% % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % This module converts Template Haskell syntax into HsSyn \begin{code} module Convert( convertToHsExpr, convertToHsDecls ) where #include "HsVersions.h" import Language.Haskell.THSyntax as Meta import HsSyn as Hs ( HsExpr(..), HsLit(..), ArithSeqInfo(..), HsStmtContext(..), TyClDecl(..), Match(..), GRHSs(..), GRHS(..), HsPred(..), HsDecl(..), TyClDecl(..), InstDecl(..), ConDecl(..), Stmt(..), HsBinds(..), MonoBinds(..), Sig(..), Pat(..), HsConDetails(..), HsOverLit, BangType(..), placeHolderType, HsType(..), HsTupCon(..), HsTyVarBndr(..), HsContext, mkSimpleMatch ) import RdrName ( RdrName, mkRdrUnqual, mkRdrQual, mkOrig ) import Module ( mkModuleName ) import RdrHsSyn ( mkHsIntegral, mkHsFractional, mkClassDecl, mkTyData ) import OccName import SrcLoc ( SrcLoc, generatedSrcLoc ) import TyCon ( DataConDetails(..) ) import Type ( Type ) import BasicTypes( Boxity(..), RecFlag(Recursive), NewOrData(..), StrictnessMark(..) ) import ForeignCall ( Safety(..), CCallConv(..), CCallTarget(..) ) import HsDecls ( CImportSpec(..), ForeignImport(..), ForeignDecl(..) ) import FastString( FastString, mkFastString, nilFS ) import Char ( ord, isAscii, isAlphaNum, isAlpha ) import List ( partition ) import ErrUtils (Message) import Outputable ------------------------------------------------------------------- convertToHsDecls :: [Meta.Dec] -> [Either (HsDecl RdrName) Message] convertToHsDecls ds = map cvt_top ds cvt_top :: Meta.Dec -> Either (HsDecl RdrName) Message cvt_top d@(Val _ _ _) = Left $ ValD (cvtd d) cvt_top d@(Fun _ _) = Left $ ValD (cvtd d) cvt_top (TySyn tc tvs rhs) = Left $ TyClD (TySynonym (tconName tc) (cvt_tvs tvs) (cvtType rhs) loc0) cvt_top (Data tc tvs constrs derivs) = Left $ TyClD (mkTyData DataType (noContext, tconName tc, cvt_tvs tvs) (DataCons (map mk_con constrs)) (mk_derivs derivs) loc0) where mk_con (Constr c tys) = ConDecl (cName c) noExistentials noContext (PrefixCon (map mk_arg tys)) loc0 mk_arg ty = BangType NotMarkedStrict (cvtType ty) mk_derivs [] = Nothing mk_derivs cs = Just [HsClassP (tconName c) [] | c <- cs] cvt_top (Class ctxt cl tvs decs) = Left $ TyClD (mkClassDecl (cvt_context ctxt, tconName cl, cvt_tvs tvs) noFunDeps sigs (Just binds) loc0) where (binds,sigs) = cvtBindsAndSigs decs cvt_top (Instance tys ty decs) = Left $ InstD (InstDecl inst_ty binds sigs Nothing loc0) where (binds, sigs) = cvtBindsAndSigs decs inst_ty = HsForAllTy Nothing (cvt_context tys) (HsPredTy (cvt_pred ty)) cvt_top (Proto nm typ) = Left $ SigD (Sig (vName nm) (cvtType typ) loc0) cvt_top (Foreign (Import callconv safety from nm typ)) = case parsed of Just (c_header, cis) -> let i = CImport callconv' safety' c_header nilFS cis in Left $ ForD (ForeignImport (vName nm) (cvtType typ) i False loc0) Nothing -> Right $ text (show from) <+> ptext SLIT("is not a valid ccall impent") where callconv' = case callconv of CCall -> CCallConv StdCall -> StdCallConv safety' = case safety of Unsafe -> PlayRisky Safe -> PlaySafe False Threadsafe -> PlaySafe True parsed = parse_ccall_impent nm from parse_ccall_impent :: String -> String -> Maybe (FastString, CImportSpec) parse_ccall_impent nm s = case lex_ccall_impent s of Just ["dynamic"] -> Just (nilFS, CFunction DynamicTarget) Just ["wrapper"] -> Just (nilFS, CWrapper) Just ("static":ts) -> parse_ccall_impent_static nm ts Just ts -> parse_ccall_impent_static nm ts Nothing -> Nothing parse_ccall_impent_static :: String -> [String] -> Maybe (FastString, CImportSpec) parse_ccall_impent_static nm ts = let ts' = case ts of [ "&", cid] -> [ cid] [fname, "&" ] -> [fname ] [fname, "&", cid] -> [fname, cid] _ -> ts in case ts' of [ cid] | is_cid cid -> Just (nilFS, mk_cid cid) [fname, cid] | is_cid cid -> Just (mkFastString fname, mk_cid cid) [ ] -> Just (nilFS, mk_cid nm) [fname ] -> Just (mkFastString fname, mk_cid nm) _ -> Nothing where is_cid :: String -> Bool is_cid x = all (/= '.') x && (isAlpha (head x) || head x == '_') mk_cid :: String -> CImportSpec mk_cid = CFunction . StaticTarget . mkFastString lex_ccall_impent :: String -> Maybe [String] lex_ccall_impent "" = Just [] lex_ccall_impent ('&':xs) = fmap ("&":) $ lex_ccall_impent xs lex_ccall_impent (' ':xs) = lex_ccall_impent xs lex_ccall_impent ('\t':xs) = lex_ccall_impent xs lex_ccall_impent xs = case span is_valid xs of ("", _) -> Nothing (t, xs') -> fmap (t:) $ lex_ccall_impent xs' where is_valid :: Char -> Bool is_valid c = isAscii c && (isAlphaNum c || c `elem` "._") noContext = [] noExistentials = [] noFunDeps = [] ------------------------------------------------------------------- convertToHsExpr :: Meta.Exp -> HsExpr RdrName convertToHsExpr = cvt cvt (Var s) = HsVar(vName s) cvt (Con s) = HsVar(cName s) cvt (Lit l) | overloadedLit l = HsOverLit (cvtOverLit l) | otherwise = HsLit (cvtLit l) cvt (App x y) = HsApp (cvt x) (cvt y) cvt (Lam ps e) = HsLam (mkSimpleMatch (map cvtp ps) (cvt e) void loc0) cvt (Tup [e]) = cvt e cvt (Tup es) = ExplicitTuple(map cvt es) Boxed cvt (Cond x y z) = HsIf (cvt x) (cvt y) (cvt z) loc0 cvt (Let ds e) = HsLet (cvtdecs ds) (cvt e) cvt (Case e ms) = HsCase (cvt e) (map cvtm ms) loc0 cvt (Do ss) = HsDo DoExpr (cvtstmts ss) [] void loc0 cvt (Comp ss) = HsDo ListComp (cvtstmts ss) [] void loc0 cvt (ArithSeq dd) = ArithSeqIn (cvtdd dd) cvt (ListExp xs) = ExplicitList void (map cvt xs) cvt (Infix (Just x) s (Just y)) = HsPar (OpApp (cvt x) (cvt s) undefined (cvt y)) cvt (Infix Nothing s (Just y)) = SectionR (cvt s) (cvt y) cvt (Infix (Just x) s Nothing ) = SectionL (cvt x) (cvt s) cvt (Infix Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing? cvt (SigExp e t) = ExprWithTySig (cvt e) (cvtType t) cvtdecs :: [Meta.Dec] -> HsBinds RdrName cvtdecs [] = EmptyBinds cvtdecs ds = MonoBind binds sigs Recursive where (binds, sigs) = cvtBindsAndSigs ds cvtBindsAndSigs ds = (cvtds non_sigs, map cvtSig sigs) where (sigs, non_sigs) = partition sigP ds cvtSig (Proto nm typ) = Sig (vName nm) (cvtType typ) loc0 cvtds :: [Meta.Dec] -> MonoBinds RdrName cvtds [] = EmptyMonoBinds cvtds (d:ds) = AndMonoBinds (cvtd d) (cvtds ds) cvtd :: Meta.Dec -> MonoBinds RdrName -- Used only for declarations in a 'let/where' clause, -- not for top level decls cvtd (Val (Pvar s) body ds) = FunMonoBind (vName s) False [cvtclause (Clause [] body ds)] loc0 cvtd (Fun nm cls) = FunMonoBind (vName nm) False (map cvtclause cls) loc0 cvtd (Val p body ds) = PatMonoBind (cvtp p) (GRHSs (cvtguard body) (cvtdecs ds) void) loc0 cvtd x = panic "Illegal kind of declaration in where clause" cvtclause :: Meta.Clause (Meta.Pat) (Meta.Exp) (Meta.Dec) -> Hs.Match RdrName cvtclause (Clause ps body wheres) = Match (map cvtp ps) Nothing (GRHSs (cvtguard body) (cvtdecs wheres) void) cvtdd :: Meta.DDt -> ArithSeqInfo RdrName cvtdd (Meta.From x) = (Hs.From (cvt x)) cvtdd (Meta.FromThen x y) = (Hs.FromThen (cvt x) (cvt y)) cvtdd (Meta.FromTo x y) = (Hs.FromTo (cvt x) (cvt y)) cvtdd (Meta.FromThenTo x y z) = (Hs.FromThenTo (cvt x) (cvt y) (cvt z)) cvtstmts :: [Meta.Stm] -> [Hs.Stmt RdrName] cvtstmts [] = [] -- this is probably an error as every [stmt] should end with ResultStmt cvtstmts [NoBindSt e] = [ResultStmt (cvt e) loc0] -- when its the last element use ResultStmt cvtstmts (NoBindSt e : ss) = ExprStmt (cvt e) void loc0 : cvtstmts ss cvtstmts (BindSt p e : ss) = BindStmt (cvtp p) (cvt e) loc0 : cvtstmts ss cvtstmts (LetSt ds : ss) = LetStmt (cvtdecs ds) : cvtstmts ss cvtstmts (ParSt dss : ss) = ParStmt(map cvtstmts dss) : cvtstmts ss cvtm :: Meta.Mat -> Hs.Match RdrName cvtm (Mat p body wheres) = Match [cvtp p] Nothing (GRHSs (cvtguard body) (cvtdecs wheres) void) cvtguard :: Meta.Rhs -> [GRHS RdrName] cvtguard (Guarded pairs) = map cvtpair pairs cvtguard (Normal e) = [GRHS [ ResultStmt (cvt e) loc0 ] loc0] cvtpair :: (Meta.Exp,Meta.Exp) -> GRHS RdrName cvtpair (x,y) = GRHS [BindStmt truePat (cvt x) loc0, ResultStmt (cvt y) loc0] loc0 cvtOverLit :: Lit -> HsOverLit cvtOverLit (Integer i) = mkHsIntegral i cvtOverLit (Rational r) = mkHsFractional r -- An Integer is like an an (overloaded) '3' in a Haskell source program -- Similarly 3.5 for fractionals cvtLit :: Lit -> HsLit cvtLit (Char c) = HsChar (ord c) cvtLit (String s) = HsString (mkFastString s) cvtp :: Meta.Pat -> Hs.Pat RdrName cvtp (Plit l) | overloadedLit l = NPatIn (cvtOverLit l) Nothing -- Not right for negative -- patterns; need to think -- about that! | otherwise = LitPat (cvtLit l) cvtp (Pvar s) = VarPat(vName s) cvtp (Ptup [p]) = cvtp p cvtp (Ptup ps) = TuplePat (map cvtp ps) Boxed cvtp (Pcon s ps) = ConPatIn (cName s) (PrefixCon (map cvtp ps)) cvtp (Ptilde p) = LazyPat (cvtp p) cvtp (Paspat s p) = AsPat (vName s) (cvtp p) cvtp Pwild = WildPat void ----------------------------------------------------------- -- Types and type variables cvt_tvs :: [String] -> [HsTyVarBndr RdrName] cvt_tvs tvs = map (UserTyVar . tName) tvs cvt_context :: Cxt -> HsContext RdrName cvt_context tys = map cvt_pred tys cvt_pred :: Typ -> HsPred RdrName cvt_pred ty = case split_ty_app ty of (Tcon (TconName tc), tys) -> HsClassP (tconName tc) (map cvtType tys) other -> panic "Malformed predicate" cvtType :: Meta.Typ -> HsType RdrName cvtType ty = trans (root ty []) where root (Tapp a b) zs = root a (cvtType b : zs) root t zs = (t,zs) trans (Tcon (Tuple n),args) | length args == n = HsTupleTy (HsTupCon Boxed n) args trans (Tcon Arrow, [x,y]) = HsFunTy x y trans (Tcon List, [x]) = HsListTy x trans (Tvar nm, args) = foldl HsAppTy (HsTyVar (tName nm)) args trans (Tcon tc, args) = foldl HsAppTy (HsTyVar (tc_name tc)) args tc_name (TconName nm) = tconName nm tc_name Arrow = tconName "->" tc_name List = tconName "[]" tc_name (Tuple 0) = tconName "()" tc_name (Tuple n) = tconName ("(" ++ replicate (n-1) ',' ++ ")") split_ty_app :: Typ -> (Typ, [Typ]) split_ty_app ty = go ty [] where go (Tapp f a) as = go f (a:as) go f as = (f,as) ----------------------------------------------------------- sigP :: Dec -> Bool sigP (Proto _ _) = True sigP other = False ----------------------------------------------------------- -- some useful things truePat = ConPatIn (cName "True") (PrefixCon []) falsePat = ConPatIn (cName "False") (PrefixCon []) overloadedLit :: Lit -> Bool -- True for literals that Haskell treats as overloaded overloadedLit (Integer l) = True overloadedLit (Rational l) = True overloadedLit l = False void :: Type.Type void = placeHolderType loc0 :: SrcLoc loc0 = generatedSrcLoc -- variable names vName :: String -> RdrName vName = mkName varName -- Constructor function names cName :: String -> RdrName cName = mkName dataName -- Type variable names tName :: String -> RdrName tName = mkName tvName -- Type Constructor names tconName = mkName tcName mkName :: NameSpace -> String -> RdrName -- Parse the string to see if it has a "." or ":" in it -- so we know whether to generate a qualified or original name -- It's a bit tricky because we need to parse -- Foo.Baz.x as Qual Foo.Baz x -- So we parse it from back to front mkName ns str = split [] (reverse str) where split occ [] = mkRdrUnqual (mk_occ occ) split occ (c:d:rev) -- 'd' is the last char before the separator | is_sep c -- E.g. Fo.x d='o' && isAlphaNum d -- Fo.+: d='+' perhaps = mk_qual (reverse (d:rev)) c occ split occ (c:rev) = split (c:occ) rev mk_qual mod '.' occ = mkRdrQual (mk_mod mod) (mk_occ occ) mk_qual mod ':' occ = mkOrig (mk_mod mod) (mk_occ occ) mk_occ occ = mkOccFS ns (mkFastString occ) mk_mod mod = mkModuleName mod is_sep '.' = True is_sep ':' = True is_sep other = False \end{code}