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
24 import BasicTypes as Hs
34 import Control.Monad( unless )
36 import Language.Haskell.TH as TH hiding (sigP)
37 import Language.Haskell.TH.Syntax as TH
41 -------------------------------------------------------------------
42 -- The external interface
44 convertToHsDecls :: SrcSpan -> [TH.Dec] -> Either Message [LHsDecl RdrName]
45 convertToHsDecls loc ds = initCvt loc (mapM cvt_dec ds)
47 cvt_dec d = wrapMsg "declaration" d (cvtDec d)
49 convertToHsExpr :: SrcSpan -> TH.Exp -> Either Message (LHsExpr RdrName)
51 = initCvt loc $ wrapMsg "expression" e $ cvtl e
53 convertToPat :: SrcSpan -> TH.Pat -> Either Message (LPat RdrName)
55 = initCvt loc $ wrapMsg "pattern" p $ cvtPat p
57 convertToHsType :: SrcSpan -> TH.Type -> Either Message (LHsType RdrName)
59 = initCvt loc $ wrapMsg "type" t $ cvtType t
61 -------------------------------------------------------------------
62 newtype CvtM a = CvtM { unCvtM :: SrcSpan -> Either Message a }
63 -- Push down the source location;
64 -- Can fail, with a single error message
66 -- NB: If the conversion succeeds with (Right x), there should
67 -- be no exception values hiding in x
68 -- Reason: so a (head []) in TH code doesn't subsequently
69 -- make GHC crash when it tries to walk the generated tree
71 -- Use the loc everywhere, for lack of anything better
72 -- In particular, we want it on binding locations, so that variables bound in
73 -- the spliced-in declarations get a location that at least relates to the splice point
75 instance Monad CvtM where
76 return x = CvtM $ \_ -> Right x
77 (CvtM m) >>= k = CvtM $ \loc -> case m loc of
79 Right v -> unCvtM (k v) loc
81 initCvt :: SrcSpan -> CvtM a -> Either Message a
82 initCvt loc (CvtM m) = m loc
85 force a = a `seq` return ()
87 failWith :: Message -> CvtM a
88 failWith m = CvtM (\_ -> Left m)
90 returnL :: a -> CvtM (Located a)
91 returnL x = CvtM (\loc -> Right (L loc x))
93 wrapMsg :: (Show a, TH.Ppr a) => String -> a -> CvtM b -> CvtM b
94 -- E.g wrapMsg "declaration" dec thing
95 wrapMsg what item (CvtM m)
96 = CvtM (\loc -> case m loc of
97 Left err -> Left (err $$ getPprStyle msg)
100 -- Show the item in pretty syntax normally,
101 -- but with all its constructors if you say -dppr-debug
102 msg sty = hang (ptext (sLit "When splicing a TH") <+> text what <> colon)
104 then text (show item)
105 else text (pprint item))
107 wrapL :: CvtM a -> CvtM (Located a)
108 wrapL (CvtM m) = CvtM (\loc -> case m loc of
110 Right v -> Right (L loc v))
112 -------------------------------------------------------------------
113 cvtDec :: TH.Dec -> CvtM (LHsDecl RdrName)
114 cvtDec (TH.ValD pat body ds)
116 = do { s' <- vNameL s
117 ; cl' <- cvtClause (Clause [] body ds)
118 ; returnL $ Hs.ValD $ mkFunBind s' [cl'] }
121 = do { pat' <- cvtPat pat
122 ; body' <- cvtGuard body
123 ; ds' <- cvtLocalDecs (ptext (sLit "a where clause")) ds
124 ; returnL $ Hs.ValD $
125 PatBind { pat_lhs = pat', pat_rhs = GRHSs body' ds'
126 , pat_rhs_ty = void, bind_fvs = placeHolderNames } }
128 cvtDec (TH.FunD nm cls)
130 = failWith (ptext (sLit "Function binding for")
131 <+> quotes (text (TH.pprint nm))
132 <+> ptext (sLit "has no equations"))
134 = do { nm' <- vNameL nm
135 ; cls' <- mapM cvtClause cls
136 ; returnL $ Hs.ValD $ mkFunBind nm' cls' }
138 cvtDec (TH.SigD nm typ)
139 = do { nm' <- vNameL nm
141 ; returnL $ Hs.SigD (TypeSig nm' ty') }
143 cvtDec (PragmaD prag)
144 = do { prag' <- cvtPragmaD prag
145 ; returnL $ Hs.SigD prag' }
147 cvtDec (TySynD tc tvs rhs)
148 = do { (_, tc', tvs') <- cvt_tycl_hdr [] tc tvs
149 ; rhs' <- cvtType rhs
150 ; returnL $ TyClD (TySynonym tc' tvs' Nothing rhs') }
152 cvtDec (DataD ctxt tc tvs constrs derivs)
153 = do { (ctxt', tc', tvs') <- cvt_tycl_hdr ctxt tc tvs
154 ; cons' <- mapM cvtConstr constrs
155 ; derivs' <- cvtDerivs derivs
156 ; returnL $ TyClD (TyData { tcdND = DataType, tcdLName = tc', tcdCtxt = ctxt'
157 , tcdTyVars = tvs', tcdTyPats = Nothing, tcdKindSig = Nothing
158 , tcdCons = cons', tcdDerivs = derivs' }) }
160 cvtDec (NewtypeD ctxt tc tvs constr derivs)
161 = do { (ctxt', tc', tvs') <- cvt_tycl_hdr ctxt tc tvs
162 ; con' <- cvtConstr constr
163 ; derivs' <- cvtDerivs derivs
164 ; returnL $ TyClD (TyData { tcdND = NewType, tcdLName = tc', tcdCtxt = ctxt'
165 , tcdTyVars = tvs', tcdTyPats = Nothing, tcdKindSig = Nothing
166 , tcdCons = [con'], tcdDerivs = derivs'}) }
168 cvtDec (ClassD ctxt cl tvs fds decs)
169 = do { (cxt', tc', tvs') <- cvt_tycl_hdr ctxt cl tvs
170 ; fds' <- mapM cvt_fundep fds
171 ; (binds', sigs', ats') <- cvt_ci_decs (ptext (sLit "a class declaration")) decs
173 TyClD $ ClassDecl { tcdCtxt = cxt', tcdLName = tc', tcdTyVars = tvs'
174 , tcdFDs = fds', tcdSigs = sigs', tcdMeths = binds'
175 , tcdATs = ats', tcdDocs = [] }
179 cvtDec (InstanceD ctxt ty decs)
180 = do { (binds', sigs', ats') <- cvt_ci_decs (ptext (sLit "an instance declaration")) decs
181 ; ctxt' <- cvtContext ctxt
182 ; L loc pred' <- cvtPredTy ty
183 ; let inst_ty' = L loc $ mkImplicitHsForAllTy ctxt' $ L loc $ HsPredTy pred'
184 ; returnL $ InstD (InstDecl inst_ty' binds' sigs' ats') }
186 cvtDec (ForeignD ford)
187 = do { ford' <- cvtForD ford
188 ; returnL $ ForD ford' }
190 cvtDec (FamilyD flav tc tvs kind)
191 = do { (_, tc', tvs') <- cvt_tycl_hdr [] tc tvs
192 ; let kind' = fmap cvtKind kind
193 ; returnL $ TyClD (TyFamily (cvtFamFlavour flav) tc' tvs' kind') }
195 cvtFamFlavour TypeFam = TypeFamily
196 cvtFamFlavour DataFam = DataFamily
198 cvtDec (DataInstD ctxt tc tys constrs derivs)
199 = do { (ctxt', tc', tvs', typats') <- cvt_tyinst_hdr ctxt tc tys
200 ; cons' <- mapM cvtConstr constrs
201 ; derivs' <- cvtDerivs derivs
202 ; returnL $ TyClD (TyData { tcdND = DataType, tcdLName = tc', tcdCtxt = ctxt'
203 , tcdTyVars = tvs', tcdTyPats = typats', tcdKindSig = Nothing
204 , tcdCons = cons', tcdDerivs = derivs' }) }
206 cvtDec (NewtypeInstD ctxt tc tys constr derivs)
207 = do { (ctxt', tc', tvs', typats') <- cvt_tyinst_hdr ctxt tc tys
208 ; con' <- cvtConstr constr
209 ; derivs' <- cvtDerivs derivs
210 ; returnL $ TyClD (TyData { tcdND = NewType, tcdLName = tc', tcdCtxt = ctxt'
211 , tcdTyVars = tvs', tcdTyPats = typats', tcdKindSig = Nothing
212 , tcdCons = [con'], tcdDerivs = derivs' })
215 cvtDec (TySynInstD tc tys rhs)
216 = do { (_, tc', tvs', tys') <- cvt_tyinst_hdr [] tc tys
217 ; rhs' <- cvtType rhs
218 ; returnL $ TyClD (TySynonym tc' tvs' tys' rhs') }
221 cvt_ci_decs :: Message -> [TH.Dec]
222 -> CvtM (LHsBinds RdrName,
225 -- Convert the declarations inside a class or instance decl
226 -- ie signatures, bindings, and associated types
228 = do { decs' <- mapM cvtDec decs
229 ; let (ats', bind_sig_decs') = partitionWith is_tycl decs'
230 ; let (sigs', prob_binds') = partitionWith is_sig bind_sig_decs'
231 ; let (binds', bads) = partitionWith is_bind prob_binds'
232 ; unless (null bads) (failWith (mkBadDecMsg doc bads))
233 ; return (listToBag binds', sigs', ats') }
236 cvt_tycl_hdr :: TH.Cxt -> TH.Name -> [TH.TyVarBndr]
237 -> CvtM ( LHsContext RdrName
239 , [LHsTyVarBndr RdrName])
240 cvt_tycl_hdr cxt tc tvs
241 = do { cxt' <- cvtContext cxt
242 ; tc' <- tconNameL tc
244 ; return (cxt', tc', tvs')
247 cvt_tyinst_hdr :: TH.Cxt -> TH.Name -> [TH.Type]
248 -> CvtM ( LHsContext RdrName
250 , [LHsTyVarBndr RdrName]
251 , Maybe [LHsType RdrName])
252 cvt_tyinst_hdr cxt tc tys
253 = do { cxt' <- cvtContext cxt
254 ; tc' <- tconNameL tc
255 ; tvs <- concatMapM collect tys
257 ; tys' <- mapM cvtType tys
258 ; return (cxt', tc', tvs', Just tys')
261 collect (ForallT _ _ _)
262 = failWith $ text "Forall type not allowed as type parameter"
263 collect (VarT tv) = return [PlainTV tv]
264 collect (ConT _) = return []
265 collect (TupleT _) = return []
266 collect ArrowT = return []
267 collect ListT = return []
269 = do { tvs1 <- collect t1
271 ; return $ tvs1 ++ tvs2
273 collect (SigT (VarT tv) ki) = return [KindedTV tv ki]
274 collect (SigT ty _) = collect ty
276 -------------------------------------------------------------------
277 -- Partitioning declarations
278 -------------------------------------------------------------------
280 is_tycl :: LHsDecl RdrName -> Either (LTyClDecl RdrName) (LHsDecl RdrName)
281 is_tycl (L loc (Hs.TyClD tcd)) = Left (L loc tcd)
282 is_tycl decl = Right decl
284 is_sig :: LHsDecl RdrName -> Either (LSig RdrName) (LHsDecl RdrName)
285 is_sig (L loc (Hs.SigD sig)) = Left (L loc sig)
286 is_sig decl = Right decl
288 is_bind :: LHsDecl RdrName -> Either (LHsBind RdrName) (LHsDecl RdrName)
289 is_bind (L loc (Hs.ValD bind)) = Left (L loc bind)
290 is_bind decl = Right decl
292 mkBadDecMsg :: Message -> [LHsDecl RdrName] -> Message
294 = sep [ ptext (sLit "Illegal declaration(s) in") <+> doc <> colon
295 , nest 2 (vcat (map Outputable.ppr bads)) ]
297 ---------------------------------------------------
299 -- Can't handle GADTs yet
300 ---------------------------------------------------
302 cvtConstr :: TH.Con -> CvtM (LConDecl RdrName)
304 cvtConstr (NormalC c strtys)
305 = do { c' <- cNameL c
307 ; tys' <- mapM cvt_arg strtys
308 ; returnL $ mkSimpleConDecl c' noExistentials cxt' (PrefixCon tys') }
310 cvtConstr (RecC c varstrtys)
311 = do { c' <- cNameL c
313 ; args' <- mapM cvt_id_arg varstrtys
314 ; returnL $ mkSimpleConDecl c' noExistentials cxt' (RecCon args') }
316 cvtConstr (InfixC st1 c st2)
317 = do { c' <- cNameL c
319 ; st1' <- cvt_arg st1
320 ; st2' <- cvt_arg st2
321 ; returnL $ mkSimpleConDecl c' noExistentials cxt' (InfixCon st1' st2') }
323 cvtConstr (ForallC tvs ctxt con)
324 = do { tvs' <- cvtTvs tvs
325 ; L loc ctxt' <- cvtContext ctxt
326 ; L _ con' <- cvtConstr con
327 ; returnL $ con' { con_qvars = tvs' ++ con_qvars con'
328 , con_cxt = L loc (ctxt' ++ (unLoc $ con_cxt con')) } }
330 cvt_arg :: (TH.Strict, TH.Type) -> CvtM (LHsType RdrName)
331 cvt_arg (IsStrict, ty) = do { ty' <- cvtType ty; returnL $ HsBangTy HsStrict ty' }
332 cvt_arg (NotStrict, ty) = cvtType ty
334 cvt_id_arg :: (TH.Name, TH.Strict, TH.Type) -> CvtM (ConDeclField RdrName)
335 cvt_id_arg (i, str, ty)
336 = do { i' <- vNameL i
337 ; ty' <- cvt_arg (str,ty)
338 ; return (ConDeclField { cd_fld_name = i', cd_fld_type = ty', cd_fld_doc = Nothing}) }
340 cvtDerivs :: [TH.Name] -> CvtM (Maybe [LHsType RdrName])
341 cvtDerivs [] = return Nothing
342 cvtDerivs cs = do { cs' <- mapM cvt_one cs
343 ; return (Just cs') }
345 cvt_one c = do { c' <- tconName c
346 ; returnL $ HsPredTy $ HsClassP c' [] }
348 cvt_fundep :: FunDep -> CvtM (Located (Class.FunDep RdrName))
349 cvt_fundep (FunDep xs ys) = do { xs' <- mapM tName xs; ys' <- mapM tName ys; returnL (xs', ys') }
351 noExistentials :: [LHsTyVarBndr RdrName]
354 ------------------------------------------
355 -- Foreign declarations
356 ------------------------------------------
358 cvtForD :: Foreign -> CvtM (ForeignDecl RdrName)
359 cvtForD (ImportF callconv safety from nm ty)
360 | Just impspec <- parseCImport (cvt_conv callconv) safety'
361 (mkFastString (TH.nameBase nm)) from
362 = do { nm' <- vNameL nm
364 ; return (ForeignImport nm' ty' impspec)
367 = failWith $ text (show from) <+> ptext (sLit "is not a valid ccall impent")
369 safety' = case safety of
371 Safe -> PlaySafe False
372 Threadsafe -> PlaySafe True
374 cvtForD (ExportF callconv as nm ty)
375 = do { nm' <- vNameL nm
377 ; let e = CExport (CExportStatic (mkFastString as) (cvt_conv callconv))
378 ; return $ ForeignExport nm' ty' e }
380 cvt_conv :: TH.Callconv -> CCallConv
381 cvt_conv TH.CCall = CCallConv
382 cvt_conv TH.StdCall = StdCallConv
384 ------------------------------------------
386 ------------------------------------------
388 cvtPragmaD :: Pragma -> CvtM (Sig RdrName)
389 cvtPragmaD (InlineP nm ispec)
390 = do { nm' <- vNameL nm
391 ; return $ InlineSig nm' (cvtInlineSpec (Just ispec)) }
393 cvtPragmaD (SpecialiseP nm ty opt_ispec)
394 = do { nm' <- vNameL nm
396 ; return $ SpecSig nm' ty' (cvtInlineSpec opt_ispec) }
398 cvtInlineSpec :: Maybe TH.InlineSpec -> Hs.InlinePragma
399 cvtInlineSpec Nothing
400 = defaultInlinePragma
401 cvtInlineSpec (Just (TH.InlineSpec inline conlike opt_activation))
402 = InlinePragma { inl_act = opt_activation', inl_rule = matchinfo, inl_inline = inline }
404 matchinfo = cvtRuleMatchInfo conlike
405 opt_activation' = cvtActivation opt_activation
407 cvtRuleMatchInfo False = FunLike
408 cvtRuleMatchInfo True = ConLike
410 cvtActivation Nothing | inline = AlwaysActive
411 | otherwise = NeverActive
412 cvtActivation (Just (False, phase)) = ActiveBefore phase
413 cvtActivation (Just (True , phase)) = ActiveAfter phase
415 ---------------------------------------------------
417 ---------------------------------------------------
419 cvtLocalDecs :: Message -> [TH.Dec] -> CvtM (HsLocalBinds RdrName)
422 = return EmptyLocalBinds
424 = do { ds' <- mapM cvtDec ds
425 ; let (binds, prob_sigs) = partitionWith is_bind ds'
426 ; let (sigs, bads) = partitionWith is_sig prob_sigs
427 ; unless (null bads) (failWith (mkBadDecMsg doc bads))
428 ; return (HsValBinds (ValBindsIn (listToBag binds) sigs)) }
430 cvtClause :: TH.Clause -> CvtM (Hs.LMatch RdrName)
431 cvtClause (Clause ps body wheres)
432 = do { ps' <- cvtPats ps
433 ; g' <- cvtGuard body
434 ; ds' <- cvtLocalDecs (ptext (sLit "a where clause")) wheres
435 ; returnL $ Hs.Match ps' Nothing (GRHSs g' ds') }
438 -------------------------------------------------------------------
440 -------------------------------------------------------------------
442 cvtl :: TH.Exp -> CvtM (LHsExpr RdrName)
443 cvtl e = wrapL (cvt e)
445 cvt (VarE s) = do { s' <- vName s; return $ HsVar s' }
446 cvt (ConE s) = do { s' <- cName s; return $ HsVar s' }
448 | overloadedLit l = do { l' <- cvtOverLit l; return $ HsOverLit l' }
449 | otherwise = do { l' <- cvtLit l; return $ HsLit l' }
451 cvt (AppE x y) = do { x' <- cvtl x; y' <- cvtl y; return $ HsApp x' y' }
452 cvt (LamE ps e) = do { ps' <- cvtPats ps; e' <- cvtl e
453 ; return $ HsLam (mkMatchGroup [mkSimpleMatch ps' e']) }
454 cvt (TupE [e]) = cvt e -- Singleton tuples treated like nothing (just parens)
455 cvt (TupE es) = do { es' <- mapM cvtl es; return $ ExplicitTuple (map Present es') Boxed }
456 cvt (CondE x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z
457 ; return $ HsIf x' y' z' }
458 cvt (LetE ds e) = do { ds' <- cvtLocalDecs (ptext (sLit "a let expression")) ds
459 ; e' <- cvtl e; return $ HsLet ds' e' }
461 | null ms = failWith (ptext (sLit "Case expression with no alternatives"))
462 | otherwise = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
463 ; return $ HsCase e' (mkMatchGroup ms') }
464 cvt (DoE ss) = cvtHsDo DoExpr ss
465 cvt (CompE ss) = cvtHsDo ListComp ss
466 cvt (ArithSeqE dd) = do { dd' <- cvtDD dd; return $ ArithSeq noPostTcExpr dd' }
468 | Just s <- allCharLs xs = do { l' <- cvtLit (StringL s); return (HsLit l') }
469 -- Note [Converting strings]
470 | otherwise = do { xs' <- mapM cvtl xs; return $ ExplicitList void xs' }
471 cvt (InfixE (Just x) s (Just y)) = do { x' <- cvtl x; s' <- cvtl s; y' <- cvtl y
472 ; e' <- returnL $ OpApp x' s' undefined y'
473 ; return $ HsPar e' }
474 cvt (InfixE Nothing s (Just y)) = do { s' <- cvtl s; y' <- cvtl y
475 ; sec <- returnL $ SectionR s' y'
476 ; return $ HsPar sec }
477 cvt (InfixE (Just x) s Nothing ) = do { x' <- cvtl x; s' <- cvtl s
478 ; sec <- returnL $ SectionL x' s'
479 ; return $ HsPar sec }
480 cvt (InfixE Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
482 cvt (SigE e t) = do { e' <- cvtl e; t' <- cvtType t
483 ; return $ ExprWithTySig e' t' }
484 cvt (RecConE c flds) = do { c' <- cNameL c
485 ; flds' <- mapM cvtFld flds
486 ; return $ RecordCon c' noPostTcExpr (HsRecFields flds' Nothing)}
487 cvt (RecUpdE e flds) = do { e' <- cvtl e
488 ; flds' <- mapM cvtFld flds
489 ; return $ RecordUpd e' (HsRecFields flds' Nothing) [] [] [] }
491 cvtFld :: (TH.Name, TH.Exp) -> CvtM (HsRecField RdrName (LHsExpr RdrName))
493 = do { v' <- vNameL v; e' <- cvtl e
494 ; return (HsRecField { hsRecFieldId = v', hsRecFieldArg = e', hsRecPun = False}) }
496 cvtDD :: Range -> CvtM (ArithSeqInfo RdrName)
497 cvtDD (FromR x) = do { x' <- cvtl x; return $ From x' }
498 cvtDD (FromThenR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromThen x' y' }
499 cvtDD (FromToR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromTo x' y' }
500 cvtDD (FromThenToR x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; return $ FromThenTo x' y' z' }
502 -------------------------------------
503 -- Do notation and statements
504 -------------------------------------
506 cvtHsDo :: HsStmtContext Name.Name -> [TH.Stmt] -> CvtM (HsExpr RdrName)
507 cvtHsDo do_or_lc stmts
508 | null stmts = failWith (ptext (sLit "Empty stmt list in do-block"))
510 = do { stmts' <- cvtStmts stmts
511 ; body <- case last stmts' of
512 L _ (ExprStmt body _ _) -> return body
513 stmt' -> failWith (bad_last stmt')
514 ; return $ HsDo do_or_lc (init stmts') body void }
516 bad_last stmt = vcat [ ptext (sLit "Illegal last statement of") <+> pprStmtContext do_or_lc <> colon
517 , nest 2 $ Outputable.ppr stmt
518 , ptext (sLit "(It should be an expression.)") ]
520 cvtStmts :: [TH.Stmt] -> CvtM [Hs.LStmt RdrName]
521 cvtStmts = mapM cvtStmt
523 cvtStmt :: TH.Stmt -> CvtM (Hs.LStmt RdrName)
524 cvtStmt (NoBindS e) = do { e' <- cvtl e; returnL $ mkExprStmt e' }
525 cvtStmt (TH.BindS p e) = do { p' <- cvtPat p; e' <- cvtl e; returnL $ mkBindStmt p' e' }
526 cvtStmt (TH.LetS ds) = do { ds' <- cvtLocalDecs (ptext (sLit "a let binding")) ds
527 ; returnL $ LetStmt ds' }
528 cvtStmt (TH.ParS dss) = do { dss' <- mapM cvt_one dss; returnL $ ParStmt dss' }
530 cvt_one ds = do { ds' <- cvtStmts ds; return (ds', undefined) }
532 cvtMatch :: TH.Match -> CvtM (Hs.LMatch RdrName)
533 cvtMatch (TH.Match p body decs)
534 = do { p' <- cvtPat p
535 ; g' <- cvtGuard body
536 ; decs' <- cvtLocalDecs (ptext (sLit "a where clause")) decs
537 ; returnL $ Hs.Match [p'] Nothing (GRHSs g' decs') }
539 cvtGuard :: TH.Body -> CvtM [LGRHS RdrName]
540 cvtGuard (GuardedB pairs) = mapM cvtpair pairs
541 cvtGuard (NormalB e) = do { e' <- cvtl e; g' <- returnL $ GRHS [] e'; return [g'] }
543 cvtpair :: (TH.Guard, TH.Exp) -> CvtM (LGRHS RdrName)
544 cvtpair (NormalG ge,rhs) = do { ge' <- cvtl ge; rhs' <- cvtl rhs
545 ; g' <- returnL $ mkExprStmt ge'
546 ; returnL $ GRHS [g'] rhs' }
547 cvtpair (PatG gs,rhs) = do { gs' <- cvtStmts gs; rhs' <- cvtl rhs
548 ; returnL $ GRHS gs' rhs' }
550 cvtOverLit :: Lit -> CvtM (HsOverLit RdrName)
551 cvtOverLit (IntegerL i)
552 = do { force i; return $ mkHsIntegral i placeHolderType}
553 cvtOverLit (RationalL r)
554 = do { force r; return $ mkHsFractional r placeHolderType}
555 cvtOverLit (StringL s)
556 = do { let { s' = mkFastString s }
558 ; return $ mkHsIsString s' placeHolderType
560 cvtOverLit _ = panic "Convert.cvtOverLit: Unexpected overloaded literal"
561 -- An Integer is like an (overloaded) '3' in a Haskell source program
562 -- Similarly 3.5 for fractionals
564 {- Note [Converting strings]
565 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
566 If we get (ListE [CharL 'x', CharL 'y']) we'd like to convert to
567 a string literal for "xy". Of course, we might hope to get
568 (LitE (StringL "xy")), but not always, and allCharLs fails quickly
569 if it isn't a literal string
572 allCharLs :: [TH.Exp] -> Maybe String
573 -- Note [Converting strings]
574 -- NB: only fire up this setup for a non-empty list, else
575 -- there's a danger of returning "" for [] :: [Int]!
578 LitE (CharL c) : ys -> go [c] ys
581 go cs [] = Just (reverse cs)
582 go cs (LitE (CharL c) : ys) = go (c:cs) ys
585 cvtLit :: Lit -> CvtM HsLit
586 cvtLit (IntPrimL i) = do { force i; return $ HsIntPrim i }
587 cvtLit (WordPrimL w) = do { force w; return $ HsWordPrim w }
588 cvtLit (FloatPrimL f) = do { force f; return $ HsFloatPrim f }
589 cvtLit (DoublePrimL f) = do { force f; return $ HsDoublePrim f }
590 cvtLit (CharL c) = do { force c; return $ HsChar c }
592 = do { let { s' = mkFastString s }
594 ; return $ HsString s'
596 cvtLit _ = panic "Convert.cvtLit: Unexpected literal"
597 -- cvtLit should not be called on IntegerL, RationalL
598 -- That precondition is established right here in
599 -- Convert.lhs, hence panic
601 cvtPats :: [TH.Pat] -> CvtM [Hs.LPat RdrName]
602 cvtPats pats = mapM cvtPat pats
604 cvtPat :: TH.Pat -> CvtM (Hs.LPat RdrName)
605 cvtPat pat = wrapL (cvtp pat)
607 cvtp :: TH.Pat -> CvtM (Hs.Pat RdrName)
609 | overloadedLit l = do { l' <- cvtOverLit l
610 ; return (mkNPat l' Nothing) }
611 -- Not right for negative patterns;
612 -- need to think about that!
613 | otherwise = do { l' <- cvtLit l; return $ Hs.LitPat l' }
614 cvtp (TH.VarP s) = do { s' <- vName s; return $ Hs.VarPat s' }
615 cvtp (TupP [p]) = cvtp p
616 cvtp (TupP ps) = do { ps' <- cvtPats ps; return $ TuplePat ps' Boxed void }
617 cvtp (ConP s ps) = do { s' <- cNameL s; ps' <- cvtPats ps; return $ ConPatIn s' (PrefixCon ps') }
618 cvtp (InfixP p1 s p2) = do { s' <- cNameL s; p1' <- cvtPat p1; p2' <- cvtPat p2
619 ; return $ ConPatIn s' (InfixCon p1' p2') }
620 cvtp (TildeP p) = do { p' <- cvtPat p; return $ LazyPat p' }
621 cvtp (BangP p) = do { p' <- cvtPat p; return $ BangPat p' }
622 cvtp (TH.AsP s p) = do { s' <- vNameL s; p' <- cvtPat p; return $ AsPat s' p' }
623 cvtp TH.WildP = return $ WildPat void
624 cvtp (RecP c fs) = do { c' <- cNameL c; fs' <- mapM cvtPatFld fs
625 ; return $ ConPatIn c' $ Hs.RecCon (HsRecFields fs' Nothing) }
626 cvtp (ListP ps) = do { ps' <- cvtPats ps; return $ ListPat ps' void }
627 cvtp (SigP p t) = do { p' <- cvtPat p; t' <- cvtType t; return $ SigPatIn p' t' }
629 cvtPatFld :: (TH.Name, TH.Pat) -> CvtM (HsRecField RdrName (LPat RdrName))
631 = do { s' <- vNameL s; p' <- cvtPat p
632 ; return (HsRecField { hsRecFieldId = s', hsRecFieldArg = p', hsRecPun = False}) }
634 -----------------------------------------------------------
635 -- Types and type variables
637 cvtTvs :: [TH.TyVarBndr] -> CvtM [LHsTyVarBndr RdrName]
638 cvtTvs tvs = mapM cvt_tv tvs
640 cvt_tv :: TH.TyVarBndr -> CvtM (LHsTyVarBndr RdrName)
641 cvt_tv (TH.PlainTV nm)
642 = do { nm' <- tName nm
643 ; returnL $ UserTyVar nm'
645 cvt_tv (TH.KindedTV nm ki)
646 = do { nm' <- tName nm
647 ; returnL $ KindedTyVar nm' (cvtKind ki)
650 cvtContext :: TH.Cxt -> CvtM (LHsContext RdrName)
651 cvtContext tys = do { preds' <- mapM cvtPred tys; returnL preds' }
653 cvtPred :: TH.Pred -> CvtM (LHsPred RdrName)
654 cvtPred (TH.ClassP cla tys)
655 = do { cla' <- if isVarName cla then tName cla else tconName cla
656 ; tys' <- mapM cvtType tys
657 ; returnL $ HsClassP cla' tys'
659 cvtPred (TH.EqualP ty1 ty2)
660 = do { ty1' <- cvtType ty1
661 ; ty2' <- cvtType ty2
662 ; returnL $ HsEqualP ty1' ty2'
665 cvtPredTy :: TH.Type -> CvtM (LHsPred RdrName)
667 = do { (head, tys') <- split_ty_app ty
669 ConT tc -> do { tc' <- tconName tc; returnL $ HsClassP tc' tys' }
670 VarT tv -> do { tv' <- tName tv; returnL $ HsClassP tv' tys' }
671 _ -> failWith (ptext (sLit "Malformed predicate") <+>
672 text (TH.pprint ty)) }
674 cvtType :: TH.Type -> CvtM (LHsType RdrName)
676 = do { (head_ty, tys') <- split_ty_app ty
679 | length tys' == n -- Saturated
680 -> if n==1 then return (head tys') -- Singleton tuples treated
681 -- like nothing (ie just parens)
682 else returnL (HsTupleTy Boxed tys')
684 -> failWith (ptext (sLit "Illegal 1-tuple type constructor"))
686 -> mk_apps (HsTyVar (getRdrName (tupleTyCon Boxed n))) tys'
688 | [x',y'] <- tys' -> returnL (HsFunTy x' y')
689 | otherwise -> mk_apps (HsTyVar (getRdrName funTyCon)) tys'
691 | [x'] <- tys' -> returnL (HsListTy x')
692 | otherwise -> mk_apps (HsTyVar (getRdrName listTyCon)) tys'
693 VarT nm -> do { nm' <- tName nm; mk_apps (HsTyVar nm') tys' }
694 ConT nm -> do { nm' <- tconName nm; mk_apps (HsTyVar nm') tys' }
698 -> do { tvs' <- cvtTvs tvs
699 ; cxt' <- cvtContext cxt
701 ; returnL $ mkExplicitHsForAllTy tvs' cxt' ty'
705 -> do { ty' <- cvtType ty
706 ; mk_apps (HsKindSig ty' (cvtKind ki)) tys'
709 _ -> failWith (ptext (sLit "Malformed type") <+> text (show ty))
712 mk_apps head_ty [] = returnL head_ty
713 mk_apps head_ty (ty:tys) = do { head_ty' <- returnL head_ty
714 ; mk_apps (HsAppTy head_ty' ty) tys }
716 split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsType RdrName])
717 split_ty_app ty = go ty []
719 go (AppT f a) as' = do { a' <- cvtType a; go f (a':as') }
720 go f as = return (f,as)
722 cvtKind :: TH.Kind -> Type.Kind
723 cvtKind StarK = liftedTypeKind
724 cvtKind (ArrowK k1 k2) = mkArrowKind (cvtKind k1) (cvtKind k2)
726 -----------------------------------------------------------
729 -----------------------------------------------------------
730 -- some useful things
732 overloadedLit :: Lit -> Bool
733 -- True for literals that Haskell treats as overloaded
734 overloadedLit (IntegerL _) = True
735 overloadedLit (RationalL _) = True
736 overloadedLit _ = False
739 void = placeHolderType
741 --------------------------------------------------------------------
742 -- Turning Name back into RdrName
743 --------------------------------------------------------------------
746 vNameL, cNameL, tconNameL :: TH.Name -> CvtM (Located RdrName)
747 vName, cName, tName, tconName :: TH.Name -> CvtM RdrName
749 vNameL n = wrapL (vName n)
750 vName n = cvtName OccName.varName n
752 -- Constructor function names; this is Haskell source, hence srcDataName
753 cNameL n = wrapL (cName n)
754 cName n = cvtName OccName.dataName n
756 -- Type variable names
757 tName n = cvtName OccName.tvName n
759 -- Type Constructor names
760 tconNameL n = wrapL (tconName n)
761 tconName n = cvtName OccName.tcClsName n
763 cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName
764 cvtName ctxt_ns (TH.Name occ flavour)
765 | not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str)
766 | otherwise = force rdr_name >> return rdr_name
768 occ_str = TH.occString occ
769 rdr_name = thRdrName ctxt_ns occ_str flavour
771 okOcc :: OccName.NameSpace -> String -> Bool
774 | OccName.isVarNameSpace ns = startsVarId c || startsVarSym c
775 | otherwise = startsConId c || startsConSym c || str == "[]"
777 -- Determine the name space of a name in a type
779 isVarName :: TH.Name -> Bool
780 isVarName (TH.Name occ _)
781 = case TH.occString occ of
783 (c:_) -> startsVarId c || startsVarSym c
785 badOcc :: OccName.NameSpace -> String -> SDoc
787 = ptext (sLit "Illegal") <+> pprNameSpace ctxt_ns
788 <+> ptext (sLit "name:") <+> quotes (text occ)
790 thRdrName :: OccName.NameSpace -> String -> TH.NameFlavour -> RdrName
791 -- This turns a Name into a RdrName
792 -- The passed-in name space tells what the context is expecting;
793 -- use it unless the TH name knows what name-space it comes
794 -- from, in which case use the latter
796 -- ToDo: we may generate silly RdrNames, by passing a name space
797 -- that doesn't match the string, like VarName ":+",
798 -- which will give confusing error messages later
800 -- The strict applications ensure that any buried exceptions get forced
801 thRdrName _ occ (TH.NameG th_ns pkg mod) = thOrigRdrName occ th_ns pkg mod
802 thRdrName ctxt_ns occ (TH.NameL uniq) = nameRdrName $! (((Name.mkInternalName $! (mk_uniq uniq)) $! (mk_occ ctxt_ns occ)) noSrcSpan)
803 thRdrName ctxt_ns occ (TH.NameQ mod) = (mkRdrQual $! (mk_mod mod)) $! (mk_occ ctxt_ns occ)
804 thRdrName ctxt_ns occ (TH.NameU uniq) = mkRdrUnqual $! (mk_uniq_occ ctxt_ns occ uniq)
805 thRdrName ctxt_ns occ TH.NameS
806 | Just name <- isBuiltInOcc ctxt_ns occ = nameRdrName $! name
807 | otherwise = mkRdrUnqual $! (mk_occ ctxt_ns occ)
809 thOrigRdrName :: String -> TH.NameSpace -> PkgName -> ModName -> RdrName
810 thOrigRdrName occ th_ns pkg mod = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
812 thRdrNameGuesses :: TH.Name -> [RdrName]
813 thRdrNameGuesses (TH.Name occ flavour)
814 -- This special case for NameG ensures that we don't generate duplicates in the output list
815 | TH.NameG th_ns pkg mod <- flavour = [thOrigRdrName occ_str th_ns pkg mod]
816 | otherwise = [ thRdrName gns occ_str flavour
817 | gns <- guessed_nss]
819 -- guessed_ns are the name spaces guessed from looking at the TH name
820 guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName, OccName.dataName]
821 | otherwise = [OccName.varName, OccName.tvName]
822 occ_str = TH.occString occ
824 isBuiltInOcc :: OccName.NameSpace -> String -> Maybe Name.Name
825 -- Built in syntax isn't "in scope" so an Unqual RdrName won't do
826 -- We must generate an Exact name, just as the parser does
827 isBuiltInOcc ctxt_ns occ
829 ":" -> Just (Name.getName consDataCon)
830 "[]" -> Just (Name.getName nilDataCon)
831 "()" -> Just (tup_name 0)
832 '(' : ',' : rest -> go_tuple 2 rest
835 go_tuple n ")" = Just (tup_name n)
836 go_tuple n (',' : rest) = go_tuple (n+1) rest
837 go_tuple _ _ = Nothing
840 | OccName.isTcClsNameSpace ctxt_ns = Name.getName (tupleTyCon Boxed n)
841 | otherwise = Name.getName (tupleCon Boxed n)
843 mk_uniq_occ :: OccName.NameSpace -> String -> Int# -> OccName.OccName
844 mk_uniq_occ ns occ uniq
845 = OccName.mkOccName ns (occ ++ '[' : shows (mk_uniq uniq) "]")
846 -- The idea here is to make a name that
847 -- a) the user could not possibly write, and
848 -- b) cannot clash with another NameU
849 -- Previously I generated an Exact RdrName with mkInternalName.
850 -- This works fine for local binders, but does not work at all for
851 -- top-level binders, which must have External Names, since they are
852 -- rapidly baked into data constructors and the like. Baling out
853 -- and generating an unqualified RdrName here is the simple solution
855 -- The packing and unpacking is rather turgid :-(
856 mk_occ :: OccName.NameSpace -> String -> OccName.OccName
857 mk_occ ns occ = OccName.mkOccNameFS ns (mkFastString occ)
859 mk_ghc_ns :: TH.NameSpace -> OccName.NameSpace
860 mk_ghc_ns TH.DataName = OccName.dataName
861 mk_ghc_ns TH.TcClsName = OccName.tcClsName
862 mk_ghc_ns TH.VarName = OccName.varName
864 mk_mod :: TH.ModName -> ModuleName
865 mk_mod mod = mkModuleName (TH.modString mod)
867 mk_pkg :: TH.PkgName -> PackageId
868 mk_pkg pkg = stringToPackageId (TH.pkgString pkg)
870 mk_uniq :: Int# -> Unique
871 mk_uniq u = mkUniqueGrimily (I# u)