% % (c) The University of Glasgow, 1996-2003 Functions over HsSyn specialised to RdrName. \begin{code} module RdrHsSyn ( extractHsTyRdrTyVars, extractHsRhoRdrTyVars, extractGenericPatTyVars, mkHsOpApp, mkHsIntegral, mkHsFractional, mkHsIsString, mkHsDo, mkHsSplice, mkTopSpliceDecl, mkClassDecl, mkTyData, mkTyFamily, mkTySynonym, splitCon, mkInlinePragma, mkRecConstrOrUpdate, -- HsExp -> [HsFieldUpdate] -> P HsExp cvBindGroup, cvBindsAndSigs, cvTopDecls, placeHolderPunRhs, -- Stuff to do with Foreign declarations mkImport, parseCImport, mkExport, mkExtName, -- RdrName -> CLabelString mkGadtDecl, -- [Located RdrName] -> LHsType RdrName -> ConDecl RdrName mkSimpleConDecl, mkDeprecatedGadtRecordDecl, -- Bunch of functions in the parser monad for -- checking and constructing values checkPrecP, -- Int -> P Int checkContext, -- HsType -> P HsContext checkTyVars, -- [LHsType RdrName] -> P () checkKindSigs, -- [LTyClDecl RdrName] -> P () checkPattern, -- HsExp -> P HsPat bang_RDR, checkPatterns, -- SrcLoc -> [HsExp] -> P [HsPat] checkMonadComp, -- P (HsStmtContext RdrName) checkValDef, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl checkValSig, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl checkDoAndIfThenElse, checkKindName, checkRecordSyntax, parseError, parseErrorSDoc, ) where import HsSyn -- Lots of it import Class ( FunDep ) import TypeRep ( Kind ) import RdrName ( RdrName, isRdrTyVar, isRdrTc, mkUnqual, rdrNameOcc, isRdrDataCon, isUnqual, getRdrName, setRdrNameSpace ) import OccName ( occNameFS ) import Name ( Name, nameOccName ) import BasicTypes ( maxPrecedence, Activation(..), RuleMatchInfo, InlinePragma(..), InlineSpec(..) ) import Lexer import TysWiredIn ( unitTyCon ) import TysPrim ( constraintKindTyConName, constraintKind ) import ForeignCall import OccName ( srcDataName, varName, isDataOcc, isTcOcc, occNameString ) import PrelNames ( forall_tv_RDR ) import DynFlags import SrcLoc import OrdList ( OrdList, fromOL ) import Bag ( Bag, emptyBag, consBag, foldrBag ) import Outputable import FastString import Maybes import Control.Applicative ((<$>)) import Control.Monad import Text.ParserCombinators.ReadP as ReadP import Data.List ( nubBy, partition ) import Data.Char #include "HsVersions.h" \end{code} %************************************************************************ %* * \subsection{A few functions over HsSyn at RdrName} %* * %************************************************************************ extractHsTyRdrNames finds the free variables of a HsType It's used when making the for-alls explicit. \begin{code} extractHsTyRdrTyVars :: LHsType RdrName -> [Located RdrName] extractHsTyRdrTyVars ty = nubBy eqLocated (extract_lty ty []) extractHsTysRdrTyVars :: [LHsType RdrName] -> [Located RdrName] extractHsTysRdrTyVars ty = nubBy eqLocated (extract_ltys ty []) extractHsRhoRdrTyVars :: LHsContext RdrName -> LHsType RdrName -> [Located RdrName] -- This one takes the context and tau-part of a -- sigma type and returns their free type variables extractHsRhoRdrTyVars ctxt ty = nubBy eqLocated $ extract_lctxt ctxt (extract_lty ty []) extract_lctxt :: LHsContext RdrName -> [Located RdrName] -> [Located RdrName] extract_lctxt ctxt acc = foldr extract_lty acc (unLoc ctxt) extract_ltys :: [LHsType RdrName] -> [Located RdrName] -> [Located RdrName] extract_ltys tys acc = foldr extract_lty acc tys extract_lty :: LHsType RdrName -> [Located RdrName] -> [Located RdrName] extract_lty (L loc ty) acc = case ty of HsTyVar tv -> extract_tv loc tv acc HsBangTy _ ty -> extract_lty ty acc HsRecTy flds -> foldr (extract_lty . cd_fld_type) acc flds HsAppTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc) HsListTy ty -> extract_lty ty acc HsPArrTy ty -> extract_lty ty acc HsTupleTy _ tys -> extract_ltys tys acc HsFunTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc) HsIParamTy _ ty -> extract_lty ty acc HsEqTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc) HsOpTy ty1 (L loc tv) ty2 -> extract_tv loc tv (extract_lty ty1 (extract_lty ty2 acc)) HsParTy ty -> extract_lty ty acc HsCoreTy {} -> acc -- The type is closed HsQuasiQuoteTy {} -> acc -- Quasi quotes mention no type variables HsSpliceTy {} -> acc -- Type splices mention no type variables HsKindSig ty _ -> extract_lty ty acc HsForAllTy _ [] cx ty -> extract_lctxt cx (extract_lty ty acc) HsForAllTy _ tvs cx ty -> acc ++ (filter ((`notElem` locals) . unLoc) $ extract_lctxt cx (extract_lty ty [])) where locals = hsLTyVarNames tvs HsDocTy ty _ -> extract_lty ty acc extract_tv :: SrcSpan -> RdrName -> [Located RdrName] -> [Located RdrName] extract_tv loc tv acc | isRdrTyVar tv = L loc tv : acc | otherwise = acc extractGenericPatTyVars :: LHsBinds RdrName -> [Located RdrName] -- Get the type variables out of the type patterns in a bunch of -- possibly-generic bindings in a class declaration extractGenericPatTyVars binds = nubBy eqLocated (foldrBag get [] binds) where get (L _ (FunBind { fun_matches = MatchGroup ms _ })) acc = foldr (get_m.unLoc) acc ms get _ acc = acc get_m _ acc = acc \end{code} %************************************************************************ %* * \subsection{Construction functions for Rdr stuff} %* * %************************************************************************ mkClassDecl builds a RdrClassDecl, filling in the names for tycon and datacon by deriving them from the name of the class. We fill in the names for the tycon and datacon corresponding to the class, by deriving them from the name of the class itself. This saves recording the names in the interface file (which would be equally good). Similarly for mkConDecl, mkClassOpSig and default-method names. *** See "THE NAMING STORY" in HsDecls **** \begin{code} mkClassDecl :: SrcSpan -> Located (Maybe (LHsContext RdrName), LHsType RdrName) -> Located [Located (FunDep RdrName)] -> Located (OrdList (LHsDecl RdrName)) -> P (LTyClDecl RdrName) mkClassDecl loc (L _ (mcxt, tycl_hdr)) fds where_cls = do { let (binds, sigs, at_stuff, docs) = cvBindsAndSigs (unLoc where_cls) (at_defs, ats) = partition (isTypeDecl . unLoc) at_stuff cxt = fromMaybe (noLoc []) mcxt ; (cls, tparams) <- checkTyClHdr tycl_hdr ; tyvars <- checkTyVars tycl_hdr tparams -- Only type vars allowed ; checkKindSigs ats ; return (L loc (ClassDecl { tcdCtxt = cxt, tcdLName = cls, tcdTyVars = tyvars, tcdFDs = unLoc fds, tcdSigs = sigs, tcdMeths = binds, tcdATs = ats, tcdATDefs = at_defs, tcdDocs = docs })) } mkTyData :: SrcSpan -> NewOrData -> Bool -- True <=> data family instance -> Located (Maybe (LHsContext RdrName), LHsType RdrName) -> Maybe Kind -> [LConDecl RdrName] -> Maybe [LHsType RdrName] -> P (LTyClDecl RdrName) mkTyData loc new_or_data is_family (L _ (mcxt, tycl_hdr)) ksig data_cons maybe_deriv = do { (tc, tparams) <- checkTyClHdr tycl_hdr ; checkDatatypeContext mcxt ; let cxt = fromMaybe (noLoc []) mcxt ; (tyvars, typats) <- checkTParams is_family tycl_hdr tparams ; return (L loc (TyData { tcdND = new_or_data, tcdCtxt = cxt, tcdLName = tc, tcdTyVars = tyvars, tcdTyPats = typats, tcdCons = data_cons, tcdKindSig = ksig, tcdDerivs = maybe_deriv })) } mkTySynonym :: SrcSpan -> Bool -- True <=> type family instances -> LHsType RdrName -- LHS -> LHsType RdrName -- RHS -> P (LTyClDecl RdrName) mkTySynonym loc is_family lhs rhs = do { (tc, tparams) <- checkTyClHdr lhs ; (tyvars, typats) <- checkTParams is_family lhs tparams ; return (L loc (TySynonym tc tyvars typats rhs)) } mkTyFamily :: SrcSpan -> FamilyFlavour -> LHsType RdrName -- LHS -> Maybe Kind -- Optional kind signature -> P (LTyClDecl RdrName) mkTyFamily loc flavour lhs ksig = do { (tc, tparams) <- checkTyClHdr lhs ; tyvars <- checkTyVars lhs tparams ; return (L loc (TyFamily flavour tc tyvars ksig)) } mkTopSpliceDecl :: LHsExpr RdrName -> HsDecl RdrName -- If the user wrote -- [pads| ... ] then return a QuasiQuoteD -- $(e) then return a SpliceD -- but if she wrote, say, -- f x then behave as if she'd written $(f x) -- ie a SpliceD mkTopSpliceDecl (L _ (HsQuasiQuoteE qq)) = QuasiQuoteD qq mkTopSpliceDecl (L _ (HsSpliceE (HsSplice _ expr))) = SpliceD (SpliceDecl expr Explicit) mkTopSpliceDecl other_expr = SpliceD (SpliceDecl other_expr Implicit) \end{code} %************************************************************************ %* * \subsection[cvBinds-etc]{Converting to @HsBinds@, etc.} %* * %************************************************************************ Function definitions are restructured here. Each is assumed to be recursive initially, and non recursive definitions are discovered by the dependency analyser. \begin{code} -- | Groups together bindings for a single function cvTopDecls :: OrdList (LHsDecl RdrName) -> [LHsDecl RdrName] cvTopDecls decls = go (fromOL decls) where go :: [LHsDecl RdrName] -> [LHsDecl RdrName] go [] = [] go (L l (ValD b) : ds) = L l' (ValD b') : go ds' where (L l' b', ds') = getMonoBind (L l b) ds go (d : ds) = d : go ds -- Declaration list may only contain value bindings and signatures. cvBindGroup :: OrdList (LHsDecl RdrName) -> HsValBinds RdrName cvBindGroup binding = case cvBindsAndSigs binding of (mbs, sigs, tydecls, _) -> ASSERT( null tydecls ) ValBindsIn mbs sigs cvBindsAndSigs :: OrdList (LHsDecl RdrName) -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName], [LDocDecl]) -- Input decls contain just value bindings and signatures -- and in case of class or instance declarations also -- associated type declarations. They might also contain Haddock comments. cvBindsAndSigs fb = go (fromOL fb) where go [] = (emptyBag, [], [], []) go (L l (SigD s) : ds) = (bs, L l s : ss, ts, docs) where (bs, ss, ts, docs) = go ds go (L l (ValD b) : ds) = (b' `consBag` bs, ss, ts, docs) where (b', ds') = getMonoBind (L l b) ds (bs, ss, ts, docs) = go ds' go (L l (TyClD t): ds) = (bs, ss, L l t : ts, docs) where (bs, ss, ts, docs) = go ds go (L l (DocD d) : ds) = (bs, ss, ts, (L l d) : docs) where (bs, ss, ts, docs) = go ds go (L _ d : _) = pprPanic "cvBindsAndSigs" (ppr d) ----------------------------------------------------------------------------- -- Group function bindings into equation groups getMonoBind :: LHsBind RdrName -> [LHsDecl RdrName] -> (LHsBind RdrName, [LHsDecl RdrName]) -- Suppose (b',ds') = getMonoBind b ds -- ds is a list of parsed bindings -- b is a MonoBinds that has just been read off the front -- Then b' is the result of grouping more equations from ds that -- belong with b into a single MonoBinds, and ds' is the depleted -- list of parsed bindings. -- -- All Haddock comments between equations inside the group are -- discarded. -- -- No AndMonoBinds or EmptyMonoBinds here; just single equations getMonoBind (L loc1 (FunBind { fun_id = fun_id1@(L _ f1), fun_infix = is_infix1, fun_matches = MatchGroup mtchs1 _ })) binds | has_args mtchs1 = go is_infix1 mtchs1 loc1 binds [] where go is_infix mtchs loc (L loc2 (ValD (FunBind { fun_id = L _ f2, fun_infix = is_infix2, fun_matches = MatchGroup mtchs2 _ })) : binds) _ | f1 == f2 = go (is_infix || is_infix2) (mtchs2 ++ mtchs) (combineSrcSpans loc loc2) binds [] go is_infix mtchs loc (doc_decl@(L loc2 (DocD _)) : binds) doc_decls = let doc_decls' = doc_decl : doc_decls in go is_infix mtchs (combineSrcSpans loc loc2) binds doc_decls' go is_infix mtchs loc binds doc_decls = (L loc (makeFunBind fun_id1 is_infix (reverse mtchs)), (reverse doc_decls) ++ binds) -- Reverse the final matches, to get it back in the right order -- Do the same thing with the trailing doc comments getMonoBind bind binds = (bind, binds) has_args :: [LMatch RdrName] -> Bool has_args [] = panic "RdrHsSyn:has_args" has_args ((L _ (Match args _ _)) : _) = not (null args) -- Don't group together FunBinds if they have -- no arguments. This is necessary now that variable bindings -- with no arguments are now treated as FunBinds rather -- than pattern bindings (tests/rename/should_fail/rnfail002). \end{code} %************************************************************************ %* * \subsection[PrefixToHS-utils]{Utilities for conversion} %* * %************************************************************************ \begin{code} ----------------------------------------------------------------------------- -- splitCon -- When parsing data declarations, we sometimes inadvertently parse -- a constructor application as a type (eg. in data T a b = C a b `D` E a b) -- This function splits up the type application, adds any pending -- arguments, and converts the type constructor back into a data constructor. splitCon :: LHsType RdrName -> P (Located RdrName, HsConDeclDetails RdrName) -- This gets given a "type" that should look like -- C Int Bool -- or C { x::Int, y::Bool } -- and returns the pieces splitCon ty = split ty [] where split (L _ (HsAppTy t u)) ts = split t (u : ts) split (L l (HsTyVar tc)) ts = do data_con <- tyConToDataCon l tc return (data_con, mk_rest ts) split (L l _) _ = parseErrorSDoc l (text "parse error in constructor in data/newtype declaration:" <+> ppr ty) mk_rest [L _ (HsRecTy flds)] = RecCon flds mk_rest ts = PrefixCon ts mkDeprecatedGadtRecordDecl :: SrcSpan -> Located RdrName -> [ConDeclField RdrName] -> LHsType RdrName -> P (LConDecl RdrName) -- This one uses the deprecated syntax -- C { x,y ::Int } :: T a b -- We give it a RecCon details right away mkDeprecatedGadtRecordDecl loc (L con_loc con) flds res_ty = do { data_con <- tyConToDataCon con_loc con ; return (L loc (ConDecl { con_old_rec = True , con_name = data_con , con_explicit = Implicit , con_qvars = [] , con_cxt = noLoc [] , con_details = RecCon flds , con_res = ResTyGADT res_ty , con_doc = Nothing })) } mkSimpleConDecl :: Located RdrName -> [LHsTyVarBndr RdrName] -> LHsContext RdrName -> HsConDeclDetails RdrName -> ConDecl RdrName mkSimpleConDecl name qvars cxt details = ConDecl { con_old_rec = False , con_name = name , con_explicit = Explicit , con_qvars = qvars , con_cxt = cxt , con_details = details , con_res = ResTyH98 , con_doc = Nothing } mkGadtDecl :: [Located RdrName] -> LHsType RdrName -- Always a HsForAllTy -> [ConDecl RdrName] -- We allow C,D :: ty -- and expand it as if it had been -- C :: ty; D :: ty -- (Just like type signatures in general.) mkGadtDecl names (L _ (HsForAllTy imp qvars cxt tau)) = [mk_gadt_con name | name <- names] where (details, res_ty) -- See Note [Sorting out the result type] = case tau of L _ (HsFunTy (L _ (HsRecTy flds)) res_ty) -> (RecCon flds, res_ty) _other -> (PrefixCon [], tau) mk_gadt_con name = ConDecl { con_old_rec = False , con_name = name , con_explicit = imp , con_qvars = qvars , con_cxt = cxt , con_details = details , con_res = ResTyGADT res_ty , con_doc = Nothing } mkGadtDecl _ other_ty = pprPanic "mkGadtDecl" (ppr other_ty) tyConToDataCon :: SrcSpan -> RdrName -> P (Located RdrName) tyConToDataCon loc tc | isTcOcc (rdrNameOcc tc) = return (L loc (setRdrNameSpace tc srcDataName)) | otherwise = parseErrorSDoc loc (msg $$ extra) where msg = text "Not a data constructor:" <+> quotes (ppr tc) extra | tc == forall_tv_RDR = text "Perhaps you intended to use -XExistentialQuantification" | otherwise = empty \end{code} Note [Sorting out the result type] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In a GADT declaration which is not a record, we put the whole constr type into the ResTyGADT for now; the renamer will unravel it once it has sorted out operator fixities. Consider for example C :: a :*: b -> a :*: b -> a :+: b Initially this type will parse as a :*: (b -> (a :*: (b -> (a :+: b)))) so it's hard to split up the arguments until we've done the precedence resolution (in the renamer) On the other hand, for a record { x,y :: Int } -> a :*: b there is no doubt. AND we need to sort records out so that we can bring x,y into scope. So: * For PrefixCon we keep all the args in the ResTyGADT * For RecCon we do not \begin{code} checkTParams :: Bool -- Type/data family -> LHsType RdrName -> [LHsType RdrName] -> P ([LHsTyVarBndr RdrName], Maybe [LHsType RdrName]) -- checkTParams checks the type parameters of a data/newtype declaration -- There are two cases: -- -- a) Vanilla data/newtype decl. In that case -- - the type parameters should all be type variables -- - they may have a kind annotation -- -- b) Family data/newtype decl. In that case -- - The type parameters may be arbitrary types -- - We find the type-varaible binders by find the -- free type vars of those types -- - We make them all kind-sig-free binders (UserTyVar) -- If there are kind sigs in the type parameters, they -- will fix the binder's kind when we kind-check the -- type parameters checkTParams is_family tycl_hdr tparams | not is_family -- Vanilla case (a) = do { tyvars <- checkTyVars tycl_hdr tparams ; return (tyvars, Nothing) } | otherwise -- Family case (b) = do { let tyvars = userHsTyVarBndrs (extractHsTysRdrTyVars tparams) ; return (tyvars, Just tparams) } checkTyVars :: LHsType RdrName -> [LHsType RdrName] -> P [LHsTyVarBndr RdrName] -- Check whether the given list of type parameters are all type variables -- (possibly with a kind signature). If the second argument is `False', -- only type variables are allowed and we raise an error on encountering a -- non-variable; otherwise, we allow non-variable arguments and return the -- entire list of parameters. checkTyVars tycl_hdr tparms = mapM chk tparms where -- Check that the name space is correct! chk (L l (HsKindSig (L _ (HsTyVar tv)) k)) | isRdrTyVar tv = return (L l (KindedTyVar tv k)) chk (L l (HsTyVar tv)) | isRdrTyVar tv = return (L l (UserTyVar tv placeHolderKind)) chk t@(L l _) = parseErrorSDoc l $ vcat [ sep [ ptext (sLit "Unexpected type") <+> quotes (ppr t) , ptext (sLit "where type variable expected") ] , ptext (sLit "In the declaration of") <+> quotes (ppr tycl_hdr) ] checkDatatypeContext :: Maybe (LHsContext RdrName) -> P () checkDatatypeContext Nothing = return () checkDatatypeContext (Just (L loc c)) = do allowed <- extension datatypeContextsEnabled unless allowed $ parseErrorSDoc loc (text "Illegal datatype context (use -XDatatypeContexts):" <+> pprHsContext c) checkRecordSyntax :: Outputable a => Located a -> P (Located a) checkRecordSyntax lr@(L loc r) = do allowed <- extension traditionalRecordSyntaxEnabled if allowed then return lr else parseErrorSDoc loc (text "Illegal record syntax (use -XTraditionalRecordSyntax):" <+> ppr r) checkTyClHdr :: LHsType RdrName -> P (Located RdrName, -- the head symbol (type or class name) [LHsType RdrName]) -- parameters of head symbol -- Well-formedness check and decomposition of type and class heads. -- Decomposes T ty1 .. tyn into (T, [ty1, ..., tyn]) -- Int :*: Bool into (:*:, [Int, Bool]) -- returning the pieces checkTyClHdr ty = goL ty [] where goL (L l ty) acc = go l ty acc go l (HsTyVar tc) acc | isRdrTc tc = return (L l tc, acc) go _ (HsOpTy t1 ltc@(L _ tc) t2) acc | isRdrTc tc = return (ltc, t1:t2:acc) go _ (HsParTy ty) acc = goL ty acc go _ (HsAppTy t1 t2) acc = goL t1 (t2:acc) go l _ _ = parseErrorSDoc l (text "Malformed head of type or class declaration:" <+> ppr ty) -- Check that associated type declarations of a class are all kind signatures. -- checkKindSigs :: [LTyClDecl RdrName] -> P () checkKindSigs = mapM_ check where check (L l tydecl) | isFamilyDecl tydecl = return () | isTypeDecl tydecl = return () | otherwise = parseErrorSDoc l (text "Type declaration in a class must be a kind signature or synonym default:" $$ ppr tydecl) checkContext :: LHsType RdrName -> P (LHsContext RdrName) checkContext (L l orig_t) = check orig_t where check (HsTupleTy _ ts) -- (Eq a, Ord b) shows up as a tuple type = return (L l ts) check (HsParTy ty) -- to be sure HsParTy doesn't get into the way = check (unLoc ty) check (HsTyVar t) -- Empty context shows up as a unit type () | t == getRdrName unitTyCon = return (L l []) check _ = return (L l [L l orig_t]) -- ------------------------------------------------------------------------- -- Checking Patterns. -- We parse patterns as expressions and check for valid patterns below, -- converting the expression into a pattern at the same time. checkPattern :: LHsExpr RdrName -> P (LPat RdrName) checkPattern e = checkLPat e checkPatterns :: [LHsExpr RdrName] -> P [LPat RdrName] checkPatterns es = mapM checkPattern es checkLPat :: LHsExpr RdrName -> P (LPat RdrName) checkLPat e@(L l _) = checkPat l e [] checkPat :: SrcSpan -> LHsExpr RdrName -> [LPat RdrName] -> P (LPat RdrName) checkPat loc (L l (HsVar c)) args | isRdrDataCon c = return (L loc (ConPatIn (L l c) (PrefixCon args))) checkPat loc e args -- OK to let this happen even if bang-patterns -- are not enabled, because there is no valid -- non-bang-pattern parse of (C ! e) | Just (e', args') <- splitBang e = do { args'' <- checkPatterns args' ; checkPat loc e' (args'' ++ args) } checkPat loc (L _ (HsApp f x)) args = do { x <- checkLPat x; checkPat loc f (x:args) } checkPat loc (L _ e) [] = do { pState <- getPState ; p <- checkAPat (dflags pState) loc e ; return (L loc p) } checkPat loc e _ = patFail loc (unLoc e) checkAPat :: DynFlags -> SrcSpan -> HsExpr RdrName -> P (Pat RdrName) checkAPat dynflags loc e0 = case e0 of EWildPat -> return (WildPat placeHolderType) HsVar x -> return (VarPat x) HsLit l -> return (LitPat l) -- Overloaded numeric patterns (e.g. f 0 x = x) -- Negation is recorded separately, so that the literal is zero or +ve -- NB. Negative *primitive* literals are already handled by the lexer HsOverLit pos_lit -> return (mkNPat pos_lit Nothing) NegApp (L _ (HsOverLit pos_lit)) _ -> return (mkNPat pos_lit (Just noSyntaxExpr)) SectionR (L _ (HsVar bang)) e -- (! x) | bang == bang_RDR -> do { bang_on <- extension bangPatEnabled ; if bang_on then checkLPat e >>= (return . BangPat) else parseErrorSDoc loc (text "Illegal bang-pattern (use -XBangPatterns):" $$ ppr e0) } ELazyPat e -> checkLPat e >>= (return . LazyPat) EAsPat n e -> checkLPat e >>= (return . AsPat n) -- view pattern is well-formed if the pattern is EViewPat expr patE -> checkLPat patE >>= (return . (\p -> ViewPat expr p placeHolderType)) ExprWithTySig e t -> do e <- checkLPat e -- Pattern signatures are parsed as sigtypes, -- but they aren't explicit forall points. Hence -- we have to remove the implicit forall here. let t' = case t of L _ (HsForAllTy Implicit _ (L _ []) ty) -> ty other -> other return (SigPatIn e t') -- n+k patterns OpApp (L nloc (HsVar n)) (L _ (HsVar plus)) _ (L _ (HsOverLit lit@(OverLit {ol_val = HsIntegral {}}))) | xopt Opt_NPlusKPatterns dynflags && (plus == plus_RDR) -> return (mkNPlusKPat (L nloc n) lit) OpApp l op _fix r -> do l <- checkLPat l r <- checkLPat r case op of L cl (HsVar c) | isDataOcc (rdrNameOcc c) -> return (ConPatIn (L cl c) (InfixCon l r)) _ -> patFail loc e0 HsPar e -> checkLPat e >>= (return . ParPat) ExplicitList _ es -> do ps <- mapM checkLPat es return (ListPat ps placeHolderType) ExplicitPArr _ es -> do ps <- mapM checkLPat es return (PArrPat ps placeHolderType) ExplicitTuple es b | all tupArgPresent es -> do ps <- mapM checkLPat [e | Present e <- es] return (TuplePat ps b placeHolderType) | otherwise -> parseErrorSDoc loc (text "Illegal tuple section in pattern:" $$ ppr e0) RecordCon c _ (HsRecFields fs dd) -> do fs <- mapM checkPatField fs return (ConPatIn c (RecCon (HsRecFields fs dd))) HsQuasiQuoteE q -> return (QuasiQuotePat q) _ -> patFail loc e0 placeHolderPunRhs :: LHsExpr RdrName -- The RHS of a punned record field will be filled in by the renamer -- It's better not to make it an error, in case we want to print it when debugging placeHolderPunRhs = noLoc (HsVar pun_RDR) plus_RDR, bang_RDR, pun_RDR :: RdrName plus_RDR = mkUnqual varName (fsLit "+") -- Hack bang_RDR = mkUnqual varName (fsLit "!") -- Hack pun_RDR = mkUnqual varName (fsLit "pun-right-hand-side") checkPatField :: HsRecField RdrName (LHsExpr RdrName) -> P (HsRecField RdrName (LPat RdrName)) checkPatField fld = do { p <- checkLPat (hsRecFieldArg fld) ; return (fld { hsRecFieldArg = p }) } patFail :: SrcSpan -> HsExpr RdrName -> P a patFail loc e = parseErrorSDoc loc (text "Parse error in pattern:" <+> ppr e) --------------------------------------------------------------------------- -- Check Equation Syntax checkValDef :: LHsExpr RdrName -> Maybe (LHsType RdrName) -> Located (GRHSs RdrName) -> P (HsBind RdrName) checkValDef lhs (Just sig) grhss -- x :: ty = rhs parses as a *pattern* binding = checkPatBind (L (combineLocs lhs sig) (ExprWithTySig lhs sig)) grhss checkValDef lhs opt_sig grhss = do { mb_fun <- isFunLhs lhs ; case mb_fun of Just (fun, is_infix, pats) -> checkFunBind (getLoc lhs) fun is_infix pats opt_sig grhss Nothing -> checkPatBind lhs grhss } checkFunBind :: SrcSpan -> Located RdrName -> Bool -> [LHsExpr RdrName] -> Maybe (LHsType RdrName) -> Located (GRHSs RdrName) -> P (HsBind RdrName) checkFunBind lhs_loc fun is_infix pats opt_sig (L rhs_span grhss) = do ps <- checkPatterns pats let match_span = combineSrcSpans lhs_loc rhs_span return (makeFunBind fun is_infix [L match_span (Match ps opt_sig grhss)]) -- The span of the match covers the entire equation. -- That isn't quite right, but it'll do for now. makeFunBind :: Located id -> Bool -> [LMatch id] -> HsBind id -- Like HsUtils.mkFunBind, but we need to be able to set the fixity too makeFunBind fn is_infix ms = FunBind { fun_id = fn, fun_infix = is_infix, fun_matches = mkMatchGroup ms, fun_co_fn = idHsWrapper, bind_fvs = placeHolderNames, fun_tick = Nothing } checkPatBind :: LHsExpr RdrName -> Located (GRHSs RdrName) -> P (HsBind RdrName) checkPatBind lhs (L _ grhss) = do { lhs <- checkPattern lhs ; return (PatBind lhs grhss placeHolderType placeHolderNames (Nothing,[])) } checkValSig :: LHsExpr RdrName -> LHsType RdrName -> P (Sig RdrName) checkValSig (L l (HsVar v)) ty | isUnqual v && not (isDataOcc (rdrNameOcc v)) = return (TypeSig [L l v] ty) checkValSig lhs@(L l _) ty = parseErrorSDoc l ((text "Invalid type signature:" <+> ppr lhs <+> text "::" <+> ppr ty) $$ text hint) where hint = if foreign_RDR `looks_like` lhs then "Perhaps you meant to use -XForeignFunctionInterface?" else if default_RDR `looks_like` lhs then "Perhaps you meant to use -XDefaultSignatures?" else "Should be of form :: " -- A common error is to forget the ForeignFunctionInterface flag -- so check for that, and suggest. cf Trac #3805 -- Sadly 'foreign import' still barfs 'parse error' because 'import' is a keyword looks_like s (L _ (HsVar v)) = v == s looks_like s (L _ (HsApp lhs _)) = looks_like s lhs looks_like _ _ = False foreign_RDR = mkUnqual varName (fsLit "foreign") default_RDR = mkUnqual varName (fsLit "default") checkDoAndIfThenElse :: LHsExpr RdrName -> Bool -> LHsExpr RdrName -> Bool -> LHsExpr RdrName -> P () checkDoAndIfThenElse guardExpr semiThen thenExpr semiElse elseExpr | semiThen || semiElse = do pState <- getPState unless (xopt Opt_DoAndIfThenElse (dflags pState)) $ do parseErrorSDoc (combineLocs guardExpr elseExpr) (text "Unexpected semi-colons in conditional:" $$ nest 4 expr $$ text "Perhaps you meant to use -XDoAndIfThenElse?") | otherwise = return () where pprOptSemi True = semi pprOptSemi False = empty expr = text "if" <+> ppr guardExpr <> pprOptSemi semiThen <+> text "then" <+> ppr thenExpr <> pprOptSemi semiElse <+> text "else" <+> ppr elseExpr checkKindName :: Located FastString -> P (Located Kind) checkKindName (L l fs) = do pState <- getPState let ext_enabled = xopt Opt_ConstraintKinds (dflags pState) is_kosher = fs == occNameFS (nameOccName constraintKindTyConName) if not ext_enabled || not is_kosher then parseErrorSDoc l (text "Unexpected named kind:" $$ nest 4 (ppr fs) $$ if (not ext_enabled && is_kosher) then text "Perhaps you meant to use -XConstraintKinds?" else empty) else return (L l constraintKind) \end{code} \begin{code} -- The parser left-associates, so there should -- not be any OpApps inside the e's splitBang :: LHsExpr RdrName -> Maybe (LHsExpr RdrName, [LHsExpr RdrName]) -- Splits (f ! g a b) into (f, [(! g), a, b]) splitBang (L loc (OpApp l_arg bang@(L _ (HsVar op)) _ r_arg)) | op == bang_RDR = Just (l_arg, L loc (SectionR bang arg1) : argns) where (arg1,argns) = split_bang r_arg [] split_bang (L _ (HsApp f e)) es = split_bang f (e:es) split_bang e es = (e,es) splitBang _ = Nothing isFunLhs :: LHsExpr RdrName -> P (Maybe (Located RdrName, Bool, [LHsExpr RdrName])) -- A variable binding is parsed as a FunBind. -- Just (fun, is_infix, arg_pats) if e is a function LHS -- -- The whole LHS is parsed as a single expression. -- Any infix operators on the LHS will parse left-associatively -- E.g. f !x y !z -- will parse (rather strangely) as -- (f ! x y) ! z -- It's up to isFunLhs to sort out the mess -- -- a .!. !b isFunLhs e = go e [] where go (L loc (HsVar f)) es | not (isRdrDataCon f) = return (Just (L loc f, False, es)) go (L _ (HsApp f e)) es = go f (e:es) go (L _ (HsPar e)) es@(_:_) = go e es -- For infix function defns, there should be only one infix *function* -- (though there may be infix *datacons* involved too). So we don't -- need fixity info to figure out which function is being defined. -- a `K1` b `op` c `K2` d -- must parse as -- (a `K1` b) `op` (c `K2` d) -- The renamer checks later that the precedences would yield such a parse. -- -- There is a complication to deal with bang patterns. -- -- ToDo: what about this? -- x + 1 `op` y = ... go e@(L loc (OpApp l (L loc' (HsVar op)) fix r)) es | Just (e',es') <- splitBang e = do { bang_on <- extension bangPatEnabled ; if bang_on then go e' (es' ++ es) else return (Just (L loc' op, True, (l:r:es))) } -- No bangs; behave just like the next case | not (isRdrDataCon op) -- We have found the function! = return (Just (L loc' op, True, (l:r:es))) | otherwise -- Infix data con; keep going = do { mb_l <- go l es ; case mb_l of Just (op', True, j : k : es') -> return (Just (op', True, j : op_app : es')) where op_app = L loc (OpApp k (L loc' (HsVar op)) fix r) _ -> return Nothing } go _ _ = return Nothing --------------------------------------------------------------------------- -- Check for monad comprehensions -- -- If the flag MonadComprehensions is set, return a `MonadComp' context, -- otherwise use the usual `ListComp' context checkMonadComp :: P (HsStmtContext Name) checkMonadComp = do pState <- getPState return $ if xopt Opt_MonadComprehensions (dflags pState) then MonadComp else ListComp --------------------------------------------------------------------------- -- Miscellaneous utilities checkPrecP :: Located Int -> P Int checkPrecP (L l i) | 0 <= i && i <= maxPrecedence = return i | otherwise = parseErrorSDoc l (text ("Precedence out of range: " ++ show i)) mkRecConstrOrUpdate :: LHsExpr RdrName -> SrcSpan -> ([HsRecField RdrName (LHsExpr RdrName)], Bool) -> P (HsExpr RdrName) mkRecConstrOrUpdate (L l (HsVar c)) _ (fs,dd) | isRdrDataCon c = return (RecordCon (L l c) noPostTcExpr (mk_rec_fields fs dd)) mkRecConstrOrUpdate exp loc (fs,dd) | null fs = parseErrorSDoc loc (text "Empty record update of:" <+> ppr exp) | otherwise = return (RecordUpd exp (mk_rec_fields fs dd) [] [] []) mk_rec_fields :: [HsRecField id arg] -> Bool -> HsRecFields id arg mk_rec_fields fs False = HsRecFields { rec_flds = fs, rec_dotdot = Nothing } mk_rec_fields fs True = HsRecFields { rec_flds = fs, rec_dotdot = Just (length fs) } mkInlinePragma :: (InlineSpec, RuleMatchInfo) -> Maybe Activation -> InlinePragma -- The Maybe is because the user can omit the activation spec (and usually does) mkInlinePragma (inl, match_info) mb_act = InlinePragma { inl_inline = inl , inl_sat = Nothing , inl_act = act , inl_rule = match_info } where act = case mb_act of Just act -> act Nothing -> -- No phase specified case inl of NoInline -> NeverActive _other -> AlwaysActive ----------------------------------------------------------------------------- -- utilities for foreign declarations -- construct a foreign import declaration -- mkImport :: CCallConv -> Safety -> (Located FastString, Located RdrName, LHsType RdrName) -> P (HsDecl RdrName) mkImport cconv safety (L loc entity, v, ty) | cconv == PrimCallConv = do let funcTarget = CFunction (StaticTarget entity Nothing) importSpec = CImport PrimCallConv safety nilFS funcTarget return (ForD (ForeignImport v ty noForeignImportCoercionYet importSpec)) | otherwise = do case parseCImport cconv safety (mkExtName (unLoc v)) (unpackFS entity) of Nothing -> parseErrorSDoc loc (text "Malformed entity string") Just importSpec -> return (ForD (ForeignImport v ty noForeignImportCoercionYet importSpec)) -- the string "foo" is ambigous: either a header or a C identifier. The -- C identifier case comes first in the alternatives below, so we pick -- that one. parseCImport :: CCallConv -> Safety -> FastString -> String -> Maybe ForeignImport parseCImport cconv safety nm str = listToMaybe $ map fst $ filter (null.snd) $ readP_to_S parse str where parse = do skipSpaces r <- choice [ string "dynamic" >> return (mk nilFS (CFunction DynamicTarget)), string "wrapper" >> return (mk nilFS CWrapper), optional (string "static" >> skipSpaces) >> (mk nilFS <$> cimp nm) +++ (do h <- munch1 hdr_char; skipSpaces; mk (mkFastString h) <$> cimp nm) ] skipSpaces return r mk = CImport cconv safety hdr_char c = not (isSpace c) -- header files are filenames, which can contain -- pretty much any char (depending on the platform), -- so just accept any non-space character id_char c = isAlphaNum c || c == '_' cimp nm = (ReadP.char '&' >> skipSpaces >> CLabel <$> cid) +++ ((\c -> CFunction (StaticTarget c Nothing)) <$> cid) where cid = return nm +++ (do c <- satisfy (\c -> isAlpha c || c == '_') cs <- many (satisfy id_char) return (mkFastString (c:cs))) -- construct a foreign export declaration -- mkExport :: CCallConv -> (Located FastString, Located RdrName, LHsType RdrName) -> P (HsDecl RdrName) mkExport cconv (L _ entity, v, ty) = return $ ForD (ForeignExport v ty noForeignExportCoercionYet (CExport (CExportStatic entity' cconv))) where entity' | nullFS entity = mkExtName (unLoc v) | otherwise = entity -- Supplying the ext_name in a foreign decl is optional; if it -- isn't there, the Haskell name is assumed. Note that no transformation -- of the Haskell name is then performed, so if you foreign export (++), -- it's external name will be "++". Too bad; it's important because we don't -- want z-encoding (e.g. names with z's in them shouldn't be doubled) -- mkExtName :: RdrName -> CLabelString mkExtName rdrNm = mkFastString (occNameString (rdrNameOcc rdrNm)) \end{code} ----------------------------------------------------------------------------- -- Misc utils \begin{code} parseError :: SrcSpan -> String -> P a parseError span s = parseErrorSDoc span (text s) parseErrorSDoc :: SrcSpan -> SDoc -> P a parseErrorSDoc span s = failSpanMsgP span s \end{code}