X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FhsSyn%2FHsTypes.lhs;h=c65929715ccbce2ace38111711486909fc47011e;hb=911a9fad0e04c6df6e895bab8e169a90766dc483;hp=b83f4b8fcd4e2fe5bd090f0c5ed961299aab7aba;hpb=9c26739695219d8343505a88457cb55c76b65449;p=ghc-hetmet.git diff --git a/ghc/compiler/hsSyn/HsTypes.lhs b/ghc/compiler/hsSyn/HsTypes.lhs index b83f4b8..c659297 100644 --- a/ghc/compiler/hsSyn/HsTypes.lhs +++ b/ghc/compiler/hsSyn/HsTypes.lhs @@ -1,239 +1,356 @@ -% -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +]% +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \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} -#include "HsVersions.h" - module HsTypes ( - HsType(..), HsTyVar(..), - SYN_IE(Context), SYN_IE(ClassAssertion) - - , mkHsForAllTy - , getTyVarName, replaceTyVarName - , pprParendHsType - , pprContext - , cmpHsType, cmpContext + HsType(..), LHsType, + HsTyVarBndr(..), LHsTyVarBndr, + HsExplicitForAll(..), + HsContext, LHsContext, + HsPred(..), LHsPred, + + mkExplicitHsForAllTy, mkImplicitHsForAllTy, + hsTyVarName, hsTyVarNames, replaceTyVarName, + hsLTyVarName, hsLTyVarNames, hsLTyVarLocName, hsLTyVarLocNames, + splitHsInstDeclTy, + + -- Type place holder + PostTcType, placeHolderType, + + -- Name place holder + SyntaxName, placeHolderName, + + -- Printing + pprParendHsType, pprHsForAll, pprHsContext, ppr_hs_context, pprHsTyVarBndr ) where -IMP_Ubiq() +#include "HsVersions.h" + +import {-# SOURCE #-} HsExpr ( HsSplice, pprSplice ) + +import TcType ( Type, Kind, liftedTypeKind, eqKind ) +import Type ( {- instance Outputable Kind -}, pprParendKind, pprKind ) +import Name ( Name, mkInternalName ) +import OccName ( mkVarOcc ) +import BasicTypes ( IPName, Boxity, tupleParens ) +import PrelNames ( unboundKey ) +import SrcLoc ( noSrcLoc, Located(..), unLoc, noSrcSpan ) +import CmdLineOpts ( opt_PprStyle_Debug ) +import Outputable +\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" + -import CmdLineOpts ( opt_PprUserLength ) -import Outputable ( Outputable(..), PprStyle(..), pprQuote, interppSP ) -import Kind ( Kind {- instance Outputable -} ) -import Name ( nameOccName ) -import Pretty -import Util ( thenCmp, cmpList, isIn, panic# ) +type SyntaxName = Name -- These names are filled in by the renamer + -- Before then they are a placeHolderName (so that + -- we can still print the HsSyn) + -- They correspond to "rebindable syntax"; + -- See RnEnv.lookupSyntaxName + +placeHolderName :: SyntaxName +placeHolderName = mkInternalName unboundKey + (mkVarOcc FSLIT("syntaxPlaceHolder")) + noSrcLoc \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) -type ClassAssertion name = (name, HsType name) - -- The type is usually a type variable, but it - -- doesn't have to be when reading interface files +data HsPred name = HsClassP name [LHsType name] + | HsIParam (IPName name) (LHsType name) + +type LHsType name = Located (HsType name) data HsType name - = HsPreForAllTy (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) - -- The renamer turns HsPreForAllTys into HsForAllTys when they - -- occur in signatures, to make the binding of variables - -- explicit. This distinction is made visible for - -- non-COMPILING_GHC code, because you probably want to do the - -- same thing. + | HsTyVar name -- Type variable or type constructor - | HsForAllTy [HsTyVar name] - (Context name) - (HsType name) + | HsAppTy (LHsType name) + (LHsType name) - | MonoTyVar name -- Type variable + | HsFunTy (LHsType name) -- function type + (LHsType name) - | MonoTyApp (HsType name) - (HsType name) + | HsListTy (LHsType name) -- Element type - | MonoFunTy (HsType name) -- function type - (HsType name) + | HsPArrTy (LHsType name) -- Elem. type of parallel array: [:t:] - | MonoListTy name -- The list TyCon name - (HsType name) -- Element type + | HsTupleTy Boxity + [LHsType name] -- Element types (length gives arity) - | MonoTupleTy name -- The tuple TyCon name - [HsType name] -- Element types (length gives arity) + | HsOpTy (LHsType name) (Located name) (LHsType name) - -- these next two are only used in unfoldings in interfaces - | MonoDictTy name -- Class - (HsType name) + | 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. -mkHsForAllTy [] [] ty = ty -mkHsForAllTy tvs ctxt ty = HsForAllTy tvs ctxt ty + | HsNumTy Integer -- Generics only -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. + | HsPredTy (LHsPred name) -- Only used in the type of an instance + -- declaration, eg. Eq [a] -> Eq a + -- ^^^^ + -- HsPredTy -getTyVarName (UserTyVar n) = n -getTyVarName (IfaceTyVar n _) = n + | HsKindSig (LHsType name) -- (ty :: kind) + Kind -- A type with a kind signature -replaceTyVarName :: HsTyVar name1 -> name2 -> HsTyVar name2 -replaceTyVarName (UserTyVar n) n' = UserTyVar n' -replaceTyVarName (IfaceTyVar n k) n' = IfaceTyVar n' k -\end{code} + | HsSpliceTy (HsSplice name) +data HsExplicitForAll = Explicit | Implicit -%************************************************************************ -%* * -\subsection{Pretty printing} -%* * -%************************************************************************ +----------------------- +-- 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 -\begin{code} +mkImplicitHsForAllTy ctxt ty = mkHsForAllTy Implicit [] ctxt ty +mkExplicitHsForAllTy tvs ctxt ty = mkHsForAllTy Explicit tvs ctxt ty -instance (Outputable name) => Outputable (HsType name) where - ppr sty ty = pprQuote sty $ \ sty -> pprHsType sty ty - -instance (Outputable name) => Outputable (HsTyVar name) where - ppr sty (UserTyVar name) = ppr sty name - ppr sty (IfaceTyVar name kind) = pprQuote sty $ \ sty -> - hsep [ppr sty name, ptext SLIT("::"), ppr sty kind] - -ppr_forall sty ctxt_prec [] [] ty - = ppr_mono_ty sty ctxt_prec ty -ppr_forall sty ctxt_prec tvs ctxt ty - = maybeParen (ctxt_prec >= pREC_FUN) $ - sep [ptext SLIT("_forall_"), brackets (interppSP sty tvs), - pprContext sty ctxt, ptext SLIT("=>"), - pprHsType sty ty] - -pprContext :: (Outputable name) => PprStyle -> (Context name) -> Doc -pprContext sty [] = empty -pprContext sty context - = hsep [braces (hsep (punctuate comma (map ppr_assert context)))] - where - ppr_assert (clas, ty) = hsep [ppr sty clas, ppr sty ty] -\end{code} +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 -\begin{code} -pREC_TOP = (0 :: Int) -pREC_FUN = (1 :: Int) -pREC_CON = (2 :: Int) +-- mk_forall_ty makes a pure for-all type (no context) +mk_forall_ty Explicit [] ty = unLoc ty -- Explicit for-all with no tyvars +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 -maybeParen :: Bool -> Doc -> Doc -maybeParen True p = parens p -maybeParen False p = p - --- printing works more-or-less as for Types +Implicit `plus` Implicit = Implicit +exp1 `plus` exp2 = Explicit -pprHsType, pprParendHsType :: (Outputable name) => PprStyle -> HsType name -> Doc +type LHsTyVarBndr name = Located (HsTyVarBndr name) -pprHsType sty ty = ppr_mono_ty sty pREC_TOP ty -pprParendHsType sty ty = ppr_mono_ty sty pREC_CON ty +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. -ppr_mono_ty sty ctxt_prec (HsPreForAllTy ctxt ty) = ppr_forall sty ctxt_prec [] ctxt ty -ppr_mono_ty sty ctxt_prec (HsForAllTy tvs ctxt ty) = ppr_forall sty ctxt_prec tvs ctxt ty +hsTyVarName :: HsTyVarBndr name -> name +hsTyVarName (UserTyVar n) = n +hsTyVarName (KindedTyVar n _) = n -ppr_mono_ty sty ctxt_prec (MonoTyVar name) = ppr sty name +hsLTyVarName :: LHsTyVarBndr name -> name +hsLTyVarName = hsTyVarName . unLoc -ppr_mono_ty sty ctxt_prec (MonoFunTy ty1 ty2) - = let p1 = ppr_mono_ty sty pREC_FUN ty1 - p2 = ppr_mono_ty sty pREC_TOP ty2 - in - maybeParen (ctxt_prec >= pREC_FUN) - (sep [p1, (<>) (ptext SLIT("-> ")) p2]) +hsTyVarNames :: [HsTyVarBndr name] -> [name] +hsTyVarNames tvs = map hsTyVarName tvs -ppr_mono_ty sty ctxt_prec (MonoTupleTy _ tys) - = parens (sep (punctuate comma (map (ppr sty) tys))) +hsLTyVarNames :: [LHsTyVarBndr name] -> [name] +hsLTyVarNames = map hsLTyVarName -ppr_mono_ty sty ctxt_prec (MonoListTy _ ty) - = brackets (ppr_mono_ty sty pREC_TOP ty) +hsLTyVarLocName :: LHsTyVarBndr name -> Located name +hsLTyVarLocName = fmap hsTyVarName -ppr_mono_ty sty ctxt_prec (MonoTyApp fun_ty arg_ty) - = maybeParen (ctxt_prec >= pREC_CON) - (hsep [ppr_mono_ty sty pREC_FUN fun_ty, ppr_mono_ty sty pREC_CON arg_ty]) +hsLTyVarLocNames :: [LHsTyVarBndr name] -> [Located name] +hsLTyVarLocNames = map hsLTyVarLocName -ppr_mono_ty sty ctxt_prec (MonoDictTy clas ty) - = hsep [ppr sty clas, ppr_mono_ty sty pREC_CON ty] +replaceTyVarName :: HsTyVarBndr name1 -> name2 -> HsTyVarBndr name2 +replaceTyVarName (UserTyVar n) n' = UserTyVar n' +replaceTyVarName (KindedTyVar n k) n' = KindedTyVar n' k +\end{code} + + +\begin{code} +splitHsInstDeclTy + :: OutputableBndr name + => HsType name + -> ([LHsTyVarBndr name], HsContext name, name, [LHsType name]) + -- Split up an instance decl type, returning the pieces + +-- In interface files, the instance declaration head is created +-- by HsTypes.toHsType, which does not guarantee to produce a +-- HsForAllTy. For example, if we had the weird decl +-- instance Foo T => Foo [T] +-- then we'd get the instance type +-- Foo T -> Foo [T] +-- So when colleting the instance context, to be on the safe side +-- we gather predicate arguments +-- +-- For source code, the parser ensures the type will have the right shape. +-- (e.g. see ParseUtil.checkInstType) + +splitHsInstDeclTy inst_ty + = case inst_ty of + HsForAllTy _ tvs cxt1 tau -- The type vars should have been + -- computed by now, even if they were implicit + -> (tvs, unLoc cxt1 ++ cxt2, cls, tys) + where + (cxt2, cls, tys) = split_tau (unLoc tau) + + other -> ([], cxt2, cls, tys) + where + (cxt2, cls, tys) = split_tau inst_ty + + where + split_tau (HsFunTy (L _ (HsPredTy p)) ty) = (p:ps, cls, tys) + where + (ps, cls, tys) = split_tau (unLoc ty) + split_tau (HsPredTy (L _ (HsClassP cls tys))) = ([], cls, tys) + split_tau other = pprPanic "splitHsInstDeclTy" (ppr inst_ty) \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 -> TAG_) -> HsTyVar a -> HsTyVar a -> TAG_ ---cmpHsType :: (a -> a -> TAG_) -> HsType a -> HsType a -> TAG_ ---cmpContext :: (a -> a -> TAG_) -> Context a -> Context a -> TAG_ +instance (OutputableBndr name) => Outputable (HsType name) where + ppr ty = pprHsType ty -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 (Outputable name) => Outputable (HsTyVarBndr name) where + ppr (UserTyVar name) = ppr name + ppr (KindedTyVar name kind) = pprHsTyVarBndr name kind +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] --- We assume that HsPreForAllTys have been smashed by now. -# ifdef DEBUG -cmpHsType _ (HsPreForAllTy _ _) _ = panic# "cmpHsType:HsPreForAllTy:1st arg" -cmpHsType _ _ (HsPreForAllTy _ _) = panic# "cmpHsType:HsPreForAllTy:2nd arg" -# endif +pprHsTyVarBndr :: Outputable name => name -> Kind -> SDoc +pprHsTyVarBndr name kind | kind `eqKind` liftedTypeKind = ppr name + | otherwise = hsep [ppr name, dcolon, pprParendKind kind] -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 - -cmpHsType cmp (MonoTyVar n1) (MonoTyVar n2) - = cmp n1 n2 - -cmpHsType cmp (MonoTupleTy _ tys1) (MonoTupleTy _ tys2) - = cmpList (cmpHsType cmp) tys1 tys2 -cmpHsType cmp (MonoListTy _ ty1) (MonoListTy _ ty2) - = cmpHsType cmp ty1 ty2 +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 (MonoTyApp fun_ty1 arg_ty1) (MonoTyApp fun_ty2 arg_ty2) - = cmpHsType cmp fun_ty1 fun_ty2 `thenCmp` cmpHsType cmp arg_ty1 arg_ty2 +pprHsContext :: (OutputableBndr name) => HsContext name -> SDoc +pprHsContext [] = empty +pprHsContext cxt = ppr_hs_context cxt <+> ptext SLIT("=>") -cmpHsType cmp (MonoFunTy a1 b1) (MonoFunTy a2 b2) - = cmpHsType cmp a1 a2 `thenCmp` cmpHsType cmp b1 b2 +ppr_hs_context [] = empty +ppr_hs_context cxt = parens (interpp'SP cxt) +\end{code} -cmpHsType cmp (MonoDictTy c1 ty1) (MonoDictTy c2 ty2) - = cmp c1 c2 `thenCmp` cmpHsType cmp ty1 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 ty1 ty2 -- tags must be different - = let tag1 = tag ty1 - tag2 = tag ty2 +pprHsType, pprParendHsType :: (OutputableBndr name) => HsType name -> SDoc + +pprHsType ty = getPprStyle $ \sty -> ppr_mono_ty pREC_TOP (prepare sty ty) +pprParendHsType ty = ppr_mono_ty pREC_CON ty + +-- 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] + +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 ty1) = ILIT(7) - tag (HsForAllTy _ _ _) = ILIT(8) - tag (HsPreForAllTy _ _) = ILIT(9) - -------------------- -cmpContext cmp a b - = cmpList cmp_ctxt a b - where - cmp_ctxt (c1, ty1) (c2, ty2) - = cmp c1 c2 `thenCmp` cmpHsType cmp ty1 ty2 + maybeParen ctxt_prec pREC_FUN $ + sep [p1, ptext SLIT("->") <+> p2] + +-------------------------- +pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") \end{code} + +