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 nilFS 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 parse_ccall_impent_static :: String
354 -> Maybe (FastString, CImportSpec)
355 parse_ccall_impent_static nm ts
356 = let ts' = case ts of
357 [ "&", cid] -> [ cid]
358 [fname, "&" ] -> [fname ]
359 [fname, "&", cid] -> [fname, cid]
362 [ cid] | is_cid cid -> Just (nilFS, mk_cid cid)
363 [fname, cid] | is_cid cid -> Just (mkFastString fname, mk_cid cid)
364 [ ] -> Just (nilFS, mk_cid nm)
365 [fname ] -> Just (mkFastString fname, mk_cid nm)
367 where is_cid :: String -> Bool
368 is_cid x = all (/= '.') x && (isAlpha (head x) || head x == '_')
369 mk_cid :: String -> CImportSpec
370 mk_cid = CFunction . StaticTarget . mkFastString
372 lex_ccall_impent :: String -> Maybe [String]
373 lex_ccall_impent "" = Just []
374 lex_ccall_impent ('&':xs) = fmap ("&":) $ lex_ccall_impent xs
375 lex_ccall_impent (' ':xs) = lex_ccall_impent xs
376 lex_ccall_impent ('\t':xs) = lex_ccall_impent xs
377 lex_ccall_impent xs = case span is_valid xs of
379 (t, xs') -> fmap (t:) $ lex_ccall_impent xs'
380 where is_valid :: Char -> Bool
381 is_valid c = isAscii c && (isAlphaNum c || c `elem` "._")
383 ------------------------------------------
385 ------------------------------------------
387 cvtPragmaD :: Pragma -> CvtM (Sig RdrName)
388 cvtPragmaD (InlineP nm ispec)
389 = do { nm' <- vNameL nm
390 ; return $ InlineSig nm' (cvtInlineSpec (Just ispec))
392 cvtPragmaD (SpecialiseP nm ty opt_ispec)
393 = do { nm' <- vNameL nm
395 ; return $ SpecSig nm' ty' (cvtInlineSpec opt_ispec)
398 cvtInlineSpec :: Maybe TH.InlineSpec -> Hs.InlineSpec
399 cvtInlineSpec Nothing
401 cvtInlineSpec (Just (TH.InlineSpec inline conlike opt_activation))
402 = mkInlineSpec opt_activation' matchinfo inline
404 matchinfo = cvtRuleMatchInfo conlike
405 opt_activation' = fmap cvtActivation opt_activation
407 cvtRuleMatchInfo False = FunLike
408 cvtRuleMatchInfo True = ConLike
410 cvtActivation (False, phase) = ActiveBefore phase
411 cvtActivation (True , phase) = ActiveAfter phase
413 ---------------------------------------------------
415 ---------------------------------------------------
417 cvtDecs :: [TH.Dec] -> CvtM (HsLocalBinds RdrName)
418 cvtDecs [] = return EmptyLocalBinds
419 cvtDecs ds = do { (binds, sigs) <- cvtBindsAndSigs ds
420 ; return (HsValBinds (ValBindsIn binds sigs)) }
422 cvtBindsAndSigs :: [TH.Dec] -> CvtM (Bag (LHsBind RdrName), [LSig RdrName])
424 = do { binds' <- mapM cvtBind binds
425 ; sigs' <- mapM cvtSig sigs
426 ; return (listToBag binds', sigs') }
428 (sigs, binds) = partition is_sig ds
430 is_sig (TH.SigD _ _) = True
431 is_sig (TH.PragmaD _) = True
434 cvtSig :: TH.Dec -> CvtM (LSig RdrName)
435 cvtSig (TH.SigD nm ty)
436 = do { nm' <- vNameL nm
438 ; returnL (Hs.TypeSig nm' ty')
440 cvtSig (TH.PragmaD prag)
441 = do { prag' <- cvtPragmaD prag
444 cvtSig _ = panic "Convert.cvtSig: Signature expected"
446 cvtBind :: TH.Dec -> CvtM (LHsBind RdrName)
447 -- Used only for declarations in a 'let/where' clause,
448 -- not for top level decls
449 cvtBind (TH.ValD (TH.VarP s) body ds)
450 = do { s' <- vNameL s
451 ; cl' <- cvtClause (Clause [] body ds)
452 ; returnL $ mkFunBind s' [cl'] }
454 cvtBind (TH.FunD nm cls)
456 = failWith (ptext (sLit "Function binding for")
457 <+> quotes (text (TH.pprint nm))
458 <+> ptext (sLit "has no equations"))
460 = do { nm' <- vNameL nm
461 ; cls' <- mapM cvtClause cls
462 ; returnL $ mkFunBind nm' cls' }
464 cvtBind (TH.ValD p body ds)
465 = do { p' <- cvtPat p
466 ; g' <- cvtGuard body
468 ; returnL $ PatBind { pat_lhs = p', pat_rhs = GRHSs g' ds',
469 pat_rhs_ty = void, bind_fvs = placeHolderNames } }
472 = failWith (sep [ptext (sLit "Illegal kind of declaration in where clause"),
473 nest 2 (text (TH.pprint d))])
475 cvtClause :: TH.Clause -> CvtM (Hs.LMatch RdrName)
476 cvtClause (Clause ps body wheres)
477 = do { ps' <- cvtPats ps
478 ; g' <- cvtGuard body
479 ; ds' <- cvtDecs wheres
480 ; returnL $ Hs.Match ps' Nothing (GRHSs g' ds') }
483 -------------------------------------------------------------------
485 -------------------------------------------------------------------
487 cvtl :: TH.Exp -> CvtM (LHsExpr RdrName)
488 cvtl e = wrapL (cvt e)
490 cvt (VarE s) = do { s' <- vName s; return $ HsVar s' }
491 cvt (ConE s) = do { s' <- cName s; return $ HsVar s' }
493 | overloadedLit l = do { l' <- cvtOverLit l; return $ HsOverLit l' }
494 | otherwise = do { l' <- cvtLit l; return $ HsLit l' }
496 cvt (AppE x y) = do { x' <- cvtl x; y' <- cvtl y; return $ HsApp x' y' }
497 cvt (LamE ps e) = do { ps' <- cvtPats ps; e' <- cvtl e
498 ; return $ HsLam (mkMatchGroup [mkSimpleMatch ps' e']) }
499 cvt (TupE [e]) = cvt e -- Singleton tuples treated like nothing (just parens)
500 cvt (TupE es) = do { es' <- mapM cvtl es; return $ ExplicitTuple es' Boxed }
501 cvt (CondE x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z
502 ; return $ HsIf x' y' z' }
503 cvt (LetE ds e) = do { ds' <- cvtDecs ds; e' <- cvtl e; return $ HsLet ds' e' }
505 | null ms = failWith (ptext (sLit "Case expression with no alternatives"))
506 | otherwise = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
507 ; return $ HsCase e' (mkMatchGroup ms') }
508 cvt (DoE ss) = cvtHsDo DoExpr ss
509 cvt (CompE ss) = cvtHsDo ListComp ss
510 cvt (ArithSeqE dd) = do { dd' <- cvtDD dd; return $ ArithSeq noPostTcExpr dd' }
512 | Just s <- allCharLs xs = do { l' <- cvtLit (StringL s); return (HsLit l') }
513 -- Note [Converting strings]
514 | otherwise = do { xs' <- mapM cvtl xs; return $ ExplicitList void xs' }
515 cvt (InfixE (Just x) s (Just y)) = do { x' <- cvtl x; s' <- cvtl s; y' <- cvtl y
516 ; e' <- returnL $ OpApp x' s' undefined y'
517 ; return $ HsPar e' }
518 cvt (InfixE Nothing s (Just y)) = do { s' <- cvtl s; y' <- cvtl y
519 ; sec <- returnL $ SectionR s' y'
520 ; return $ HsPar sec }
521 cvt (InfixE (Just x) s Nothing ) = do { x' <- cvtl x; s' <- cvtl s
522 ; sec <- returnL $ SectionL x' s'
523 ; return $ HsPar sec }
524 cvt (InfixE Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
526 cvt (SigE e t) = do { e' <- cvtl e; t' <- cvtType t
527 ; return $ ExprWithTySig e' t' }
528 cvt (RecConE c flds) = do { c' <- cNameL c
529 ; flds' <- mapM cvtFld flds
530 ; return $ RecordCon c' noPostTcExpr (HsRecFields flds' Nothing)}
531 cvt (RecUpdE e flds) = do { e' <- cvtl e
532 ; flds' <- mapM cvtFld flds
533 ; return $ RecordUpd e' (HsRecFields flds' Nothing) [] [] [] }
535 cvtFld :: (TH.Name, TH.Exp) -> CvtM (HsRecField RdrName (LHsExpr RdrName))
537 = do { v' <- vNameL v; e' <- cvtl e
538 ; return (HsRecField { hsRecFieldId = v', hsRecFieldArg = e', hsRecPun = False}) }
540 cvtDD :: Range -> CvtM (ArithSeqInfo RdrName)
541 cvtDD (FromR x) = do { x' <- cvtl x; return $ From x' }
542 cvtDD (FromThenR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromThen x' y' }
543 cvtDD (FromToR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromTo x' y' }
544 cvtDD (FromThenToR x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; return $ FromThenTo x' y' z' }
546 -------------------------------------
547 -- Do notation and statements
548 -------------------------------------
550 cvtHsDo :: HsStmtContext Name.Name -> [TH.Stmt] -> CvtM (HsExpr RdrName)
551 cvtHsDo do_or_lc stmts
552 | null stmts = failWith (ptext (sLit "Empty stmt list in do-block"))
554 = do { stmts' <- cvtStmts stmts
555 ; let body = case last stmts' of
556 L _ (ExprStmt body _ _) -> body
557 _ -> panic "Malformed body"
558 ; return $ HsDo do_or_lc (init stmts') body void }
560 cvtStmts :: [TH.Stmt] -> CvtM [Hs.LStmt RdrName]
561 cvtStmts = mapM cvtStmt
563 cvtStmt :: TH.Stmt -> CvtM (Hs.LStmt RdrName)
564 cvtStmt (NoBindS e) = do { e' <- cvtl e; returnL $ mkExprStmt e' }
565 cvtStmt (TH.BindS p e) = do { p' <- cvtPat p; e' <- cvtl e; returnL $ mkBindStmt p' e' }
566 cvtStmt (TH.LetS ds) = do { ds' <- cvtDecs ds; returnL $ LetStmt ds' }
567 cvtStmt (TH.ParS dss) = do { dss' <- mapM cvt_one dss; returnL $ ParStmt dss' }
569 cvt_one ds = do { ds' <- cvtStmts ds; return (ds', undefined) }
571 cvtMatch :: TH.Match -> CvtM (Hs.LMatch RdrName)
572 cvtMatch (TH.Match p body decs)
573 = do { p' <- cvtPat p
574 ; g' <- cvtGuard body
575 ; decs' <- cvtDecs decs
576 ; returnL $ Hs.Match [p'] Nothing (GRHSs g' decs') }
578 cvtGuard :: TH.Body -> CvtM [LGRHS RdrName]
579 cvtGuard (GuardedB pairs) = mapM cvtpair pairs
580 cvtGuard (NormalB e) = do { e' <- cvtl e; g' <- returnL $ GRHS [] e'; return [g'] }
582 cvtpair :: (TH.Guard, TH.Exp) -> CvtM (LGRHS RdrName)
583 cvtpair (NormalG ge,rhs) = do { ge' <- cvtl ge; rhs' <- cvtl rhs
584 ; g' <- returnL $ mkExprStmt ge'
585 ; returnL $ GRHS [g'] rhs' }
586 cvtpair (PatG gs,rhs) = do { gs' <- cvtStmts gs; rhs' <- cvtl rhs
587 ; returnL $ GRHS gs' rhs' }
589 cvtOverLit :: Lit -> CvtM (HsOverLit RdrName)
590 cvtOverLit (IntegerL i)
591 = do { force i; return $ mkHsIntegral i placeHolderType}
592 cvtOverLit (RationalL r)
593 = do { force r; return $ mkHsFractional r placeHolderType}
594 cvtOverLit (StringL s)
595 = do { let { s' = mkFastString s }
597 ; return $ mkHsIsString s' placeHolderType
599 cvtOverLit _ = panic "Convert.cvtOverLit: Unexpected overloaded literal"
600 -- An Integer is like an (overloaded) '3' in a Haskell source program
601 -- Similarly 3.5 for fractionals
603 {- Note [Converting strings]
604 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
605 If we get (ListE [CharL 'x', CharL 'y']) we'd like to convert to
606 a string literal for "xy". Of course, we might hope to get
607 (LitE (StringL "xy")), but not always, and allCharLs fails quickly
608 if it isn't a literal string
611 allCharLs :: [TH.Exp] -> Maybe String
612 -- Note [Converting strings]
613 allCharLs (LitE (CharL c) : xs)
614 | Just cs <- allCharLs xs = Just (c:cs)
615 allCharLs [] = Just []
616 allCharLs _ = Nothing
618 cvtLit :: Lit -> CvtM HsLit
619 cvtLit (IntPrimL i) = do { force i; return $ HsIntPrim i }
620 cvtLit (WordPrimL w) = do { force w; return $ HsWordPrim w }
621 cvtLit (FloatPrimL f) = do { force f; return $ HsFloatPrim f }
622 cvtLit (DoublePrimL f) = do { force f; return $ HsDoublePrim f }
623 cvtLit (CharL c) = do { force c; return $ HsChar c }
625 = do { let { s' = mkFastString s }
627 ; return $ HsString s'
629 cvtLit _ = panic "Convert.cvtLit: Unexpected literal"
631 cvtPats :: [TH.Pat] -> CvtM [Hs.LPat RdrName]
632 cvtPats pats = mapM cvtPat pats
634 cvtPat :: TH.Pat -> CvtM (Hs.LPat RdrName)
635 cvtPat pat = wrapL (cvtp pat)
637 cvtp :: TH.Pat -> CvtM (Hs.Pat RdrName)
639 | overloadedLit l = do { l' <- cvtOverLit l
640 ; return (mkNPat l' Nothing) }
641 -- Not right for negative patterns;
642 -- need to think about that!
643 | otherwise = do { l' <- cvtLit l; return $ Hs.LitPat l' }
644 cvtp (TH.VarP s) = do { s' <- vName s; return $ Hs.VarPat s' }
645 cvtp (TupP [p]) = cvtp p
646 cvtp (TupP ps) = do { ps' <- cvtPats ps; return $ TuplePat ps' Boxed void }
647 cvtp (ConP s ps) = do { s' <- cNameL s; ps' <- cvtPats ps; return $ ConPatIn s' (PrefixCon ps') }
648 cvtp (InfixP p1 s p2) = do { s' <- cNameL s; p1' <- cvtPat p1; p2' <- cvtPat p2
649 ; return $ ConPatIn s' (InfixCon p1' p2') }
650 cvtp (TildeP p) = do { p' <- cvtPat p; return $ LazyPat p' }
651 cvtp (BangP p) = do { p' <- cvtPat p; return $ BangPat p' }
652 cvtp (TH.AsP s p) = do { s' <- vNameL s; p' <- cvtPat p; return $ AsPat s' p' }
653 cvtp TH.WildP = return $ WildPat void
654 cvtp (RecP c fs) = do { c' <- cNameL c; fs' <- mapM cvtPatFld fs
655 ; return $ ConPatIn c' $ Hs.RecCon (HsRecFields fs' Nothing) }
656 cvtp (ListP ps) = do { ps' <- cvtPats ps; return $ ListPat ps' void }
657 cvtp (SigP p t) = do { p' <- cvtPat p; t' <- cvtType t; return $ SigPatIn p' t' }
659 cvtPatFld :: (TH.Name, TH.Pat) -> CvtM (HsRecField RdrName (LPat RdrName))
661 = do { s' <- vNameL s; p' <- cvtPat p
662 ; return (HsRecField { hsRecFieldId = s', hsRecFieldArg = p', hsRecPun = False}) }
664 -----------------------------------------------------------
665 -- Types and type variables
667 cvtTvs :: [TH.TyVarBndr] -> CvtM [LHsTyVarBndr RdrName]
668 cvtTvs tvs = mapM cvt_tv tvs
670 cvt_tv :: TH.TyVarBndr -> CvtM (LHsTyVarBndr RdrName)
671 cvt_tv (TH.PlainTV nm)
672 = do { nm' <- tName nm
673 ; returnL $ UserTyVar nm'
675 cvt_tv (TH.KindedTV nm ki)
676 = do { nm' <- tName nm
677 ; returnL $ KindedTyVar nm' (cvtKind ki)
680 cvtContext :: TH.Cxt -> CvtM (LHsContext RdrName)
681 cvtContext tys = do { preds' <- mapM cvtPred tys; returnL preds' }
683 cvtPred :: TH.Pred -> CvtM (LHsPred RdrName)
684 cvtPred (TH.ClassP cla tys)
685 = do { cla' <- if isVarName cla then tName cla else tconName cla
686 ; tys' <- mapM cvtType tys
687 ; returnL $ HsClassP cla' tys'
689 cvtPred (TH.EqualP ty1 ty2)
690 = do { ty1' <- cvtType ty1
691 ; ty2' <- cvtType ty2
692 ; returnL $ HsEqualP ty1' ty2'
695 cvtPredTy :: TH.Type -> CvtM (LHsPred RdrName)
697 = do { (head, tys') <- split_ty_app ty
699 ConT tc -> do { tc' <- tconName tc; returnL $ HsClassP tc' tys' }
700 VarT tv -> do { tv' <- tName tv; returnL $ HsClassP tv' tys' }
701 _ -> failWith (ptext (sLit "Malformed predicate") <+>
702 text (TH.pprint ty)) }
704 cvtType :: TH.Type -> CvtM (LHsType RdrName)
706 = do { (head_ty, tys') <- split_ty_app ty
709 | length tys' == n -- Saturated
710 -> if n==1 then return (head tys') -- Singleton tuples treated
711 -- like nothing (ie just parens)
712 else returnL (HsTupleTy Boxed tys')
714 -> failWith (ptext (sLit "Illegal 1-tuple type constructor"))
716 -> mk_apps (HsTyVar (getRdrName (tupleTyCon Boxed n))) tys'
718 | [x',y'] <- tys' -> returnL (HsFunTy x' y')
719 | otherwise -> mk_apps (HsTyVar (getRdrName funTyCon)) tys'
721 | [x'] <- tys' -> returnL (HsListTy x')
722 | otherwise -> mk_apps (HsTyVar (getRdrName listTyCon)) tys'
723 VarT nm -> do { nm' <- tName nm; mk_apps (HsTyVar nm') tys' }
724 ConT nm -> do { nm' <- tconName nm; mk_apps (HsTyVar nm') tys' }
728 -> do { tvs' <- cvtTvs tvs
729 ; cxt' <- cvtContext cxt
731 ; returnL $ mkExplicitHsForAllTy tvs' cxt' ty'
735 -> do { ty' <- cvtType ty
736 ; mk_apps (HsKindSig ty' (cvtKind ki)) tys'
739 _ -> failWith (ptext (sLit "Malformed type") <+> text (show ty))
742 mk_apps head_ty [] = returnL head_ty
743 mk_apps head_ty (ty:tys) = do { head_ty' <- returnL head_ty
744 ; mk_apps (HsAppTy head_ty' ty) tys }
746 split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsType RdrName])
747 split_ty_app ty = go ty []
749 go (AppT f a) as' = do { a' <- cvtType a; go f (a':as') }
750 go f as = return (f,as)
752 cvtKind :: TH.Kind -> Type.Kind
753 cvtKind StarK = liftedTypeKind
754 cvtKind (ArrowK k1 k2) = mkArrowKind (cvtKind k1) (cvtKind k2)
756 -----------------------------------------------------------
759 -----------------------------------------------------------
760 -- some useful things
762 overloadedLit :: Lit -> Bool
763 -- True for literals that Haskell treats as overloaded
764 overloadedLit (IntegerL _) = True
765 overloadedLit (RationalL _) = True
766 overloadedLit _ = False
769 void = placeHolderType
771 --------------------------------------------------------------------
772 -- Turning Name back into RdrName
773 --------------------------------------------------------------------
776 vNameL, cNameL, tconNameL :: TH.Name -> CvtM (Located RdrName)
777 vName, cName, tName, tconName :: TH.Name -> CvtM RdrName
779 vNameL n = wrapL (vName n)
780 vName n = cvtName OccName.varName n
782 -- Constructor function names; this is Haskell source, hence srcDataName
783 cNameL n = wrapL (cName n)
784 cName n = cvtName OccName.dataName n
786 -- Type variable names
787 tName n = cvtName OccName.tvName n
789 -- Type Constructor names
790 tconNameL n = wrapL (tconName n)
791 tconName n = cvtName OccName.tcClsName n
793 cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName
794 cvtName ctxt_ns (TH.Name occ flavour)
795 | not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str)
796 | otherwise = force (thRdrName ctxt_ns occ_str flavour)
798 occ_str = TH.occString occ
800 okOcc :: OccName.NameSpace -> String -> Bool
803 | OccName.isVarNameSpace ns = startsVarId c || startsVarSym c
804 | otherwise = startsConId c || startsConSym c || str == "[]"
806 -- Determine the name space of a name in a type
808 isVarName :: TH.Name -> Bool
809 isVarName (TH.Name occ _)
810 = case TH.occString occ of
812 (c:_) -> startsVarId c || startsVarSym c
814 badOcc :: OccName.NameSpace -> String -> SDoc
816 = ptext (sLit "Illegal") <+> pprNameSpace ctxt_ns
817 <+> ptext (sLit "name:") <+> quotes (text occ)
819 thRdrName :: OccName.NameSpace -> String -> TH.NameFlavour -> RdrName
820 -- This turns a Name into a RdrName
821 -- The passed-in name space tells what the context is expecting;
822 -- use it unless the TH name knows what name-space it comes
823 -- from, in which case use the latter
825 -- ToDo: we may generate silly RdrNames, by passing a name space
826 -- that doesn't match the string, like VarName ":+",
827 -- which will give confusing error messages later
829 -- The strict applications ensure that any buried exceptions get forced
830 thRdrName _ occ (TH.NameG th_ns pkg mod) = thOrigRdrName occ th_ns pkg mod
831 thRdrName ctxt_ns occ (TH.NameL uniq) = nameRdrName $! (((Name.mkInternalName $! (mk_uniq uniq)) $! (mk_occ ctxt_ns occ)) noSrcSpan)
832 thRdrName ctxt_ns occ (TH.NameQ mod) = (mkRdrQual $! (mk_mod mod)) $! (mk_occ ctxt_ns occ)
833 thRdrName ctxt_ns occ (TH.NameU uniq) = mkRdrUnqual $! (mk_uniq_occ ctxt_ns occ uniq)
834 thRdrName ctxt_ns occ TH.NameS
835 | Just name <- isBuiltInOcc ctxt_ns occ = nameRdrName $! name
836 | otherwise = mkRdrUnqual $! (mk_occ ctxt_ns occ)
838 thOrigRdrName :: String -> TH.NameSpace -> PkgName -> ModName -> RdrName
839 thOrigRdrName occ th_ns pkg mod = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
841 thRdrNameGuesses :: TH.Name -> [RdrName]
842 thRdrNameGuesses (TH.Name occ flavour)
843 -- This special case for NameG ensures that we don't generate duplicates in the output list
844 | TH.NameG th_ns pkg mod <- flavour = [thOrigRdrName occ_str th_ns pkg mod]
845 | otherwise = [ thRdrName gns occ_str flavour
846 | gns <- guessed_nss]
848 -- guessed_ns are the name spaces guessed from looking at the TH name
849 guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName, OccName.dataName]
850 | otherwise = [OccName.varName, OccName.tvName]
851 occ_str = TH.occString occ
853 isBuiltInOcc :: OccName.NameSpace -> String -> Maybe Name.Name
854 -- Built in syntax isn't "in scope" so an Unqual RdrName won't do
855 -- We must generate an Exact name, just as the parser does
856 isBuiltInOcc ctxt_ns occ
858 ":" -> Just (Name.getName consDataCon)
859 "[]" -> Just (Name.getName nilDataCon)
860 "()" -> Just (tup_name 0)
861 '(' : ',' : rest -> go_tuple 2 rest
864 go_tuple n ")" = Just (tup_name n)
865 go_tuple n (',' : rest) = go_tuple (n+1) rest
866 go_tuple _ _ = Nothing
869 | OccName.isTcClsNameSpace ctxt_ns = Name.getName (tupleTyCon Boxed n)
870 | otherwise = Name.getName (tupleCon Boxed n)
872 mk_uniq_occ :: OccName.NameSpace -> String -> Int# -> OccName.OccName
873 mk_uniq_occ ns occ uniq
874 = OccName.mkOccName ns (occ ++ '[' : shows (mk_uniq uniq) "]")
875 -- The idea here is to make a name that
876 -- a) the user could not possibly write, and
877 -- b) cannot clash with another NameU
878 -- Previously I generated an Exact RdrName with mkInternalName.
879 -- This works fine for local binders, but does not work at all for
880 -- top-level binders, which must have External Names, since they are
881 -- rapidly baked into data constructors and the like. Baling out
882 -- and generating an unqualified RdrName here is the simple solution
884 -- The packing and unpacking is rather turgid :-(
885 mk_occ :: OccName.NameSpace -> String -> OccName.OccName
886 mk_occ ns occ = OccName.mkOccNameFS ns (mkFastString occ)
888 mk_ghc_ns :: TH.NameSpace -> OccName.NameSpace
889 mk_ghc_ns TH.DataName = OccName.dataName
890 mk_ghc_ns TH.TcClsName = OccName.tcClsName
891 mk_ghc_ns TH.VarName = OccName.varName
893 mk_mod :: TH.ModName -> ModuleName
894 mk_mod mod = mkModuleName (TH.modString mod)
896 mk_pkg :: TH.PkgName -> PackageId
897 mk_pkg pkg = stringToPackageId (TH.pkgString pkg)
899 mk_uniq :: Int# -> Unique
900 mk_uniq u = mkUniqueGrimily (I# u)