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
33 import Control.Monad( unless )
35 import Language.Haskell.TH as TH hiding (sigP)
36 import Language.Haskell.TH.Syntax as TH
40 -------------------------------------------------------------------
41 -- The external interface
43 convertToHsDecls :: SrcSpan -> [TH.Dec] -> Either Message [LHsDecl RdrName]
44 convertToHsDecls loc ds = initCvt loc (mapM cvt_dec ds)
46 cvt_dec d = wrapMsg "declaration" d (cvtDec d)
48 convertToHsExpr :: SrcSpan -> TH.Exp -> Either Message (LHsExpr RdrName)
50 = initCvt loc $ wrapMsg "expression" e $ cvtl e
52 convertToPat :: SrcSpan -> TH.Pat -> Either Message (LPat RdrName)
54 = initCvt loc $ wrapMsg "pattern" p $ cvtPat p
56 convertToHsType :: SrcSpan -> TH.Type -> Either Message (LHsType RdrName)
58 = initCvt loc $ wrapMsg "type" t $ cvtType t
60 -------------------------------------------------------------------
61 newtype CvtM a = CvtM { unCvtM :: SrcSpan -> Either Message a }
62 -- Push down the source location;
63 -- Can fail, with a single error message
65 -- NB: If the conversion succeeds with (Right x), there should
66 -- be no exception values hiding in x
67 -- Reason: so a (head []) in TH code doesn't subsequently
68 -- make GHC crash when it tries to walk the generated tree
70 -- Use the loc everywhere, for lack of anything better
71 -- In particular, we want it on binding locations, so that variables bound in
72 -- the spliced-in declarations get a location that at least relates to the splice point
74 instance Monad CvtM where
75 return x = CvtM $ \_ -> Right x
76 (CvtM m) >>= k = CvtM $ \loc -> case m loc of
78 Right v -> unCvtM (k v) loc
80 initCvt :: SrcSpan -> CvtM a -> Either Message a
81 initCvt loc (CvtM m) = m loc
84 force a = a `seq` return ()
86 failWith :: Message -> CvtM a
87 failWith m = CvtM (\_ -> Left m)
89 returnL :: a -> CvtM (Located a)
90 returnL x = CvtM (\loc -> Right (L loc x))
92 wrapMsg :: (Show a, TH.Ppr a) => String -> a -> CvtM b -> CvtM b
93 -- E.g wrapMsg "declaration" dec thing
94 wrapMsg what item (CvtM m)
95 = CvtM (\loc -> case m loc of
96 Left err -> Left (err $$ getPprStyle msg)
99 -- Show the item in pretty syntax normally,
100 -- but with all its constructors if you say -dppr-debug
101 msg sty = hang (ptext (sLit "When splicing a TH") <+> text what <> colon)
103 then text (show item)
104 else text (pprint item))
106 wrapL :: CvtM a -> CvtM (Located a)
107 wrapL (CvtM m) = CvtM (\loc -> case m loc of
109 Right v -> Right (L loc v))
111 -------------------------------------------------------------------
112 cvtDec :: TH.Dec -> CvtM (LHsDecl RdrName)
113 cvtDec (TH.ValD pat body ds)
115 = do { s' <- vNameL s
116 ; cl' <- cvtClause (Clause [] body ds)
117 ; returnL $ Hs.ValD $ mkFunBind s' [cl'] }
120 = do { pat' <- cvtPat pat
121 ; body' <- cvtGuard body
122 ; ds' <- cvtLocalDecs (ptext (sLit "a where clause")) ds
123 ; returnL $ Hs.ValD $
124 PatBind { pat_lhs = pat', pat_rhs = GRHSs body' ds'
125 , pat_rhs_ty = void, bind_fvs = placeHolderNames } }
127 cvtDec (TH.FunD nm cls)
129 = failWith (ptext (sLit "Function binding for")
130 <+> quotes (text (TH.pprint nm))
131 <+> ptext (sLit "has no equations"))
133 = do { nm' <- vNameL nm
134 ; cls' <- mapM cvtClause cls
135 ; returnL $ Hs.ValD $ mkFunBind nm' cls' }
137 cvtDec (TH.SigD nm typ)
138 = do { nm' <- vNameL nm
140 ; returnL $ Hs.SigD (TypeSig nm' ty') }
142 cvtDec (PragmaD prag)
143 = do { prag' <- cvtPragmaD prag
144 ; returnL $ Hs.SigD prag' }
146 cvtDec (TySynD tc tvs rhs)
147 = do { (_, tc', tvs') <- cvt_tycl_hdr [] tc tvs
148 ; rhs' <- cvtType rhs
149 ; returnL $ TyClD (TySynonym tc' tvs' Nothing rhs') }
151 cvtDec (DataD ctxt tc tvs constrs derivs)
152 = do { (ctxt', tc', tvs') <- cvt_tycl_hdr ctxt tc tvs
153 ; cons' <- mapM cvtConstr constrs
154 ; derivs' <- cvtDerivs derivs
155 ; returnL $ TyClD (TyData { tcdND = DataType, tcdLName = tc', tcdCtxt = ctxt'
156 , tcdTyVars = tvs', tcdTyPats = Nothing, tcdKindSig = Nothing
157 , tcdCons = cons', tcdDerivs = derivs' }) }
159 cvtDec (NewtypeD ctxt tc tvs constr derivs)
160 = do { (ctxt', tc', tvs') <- cvt_tycl_hdr ctxt tc tvs
161 ; con' <- cvtConstr constr
162 ; derivs' <- cvtDerivs derivs
163 ; returnL $ TyClD (TyData { tcdND = NewType, tcdLName = tc', tcdCtxt = ctxt'
164 , tcdTyVars = tvs', tcdTyPats = Nothing, tcdKindSig = Nothing
165 , tcdCons = [con'], tcdDerivs = derivs'}) }
167 cvtDec (ClassD ctxt cl tvs fds decs)
168 = do { (cxt', tc', tvs') <- cvt_tycl_hdr ctxt cl tvs
169 ; fds' <- mapM cvt_fundep fds
170 ; (binds', sigs', ats') <- cvt_ci_decs (ptext (sLit "a class declaration")) decs
172 TyClD $ ClassDecl { tcdCtxt = cxt', tcdLName = tc', tcdTyVars = tvs'
173 , tcdFDs = fds', tcdSigs = sigs', tcdMeths = binds'
174 , tcdATs = ats', tcdDocs = [] }
178 cvtDec (InstanceD ctxt ty decs)
179 = do { (binds', sigs', ats') <- cvt_ci_decs (ptext (sLit "an instance declaration")) decs
180 ; ctxt' <- cvtContext ctxt
181 ; L loc pred' <- cvtPredTy ty
182 ; let inst_ty' = L loc $ mkImplicitHsForAllTy ctxt' $ L loc $ HsPredTy pred'
183 ; returnL $ InstD (InstDecl inst_ty' binds' sigs' ats') }
185 cvtDec (ForeignD ford)
186 = do { ford' <- cvtForD ford
187 ; returnL $ ForD ford' }
189 cvtDec (FamilyD flav tc tvs kind)
190 = do { (_, tc', tvs') <- cvt_tycl_hdr [] tc tvs
191 ; let kind' = fmap cvtKind kind
192 ; returnL $ TyClD (TyFamily (cvtFamFlavour flav) tc' tvs' kind') }
194 cvtFamFlavour TypeFam = TypeFamily
195 cvtFamFlavour DataFam = DataFamily
197 cvtDec (DataInstD ctxt tc tys constrs derivs)
198 = do { (ctxt', tc', tvs', typats') <- cvt_tyinst_hdr ctxt tc tys
199 ; cons' <- mapM cvtConstr constrs
200 ; derivs' <- cvtDerivs derivs
201 ; returnL $ TyClD (TyData { tcdND = DataType, tcdLName = tc', tcdCtxt = ctxt'
202 , tcdTyVars = tvs', tcdTyPats = typats', tcdKindSig = Nothing
203 , tcdCons = cons', tcdDerivs = derivs' }) }
205 cvtDec (NewtypeInstD ctxt tc tys constr derivs)
206 = do { (ctxt', tc', tvs', typats') <- cvt_tyinst_hdr ctxt tc tys
207 ; con' <- cvtConstr constr
208 ; derivs' <- cvtDerivs derivs
209 ; returnL $ TyClD (TyData { tcdND = NewType, tcdLName = tc', tcdCtxt = ctxt'
210 , tcdTyVars = tvs', tcdTyPats = typats', tcdKindSig = Nothing
211 , tcdCons = [con'], tcdDerivs = derivs' })
214 cvtDec (TySynInstD tc tys rhs)
215 = do { (_, tc', tvs', tys') <- cvt_tyinst_hdr [] tc tys
216 ; rhs' <- cvtType rhs
217 ; returnL $ TyClD (TySynonym tc' tvs' tys' rhs') }
220 cvt_ci_decs :: Message -> [TH.Dec]
221 -> CvtM (LHsBinds RdrName,
224 -- Convert the declarations inside a class or instance decl
225 -- ie signatures, bindings, and associated types
227 = do { decs' <- mapM cvtDec decs
228 ; let (ats', bind_sig_decs') = partitionWith is_tycl decs'
229 ; let (sigs', prob_binds') = partitionWith is_sig bind_sig_decs'
230 ; let (binds', bads) = partitionWith is_bind prob_binds'
231 ; unless (null bads) (failWith (mkBadDecMsg doc bads))
232 ; return (listToBag binds', sigs', ats') }
235 cvt_tycl_hdr :: TH.Cxt -> TH.Name -> [TH.TyVarBndr]
236 -> CvtM ( LHsContext RdrName
238 , [LHsTyVarBndr RdrName])
239 cvt_tycl_hdr cxt tc tvs
240 = do { cxt' <- cvtContext cxt
241 ; tc' <- tconNameL tc
243 ; return (cxt', tc', tvs')
246 cvt_tyinst_hdr :: TH.Cxt -> TH.Name -> [TH.Type]
247 -> CvtM ( LHsContext RdrName
249 , [LHsTyVarBndr RdrName]
250 , Maybe [LHsType RdrName])
251 cvt_tyinst_hdr cxt tc tys
252 = do { cxt' <- cvtContext cxt
253 ; tc' <- tconNameL tc
254 ; tvs <- concatMapM collect tys
256 ; tys' <- mapM cvtType tys
257 ; return (cxt', tc', tvs', Just tys')
260 collect (ForallT _ _ _)
261 = failWith $ text "Forall type not allowed as type parameter"
262 collect (VarT tv) = return [PlainTV tv]
263 collect (ConT _) = return []
264 collect (TupleT _) = return []
265 collect ArrowT = return []
266 collect ListT = return []
268 = do { tvs1 <- collect t1
270 ; return $ tvs1 ++ tvs2
272 collect (SigT (VarT tv) ki) = return [KindedTV tv ki]
273 collect (SigT ty _) = collect ty
275 -------------------------------------------------------------------
276 -- Partitioning declarations
277 -------------------------------------------------------------------
279 is_tycl :: LHsDecl RdrName -> Either (LTyClDecl RdrName) (LHsDecl RdrName)
280 is_tycl (L loc (Hs.TyClD tcd)) = Left (L loc tcd)
281 is_tycl decl = Right decl
283 is_sig :: LHsDecl RdrName -> Either (LSig RdrName) (LHsDecl RdrName)
284 is_sig (L loc (Hs.SigD sig)) = Left (L loc sig)
285 is_sig decl = Right decl
287 is_bind :: LHsDecl RdrName -> Either (LHsBind RdrName) (LHsDecl RdrName)
288 is_bind (L loc (Hs.ValD bind)) = Left (L loc bind)
289 is_bind decl = Right decl
291 mkBadDecMsg :: Message -> [LHsDecl RdrName] -> Message
293 = sep [ ptext (sLit "Illegal declaration(s) in") <+> doc <> colon
294 , nest 2 (vcat (map Outputable.ppr bads)) ]
296 ---------------------------------------------------
298 -- Can't handle GADTs yet
299 ---------------------------------------------------
301 cvtConstr :: TH.Con -> CvtM (LConDecl RdrName)
303 cvtConstr (NormalC c strtys)
304 = do { c' <- cNameL c
306 ; tys' <- mapM cvt_arg strtys
307 ; returnL $ mkSimpleConDecl c' noExistentials cxt' (PrefixCon tys') }
309 cvtConstr (RecC c varstrtys)
310 = do { c' <- cNameL c
312 ; args' <- mapM cvt_id_arg varstrtys
313 ; returnL $ mkSimpleConDecl c' noExistentials cxt' (RecCon args') }
315 cvtConstr (InfixC st1 c st2)
316 = do { c' <- cNameL c
318 ; st1' <- cvt_arg st1
319 ; st2' <- cvt_arg st2
320 ; returnL $ mkSimpleConDecl c' noExistentials cxt' (InfixCon st1' st2') }
322 cvtConstr (ForallC tvs ctxt con)
323 = do { tvs' <- cvtTvs tvs
324 ; L loc ctxt' <- cvtContext ctxt
325 ; L _ con' <- cvtConstr con
326 ; returnL $ con' { con_qvars = tvs' ++ con_qvars con'
327 , con_cxt = L loc (ctxt' ++ (unLoc $ con_cxt con')) } }
329 cvt_arg :: (TH.Strict, TH.Type) -> CvtM (LHsType RdrName)
330 cvt_arg (IsStrict, ty) = do { ty' <- cvtType ty; returnL $ HsBangTy HsStrict ty' }
331 cvt_arg (NotStrict, ty) = cvtType ty
333 cvt_id_arg :: (TH.Name, TH.Strict, TH.Type) -> CvtM (ConDeclField RdrName)
334 cvt_id_arg (i, str, ty)
335 = do { i' <- vNameL i
336 ; ty' <- cvt_arg (str,ty)
337 ; return (ConDeclField { cd_fld_name = i', cd_fld_type = ty', cd_fld_doc = Nothing}) }
339 cvtDerivs :: [TH.Name] -> CvtM (Maybe [LHsType RdrName])
340 cvtDerivs [] = return Nothing
341 cvtDerivs cs = do { cs' <- mapM cvt_one cs
342 ; return (Just cs') }
344 cvt_one c = do { c' <- tconName c
345 ; returnL $ HsPredTy $ HsClassP c' [] }
347 cvt_fundep :: FunDep -> CvtM (Located (Class.FunDep RdrName))
348 cvt_fundep (FunDep xs ys) = do { xs' <- mapM tName xs; ys' <- mapM tName ys; returnL (xs', ys') }
350 noExistentials :: [LHsTyVarBndr RdrName]
353 ------------------------------------------
354 -- Foreign declarations
355 ------------------------------------------
357 cvtForD :: Foreign -> CvtM (ForeignDecl RdrName)
358 cvtForD (ImportF callconv safety from nm ty)
359 | Just impspec <- parseCImport (cvt_conv callconv) safety'
360 (mkFastString (TH.nameBase nm)) from
361 = do { nm' <- vNameL nm
363 ; return (ForeignImport nm' ty' impspec)
366 = failWith $ text (show from) <+> ptext (sLit "is not a valid ccall impent")
368 safety' = case safety of
370 Safe -> PlaySafe False
371 Threadsafe -> PlaySafe True
373 cvtForD (ExportF callconv as nm ty)
374 = do { nm' <- vNameL nm
376 ; let e = CExport (CExportStatic (mkFastString as) (cvt_conv callconv))
377 ; return $ ForeignExport nm' ty' e }
379 cvt_conv :: TH.Callconv -> CCallConv
380 cvt_conv TH.CCall = CCallConv
381 cvt_conv TH.StdCall = StdCallConv
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) }
397 cvtInlineSpec :: Maybe TH.InlineSpec -> Hs.InlineSpec
398 cvtInlineSpec Nothing
400 cvtInlineSpec (Just (TH.InlineSpec inline conlike opt_activation))
401 = mkInlineSpec opt_activation' matchinfo inline
403 matchinfo = cvtRuleMatchInfo conlike
404 opt_activation' = fmap cvtActivation opt_activation
406 cvtRuleMatchInfo False = FunLike
407 cvtRuleMatchInfo True = ConLike
409 cvtActivation (False, phase) = ActiveBefore phase
410 cvtActivation (True , phase) = ActiveAfter phase
412 ---------------------------------------------------
414 ---------------------------------------------------
416 cvtLocalDecs :: Message -> [TH.Dec] -> CvtM (HsLocalBinds RdrName)
419 = return EmptyLocalBinds
421 = do { ds' <- mapM cvtDec ds
422 ; let (binds, prob_sigs) = partitionWith is_bind ds'
423 ; let (sigs, bads) = partitionWith is_sig prob_sigs
424 ; unless (null bads) (failWith (mkBadDecMsg doc bads))
425 ; return (HsValBinds (ValBindsIn (listToBag binds) sigs)) }
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' <- cvtLocalDecs (ptext (sLit "a where clause")) 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 (map Present 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' <- cvtLocalDecs (ptext (sLit "a let expression")) ds
456 ; e' <- cvtl e; return $ HsLet ds' e' }
458 | null ms = failWith (ptext (sLit "Case expression with no alternatives"))
459 | otherwise = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
460 ; return $ HsCase e' (mkMatchGroup ms') }
461 cvt (DoE ss) = cvtHsDo DoExpr ss
462 cvt (CompE ss) = cvtHsDo ListComp ss
463 cvt (ArithSeqE dd) = do { dd' <- cvtDD dd; return $ ArithSeq noPostTcExpr dd' }
465 | Just s <- allCharLs xs = do { l' <- cvtLit (StringL s); return (HsLit l') }
466 -- Note [Converting strings]
467 | otherwise = do { xs' <- mapM cvtl xs; return $ ExplicitList void xs' }
468 cvt (InfixE (Just x) s (Just y)) = do { x' <- cvtl x; s' <- cvtl s; y' <- cvtl y
469 ; e' <- returnL $ OpApp x' s' undefined y'
470 ; return $ HsPar e' }
471 cvt (InfixE Nothing s (Just y)) = do { s' <- cvtl s; y' <- cvtl y
472 ; sec <- returnL $ SectionR s' y'
473 ; return $ HsPar sec }
474 cvt (InfixE (Just x) s Nothing ) = do { x' <- cvtl x; s' <- cvtl s
475 ; sec <- returnL $ SectionL x' s'
476 ; return $ HsPar sec }
477 cvt (InfixE Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
479 cvt (SigE e t) = do { e' <- cvtl e; t' <- cvtType t
480 ; return $ ExprWithTySig e' t' }
481 cvt (RecConE c flds) = do { c' <- cNameL c
482 ; flds' <- mapM cvtFld flds
483 ; return $ RecordCon c' noPostTcExpr (HsRecFields flds' Nothing)}
484 cvt (RecUpdE e flds) = do { e' <- cvtl e
485 ; flds' <- mapM cvtFld flds
486 ; return $ RecordUpd e' (HsRecFields flds' Nothing) [] [] [] }
488 cvtFld :: (TH.Name, TH.Exp) -> CvtM (HsRecField RdrName (LHsExpr RdrName))
490 = do { v' <- vNameL v; e' <- cvtl e
491 ; return (HsRecField { hsRecFieldId = v', hsRecFieldArg = e', hsRecPun = False}) }
493 cvtDD :: Range -> CvtM (ArithSeqInfo RdrName)
494 cvtDD (FromR x) = do { x' <- cvtl x; return $ From x' }
495 cvtDD (FromThenR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromThen x' y' }
496 cvtDD (FromToR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromTo x' y' }
497 cvtDD (FromThenToR x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; return $ FromThenTo x' y' z' }
499 -------------------------------------
500 -- Do notation and statements
501 -------------------------------------
503 cvtHsDo :: HsStmtContext Name.Name -> [TH.Stmt] -> CvtM (HsExpr RdrName)
504 cvtHsDo do_or_lc stmts
505 | null stmts = failWith (ptext (sLit "Empty stmt list in do-block"))
507 = do { stmts' <- cvtStmts stmts
508 ; body <- case last stmts' of
509 L _ (ExprStmt body _ _) -> return body
510 stmt' -> failWith (bad_last stmt')
511 ; return $ HsDo do_or_lc (init stmts') body void }
513 bad_last stmt = vcat [ ptext (sLit "Illegal last statement of") <+> pprStmtContext do_or_lc <> colon
514 , nest 2 $ Outputable.ppr stmt
515 , ptext (sLit "(It should be an expression.)") ]
517 cvtStmts :: [TH.Stmt] -> CvtM [Hs.LStmt RdrName]
518 cvtStmts = mapM cvtStmt
520 cvtStmt :: TH.Stmt -> CvtM (Hs.LStmt RdrName)
521 cvtStmt (NoBindS e) = do { e' <- cvtl e; returnL $ mkExprStmt e' }
522 cvtStmt (TH.BindS p e) = do { p' <- cvtPat p; e' <- cvtl e; returnL $ mkBindStmt p' e' }
523 cvtStmt (TH.LetS ds) = do { ds' <- cvtLocalDecs (ptext (sLit "a let binding")) ds
524 ; returnL $ LetStmt ds' }
525 cvtStmt (TH.ParS dss) = do { dss' <- mapM cvt_one dss; returnL $ ParStmt dss' }
527 cvt_one ds = do { ds' <- cvtStmts ds; return (ds', undefined) }
529 cvtMatch :: TH.Match -> CvtM (Hs.LMatch RdrName)
530 cvtMatch (TH.Match p body decs)
531 = do { p' <- cvtPat p
532 ; g' <- cvtGuard body
533 ; decs' <- cvtLocalDecs (ptext (sLit "a where clause")) decs
534 ; returnL $ Hs.Match [p'] Nothing (GRHSs g' decs') }
536 cvtGuard :: TH.Body -> CvtM [LGRHS RdrName]
537 cvtGuard (GuardedB pairs) = mapM cvtpair pairs
538 cvtGuard (NormalB e) = do { e' <- cvtl e; g' <- returnL $ GRHS [] e'; return [g'] }
540 cvtpair :: (TH.Guard, TH.Exp) -> CvtM (LGRHS RdrName)
541 cvtpair (NormalG ge,rhs) = do { ge' <- cvtl ge; rhs' <- cvtl rhs
542 ; g' <- returnL $ mkExprStmt ge'
543 ; returnL $ GRHS [g'] rhs' }
544 cvtpair (PatG gs,rhs) = do { gs' <- cvtStmts gs; rhs' <- cvtl rhs
545 ; returnL $ GRHS gs' rhs' }
547 cvtOverLit :: Lit -> CvtM (HsOverLit RdrName)
548 cvtOverLit (IntegerL i)
549 = do { force i; return $ mkHsIntegral i placeHolderType}
550 cvtOverLit (RationalL r)
551 = do { force r; return $ mkHsFractional r placeHolderType}
552 cvtOverLit (StringL s)
553 = do { let { s' = mkFastString s }
555 ; return $ mkHsIsString s' placeHolderType
557 cvtOverLit _ = panic "Convert.cvtOverLit: Unexpected overloaded literal"
558 -- An Integer is like an (overloaded) '3' in a Haskell source program
559 -- Similarly 3.5 for fractionals
561 {- Note [Converting strings]
562 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
563 If we get (ListE [CharL 'x', CharL 'y']) we'd like to convert to
564 a string literal for "xy". Of course, we might hope to get
565 (LitE (StringL "xy")), but not always, and allCharLs fails quickly
566 if it isn't a literal string
569 allCharLs :: [TH.Exp] -> Maybe String
570 -- Note [Converting strings]
571 allCharLs (LitE (CharL c) : xs)
572 | Just cs <- allCharLs xs = Just (c:cs)
573 allCharLs [] = Just []
574 allCharLs _ = Nothing
576 cvtLit :: Lit -> CvtM HsLit
577 cvtLit (IntPrimL i) = do { force i; return $ HsIntPrim i }
578 cvtLit (WordPrimL w) = do { force w; return $ HsWordPrim w }
579 cvtLit (FloatPrimL f) = do { force f; return $ HsFloatPrim f }
580 cvtLit (DoublePrimL f) = do { force f; return $ HsDoublePrim f }
581 cvtLit (CharL c) = do { force c; return $ HsChar c }
583 = do { let { s' = mkFastString s }
585 ; return $ HsString s'
587 cvtLit _ = panic "Convert.cvtLit: Unexpected literal"
588 -- cvtLit should not be called on IntegerL, RationalL
589 -- That precondition is established right here in
590 -- Convert.lhs, hence panic
592 cvtPats :: [TH.Pat] -> CvtM [Hs.LPat RdrName]
593 cvtPats pats = mapM cvtPat pats
595 cvtPat :: TH.Pat -> CvtM (Hs.LPat RdrName)
596 cvtPat pat = wrapL (cvtp pat)
598 cvtp :: TH.Pat -> CvtM (Hs.Pat RdrName)
600 | overloadedLit l = do { l' <- cvtOverLit l
601 ; return (mkNPat l' Nothing) }
602 -- Not right for negative patterns;
603 -- need to think about that!
604 | otherwise = do { l' <- cvtLit l; return $ Hs.LitPat l' }
605 cvtp (TH.VarP s) = do { s' <- vName s; return $ Hs.VarPat s' }
606 cvtp (TupP [p]) = cvtp p
607 cvtp (TupP ps) = do { ps' <- cvtPats ps; return $ TuplePat ps' Boxed void }
608 cvtp (ConP s ps) = do { s' <- cNameL s; ps' <- cvtPats ps; return $ ConPatIn s' (PrefixCon ps') }
609 cvtp (InfixP p1 s p2) = do { s' <- cNameL s; p1' <- cvtPat p1; p2' <- cvtPat p2
610 ; return $ ConPatIn s' (InfixCon p1' p2') }
611 cvtp (TildeP p) = do { p' <- cvtPat p; return $ LazyPat p' }
612 cvtp (BangP p) = do { p' <- cvtPat p; return $ BangPat p' }
613 cvtp (TH.AsP s p) = do { s' <- vNameL s; p' <- cvtPat p; return $ AsPat s' p' }
614 cvtp TH.WildP = return $ WildPat void
615 cvtp (RecP c fs) = do { c' <- cNameL c; fs' <- mapM cvtPatFld fs
616 ; return $ ConPatIn c' $ Hs.RecCon (HsRecFields fs' Nothing) }
617 cvtp (ListP ps) = do { ps' <- cvtPats ps; return $ ListPat ps' void }
618 cvtp (SigP p t) = do { p' <- cvtPat p; t' <- cvtType t; return $ SigPatIn p' t' }
620 cvtPatFld :: (TH.Name, TH.Pat) -> CvtM (HsRecField RdrName (LPat RdrName))
622 = do { s' <- vNameL s; p' <- cvtPat p
623 ; return (HsRecField { hsRecFieldId = s', hsRecFieldArg = p', hsRecPun = False}) }
625 -----------------------------------------------------------
626 -- Types and type variables
628 cvtTvs :: [TH.TyVarBndr] -> CvtM [LHsTyVarBndr RdrName]
629 cvtTvs tvs = mapM cvt_tv tvs
631 cvt_tv :: TH.TyVarBndr -> CvtM (LHsTyVarBndr RdrName)
632 cvt_tv (TH.PlainTV nm)
633 = do { nm' <- tName nm
634 ; returnL $ UserTyVar nm'
636 cvt_tv (TH.KindedTV nm ki)
637 = do { nm' <- tName nm
638 ; returnL $ KindedTyVar nm' (cvtKind ki)
641 cvtContext :: TH.Cxt -> CvtM (LHsContext RdrName)
642 cvtContext tys = do { preds' <- mapM cvtPred tys; returnL preds' }
644 cvtPred :: TH.Pred -> CvtM (LHsPred RdrName)
645 cvtPred (TH.ClassP cla tys)
646 = do { cla' <- if isVarName cla then tName cla else tconName cla
647 ; tys' <- mapM cvtType tys
648 ; returnL $ HsClassP cla' tys'
650 cvtPred (TH.EqualP ty1 ty2)
651 = do { ty1' <- cvtType ty1
652 ; ty2' <- cvtType ty2
653 ; returnL $ HsEqualP ty1' ty2'
656 cvtPredTy :: TH.Type -> CvtM (LHsPred RdrName)
658 = do { (head, tys') <- split_ty_app ty
660 ConT tc -> do { tc' <- tconName tc; returnL $ HsClassP tc' tys' }
661 VarT tv -> do { tv' <- tName tv; returnL $ HsClassP tv' tys' }
662 _ -> failWith (ptext (sLit "Malformed predicate") <+>
663 text (TH.pprint ty)) }
665 cvtType :: TH.Type -> CvtM (LHsType RdrName)
667 = do { (head_ty, tys') <- split_ty_app ty
670 | length tys' == n -- Saturated
671 -> if n==1 then return (head tys') -- Singleton tuples treated
672 -- like nothing (ie just parens)
673 else returnL (HsTupleTy Boxed tys')
675 -> failWith (ptext (sLit "Illegal 1-tuple type constructor"))
677 -> mk_apps (HsTyVar (getRdrName (tupleTyCon Boxed n))) tys'
679 | [x',y'] <- tys' -> returnL (HsFunTy x' y')
680 | otherwise -> mk_apps (HsTyVar (getRdrName funTyCon)) tys'
682 | [x'] <- tys' -> returnL (HsListTy x')
683 | otherwise -> mk_apps (HsTyVar (getRdrName listTyCon)) tys'
684 VarT nm -> do { nm' <- tName nm; mk_apps (HsTyVar nm') tys' }
685 ConT nm -> do { nm' <- tconName nm; mk_apps (HsTyVar nm') tys' }
689 -> do { tvs' <- cvtTvs tvs
690 ; cxt' <- cvtContext cxt
692 ; returnL $ mkExplicitHsForAllTy tvs' cxt' ty'
696 -> do { ty' <- cvtType ty
697 ; mk_apps (HsKindSig ty' (cvtKind ki)) tys'
700 _ -> failWith (ptext (sLit "Malformed type") <+> text (show ty))
703 mk_apps head_ty [] = returnL head_ty
704 mk_apps head_ty (ty:tys) = do { head_ty' <- returnL head_ty
705 ; mk_apps (HsAppTy head_ty' ty) tys }
707 split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsType RdrName])
708 split_ty_app ty = go ty []
710 go (AppT f a) as' = do { a' <- cvtType a; go f (a':as') }
711 go f as = return (f,as)
713 cvtKind :: TH.Kind -> Type.Kind
714 cvtKind StarK = liftedTypeKind
715 cvtKind (ArrowK k1 k2) = mkArrowKind (cvtKind k1) (cvtKind k2)
717 -----------------------------------------------------------
720 -----------------------------------------------------------
721 -- some useful things
723 overloadedLit :: Lit -> Bool
724 -- True for literals that Haskell treats as overloaded
725 overloadedLit (IntegerL _) = True
726 overloadedLit (RationalL _) = True
727 overloadedLit _ = False
730 void = placeHolderType
732 --------------------------------------------------------------------
733 -- Turning Name back into RdrName
734 --------------------------------------------------------------------
737 vNameL, cNameL, tconNameL :: TH.Name -> CvtM (Located RdrName)
738 vName, cName, tName, tconName :: TH.Name -> CvtM RdrName
740 vNameL n = wrapL (vName n)
741 vName n = cvtName OccName.varName n
743 -- Constructor function names; this is Haskell source, hence srcDataName
744 cNameL n = wrapL (cName n)
745 cName n = cvtName OccName.dataName n
747 -- Type variable names
748 tName n = cvtName OccName.tvName n
750 -- Type Constructor names
751 tconNameL n = wrapL (tconName n)
752 tconName n = cvtName OccName.tcClsName n
754 cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName
755 cvtName ctxt_ns (TH.Name occ flavour)
756 | not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str)
757 | otherwise = force rdr_name >> return rdr_name
759 occ_str = TH.occString occ
760 rdr_name = thRdrName ctxt_ns occ_str flavour
762 okOcc :: OccName.NameSpace -> String -> Bool
765 | OccName.isVarNameSpace ns = startsVarId c || startsVarSym c
766 | otherwise = startsConId c || startsConSym c || str == "[]"
768 -- Determine the name space of a name in a type
770 isVarName :: TH.Name -> Bool
771 isVarName (TH.Name occ _)
772 = case TH.occString occ of
774 (c:_) -> startsVarId c || startsVarSym c
776 badOcc :: OccName.NameSpace -> String -> SDoc
778 = ptext (sLit "Illegal") <+> pprNameSpace ctxt_ns
779 <+> ptext (sLit "name:") <+> quotes (text occ)
781 thRdrName :: OccName.NameSpace -> String -> TH.NameFlavour -> RdrName
782 -- This turns a Name into a RdrName
783 -- The passed-in name space tells what the context is expecting;
784 -- use it unless the TH name knows what name-space it comes
785 -- from, in which case use the latter
787 -- ToDo: we may generate silly RdrNames, by passing a name space
788 -- that doesn't match the string, like VarName ":+",
789 -- which will give confusing error messages later
791 -- The strict applications ensure that any buried exceptions get forced
792 thRdrName _ occ (TH.NameG th_ns pkg mod) = thOrigRdrName occ th_ns pkg mod
793 thRdrName ctxt_ns occ (TH.NameL uniq) = nameRdrName $! (((Name.mkInternalName $! (mk_uniq uniq)) $! (mk_occ ctxt_ns occ)) noSrcSpan)
794 thRdrName ctxt_ns occ (TH.NameQ mod) = (mkRdrQual $! (mk_mod mod)) $! (mk_occ ctxt_ns occ)
795 thRdrName ctxt_ns occ (TH.NameU uniq) = mkRdrUnqual $! (mk_uniq_occ ctxt_ns occ uniq)
796 thRdrName ctxt_ns occ TH.NameS
797 | Just name <- isBuiltInOcc ctxt_ns occ = nameRdrName $! name
798 | otherwise = mkRdrUnqual $! (mk_occ ctxt_ns occ)
800 thOrigRdrName :: String -> TH.NameSpace -> PkgName -> ModName -> RdrName
801 thOrigRdrName occ th_ns pkg mod = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
803 thRdrNameGuesses :: TH.Name -> [RdrName]
804 thRdrNameGuesses (TH.Name occ flavour)
805 -- This special case for NameG ensures that we don't generate duplicates in the output list
806 | TH.NameG th_ns pkg mod <- flavour = [thOrigRdrName occ_str th_ns pkg mod]
807 | otherwise = [ thRdrName gns occ_str flavour
808 | gns <- guessed_nss]
810 -- guessed_ns are the name spaces guessed from looking at the TH name
811 guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName, OccName.dataName]
812 | otherwise = [OccName.varName, OccName.tvName]
813 occ_str = TH.occString occ
815 isBuiltInOcc :: OccName.NameSpace -> String -> Maybe Name.Name
816 -- Built in syntax isn't "in scope" so an Unqual RdrName won't do
817 -- We must generate an Exact name, just as the parser does
818 isBuiltInOcc ctxt_ns occ
820 ":" -> Just (Name.getName consDataCon)
821 "[]" -> Just (Name.getName nilDataCon)
822 "()" -> Just (tup_name 0)
823 '(' : ',' : rest -> go_tuple 2 rest
826 go_tuple n ")" = Just (tup_name n)
827 go_tuple n (',' : rest) = go_tuple (n+1) rest
828 go_tuple _ _ = Nothing
831 | OccName.isTcClsNameSpace ctxt_ns = Name.getName (tupleTyCon Boxed n)
832 | otherwise = Name.getName (tupleCon Boxed n)
834 mk_uniq_occ :: OccName.NameSpace -> String -> Int# -> OccName.OccName
835 mk_uniq_occ ns occ uniq
836 = OccName.mkOccName ns (occ ++ '[' : shows (mk_uniq uniq) "]")
837 -- The idea here is to make a name that
838 -- a) the user could not possibly write, and
839 -- b) cannot clash with another NameU
840 -- Previously I generated an Exact RdrName with mkInternalName.
841 -- This works fine for local binders, but does not work at all for
842 -- top-level binders, which must have External Names, since they are
843 -- rapidly baked into data constructors and the like. Baling out
844 -- and generating an unqualified RdrName here is the simple solution
846 -- The packing and unpacking is rather turgid :-(
847 mk_occ :: OccName.NameSpace -> String -> OccName.OccName
848 mk_occ ns occ = OccName.mkOccNameFS ns (mkFastString occ)
850 mk_ghc_ns :: TH.NameSpace -> OccName.NameSpace
851 mk_ghc_ns TH.DataName = OccName.dataName
852 mk_ghc_ns TH.TcClsName = OccName.tcClsName
853 mk_ghc_ns TH.VarName = OccName.varName
855 mk_mod :: TH.ModName -> ModuleName
856 mk_mod mod = mkModuleName (TH.modString mod)
858 mk_pkg :: TH.PkgName -> PackageId
859 mk_pkg pkg = stringToPackageId (TH.pkgString pkg)
861 mk_uniq :: Int# -> Unique
862 mk_uniq u = mkUniqueGrimily (I# u)