2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
6 This module converts Template Haskell syntax into HsSyn
9 module Convert( convertToHsExpr, convertToPat, convertToHsDecls,
10 convertToHsType, thRdrNameGuesses ) where
13 import qualified Class
18 import qualified OccName
34 import Language.Haskell.TH as TH hiding (sigP)
35 import Language.Haskell.TH.Syntax as TH
39 -------------------------------------------------------------------
40 -- The external interface
42 convertToHsDecls :: SrcSpan -> [TH.Dec] -> Either Message [LHsDecl RdrName]
43 convertToHsDecls loc ds = initCvt loc (mapM cvtTop ds)
45 convertToHsExpr :: SrcSpan -> TH.Exp -> Either Message (LHsExpr RdrName)
47 = case initCvt loc (cvtl e) of
48 Left msg -> Left (msg $$ (ptext (sLit "When splicing TH expression:")
50 Right res -> Right res
52 convertToPat :: SrcSpan -> TH.Pat -> Either Message (LPat RdrName)
54 = case initCvt loc (cvtPat e) of
55 Left msg -> Left (msg $$ (ptext (sLit "When splicing TH pattern:")
57 Right res -> Right res
59 convertToHsType :: SrcSpan -> TH.Type -> Either Message (LHsType RdrName)
60 convertToHsType loc t = initCvt loc (cvtType t)
63 -------------------------------------------------------------------
64 newtype CvtM a = CvtM { unCvtM :: SrcSpan -> Either Message a }
65 -- Push down the source location;
66 -- Can fail, with a single error message
68 -- NB: If the conversion succeeds with (Right x), there should
69 -- be no exception values hiding in x
70 -- Reason: so a (head []) in TH code doesn't subsequently
71 -- make GHC crash when it tries to walk the generated tree
73 -- Use the loc everywhere, for lack of anything better
74 -- In particular, we want it on binding locations, so that variables bound in
75 -- the spliced-in declarations get a location that at least relates to the splice point
77 instance Monad CvtM where
78 return x = CvtM $ \_ -> Right x
79 (CvtM m) >>= k = CvtM $ \loc -> case m loc of
81 Right v -> unCvtM (k v) loc
83 initCvt :: SrcSpan -> CvtM a -> Either Message a
84 initCvt loc (CvtM m) = m loc
87 force a = a `seq` return a
89 failWith :: Message -> CvtM a
90 failWith m = CvtM (\_ -> Left full_msg)
92 full_msg = m $$ ptext (sLit "When splicing generated code into the program")
94 returnL :: a -> CvtM (Located a)
95 returnL x = CvtM (\loc -> Right (L loc x))
97 wrapL :: CvtM a -> CvtM (Located a)
98 wrapL (CvtM m) = CvtM (\loc -> case m loc of
100 Right v -> Right (L loc v))
102 -------------------------------------------------------------------
103 cvtTop :: TH.Dec -> CvtM (LHsDecl RdrName)
104 cvtTop d@(TH.ValD _ _ _)
105 = do { L loc d' <- cvtBind d
106 ; return (L loc $ Hs.ValD d') }
108 cvtTop d@(TH.FunD _ _)
109 = do { L loc d' <- cvtBind d
110 ; return (L loc $ Hs.ValD d') }
112 cvtTop (TH.SigD nm typ)
113 = do { nm' <- vNameL nm
115 ; returnL $ Hs.SigD (TypeSig nm' ty') }
117 cvtTop (TySynD tc tvs rhs)
118 = do { (_, tc', tvs', _) <- cvt_tycl_hdr [] tc tvs
119 ; rhs' <- cvtType rhs
120 ; returnL $ TyClD (TySynonym tc' tvs' Nothing rhs') }
122 cvtTop (DataD ctxt tc tvs constrs derivs)
123 = do { stuff <- cvt_tycl_hdr ctxt tc tvs
124 ; cons' <- mapM cvtConstr constrs
125 ; derivs' <- cvtDerivs derivs
126 ; returnL $ TyClD (mkTyData DataType stuff Nothing cons' derivs') }
128 cvtTop (NewtypeD ctxt tc tvs constr derivs)
129 = do { stuff <- cvt_tycl_hdr ctxt tc tvs
130 ; con' <- cvtConstr constr
131 ; derivs' <- cvtDerivs derivs
132 ; returnL $ TyClD (mkTyData NewType stuff Nothing [con'] derivs') }
134 cvtTop (ClassD ctxt cl tvs fds decs)
135 = do { (cxt', tc', tvs', _) <- cvt_tycl_hdr ctxt cl tvs
136 ; fds' <- mapM cvt_fundep fds
137 ; let (ats, bind_sig_decs) = partition isFamilyD decs
138 ; (binds', sigs') <- cvtBindsAndSigs bind_sig_decs
139 ; ats' <- mapM cvtTop ats
140 ; let ats'' = map unTyClD ats'
142 TyClD $ mkClassDecl (cxt', tc', tvs') fds' sigs' binds' ats'' []
146 isFamilyD (FamilyD _ _ _) = True
149 cvtTop (InstanceD tys ty decs)
150 = do { let (ats, bind_sig_decs) = partition isFamInstD decs
151 ; (binds', sigs') <- cvtBindsAndSigs bind_sig_decs
152 ; ats' <- mapM cvtTop ats
153 ; let ats'' = map unTyClD ats'
154 ; ctxt' <- cvtContext tys
155 ; L loc pred' <- cvtPred ty
156 ; inst_ty' <- returnL $
157 mkImplicitHsForAllTy ctxt' (L loc (HsPredTy pred'))
158 ; returnL $ InstD (InstDecl inst_ty' binds' sigs' ats'')
161 isFamInstD (DataInstD _ _ _ _ _) = True
162 isFamInstD (NewtypeInstD _ _ _ _ _) = True
163 isFamInstD (TySynInstD _ _ _) = True
166 cvtTop (ForeignD ford) = do { ford' <- cvtForD ford; returnL $ ForD ford' }
168 cvtTop (FamilyD flav tc tvs)
169 = do { (_, tc', tvs', _) <- cvt_tycl_hdr [] tc tvs
170 ; returnL $ TyClD (TyFamily (cvtFamFlavour flav) tc' tvs' Nothing)
174 cvtFamFlavour TypeFam = TypeFamily
175 cvtFamFlavour DataFam = DataFamily
177 cvtTop (DataInstD ctxt tc tys constrs derivs)
178 = do { stuff <- cvt_tyinst_hdr ctxt tc tys
179 ; cons' <- mapM cvtConstr constrs
180 ; derivs' <- cvtDerivs derivs
181 ; returnL $ TyClD (mkTyData DataType stuff Nothing cons' derivs')
184 cvtTop (NewtypeInstD ctxt tc tys constr derivs)
185 = do { stuff <- cvt_tyinst_hdr ctxt tc tys
186 ; con' <- cvtConstr constr
187 ; derivs' <- cvtDerivs derivs
188 ; returnL $ TyClD (mkTyData NewType stuff Nothing [con'] derivs')
191 cvtTop (TySynInstD tc tys rhs)
192 = do { (_, tc', tvs', tys') <- cvt_tyinst_hdr [] tc tys
193 ; rhs' <- cvtType rhs
194 ; returnL $ TyClD (TySynonym tc' tvs' tys' rhs') }
196 -- FIXME: This projection is not nice, but to remove it, cvtTop should be
198 unTyClD :: LHsDecl a -> LTyClDecl a
199 unTyClD (L l (TyClD d)) = L l d
200 unTyClD _ = panic "Convert.unTyClD: internal error"
202 cvt_tycl_hdr :: TH.Cxt -> TH.Name -> [TH.Name]
203 -> CvtM ( LHsContext RdrName
205 , [LHsTyVarBndr RdrName]
206 , Maybe [LHsType RdrName])
207 cvt_tycl_hdr cxt tc tvs
208 = do { cxt' <- cvtContext cxt
209 ; tc' <- tconNameL tc
211 ; return (cxt', tc', tvs', Nothing)
214 cvt_tyinst_hdr :: TH.Cxt -> TH.Name -> [TH.Type]
215 -> CvtM ( LHsContext RdrName
217 , [LHsTyVarBndr RdrName]
218 , Maybe [LHsType RdrName])
219 cvt_tyinst_hdr cxt tc tys
220 = do { cxt' <- cvtContext cxt
221 ; tc' <- tconNameL tc
222 ; tvs <- concatMapM collect tys
224 ; tys' <- mapM cvtType tys
225 ; return (cxt', tc', tvs', Just tys')
228 collect (ForallT _ _ _)
229 = failWith $ text "Forall type not allowed as type parameter"
230 collect (VarT tv) = return [tv]
231 collect (ConT _) = return []
232 collect (TupleT _) = return []
233 collect ArrowT = return []
234 collect ListT = return []
236 = do { tvs1 <- collect t1
238 ; return $ tvs1 ++ tvs2
241 ---------------------------------------------------
243 -- Can't handle GADTs yet
244 ---------------------------------------------------
246 cvtConstr :: TH.Con -> CvtM (LConDecl RdrName)
248 cvtConstr (NormalC c strtys)
249 = do { c' <- cNameL c
251 ; tys' <- mapM cvt_arg strtys
252 ; returnL $ ConDecl c' Explicit noExistentials cxt' (PrefixCon tys') ResTyH98 Nothing }
254 cvtConstr (RecC c varstrtys)
255 = do { c' <- cNameL c
257 ; args' <- mapM cvt_id_arg varstrtys
258 ; returnL $ ConDecl c' Explicit noExistentials cxt' (RecCon args') ResTyH98 Nothing }
260 cvtConstr (InfixC st1 c st2)
261 = do { c' <- cNameL c
263 ; st1' <- cvt_arg st1
264 ; st2' <- cvt_arg st2
265 ; returnL $ ConDecl c' Explicit noExistentials cxt' (InfixCon st1' st2') ResTyH98 Nothing }
267 cvtConstr (ForallC tvs ctxt (ForallC tvs' ctxt' con'))
268 = cvtConstr (ForallC (tvs ++ tvs') (ctxt ++ ctxt') con')
270 cvtConstr (ForallC tvs ctxt con)
271 = do { L _ con' <- cvtConstr con
273 ; ctxt' <- cvtContext ctxt
275 ConDecl l _ [] (L _ []) x ResTyH98 _
276 -> returnL $ ConDecl l Explicit tvs' ctxt' x ResTyH98 Nothing
277 _ -> panic "ForallC: Can't happen" }
279 cvt_arg :: (TH.Strict, TH.Type) -> CvtM (LHsType RdrName)
280 cvt_arg (IsStrict, ty) = do { ty' <- cvtType ty; returnL $ HsBangTy HsStrict ty' }
281 cvt_arg (NotStrict, ty) = cvtType ty
283 cvt_id_arg :: (TH.Name, TH.Strict, TH.Type) -> CvtM (ConDeclField RdrName)
284 cvt_id_arg (i, str, ty)
285 = do { i' <- vNameL i
286 ; ty' <- cvt_arg (str,ty)
287 ; return (ConDeclField { cd_fld_name = i', cd_fld_type = ty', cd_fld_doc = Nothing}) }
289 cvtDerivs :: [TH.Name] -> CvtM (Maybe [LHsType RdrName])
290 cvtDerivs [] = return Nothing
291 cvtDerivs cs = do { cs' <- mapM cvt_one cs
292 ; return (Just cs') }
294 cvt_one c = do { c' <- tconName c
295 ; returnL $ HsPredTy $ HsClassP c' [] }
297 cvt_fundep :: FunDep -> CvtM (Located (Class.FunDep RdrName))
298 cvt_fundep (FunDep xs ys) = do { xs' <- mapM tName xs; ys' <- mapM tName ys; returnL (xs', ys') }
300 noExistentials :: [LHsTyVarBndr RdrName]
303 ------------------------------------------
304 -- Foreign declarations
305 ------------------------------------------
307 cvtForD :: Foreign -> CvtM (ForeignDecl RdrName)
308 cvtForD (ImportF callconv safety from nm ty)
309 | Just (c_header, cis) <- parse_ccall_impent (TH.nameBase nm) from
310 = do { nm' <- vNameL nm
312 ; let i = CImport (cvt_conv callconv) safety' c_header nilFS cis
313 ; return $ ForeignImport nm' ty' i }
316 = failWith $ text (show from)<+> ptext (sLit "is not a valid ccall impent")
318 safety' = case safety of
320 Safe -> PlaySafe False
321 Threadsafe -> PlaySafe True
323 cvtForD (ExportF callconv as nm ty)
324 = do { nm' <- vNameL nm
326 ; let e = CExport (CExportStatic (mkFastString as) (cvt_conv callconv))
327 ; return $ ForeignExport nm' ty' e }
329 cvt_conv :: TH.Callconv -> CCallConv
330 cvt_conv TH.CCall = CCallConv
331 cvt_conv TH.StdCall = StdCallConv
333 parse_ccall_impent :: String -> String -> Maybe (FastString, CImportSpec)
334 parse_ccall_impent nm s
335 = case lex_ccall_impent s of
336 Just ["dynamic"] -> Just (nilFS, CFunction DynamicTarget)
337 Just ["wrapper"] -> Just (nilFS, CWrapper)
338 Just ("static":ts) -> parse_ccall_impent_static nm ts
339 Just ts -> parse_ccall_impent_static nm ts
342 parse_ccall_impent_static :: String
344 -> Maybe (FastString, CImportSpec)
345 parse_ccall_impent_static nm ts
346 = let ts' = case ts of
347 [ "&", cid] -> [ cid]
348 [fname, "&" ] -> [fname ]
349 [fname, "&", cid] -> [fname, cid]
352 [ cid] | is_cid cid -> Just (nilFS, mk_cid cid)
353 [fname, cid] | is_cid cid -> Just (mkFastString fname, mk_cid cid)
354 [ ] -> Just (nilFS, mk_cid nm)
355 [fname ] -> Just (mkFastString fname, mk_cid nm)
357 where is_cid :: String -> Bool
358 is_cid x = all (/= '.') x && (isAlpha (head x) || head x == '_')
359 mk_cid :: String -> CImportSpec
360 mk_cid = CFunction . StaticTarget . mkFastString
362 lex_ccall_impent :: String -> Maybe [String]
363 lex_ccall_impent "" = Just []
364 lex_ccall_impent ('&':xs) = fmap ("&":) $ lex_ccall_impent xs
365 lex_ccall_impent (' ':xs) = lex_ccall_impent xs
366 lex_ccall_impent ('\t':xs) = lex_ccall_impent xs
367 lex_ccall_impent xs = case span is_valid xs of
369 (t, xs') -> fmap (t:) $ lex_ccall_impent xs'
370 where is_valid :: Char -> Bool
371 is_valid c = isAscii c && (isAlphaNum c || c `elem` "._")
374 ---------------------------------------------------
376 ---------------------------------------------------
378 cvtDecs :: [TH.Dec] -> CvtM (HsLocalBinds RdrName)
379 cvtDecs [] = return EmptyLocalBinds
380 cvtDecs ds = do { (binds,sigs) <- cvtBindsAndSigs ds
381 ; return (HsValBinds (ValBindsIn binds sigs)) }
383 cvtBindsAndSigs :: [TH.Dec] -> CvtM (Bag (LHsBind RdrName), [LSig RdrName])
385 = do { binds' <- mapM cvtBind binds; sigs' <- mapM cvtSig sigs
386 ; return (listToBag binds', sigs') }
388 (sigs, binds) = partition is_sig ds
390 is_sig (TH.SigD _ _) = True
393 cvtSig :: TH.Dec -> CvtM (LSig RdrName)
394 cvtSig (TH.SigD nm ty)
395 = do { nm' <- vNameL nm; ty' <- cvtType ty; returnL (Hs.TypeSig nm' ty') }
396 cvtSig _ = panic "Convert.cvtSig: Signature expected"
398 cvtBind :: TH.Dec -> CvtM (LHsBind RdrName)
399 -- Used only for declarations in a 'let/where' clause,
400 -- not for top level decls
401 cvtBind (TH.ValD (TH.VarP s) body ds)
402 = do { s' <- vNameL s
403 ; cl' <- cvtClause (Clause [] body ds)
404 ; returnL $ mkFunBind s' [cl'] }
406 cvtBind (TH.FunD nm cls)
408 = failWith (ptext (sLit "Function binding for")
409 <+> quotes (text (TH.pprint nm))
410 <+> ptext (sLit "has no equations"))
412 = do { nm' <- vNameL nm
413 ; cls' <- mapM cvtClause cls
414 ; returnL $ mkFunBind nm' cls' }
416 cvtBind (TH.ValD p body ds)
417 = do { p' <- cvtPat p
418 ; g' <- cvtGuard body
420 ; returnL $ PatBind { pat_lhs = p', pat_rhs = GRHSs g' ds',
421 pat_rhs_ty = void, bind_fvs = placeHolderNames } }
424 = failWith (sep [ptext (sLit "Illegal kind of declaration in where clause"),
425 nest 2 (text (TH.pprint d))])
427 cvtClause :: TH.Clause -> CvtM (Hs.LMatch RdrName)
428 cvtClause (Clause ps body wheres)
429 = do { ps' <- cvtPats ps
430 ; g' <- cvtGuard body
431 ; ds' <- cvtDecs wheres
432 ; returnL $ Hs.Match ps' Nothing (GRHSs g' ds') }
435 -------------------------------------------------------------------
437 -------------------------------------------------------------------
439 cvtl :: TH.Exp -> CvtM (LHsExpr RdrName)
440 cvtl e = wrapL (cvt e)
442 cvt (VarE s) = do { s' <- vName s; return $ HsVar s' }
443 cvt (ConE s) = do { s' <- cName s; return $ HsVar s' }
445 | overloadedLit l = do { l' <- cvtOverLit l; return $ HsOverLit l' }
446 | otherwise = do { l' <- cvtLit l; return $ HsLit l' }
448 cvt (AppE x y) = do { x' <- cvtl x; y' <- cvtl y; return $ HsApp x' y' }
449 cvt (LamE ps e) = do { ps' <- cvtPats ps; e' <- cvtl e
450 ; return $ HsLam (mkMatchGroup [mkSimpleMatch ps' e']) }
451 cvt (TupE [e]) = cvt e -- Singleton tuples treated like nothing (just parens)
452 cvt (TupE es) = do { es' <- mapM cvtl es; return $ ExplicitTuple es' Boxed }
453 cvt (CondE x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z
454 ; return $ HsIf x' y' z' }
455 cvt (LetE ds e) = do { ds' <- cvtDecs ds; e' <- cvtl e; return $ HsLet ds' e' }
457 | null ms = failWith (ptext (sLit "Case expression with no alternatives"))
458 | otherwise = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
459 ; return $ HsCase e' (mkMatchGroup ms') }
460 cvt (DoE ss) = cvtHsDo DoExpr ss
461 cvt (CompE ss) = cvtHsDo ListComp ss
462 cvt (ArithSeqE dd) = do { dd' <- cvtDD dd; return $ ArithSeq noPostTcExpr dd' }
463 cvt (ListE xs) = do { xs' <- mapM cvtl xs; return $ ExplicitList void xs' }
464 cvt (InfixE (Just x) s (Just y)) = do { x' <- cvtl x; s' <- cvtl s; y' <- cvtl y
465 ; e' <- returnL $ OpApp x' s' undefined y'
466 ; return $ HsPar e' }
467 cvt (InfixE Nothing s (Just y)) = do { s' <- cvtl s; y' <- cvtl y
468 ; sec <- returnL $ SectionR s' y'
469 ; return $ HsPar sec }
470 cvt (InfixE (Just x) s Nothing ) = do { x' <- cvtl x; s' <- cvtl s
471 ; sec <- returnL $ SectionL x' s'
472 ; return $ HsPar sec }
473 cvt (InfixE Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
475 cvt (SigE e t) = do { e' <- cvtl e; t' <- cvtType t
476 ; return $ ExprWithTySig e' t' }
477 cvt (RecConE c flds) = do { c' <- cNameL c
478 ; flds' <- mapM cvtFld flds
479 ; return $ RecordCon c' noPostTcExpr (HsRecFields flds' Nothing)}
480 cvt (RecUpdE e flds) = do { e' <- cvtl e
481 ; flds' <- mapM cvtFld flds
482 ; return $ RecordUpd e' (HsRecFields flds' Nothing) [] [] [] }
484 cvtFld :: (TH.Name, TH.Exp) -> CvtM (HsRecField RdrName (LHsExpr RdrName))
486 = do { v' <- vNameL v; e' <- cvtl e
487 ; return (HsRecField { hsRecFieldId = v', hsRecFieldArg = e', hsRecPun = False}) }
489 cvtDD :: Range -> CvtM (ArithSeqInfo RdrName)
490 cvtDD (FromR x) = do { x' <- cvtl x; return $ From x' }
491 cvtDD (FromThenR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromThen x' y' }
492 cvtDD (FromToR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromTo x' y' }
493 cvtDD (FromThenToR x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; return $ FromThenTo x' y' z' }
495 -------------------------------------
496 -- Do notation and statements
497 -------------------------------------
499 cvtHsDo :: HsStmtContext Name.Name -> [TH.Stmt] -> CvtM (HsExpr RdrName)
500 cvtHsDo do_or_lc stmts
501 | null stmts = failWith (ptext (sLit "Empty stmt list in do-block"))
503 = do { stmts' <- cvtStmts stmts
504 ; let body = case last stmts' of
505 L _ (ExprStmt body _ _) -> body
506 _ -> panic "Malformed body"
507 ; return $ HsDo do_or_lc (init stmts') body void }
509 cvtStmts :: [TH.Stmt] -> CvtM [Hs.LStmt RdrName]
510 cvtStmts = mapM cvtStmt
512 cvtStmt :: TH.Stmt -> CvtM (Hs.LStmt RdrName)
513 cvtStmt (NoBindS e) = do { e' <- cvtl e; returnL $ mkExprStmt e' }
514 cvtStmt (TH.BindS p e) = do { p' <- cvtPat p; e' <- cvtl e; returnL $ mkBindStmt p' e' }
515 cvtStmt (TH.LetS ds) = do { ds' <- cvtDecs ds; returnL $ LetStmt ds' }
516 cvtStmt (TH.ParS dss) = do { dss' <- mapM cvt_one dss; returnL $ ParStmt dss' }
518 cvt_one ds = do { ds' <- cvtStmts ds; return (ds', undefined) }
520 cvtMatch :: TH.Match -> CvtM (Hs.LMatch RdrName)
521 cvtMatch (TH.Match p body decs)
522 = do { p' <- cvtPat p
523 ; g' <- cvtGuard body
524 ; decs' <- cvtDecs decs
525 ; returnL $ Hs.Match [p'] Nothing (GRHSs g' decs') }
527 cvtGuard :: TH.Body -> CvtM [LGRHS RdrName]
528 cvtGuard (GuardedB pairs) = mapM cvtpair pairs
529 cvtGuard (NormalB e) = do { e' <- cvtl e; g' <- returnL $ GRHS [] e'; return [g'] }
531 cvtpair :: (TH.Guard, TH.Exp) -> CvtM (LGRHS RdrName)
532 cvtpair (NormalG ge,rhs) = do { ge' <- cvtl ge; rhs' <- cvtl rhs
533 ; g' <- returnL $ mkExprStmt ge'
534 ; returnL $ GRHS [g'] rhs' }
535 cvtpair (PatG gs,rhs) = do { gs' <- cvtStmts gs; rhs' <- cvtl rhs
536 ; returnL $ GRHS gs' rhs' }
538 cvtOverLit :: Lit -> CvtM (HsOverLit RdrName)
539 cvtOverLit (IntegerL i)
540 = do { force i; return $ mkHsIntegral i placeHolderType}
541 cvtOverLit (RationalL r)
542 = do { force r; return $ mkHsFractional r placeHolderType}
543 cvtOverLit (StringL s)
544 = do { let { s' = mkFastString s }
546 ; return $ mkHsIsString s' placeHolderType
548 cvtOverLit _ = panic "Convert.cvtOverLit: Unexpected overloaded literal"
549 -- An Integer is like an (overloaded) '3' in a Haskell source program
550 -- Similarly 3.5 for fractionals
552 cvtLit :: Lit -> CvtM HsLit
553 cvtLit (IntPrimL i) = do { force i; return $ HsIntPrim i }
554 cvtLit (WordPrimL w) = do { force w; return $ HsWordPrim w }
555 cvtLit (FloatPrimL f) = do { force f; return $ HsFloatPrim f }
556 cvtLit (DoublePrimL f) = do { force f; return $ HsDoublePrim f }
557 cvtLit (CharL c) = do { force c; return $ HsChar c }
559 = do { let { s' = mkFastString s }
561 ; return $ HsString s'
563 cvtLit _ = panic "Convert.cvtLit: Unexpected literal"
565 cvtPats :: [TH.Pat] -> CvtM [Hs.LPat RdrName]
566 cvtPats pats = mapM cvtPat pats
568 cvtPat :: TH.Pat -> CvtM (Hs.LPat RdrName)
569 cvtPat pat = wrapL (cvtp pat)
571 cvtp :: TH.Pat -> CvtM (Hs.Pat RdrName)
573 | overloadedLit l = do { l' <- cvtOverLit l
574 ; return (mkNPat l' Nothing) }
575 -- Not right for negative patterns;
576 -- need to think about that!
577 | otherwise = do { l' <- cvtLit l; return $ Hs.LitPat l' }
578 cvtp (TH.VarP s) = do { s' <- vName s; return $ Hs.VarPat s' }
579 cvtp (TupP [p]) = cvtp p
580 cvtp (TupP ps) = do { ps' <- cvtPats ps; return $ TuplePat ps' Boxed void }
581 cvtp (ConP s ps) = do { s' <- cNameL s; ps' <- cvtPats ps; return $ ConPatIn s' (PrefixCon ps') }
582 cvtp (InfixP p1 s p2) = do { s' <- cNameL s; p1' <- cvtPat p1; p2' <- cvtPat p2
583 ; return $ ConPatIn s' (InfixCon p1' p2') }
584 cvtp (TildeP p) = do { p' <- cvtPat p; return $ LazyPat p' }
585 cvtp (TH.AsP s p) = do { s' <- vNameL s; p' <- cvtPat p; return $ AsPat s' p' }
586 cvtp TH.WildP = return $ WildPat void
587 cvtp (RecP c fs) = do { c' <- cNameL c; fs' <- mapM cvtPatFld fs
588 ; return $ ConPatIn c' $ Hs.RecCon (HsRecFields fs' Nothing) }
589 cvtp (ListP ps) = do { ps' <- cvtPats ps; return $ ListPat ps' void }
590 cvtp (SigP p t) = do { p' <- cvtPat p; t' <- cvtType t; return $ SigPatIn p' t' }
592 cvtPatFld :: (TH.Name, TH.Pat) -> CvtM (HsRecField RdrName (LPat RdrName))
594 = do { s' <- vNameL s; p' <- cvtPat p
595 ; return (HsRecField { hsRecFieldId = s', hsRecFieldArg = p', hsRecPun = False}) }
597 -----------------------------------------------------------
598 -- Types and type variables
600 cvtTvs :: [TH.Name] -> CvtM [LHsTyVarBndr RdrName]
601 cvtTvs tvs = mapM cvt_tv tvs
603 cvt_tv :: TH.Name -> CvtM (LHsTyVarBndr RdrName)
604 cvt_tv tv = do { tv' <- tName tv; returnL $ UserTyVar tv' }
606 cvtContext :: Cxt -> CvtM (LHsContext RdrName)
607 cvtContext tys = do { preds' <- mapM cvtPred tys; returnL preds' }
609 cvtPred :: TH.Type -> CvtM (LHsPred RdrName)
611 = do { (head, tys') <- split_ty_app ty
613 ConT tc -> do { tc' <- tconName tc; returnL $ HsClassP tc' tys' }
614 VarT tv -> do { tv' <- tName tv; returnL $ HsClassP tv' tys' }
615 _ -> failWith (ptext (sLit "Malformed predicate") <+> text (TH.pprint ty)) }
617 cvtType :: TH.Type -> CvtM (LHsType RdrName)
618 cvtType ty = do { (head_ty, tys') <- split_ty_app ty
620 TupleT n | length tys' == n -- Saturated
621 -> if n==1 then return (head tys') -- Singleton tuples treated
622 -- like nothing (ie just parens)
623 else returnL (HsTupleTy Boxed tys')
624 | n == 1 -> failWith (ptext (sLit "Illegal 1-tuple type constructor"))
625 | otherwise -> mk_apps (HsTyVar (getRdrName (tupleTyCon Boxed n))) tys'
626 ArrowT | [x',y'] <- tys' -> returnL (HsFunTy x' y')
627 | otherwise -> mk_apps (HsTyVar (getRdrName funTyCon)) tys'
628 ListT | [x'] <- tys' -> returnL (HsListTy x')
629 | otherwise -> mk_apps (HsTyVar (getRdrName listTyCon)) tys'
630 VarT nm -> do { nm' <- tName nm; mk_apps (HsTyVar nm') tys' }
631 ConT nm -> do { nm' <- tconName nm; mk_apps (HsTyVar nm') tys' }
633 ForallT tvs cxt ty | null tys' -> do { tvs' <- cvtTvs tvs
634 ; cxt' <- cvtContext cxt
636 ; returnL $ mkExplicitHsForAllTy tvs' cxt' ty' }
637 _ -> failWith (ptext (sLit "Malformed type") <+> text (show ty))
640 mk_apps head_ty [] = returnL head_ty
641 mk_apps head_ty (ty:tys) = do { head_ty' <- returnL head_ty
642 ; mk_apps (HsAppTy head_ty' ty) tys }
644 split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsType RdrName])
645 split_ty_app ty = go ty []
647 go (AppT f a) as' = do { a' <- cvtType a; go f (a':as') }
648 go f as = return (f,as)
650 -----------------------------------------------------------
653 -----------------------------------------------------------
654 -- some useful things
656 overloadedLit :: Lit -> Bool
657 -- True for literals that Haskell treats as overloaded
658 overloadedLit (IntegerL _) = True
659 overloadedLit (RationalL _) = True
660 overloadedLit _ = False
663 void = placeHolderType
665 --------------------------------------------------------------------
666 -- Turning Name back into RdrName
667 --------------------------------------------------------------------
670 vNameL, cNameL, tconNameL :: TH.Name -> CvtM (Located RdrName)
671 vName, cName, tName, tconName :: TH.Name -> CvtM RdrName
673 vNameL n = wrapL (vName n)
674 vName n = cvtName OccName.varName n
676 -- Constructor function names; this is Haskell source, hence srcDataName
677 cNameL n = wrapL (cName n)
678 cName n = cvtName OccName.dataName n
680 -- Type variable names
681 tName n = cvtName OccName.tvName n
683 -- Type Constructor names
684 tconNameL n = wrapL (tconName n)
685 tconName n = cvtName OccName.tcClsName n
687 cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName
688 cvtName ctxt_ns (TH.Name occ flavour)
689 | not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str)
690 | otherwise = force (thRdrName ctxt_ns occ_str flavour)
692 occ_str = TH.occString occ
694 okOcc :: OccName.NameSpace -> String -> Bool
697 | OccName.isVarNameSpace ns = startsVarId c || startsVarSym c
698 | otherwise = startsConId c || startsConSym c || str == "[]"
700 badOcc :: OccName.NameSpace -> String -> SDoc
702 = ptext (sLit "Illegal") <+> pprNameSpace ctxt_ns
703 <+> ptext (sLit "name:") <+> quotes (text occ)
705 thRdrName :: OccName.NameSpace -> String -> TH.NameFlavour -> RdrName
706 -- This turns a Name into a RdrName
707 -- The passed-in name space tells what the context is expecting;
708 -- use it unless the TH name knows what name-space it comes
709 -- from, in which case use the latter
711 -- ToDo: we may generate silly RdrNames, by passing a name space
712 -- that doesn't match the string, like VarName ":+",
713 -- which will give confusing error messages later
715 -- The strict applications ensure that any buried exceptions get forced
716 thRdrName _ occ (TH.NameG th_ns pkg mod) = thOrigRdrName occ th_ns pkg mod
717 thRdrName ctxt_ns occ (TH.NameL uniq) = nameRdrName $! (((Name.mkInternalName $! (mk_uniq uniq)) $! (mk_occ ctxt_ns occ)) noSrcSpan)
718 thRdrName ctxt_ns occ (TH.NameQ mod) = (mkRdrQual $! (mk_mod mod)) $! (mk_occ ctxt_ns occ)
719 thRdrName ctxt_ns occ (TH.NameU uniq) = mkRdrUnqual $! (mk_uniq_occ ctxt_ns occ uniq)
720 thRdrName ctxt_ns occ TH.NameS
721 | Just name <- isBuiltInOcc ctxt_ns occ = nameRdrName $! name
722 | otherwise = mkRdrUnqual $! (mk_occ ctxt_ns occ)
724 thOrigRdrName :: String -> TH.NameSpace -> PkgName -> ModName -> RdrName
725 thOrigRdrName occ th_ns pkg mod = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
727 thRdrNameGuesses :: TH.Name -> [RdrName]
728 thRdrNameGuesses (TH.Name occ flavour)
729 -- This special case for NameG ensures that we don't generate duplicates in the output list
730 | TH.NameG th_ns pkg mod <- flavour = [thOrigRdrName occ_str th_ns pkg mod]
731 | otherwise = [ thRdrName gns occ_str flavour
732 | gns <- guessed_nss]
734 -- guessed_ns are the name spaces guessed from looking at the TH name
735 guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName, OccName.dataName]
736 | otherwise = [OccName.varName, OccName.tvName]
737 occ_str = TH.occString occ
739 isBuiltInOcc :: OccName.NameSpace -> String -> Maybe Name.Name
740 -- Built in syntax isn't "in scope" so an Unqual RdrName won't do
741 -- We must generate an Exact name, just as the parser does
742 isBuiltInOcc ctxt_ns occ
744 ":" -> Just (Name.getName consDataCon)
745 "[]" -> Just (Name.getName nilDataCon)
746 "()" -> Just (tup_name 0)
747 '(' : ',' : rest -> go_tuple 2 rest
750 go_tuple n ")" = Just (tup_name n)
751 go_tuple n (',' : rest) = go_tuple (n+1) rest
752 go_tuple _ _ = Nothing
755 | OccName.isTcClsNameSpace ctxt_ns = Name.getName (tupleTyCon Boxed n)
756 | otherwise = Name.getName (tupleCon Boxed n)
758 mk_uniq_occ :: OccName.NameSpace -> String -> Int# -> OccName.OccName
759 mk_uniq_occ ns occ uniq
760 = OccName.mkOccName ns (occ ++ '[' : shows (mk_uniq uniq) "]")
761 -- The idea here is to make a name that
762 -- a) the user could not possibly write, and
763 -- b) cannot clash with another NameU
764 -- Previously I generated an Exact RdrName with mkInternalName.
765 -- This works fine for local binders, but does not work at all for
766 -- top-level binders, which must have External Names, since they are
767 -- rapidly baked into data constructors and the like. Baling out
768 -- and generating an unqualified RdrName here is the simple solution
770 -- The packing and unpacking is rather turgid :-(
771 mk_occ :: OccName.NameSpace -> String -> OccName.OccName
772 mk_occ ns occ = OccName.mkOccNameFS ns (mkFastString occ)
774 mk_ghc_ns :: TH.NameSpace -> OccName.NameSpace
775 mk_ghc_ns TH.DataName = OccName.dataName
776 mk_ghc_ns TH.TcClsName = OccName.tcClsName
777 mk_ghc_ns TH.VarName = OccName.varName
779 mk_mod :: TH.ModName -> ModuleName
780 mk_mod mod = mkModuleName (TH.modString mod)
782 mk_pkg :: TH.ModName -> PackageId
783 mk_pkg pkg = stringToPackageId (TH.pkgString pkg)
785 mk_uniq :: Int# -> Unique
786 mk_uniq u = mkUniqueGrimily (I# u)