful! +NB: these types get printed into interface files, so + don't change the printing format lightly \begin{code} -cmpHsTyVar :: (a -> a -> Ordering) -> HsTyVar a -> HsTyVar a -> Ordering -cmpHsType :: (a -> a -> Ordering) -> HsType a -> HsType a -> Ordering -cmpHsTypes :: (a -> a -> Ordering) -> [HsType a] -> [HsType a] -> Ordering -cmpContext :: (a -> a -> Ordering) -> Context a -> Context a -> Ordering - -cmpHsTyVar cmp (UserTyVar v1) (UserTyVar v2) = v1 `cmp` v2 -cmpHsTyVar cmp (IfaceTyVar v1 _) (IfaceTyVar v2 _) = v1 `cmp` v2 -cmpHsTyVar cmp (UserTyVar _) other = LT -cmpHsTyVar cmp other1 other2 = GT +instance (OutputableBndr name) => Outputable (HsType name) where + ppr ty = pprHsType ty +instance (Outputable name) => Outputable (HsTyVarBndr name) where + ppr (UserTyVar name) = ppr name + ppr (KindedTyVar name kind) = pprHsTyVarBndr name kind -cmpHsTypes cmp [] [] = EQ -cmpHsTypes cmp [] tys2 = LT -cmpHsTypes cmp tys1 [] = GT -cmpHsTypes cmp (ty1:tys1) (ty2:tys2) = cmpHsType cmp ty1 ty2 `thenCmp` cmpHsTypes cmp tys1 tys2 +instance OutputableBndr name => Outputable (HsPred name) where + ppr (HsClassP clas tys) = ppr clas <+> hsep (map (pprParendHsType.unLoc) tys) + ppr (HsIParam n ty) = hsep [ppr n, dcolon, ppr ty] -cmpHsType cmp (HsForAllTy tvs1 c1 t1) (HsForAllTy tvs2 c2 t2) - = cmpList (cmpHsTyVar cmp) tvs1 tvs2 `thenCmp` - cmpContext cmp c1 c2 `thenCmp` - cmpHsType cmp t1 t2 +pprHsTyVarBndr :: Outputable name => name -> Kind -> SDoc +pprHsTyVarBndr name kind | isLiftedTypeKind kind = ppr name + | otherwise = hsep [ppr name, dcolon, pprParendKind kind] -cmpHsType cmp (MonoTyVar n1) (MonoTyVar n2) - = cmp n1 n2 +pprHsForAll exp tvs cxt + | show_forall = forall_part <+> pprHsContext (unLoc cxt) + | otherwise = pprHsContext (unLoc cxt) + where + show_forall = opt_PprStyle_Debug + || (not (null tvs) && is_explicit) + is_explicit = case exp of {Explicit -> True; Implicit -> False} + forall_part = ptext SLIT("forall") <+> interppSP tvs <> dot -cmpHsType cmp (MonoTupleTy tys1 b1) (MonoTupleTy tys2 b2) - = (b1 `compare` b2) `thenCmp` cmpHsTypes cmp tys1 tys2 +pprHsContext :: (OutputableBndr name) => HsContext name -> SDoc +pprHsContext [] = empty +pprHsContext cxt = ppr_hs_context cxt <+> ptext SLIT("=>") -cmpHsType cmp (MonoListTy ty1) (MonoListTy ty2) - = cmpHsType cmp ty1 ty2 +ppr_hs_context [] = empty +ppr_hs_context cxt = parens (interpp'SP cxt) +\end{code} -cmpHsType cmp (MonoTyApp fun_ty1 arg_ty1) (MonoTyApp fun_ty2 arg_ty2) - = cmpHsType cmp fun_ty1 fun_ty2 `thenCmp` cmpHsType cmp arg_ty1 arg_ty2 +\begin{code} +pREC_TOP = (0 :: Int) -- type in ParseIface.y +pREC_FUN = (1 :: Int) -- btype in ParseIface.y + -- Used for LH arg of (->) +pREC_OP = (2 :: Int) -- Used for arg of any infix operator + -- (we don't keep their fixities around) +pREC_CON = (3 :: Int) -- Used for arg of type applicn: + -- always parenthesise unless atomic + +maybeParen :: Int -- Precedence of context + -> Int -- Precedence of top-level operator + -> SDoc -> SDoc -- Wrap in parens if (ctxt >= op) +maybeParen ctxt_prec op_prec p | ctxt_prec >= op_prec = parens p + | otherwise = p + +-- printing works more-or-less as for Types -cmpHsType cmp (MonoFunTy a1 b1) (MonoFunTy a2 b2) - = cmpHsType cmp a1 a2 `thenCmp` cmpHsType cmp b1 b2 +pprHsType, pprParendHsType :: (OutputableBndr name) => HsType name -> SDoc -cmpHsType cmp (MonoDictTy c1 tys1) (MonoDictTy c2 tys2) - = cmp c1 c2 `thenCmp` cmpHsTypes cmp tys1 tys2 +pprHsType ty = getPprStyle $ \sty -> ppr_mono_ty pREC_TOP (prepare sty ty) +pprParendHsType ty = ppr_mono_ty pREC_CON ty -cmpHsType cmp ty1 ty2 -- tags must be different - = let tag1 = tag ty1 - tag2 = tag ty2 +-- Before printing a type +-- (a) Remove outermost HsParTy parens +-- (b) Drop top-level for-all type variables in user style +-- since they are implicit in Haskell +prepare sty (HsParTy ty) = prepare sty (unLoc ty) +prepare sty ty = ty + +ppr_mono_lty ctxt_prec ty = ppr_mono_ty ctxt_prec (unLoc ty) + +ppr_mono_ty ctxt_prec (HsForAllTy exp tvs ctxt ty) + = maybeParen ctxt_prec pREC_FUN $ + sep [pprHsForAll exp tvs ctxt, ppr_mono_lty pREC_TOP ty] + +-- gaw 2004 +ppr_mono_ty ctxt_prec (HsBangTy b ty) = ppr b <> ppr ty +ppr_mono_ty ctxt_prec (HsTyVar name) = ppr name +ppr_mono_ty ctxt_prec (HsFunTy ty1 ty2) = ppr_fun_ty ctxt_prec ty1 ty2 +ppr_mono_ty ctxt_prec (HsTupleTy con tys) = tupleParens con (interpp'SP tys) +ppr_mono_ty ctxt_prec (HsKindSig ty kind) = parens (ppr_mono_lty pREC_TOP ty <+> dcolon <+> pprKind kind) +ppr_mono_ty ctxt_prec (HsListTy ty) = brackets (ppr_mono_lty pREC_TOP ty) +ppr_mono_ty ctxt_prec (HsPArrTy ty) = pabrackets (ppr_mono_lty pREC_TOP ty) +ppr_mono_ty ctxt_prec (HsPredTy pred) = braces (ppr pred) +ppr_mono_ty ctxt_prec (HsNumTy n) = integer n -- generics only +ppr_mono_ty ctxt_prec (HsSpliceTy s) = pprSplice s + +ppr_mono_ty ctxt_prec (HsAppTy fun_ty arg_ty) + = maybeParen ctxt_prec pREC_CON $ + hsep [ppr_mono_lty pREC_FUN fun_ty, ppr_mono_lty pREC_CON arg_ty] + +ppr_mono_ty ctxt_prec (HsOpTy ty1 op ty2) + = maybeParen ctxt_prec pREC_OP $ + ppr_mono_lty pREC_OP ty1 <+> ppr op <+> ppr_mono_lty pREC_OP ty2 + +ppr_mono_ty ctxt_prec (HsParTy ty) + = parens (ppr_mono_lty pREC_TOP ty) + -- Put the parens in where the user did + -- But we still use the precedence stuff to add parens because + -- toHsType doesn't put in any HsParTys, so we may still need them + +-------------------------- +ppr_fun_ty ctxt_prec ty1 ty2 + = let p1 = ppr_mono_lty pREC_FUN ty1 + p2 = ppr_mono_lty pREC_TOP ty2 in - if tag1 _LT_ tag2 then LT else GT - where - tag (MonoTyVar n1) = (ILIT(1) :: FAST_INT) - tag (MonoTupleTy tys1 _) = ILIT(2) - tag (MonoListTy ty1) = ILIT(3) - tag (MonoTyApp tc1 tys1) = ILIT(4) - tag (MonoFunTy a1 b1) = ILIT(5) - tag (MonoDictTy c1 tys1) = ILIT(7) - tag (HsForAllTy _ _ _) = ILIT(8) - -------------------- -cmpContext cmp a b - = cmpList cmp_ctxt a b - where - cmp_ctxt (c1, tys1) (c2, tys2) - = cmp c1 c2 `thenCmp` cmpHsTypes cmp tys1 tys2 + maybeParen ctxt_prec pREC_FUN $ + sep [p1, ptext SLIT("->") <+> p2] + +-------------------------- +pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") \end{code} + +