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
23 import BasicTypes as Hs
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 ctxt 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 ctxt
155 ; L loc pred' <- cvtPredTy 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)
167 = do { ford' <- cvtForD ford
168 ; returnL $ ForD ford'
171 cvtTop (PragmaD prag)
172 = do { prag' <- cvtPragmaD prag
173 ; returnL $ Hs.SigD prag'
176 cvtTop (FamilyD flav tc tvs kind)
177 = do { (_, tc', tvs', _) <- cvt_tycl_hdr [] tc tvs
178 ; let kind' = fmap cvtKind kind
179 ; returnL $ TyClD (TyFamily (cvtFamFlavour flav) tc' tvs' kind')
182 cvtFamFlavour TypeFam = TypeFamily
183 cvtFamFlavour DataFam = DataFamily
185 cvtTop (DataInstD ctxt tc tys constrs derivs)
186 = do { stuff <- cvt_tyinst_hdr ctxt tc tys
187 ; cons' <- mapM cvtConstr constrs
188 ; derivs' <- cvtDerivs derivs
189 ; returnL $ TyClD (mkTyData DataType stuff Nothing cons' derivs')
192 cvtTop (NewtypeInstD ctxt tc tys constr derivs)
193 = do { stuff <- cvt_tyinst_hdr ctxt tc tys
194 ; con' <- cvtConstr constr
195 ; derivs' <- cvtDerivs derivs
196 ; returnL $ TyClD (mkTyData NewType stuff Nothing [con'] derivs')
199 cvtTop (TySynInstD tc tys rhs)
200 = do { (_, tc', tvs', tys') <- cvt_tyinst_hdr [] tc tys
201 ; rhs' <- cvtType rhs
202 ; returnL $ TyClD (TySynonym tc' tvs' tys' rhs') }
204 -- FIXME: This projection is not nice, but to remove it, cvtTop should be
206 unTyClD :: LHsDecl a -> LTyClDecl a
207 unTyClD (L l (TyClD d)) = L l d
208 unTyClD _ = panic "Convert.unTyClD: internal error"
210 cvt_tycl_hdr :: TH.Cxt -> TH.Name -> [TH.TyVarBndr]
211 -> CvtM ( LHsContext RdrName
213 , [LHsTyVarBndr RdrName]
214 , Maybe [LHsType RdrName])
215 cvt_tycl_hdr cxt tc tvs
216 = do { cxt' <- cvtContext cxt
217 ; tc' <- tconNameL tc
219 ; return (cxt', tc', tvs', Nothing)
222 cvt_tyinst_hdr :: TH.Cxt -> TH.Name -> [TH.Type]
223 -> CvtM ( LHsContext RdrName
225 , [LHsTyVarBndr RdrName]
226 , Maybe [LHsType RdrName])
227 cvt_tyinst_hdr cxt tc tys
228 = do { cxt' <- cvtContext cxt
229 ; tc' <- tconNameL tc
230 ; tvs <- concatMapM collect tys
232 ; tys' <- mapM cvtType tys
233 ; return (cxt', tc', tvs', Just tys')
236 collect (ForallT _ _ _)
237 = failWith $ text "Forall type not allowed as type parameter"
238 collect (VarT tv) = return [PlainTV tv]
239 collect (ConT _) = return []
240 collect (TupleT _) = return []
241 collect ArrowT = return []
242 collect ListT = return []
244 = do { tvs1 <- collect t1
246 ; return $ tvs1 ++ tvs2
248 collect (SigT (VarT tv) ki) = return [KindedTV tv ki]
249 collect (SigT ty _) = collect ty
251 ---------------------------------------------------
253 -- Can't handle GADTs yet
254 ---------------------------------------------------
256 cvtConstr :: TH.Con -> CvtM (LConDecl RdrName)
258 cvtConstr (NormalC c strtys)
259 = do { c' <- cNameL c
261 ; tys' <- mapM cvt_arg strtys
262 ; returnL $ ConDecl c' Explicit noExistentials cxt' (PrefixCon tys') ResTyH98 Nothing }
264 cvtConstr (RecC c varstrtys)
265 = do { c' <- cNameL c
267 ; args' <- mapM cvt_id_arg varstrtys
268 ; returnL $ ConDecl c' Explicit noExistentials cxt' (RecCon args') ResTyH98 Nothing }
270 cvtConstr (InfixC st1 c st2)
271 = do { c' <- cNameL c
273 ; st1' <- cvt_arg st1
274 ; st2' <- cvt_arg st2
275 ; returnL $ ConDecl c' Explicit noExistentials cxt' (InfixCon st1' st2') ResTyH98 Nothing }
277 cvtConstr (ForallC tvs ctxt (ForallC tvs' ctxt' con'))
278 = cvtConstr (ForallC (tvs ++ tvs') (ctxt ++ ctxt') con')
280 cvtConstr (ForallC tvs ctxt con)
281 = do { L _ con' <- cvtConstr con
283 ; ctxt' <- cvtContext ctxt
285 ConDecl l _ [] (L _ []) x ResTyH98 _
286 -> returnL $ ConDecl l Explicit tvs' ctxt' x ResTyH98 Nothing
287 _ -> panic "ForallC: Can't happen" }
289 cvt_arg :: (TH.Strict, TH.Type) -> CvtM (LHsType RdrName)
290 cvt_arg (IsStrict, ty) = do { ty' <- cvtType ty; returnL $ HsBangTy HsStrict ty' }
291 cvt_arg (NotStrict, ty) = cvtType ty
293 cvt_id_arg :: (TH.Name, TH.Strict, TH.Type) -> CvtM (ConDeclField RdrName)
294 cvt_id_arg (i, str, ty)
295 = do { i' <- vNameL i
296 ; ty' <- cvt_arg (str,ty)
297 ; return (ConDeclField { cd_fld_name = i', cd_fld_type = ty', cd_fld_doc = Nothing}) }
299 cvtDerivs :: [TH.Name] -> CvtM (Maybe [LHsType RdrName])
300 cvtDerivs [] = return Nothing
301 cvtDerivs cs = do { cs' <- mapM cvt_one cs
302 ; return (Just cs') }
304 cvt_one c = do { c' <- tconName c
305 ; returnL $ HsPredTy $ HsClassP c' [] }
307 cvt_fundep :: FunDep -> CvtM (Located (Class.FunDep RdrName))
308 cvt_fundep (FunDep xs ys) = do { xs' <- mapM tName xs; ys' <- mapM tName ys; returnL (xs', ys') }
310 noExistentials :: [LHsTyVarBndr RdrName]
313 ------------------------------------------
314 -- Foreign declarations
315 ------------------------------------------
317 cvtForD :: Foreign -> CvtM (ForeignDecl RdrName)
318 cvtForD (ImportF callconv safety from nm ty)
319 | Just (c_header, cis) <- parse_ccall_impent (TH.nameBase nm) from
320 = do { nm' <- vNameL nm
322 ; let i = CImport (cvt_conv callconv) safety' c_header cis
323 ; return $ ForeignImport nm' ty' i }
326 = failWith $ text (show from)<+> ptext (sLit "is not a valid ccall impent")
328 safety' = case safety of
330 Safe -> PlaySafe False
331 Threadsafe -> PlaySafe True
333 cvtForD (ExportF callconv as nm ty)
334 = do { nm' <- vNameL nm
336 ; let e = CExport (CExportStatic (mkFastString as) (cvt_conv callconv))
337 ; return $ ForeignExport nm' ty' e }
339 cvt_conv :: TH.Callconv -> CCallConv
340 cvt_conv TH.CCall = CCallConv
341 cvt_conv TH.StdCall = StdCallConv
343 parse_ccall_impent :: String -> String -> Maybe (FastString, CImportSpec)
344 parse_ccall_impent nm s
345 = case lex_ccall_impent s of
346 Just ["dynamic"] -> Just (nilFS, CFunction DynamicTarget)
347 Just ["wrapper"] -> Just (nilFS, CWrapper)
348 Just ("static":ts) -> parse_ccall_impent_static nm ts
349 Just ts -> parse_ccall_impent_static nm ts
352 -- XXX we should be sharing code with RdrHsSyn.parseCImport
353 parse_ccall_impent_static :: String
355 -> Maybe (FastString, CImportSpec)
356 parse_ccall_impent_static nm ts
358 [ ] -> mkFun nilFS nm
359 [ "&", cid] -> mkLbl nilFS cid
360 [fname, "&" ] -> mkLbl (mkFastString fname) nm
361 [fname, "&", cid] -> mkLbl (mkFastString fname) cid
362 [ "&" ] -> mkLbl nilFS nm
363 [fname, cid] -> mkFun (mkFastString fname) cid
365 | is_cid cid -> mkFun nilFS cid
366 | otherwise -> mkFun (mkFastString cid) nm
367 -- tricky case when there's a single string: "foo.h" is a header,
368 -- but "foo" is a C identifier, and we tell the difference by
369 -- checking for a valid C identifier (see is_cid below).
370 _anything_else -> Nothing
372 where is_cid :: String -> Bool
373 is_cid x = all (/= '.') x && (isAlpha (head x) || head x == '_')
375 mkLbl :: FastString -> String -> Maybe (FastString, CImportSpec)
376 mkLbl fname lbl = Just (fname, CLabel (mkFastString lbl))
378 mkFun :: FastString -> String -> Maybe (FastString, CImportSpec)
379 mkFun fname lbl = Just (fname, CFunction (StaticTarget (mkFastString lbl)))
381 -- This code is tokenising something like "foo.h &bar", eg.
383 -- "foo.h" -> Just ["foo.h"]
384 -- "foo.h &bar" -> Just ["foo.h","&","bar"]
386 -- Nothing is returned for a parse error.
387 lex_ccall_impent :: String -> Maybe [String]
388 lex_ccall_impent "" = Just []
389 lex_ccall_impent ('&':xs) = fmap ("&":) $ lex_ccall_impent xs
390 lex_ccall_impent (' ':xs) = lex_ccall_impent xs
391 lex_ccall_impent ('\t':xs) = lex_ccall_impent xs
392 lex_ccall_impent xs = case span is_valid xs of
394 (t, xs') -> fmap (t:) $ lex_ccall_impent xs'
395 where is_valid :: Char -> Bool
396 is_valid c = isAscii c && (isAlphaNum c || c `elem` "._")
398 ------------------------------------------
400 ------------------------------------------
402 cvtPragmaD :: Pragma -> CvtM (Sig RdrName)
403 cvtPragmaD (InlineP nm ispec)
404 = do { nm' <- vNameL nm
405 ; return $ InlineSig nm' (cvtInlineSpec (Just ispec))
407 cvtPragmaD (SpecialiseP nm ty opt_ispec)
408 = do { nm' <- vNameL nm
410 ; return $ SpecSig nm' ty' (cvtInlineSpec opt_ispec)
413 cvtInlineSpec :: Maybe TH.InlineSpec -> Hs.InlineSpec
414 cvtInlineSpec Nothing
416 cvtInlineSpec (Just (TH.InlineSpec inline conlike opt_activation))
417 = mkInlineSpec opt_activation' matchinfo inline
419 matchinfo = cvtRuleMatchInfo conlike
420 opt_activation' = fmap cvtActivation opt_activation
422 cvtRuleMatchInfo False = FunLike
423 cvtRuleMatchInfo True = ConLike
425 cvtActivation (False, phase) = ActiveBefore phase
426 cvtActivation (True , phase) = ActiveAfter phase
428 ---------------------------------------------------
430 ---------------------------------------------------
432 cvtDecs :: [TH.Dec] -> CvtM (HsLocalBinds RdrName)
433 cvtDecs [] = return EmptyLocalBinds
434 cvtDecs ds = do { (binds, sigs) <- cvtBindsAndSigs ds
435 ; return (HsValBinds (ValBindsIn binds sigs)) }
437 cvtBindsAndSigs :: [TH.Dec] -> CvtM (Bag (LHsBind RdrName), [LSig RdrName])
439 = do { binds' <- mapM cvtBind binds
440 ; sigs' <- mapM cvtSig sigs
441 ; return (listToBag binds', sigs') }
443 (sigs, binds) = partition is_sig ds
445 is_sig (TH.SigD _ _) = True
446 is_sig (TH.PragmaD _) = True
449 cvtSig :: TH.Dec -> CvtM (LSig RdrName)
450 cvtSig (TH.SigD nm ty)
451 = do { nm' <- vNameL nm
453 ; returnL (Hs.TypeSig nm' ty')
455 cvtSig (TH.PragmaD prag)
456 = do { prag' <- cvtPragmaD prag
459 cvtSig _ = panic "Convert.cvtSig: Signature expected"
461 cvtBind :: TH.Dec -> CvtM (LHsBind RdrName)
462 -- Used only for declarations in a 'let/where' clause,
463 -- not for top level decls
464 cvtBind (TH.ValD (TH.VarP s) body ds)
465 = do { s' <- vNameL s
466 ; cl' <- cvtClause (Clause [] body ds)
467 ; returnL $ mkFunBind s' [cl'] }
469 cvtBind (TH.FunD nm cls)
471 = failWith (ptext (sLit "Function binding for")
472 <+> quotes (text (TH.pprint nm))
473 <+> ptext (sLit "has no equations"))
475 = do { nm' <- vNameL nm
476 ; cls' <- mapM cvtClause cls
477 ; returnL $ mkFunBind nm' cls' }
479 cvtBind (TH.ValD p body ds)
480 = do { p' <- cvtPat p
481 ; g' <- cvtGuard body
483 ; returnL $ PatBind { pat_lhs = p', pat_rhs = GRHSs g' ds',
484 pat_rhs_ty = void, bind_fvs = placeHolderNames } }
487 = failWith (sep [ptext (sLit "Illegal kind of declaration in where clause"),
488 nest 2 (text (TH.pprint d))])
490 cvtClause :: TH.Clause -> CvtM (Hs.LMatch RdrName)
491 cvtClause (Clause ps body wheres)
492 = do { ps' <- cvtPats ps
493 ; g' <- cvtGuard body
494 ; ds' <- cvtDecs wheres
495 ; returnL $ Hs.Match ps' Nothing (GRHSs g' ds') }
498 -------------------------------------------------------------------
500 -------------------------------------------------------------------
502 cvtl :: TH.Exp -> CvtM (LHsExpr RdrName)
503 cvtl e = wrapL (cvt e)
505 cvt (VarE s) = do { s' <- vName s; return $ HsVar s' }
506 cvt (ConE s) = do { s' <- cName s; return $ HsVar s' }
508 | overloadedLit l = do { l' <- cvtOverLit l; return $ HsOverLit l' }
509 | otherwise = do { l' <- cvtLit l; return $ HsLit l' }
511 cvt (AppE x y) = do { x' <- cvtl x; y' <- cvtl y; return $ HsApp x' y' }
512 cvt (LamE ps e) = do { ps' <- cvtPats ps; e' <- cvtl e
513 ; return $ HsLam (mkMatchGroup [mkSimpleMatch ps' e']) }
514 cvt (TupE [e]) = cvt e -- Singleton tuples treated like nothing (just parens)
515 cvt (TupE es) = do { es' <- mapM cvtl es; return $ ExplicitTuple es' Boxed }
516 cvt (CondE x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z
517 ; return $ HsIf x' y' z' }
518 cvt (LetE ds e) = do { ds' <- cvtDecs ds; e' <- cvtl e; return $ HsLet ds' e' }
520 | null ms = failWith (ptext (sLit "Case expression with no alternatives"))
521 | otherwise = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
522 ; return $ HsCase e' (mkMatchGroup ms') }
523 cvt (DoE ss) = cvtHsDo DoExpr ss
524 cvt (CompE ss) = cvtHsDo ListComp ss
525 cvt (ArithSeqE dd) = do { dd' <- cvtDD dd; return $ ArithSeq noPostTcExpr dd' }
527 | Just s <- allCharLs xs = do { l' <- cvtLit (StringL s); return (HsLit l') }
528 -- Note [Converting strings]
529 | otherwise = do { xs' <- mapM cvtl xs; return $ ExplicitList void xs' }
530 cvt (InfixE (Just x) s (Just y)) = do { x' <- cvtl x; s' <- cvtl s; y' <- cvtl y
531 ; e' <- returnL $ OpApp x' s' undefined y'
532 ; return $ HsPar e' }
533 cvt (InfixE Nothing s (Just y)) = do { s' <- cvtl s; y' <- cvtl y
534 ; sec <- returnL $ SectionR s' y'
535 ; return $ HsPar sec }
536 cvt (InfixE (Just x) s Nothing ) = do { x' <- cvtl x; s' <- cvtl s
537 ; sec <- returnL $ SectionL x' s'
538 ; return $ HsPar sec }
539 cvt (InfixE Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
541 cvt (SigE e t) = do { e' <- cvtl e; t' <- cvtType t
542 ; return $ ExprWithTySig e' t' }
543 cvt (RecConE c flds) = do { c' <- cNameL c
544 ; flds' <- mapM cvtFld flds
545 ; return $ RecordCon c' noPostTcExpr (HsRecFields flds' Nothing)}
546 cvt (RecUpdE e flds) = do { e' <- cvtl e
547 ; flds' <- mapM cvtFld flds
548 ; return $ RecordUpd e' (HsRecFields flds' Nothing) [] [] [] }
550 cvtFld :: (TH.Name, TH.Exp) -> CvtM (HsRecField RdrName (LHsExpr RdrName))
552 = do { v' <- vNameL v; e' <- cvtl e
553 ; return (HsRecField { hsRecFieldId = v', hsRecFieldArg = e', hsRecPun = False}) }
555 cvtDD :: Range -> CvtM (ArithSeqInfo RdrName)
556 cvtDD (FromR x) = do { x' <- cvtl x; return $ From x' }
557 cvtDD (FromThenR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromThen x' y' }
558 cvtDD (FromToR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromTo x' y' }
559 cvtDD (FromThenToR x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; return $ FromThenTo x' y' z' }
561 -------------------------------------
562 -- Do notation and statements
563 -------------------------------------
565 cvtHsDo :: HsStmtContext Name.Name -> [TH.Stmt] -> CvtM (HsExpr RdrName)
566 cvtHsDo do_or_lc stmts
567 | null stmts = failWith (ptext (sLit "Empty stmt list in do-block"))
569 = do { stmts' <- cvtStmts stmts
570 ; let body = case last stmts' of
571 L _ (ExprStmt body _ _) -> body
572 _ -> panic "Malformed body"
573 ; return $ HsDo do_or_lc (init stmts') body void }
575 cvtStmts :: [TH.Stmt] -> CvtM [Hs.LStmt RdrName]
576 cvtStmts = mapM cvtStmt
578 cvtStmt :: TH.Stmt -> CvtM (Hs.LStmt RdrName)
579 cvtStmt (NoBindS e) = do { e' <- cvtl e; returnL $ mkExprStmt e' }
580 cvtStmt (TH.BindS p e) = do { p' <- cvtPat p; e' <- cvtl e; returnL $ mkBindStmt p' e' }
581 cvtStmt (TH.LetS ds) = do { ds' <- cvtDecs ds; returnL $ LetStmt ds' }
582 cvtStmt (TH.ParS dss) = do { dss' <- mapM cvt_one dss; returnL $ ParStmt dss' }
584 cvt_one ds = do { ds' <- cvtStmts ds; return (ds', undefined) }
586 cvtMatch :: TH.Match -> CvtM (Hs.LMatch RdrName)
587 cvtMatch (TH.Match p body decs)
588 = do { p' <- cvtPat p
589 ; g' <- cvtGuard body
590 ; decs' <- cvtDecs decs
591 ; returnL $ Hs.Match [p'] Nothing (GRHSs g' decs') }
593 cvtGuard :: TH.Body -> CvtM [LGRHS RdrName]
594 cvtGuard (GuardedB pairs) = mapM cvtpair pairs
595 cvtGuard (NormalB e) = do { e' <- cvtl e; g' <- returnL $ GRHS [] e'; return [g'] }
597 cvtpair :: (TH.Guard, TH.Exp) -> CvtM (LGRHS RdrName)
598 cvtpair (NormalG ge,rhs) = do { ge' <- cvtl ge; rhs' <- cvtl rhs
599 ; g' <- returnL $ mkExprStmt ge'
600 ; returnL $ GRHS [g'] rhs' }
601 cvtpair (PatG gs,rhs) = do { gs' <- cvtStmts gs; rhs' <- cvtl rhs
602 ; returnL $ GRHS gs' rhs' }
604 cvtOverLit :: Lit -> CvtM (HsOverLit RdrName)
605 cvtOverLit (IntegerL i)
606 = do { force i; return $ mkHsIntegral i placeHolderType}
607 cvtOverLit (RationalL r)
608 = do { force r; return $ mkHsFractional r placeHolderType}
609 cvtOverLit (StringL s)
610 = do { let { s' = mkFastString s }
612 ; return $ mkHsIsString s' placeHolderType
614 cvtOverLit _ = panic "Convert.cvtOverLit: Unexpected overloaded literal"
615 -- An Integer is like an (overloaded) '3' in a Haskell source program
616 -- Similarly 3.5 for fractionals
618 {- Note [Converting strings]
619 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
620 If we get (ListE [CharL 'x', CharL 'y']) we'd like to convert to
621 a string literal for "xy". Of course, we might hope to get
622 (LitE (StringL "xy")), but not always, and allCharLs fails quickly
623 if it isn't a literal string
626 allCharLs :: [TH.Exp] -> Maybe String
627 -- Note [Converting strings]
628 allCharLs (LitE (CharL c) : xs)
629 | Just cs <- allCharLs xs = Just (c:cs)
630 allCharLs [] = Just []
631 allCharLs _ = Nothing
633 cvtLit :: Lit -> CvtM HsLit
634 cvtLit (IntPrimL i) = do { force i; return $ HsIntPrim i }
635 cvtLit (WordPrimL w) = do { force w; return $ HsWordPrim w }
636 cvtLit (FloatPrimL f) = do { force f; return $ HsFloatPrim f }
637 cvtLit (DoublePrimL f) = do { force f; return $ HsDoublePrim f }
638 cvtLit (CharL c) = do { force c; return $ HsChar c }
640 = do { let { s' = mkFastString s }
642 ; return $ HsString s'
644 cvtLit _ = panic "Convert.cvtLit: Unexpected literal"
646 cvtPats :: [TH.Pat] -> CvtM [Hs.LPat RdrName]
647 cvtPats pats = mapM cvtPat pats
649 cvtPat :: TH.Pat -> CvtM (Hs.LPat RdrName)
650 cvtPat pat = wrapL (cvtp pat)
652 cvtp :: TH.Pat -> CvtM (Hs.Pat RdrName)
654 | overloadedLit l = do { l' <- cvtOverLit l
655 ; return (mkNPat l' Nothing) }
656 -- Not right for negative patterns;
657 -- need to think about that!
658 | otherwise = do { l' <- cvtLit l; return $ Hs.LitPat l' }
659 cvtp (TH.VarP s) = do { s' <- vName s; return $ Hs.VarPat s' }
660 cvtp (TupP [p]) = cvtp p
661 cvtp (TupP ps) = do { ps' <- cvtPats ps; return $ TuplePat ps' Boxed void }
662 cvtp (ConP s ps) = do { s' <- cNameL s; ps' <- cvtPats ps; return $ ConPatIn s' (PrefixCon ps') }
663 cvtp (InfixP p1 s p2) = do { s' <- cNameL s; p1' <- cvtPat p1; p2' <- cvtPat p2
664 ; return $ ConPatIn s' (InfixCon p1' p2') }
665 cvtp (TildeP p) = do { p' <- cvtPat p; return $ LazyPat p' }
666 cvtp (BangP p) = do { p' <- cvtPat p; return $ BangPat p' }
667 cvtp (TH.AsP s p) = do { s' <- vNameL s; p' <- cvtPat p; return $ AsPat s' p' }
668 cvtp TH.WildP = return $ WildPat void
669 cvtp (RecP c fs) = do { c' <- cNameL c; fs' <- mapM cvtPatFld fs
670 ; return $ ConPatIn c' $ Hs.RecCon (HsRecFields fs' Nothing) }
671 cvtp (ListP ps) = do { ps' <- cvtPats ps; return $ ListPat ps' void }
672 cvtp (SigP p t) = do { p' <- cvtPat p; t' <- cvtType t; return $ SigPatIn p' t' }
674 cvtPatFld :: (TH.Name, TH.Pat) -> CvtM (HsRecField RdrName (LPat RdrName))
676 = do { s' <- vNameL s; p' <- cvtPat p
677 ; return (HsRecField { hsRecFieldId = s', hsRecFieldArg = p', hsRecPun = False}) }
679 -----------------------------------------------------------
680 -- Types and type variables
682 cvtTvs :: [TH.TyVarBndr] -> CvtM [LHsTyVarBndr RdrName]
683 cvtTvs tvs = mapM cvt_tv tvs
685 cvt_tv :: TH.TyVarBndr -> CvtM (LHsTyVarBndr RdrName)
686 cvt_tv (TH.PlainTV nm)
687 = do { nm' <- tName nm
688 ; returnL $ UserTyVar nm'
690 cvt_tv (TH.KindedTV nm ki)
691 = do { nm' <- tName nm
692 ; returnL $ KindedTyVar nm' (cvtKind ki)
695 cvtContext :: TH.Cxt -> CvtM (LHsContext RdrName)
696 cvtContext tys = do { preds' <- mapM cvtPred tys; returnL preds' }
698 cvtPred :: TH.Pred -> CvtM (LHsPred RdrName)
699 cvtPred (TH.ClassP cla tys)
700 = do { cla' <- if isVarName cla then tName cla else tconName cla
701 ; tys' <- mapM cvtType tys
702 ; returnL $ HsClassP cla' tys'
704 cvtPred (TH.EqualP ty1 ty2)
705 = do { ty1' <- cvtType ty1
706 ; ty2' <- cvtType ty2
707 ; returnL $ HsEqualP ty1' ty2'
710 cvtPredTy :: TH.Type -> CvtM (LHsPred RdrName)
712 = do { (head, tys') <- split_ty_app ty
714 ConT tc -> do { tc' <- tconName tc; returnL $ HsClassP tc' tys' }
715 VarT tv -> do { tv' <- tName tv; returnL $ HsClassP tv' tys' }
716 _ -> failWith (ptext (sLit "Malformed predicate") <+>
717 text (TH.pprint ty)) }
719 cvtType :: TH.Type -> CvtM (LHsType RdrName)
721 = do { (head_ty, tys') <- split_ty_app ty
724 | length tys' == n -- Saturated
725 -> if n==1 then return (head tys') -- Singleton tuples treated
726 -- like nothing (ie just parens)
727 else returnL (HsTupleTy Boxed tys')
729 -> failWith (ptext (sLit "Illegal 1-tuple type constructor"))
731 -> mk_apps (HsTyVar (getRdrName (tupleTyCon Boxed n))) tys'
733 | [x',y'] <- tys' -> returnL (HsFunTy x' y')
734 | otherwise -> mk_apps (HsTyVar (getRdrName funTyCon)) tys'
736 | [x'] <- tys' -> returnL (HsListTy x')
737 | otherwise -> mk_apps (HsTyVar (getRdrName listTyCon)) tys'
738 VarT nm -> do { nm' <- tName nm; mk_apps (HsTyVar nm') tys' }
739 ConT nm -> do { nm' <- tconName nm; mk_apps (HsTyVar nm') tys' }
743 -> do { tvs' <- cvtTvs tvs
744 ; cxt' <- cvtContext cxt
746 ; returnL $ mkExplicitHsForAllTy tvs' cxt' ty'
750 -> do { ty' <- cvtType ty
751 ; mk_apps (HsKindSig ty' (cvtKind ki)) tys'
754 _ -> failWith (ptext (sLit "Malformed type") <+> text (show ty))
757 mk_apps head_ty [] = returnL head_ty
758 mk_apps head_ty (ty:tys) = do { head_ty' <- returnL head_ty
759 ; mk_apps (HsAppTy head_ty' ty) tys }
761 split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsType RdrName])
762 split_ty_app ty = go ty []
764 go (AppT f a) as' = do { a' <- cvtType a; go f (a':as') }
765 go f as = return (f,as)
767 cvtKind :: TH.Kind -> Type.Kind
768 cvtKind StarK = liftedTypeKind
769 cvtKind (ArrowK k1 k2) = mkArrowKind (cvtKind k1) (cvtKind k2)
771 -----------------------------------------------------------
774 -----------------------------------------------------------
775 -- some useful things
777 overloadedLit :: Lit -> Bool
778 -- True for literals that Haskell treats as overloaded
779 overloadedLit (IntegerL _) = True
780 overloadedLit (RationalL _) = True
781 overloadedLit _ = False
784 void = placeHolderType
786 --------------------------------------------------------------------
787 -- Turning Name back into RdrName
788 --------------------------------------------------------------------
791 vNameL, cNameL, tconNameL :: TH.Name -> CvtM (Located RdrName)
792 vName, cName, tName, tconName :: TH.Name -> CvtM RdrName
794 vNameL n = wrapL (vName n)
795 vName n = cvtName OccName.varName n
797 -- Constructor function names; this is Haskell source, hence srcDataName
798 cNameL n = wrapL (cName n)
799 cName n = cvtName OccName.dataName n
801 -- Type variable names
802 tName n = cvtName OccName.tvName n
804 -- Type Constructor names
805 tconNameL n = wrapL (tconName n)
806 tconName n = cvtName OccName.tcClsName n
808 cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName
809 cvtName ctxt_ns (TH.Name occ flavour)
810 | not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str)
811 | otherwise = force (thRdrName ctxt_ns occ_str flavour)
813 occ_str = TH.occString occ
815 okOcc :: OccName.NameSpace -> String -> Bool
818 | OccName.isVarNameSpace ns = startsVarId c || startsVarSym c
819 | otherwise = startsConId c || startsConSym c || str == "[]"
821 -- Determine the name space of a name in a type
823 isVarName :: TH.Name -> Bool
824 isVarName (TH.Name occ _)
825 = case TH.occString occ of
827 (c:_) -> startsVarId c || startsVarSym c
829 badOcc :: OccName.NameSpace -> String -> SDoc
831 = ptext (sLit "Illegal") <+> pprNameSpace ctxt_ns
832 <+> ptext (sLit "name:") <+> quotes (text occ)
834 thRdrName :: OccName.NameSpace -> String -> TH.NameFlavour -> RdrName
835 -- This turns a Name into a RdrName
836 -- The passed-in name space tells what the context is expecting;
837 -- use it unless the TH name knows what name-space it comes
838 -- from, in which case use the latter
840 -- ToDo: we may generate silly RdrNames, by passing a name space
841 -- that doesn't match the string, like VarName ":+",
842 -- which will give confusing error messages later
844 -- The strict applications ensure that any buried exceptions get forced
845 thRdrName _ occ (TH.NameG th_ns pkg mod) = thOrigRdrName occ th_ns pkg mod
846 thRdrName ctxt_ns occ (TH.NameL uniq) = nameRdrName $! (((Name.mkInternalName $! (mk_uniq uniq)) $! (mk_occ ctxt_ns occ)) noSrcSpan)
847 thRdrName ctxt_ns occ (TH.NameQ mod) = (mkRdrQual $! (mk_mod mod)) $! (mk_occ ctxt_ns occ)
848 thRdrName ctxt_ns occ (TH.NameU uniq) = mkRdrUnqual $! (mk_uniq_occ ctxt_ns occ uniq)
849 thRdrName ctxt_ns occ TH.NameS
850 | Just name <- isBuiltInOcc ctxt_ns occ = nameRdrName $! name
851 | otherwise = mkRdrUnqual $! (mk_occ ctxt_ns occ)
853 thOrigRdrName :: String -> TH.NameSpace -> PkgName -> ModName -> RdrName
854 thOrigRdrName occ th_ns pkg mod = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
856 thRdrNameGuesses :: TH.Name -> [RdrName]
857 thRdrNameGuesses (TH.Name occ flavour)
858 -- This special case for NameG ensures that we don't generate duplicates in the output list
859 | TH.NameG th_ns pkg mod <- flavour = [thOrigRdrName occ_str th_ns pkg mod]
860 | otherwise = [ thRdrName gns occ_str flavour
861 | gns <- guessed_nss]
863 -- guessed_ns are the name spaces guessed from looking at the TH name
864 guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName, OccName.dataName]
865 | otherwise = [OccName.varName, OccName.tvName]
866 occ_str = TH.occString occ
868 isBuiltInOcc :: OccName.NameSpace -> String -> Maybe Name.Name
869 -- Built in syntax isn't "in scope" so an Unqual RdrName won't do
870 -- We must generate an Exact name, just as the parser does
871 isBuiltInOcc ctxt_ns occ
873 ":" -> Just (Name.getName consDataCon)
874 "[]" -> Just (Name.getName nilDataCon)
875 "()" -> Just (tup_name 0)
876 '(' : ',' : rest -> go_tuple 2 rest
879 go_tuple n ")" = Just (tup_name n)
880 go_tuple n (',' : rest) = go_tuple (n+1) rest
881 go_tuple _ _ = Nothing
884 | OccName.isTcClsNameSpace ctxt_ns = Name.getName (tupleTyCon Boxed n)
885 | otherwise = Name.getName (tupleCon Boxed n)
887 mk_uniq_occ :: OccName.NameSpace -> String -> Int# -> OccName.OccName
888 mk_uniq_occ ns occ uniq
889 = OccName.mkOccName ns (occ ++ '[' : shows (mk_uniq uniq) "]")
890 -- The idea here is to make a name that
891 -- a) the user could not possibly write, and
892 -- b) cannot clash with another NameU
893 -- Previously I generated an Exact RdrName with mkInternalName.
894 -- This works fine for local binders, but does not work at all for
895 -- top-level binders, which must have External Names, since they are
896 -- rapidly baked into data constructors and the like. Baling out
897 -- and generating an unqualified RdrName here is the simple solution
899 -- The packing and unpacking is rather turgid :-(
900 mk_occ :: OccName.NameSpace -> String -> OccName.OccName
901 mk_occ ns occ = OccName.mkOccNameFS ns (mkFastString occ)
903 mk_ghc_ns :: TH.NameSpace -> OccName.NameSpace
904 mk_ghc_ns TH.DataName = OccName.dataName
905 mk_ghc_ns TH.TcClsName = OccName.tcClsName
906 mk_ghc_ns TH.VarName = OccName.varName
908 mk_mod :: TH.ModName -> ModuleName
909 mk_mod mod = mkModuleName (TH.modString mod)
911 mk_pkg :: TH.PkgName -> PackageId
912 mk_pkg pkg = stringToPackageId (TH.pkgString pkg)
914 mk_uniq :: Int# -> Unique
915 mk_uniq u = mkUniqueGrimily (I# u)