diff options
Diffstat (limited to 'compiler/parser/RdrHsSyn.lhs')
| -rw-r--r-- | compiler/parser/RdrHsSyn.lhs | 78 |
1 files changed, 56 insertions, 22 deletions
diff --git a/compiler/parser/RdrHsSyn.lhs b/compiler/parser/RdrHsSyn.lhs index 03ec622223..93a98d068e 100644 --- a/compiler/parser/RdrHsSyn.lhs +++ b/compiler/parser/RdrHsSyn.lhs @@ -4,6 +4,8 @@ o% Functions over HsSyn specialised to RdrName. \begin{code} +{-# LANGUAGE CPP #-} + module RdrHsSyn ( mkHsOpApp, mkHsIntegral, mkHsFractional, mkHsIsString, @@ -32,6 +34,7 @@ module RdrHsSyn ( mkGadtDecl, -- [Located RdrName] -> LHsType RdrName -> ConDecl RdrName mkSimpleConDecl, mkDeprecatedGadtRecordDecl, + mkATDefault, -- Bunch of functions in the parser monad for -- checking and constructing values @@ -71,7 +74,7 @@ import TysWiredIn ( unitTyCon, unitDataCon ) import ForeignCall import OccName ( srcDataName, varName, isDataOcc, isTcOcc, occNameString ) -import PrelNames ( forall_tv_RDR ) +import PrelNames ( forall_tv_RDR, allNameStrings ) import DynFlags import SrcLoc import OrdList ( OrdList, fromOL ) @@ -122,16 +125,31 @@ mkClassDecl :: SrcSpan -> P (LTyClDecl RdrName) mkClassDecl loc (L _ (mcxt, tycl_hdr)) fds where_cls - = do { let (binds, sigs, ats, at_defs, _, docs) = cvBindsAndSigs (unLoc where_cls) + = do { let (binds, sigs, ats, at_insts, _, docs) = cvBindsAndSigs (unLoc where_cls) cxt = fromMaybe (noLoc []) mcxt ; (cls, tparams) <- checkTyClHdr tycl_hdr - ; tyvars <- checkTyVars (ptext (sLit "class")) whereDots - cls tparams -- Only type vars allowed + ; tyvars <- checkTyVarsP (ptext (sLit "class")) whereDots cls tparams + ; at_defs <- mapM (eitherToP . mkATDefault) at_insts ; return (L loc (ClassDecl { tcdCtxt = cxt, tcdLName = cls, tcdTyVars = tyvars, tcdFDs = unLoc fds, tcdSigs = sigs, tcdMeths = binds, tcdATs = ats, tcdATDefs = at_defs, tcdDocs = docs, tcdFVs = placeHolderNames })) } +mkATDefault :: LTyFamInstDecl RdrName + -> Either (SrcSpan, SDoc) (LTyFamDefltEqn RdrName) +-- Take a type-family instance declaration and turn it into +-- a type-family default equation for a class declaration +-- We parse things as the former and use this function to convert to the latter +-- +-- We use the Either monad because this also called +-- from Convert.hs +mkATDefault (L loc (TyFamInstDecl { tfid_eqn = L _ e })) + | TyFamEqn { tfe_tycon = tc, tfe_pats = pats, tfe_rhs = rhs } <- e + = do { tvs <- checkTyVars (ptext (sLit "default")) equalsDots tc (hswb_cts pats) + ; return (L loc (TyFamEqn { tfe_tycon = tc + , tfe_pats = tvs + , tfe_rhs = rhs })) } + mkTyData :: SrcSpan -> NewOrData -> Maybe CType @@ -142,7 +160,7 @@ mkTyData :: SrcSpan -> P (LTyClDecl RdrName) mkTyData loc new_or_data cType (L _ (mcxt, tycl_hdr)) ksig data_cons maybe_deriv = do { (tc, tparams) <- checkTyClHdr tycl_hdr - ; tyvars <- checkTyVars (ppr new_or_data) equalsDots tc tparams + ; tyvars <- checkTyVarsP (ppr new_or_data) equalsDots tc tparams ; defn <- mkDataDefn new_or_data cType mcxt ksig data_cons maybe_deriv ; return (L loc (DataDecl { tcdLName = tc, tcdTyVars = tyvars, tcdDataDefn = defn, @@ -170,7 +188,7 @@ mkTySynonym :: SrcSpan -> P (LTyClDecl RdrName) mkTySynonym loc lhs rhs = do { (tc, tparams) <- checkTyClHdr lhs - ; tyvars <- checkTyVars (ptext (sLit "type")) equalsDots tc tparams + ; tyvars <- checkTyVarsP (ptext (sLit "type")) equalsDots tc tparams ; return (L loc (SynDecl { tcdLName = tc, tcdTyVars = tyvars , tcdRhs = rhs, tcdFVs = placeHolderNames })) } @@ -179,9 +197,9 @@ mkTyFamInstEqn :: LHsType RdrName -> P (TyFamInstEqn RdrName) mkTyFamInstEqn lhs rhs = do { (tc, tparams) <- checkTyClHdr lhs - ; return (TyFamInstEqn { tfie_tycon = tc - , tfie_pats = mkHsWithBndrs tparams - , tfie_rhs = rhs }) } + ; return (TyFamEqn { tfe_tycon = tc + , tfe_pats = mkHsWithBndrs tparams + , tfe_rhs = rhs }) } mkDataFamInst :: SrcSpan -> NewOrData @@ -212,7 +230,7 @@ mkFamDecl :: SrcSpan -> P (LTyClDecl RdrName) mkFamDecl loc info lhs ksig = do { (tc, tparams) <- checkTyClHdr lhs - ; tyvars <- checkTyVars (ppr info) equals_or_where tc tparams + ; tyvars <- checkTyVarsP (ppr info) equals_or_where tc tparams ; return (L loc (FamDecl (FamilyDecl { fdInfo = info, fdLName = tc , fdTyVars = tyvars, fdKindSig = ksig }))) } where @@ -500,26 +518,42 @@ we can bring x,y into scope. So: * For RecCon we do not \begin{code} -checkTyVars :: SDoc -> SDoc -> Located RdrName -> [LHsType RdrName] -> P (LHsTyVarBndrs RdrName) +checkTyVarsP :: SDoc -> SDoc -> Located RdrName -> [LHsType RdrName] -> P (LHsTyVarBndrs RdrName) +-- Same as checkTyVars, but in the P monad +checkTyVarsP pp_what equals_or_where tc tparms + = eitherToP $ checkTyVars pp_what equals_or_where tc tparms + +eitherToP :: Either (SrcSpan, SDoc) a -> P a +-- Adapts the Either monad to the P monad +eitherToP (Left (loc, doc)) = parseErrorSDoc loc doc +eitherToP (Right thing) = return thing +checkTyVars :: SDoc -> SDoc -> Located RdrName -> [LHsType RdrName] + -> Either (SrcSpan, SDoc) (LHsTyVarBndrs RdrName) -- Check whether the given list of type parameters are all type variables --- (possibly with a kind signature). -checkTyVars pp_what equals_or_where tc tparms = do { tvs <- mapM chk tparms - ; return (mkHsQTvs tvs) } +-- (possibly with a kind signature) +-- We use the Either monad because it's also called (via mkATDefault) from +-- Convert.hs +checkTyVars pp_what equals_or_where tc tparms + = do { tvs <- mapM chk tparms + ; return (mkHsQTvs tvs) } 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)) - chk t@(L l _) - = parseErrorSDoc l $ - vcat [ ptext (sLit "Unexpected type") <+> quotes (ppr t) - , ptext (sLit "In the") <+> pp_what <+> ptext (sLit "declaration for") <+> quotes (ppr tc) - , vcat[ (ptext (sLit "A") <+> pp_what <+> ptext (sLit "declaration should have form")) - , nest 2 (pp_what <+> ppr tc <+> ptext (sLit "a b c") - <+> equals_or_where) ] ] + chk t@(L loc _) + = Left (loc, + vcat [ ptext (sLit "Unexpected type") <+> quotes (ppr t) + , ptext (sLit "In the") <+> pp_what <+> ptext (sLit "declaration for") <+> quotes (ppr tc) + , vcat[ (ptext (sLit "A") <+> pp_what <+> ptext (sLit "declaration should have form")) + , nest 2 (pp_what <+> ppr tc + <+> hsep (map text (takeList tparms allNameStrings)) + <+> equals_or_where) ] ]) whereDots, equalsDots :: SDoc +-- Second argument to checkTyVars whereDots = ptext (sLit "where ...") equalsDots = ptext (sLit "= ...") @@ -666,7 +700,7 @@ checkAPat msg loc e0 = do ExplicitTuple es b | all tupArgPresent es -> do ps <- mapM (checkLPat msg) [e | Present e <- es] - return (TuplePat ps b placeHolderType) + return (TuplePat ps b []) | otherwise -> parseErrorSDoc loc (text "Illegal tuple section in pattern:" $$ ppr e0) RecordCon c _ (HsRecFields fs dd) |