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
10 -- The above warning supression flag is a temporary kludge.
11 -- While working on this module you are encouraged to remove it and fix
12 -- any warnings in the module. See
13 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
16 module Convert( convertToHsExpr, convertToPat, convertToHsDecls,
17 convertToHsType, thRdrName ) where
19 #include "HsVersions.h"
22 import qualified Class
27 import qualified OccName
43 import Language.Haskell.TH as TH hiding (sigP)
44 import Language.Haskell.TH.Syntax as TH
48 -------------------------------------------------------------------
49 -- The external interface
51 convertToHsDecls :: SrcSpan -> [TH.Dec] -> Either Message [LHsDecl RdrName]
52 convertToHsDecls loc ds = initCvt loc (mapM cvtTop ds)
54 convertToHsExpr :: SrcSpan -> TH.Exp -> Either Message (LHsExpr RdrName)
56 = case initCvt loc (cvtl e) of
57 Left msg -> Left (msg $$ (ptext SLIT("When converting TH expression")
59 Right res -> Right res
61 convertToPat :: SrcSpan -> TH.Pat -> Either Message (LPat RdrName)
63 = case initCvt loc (cvtPat e) of
64 Left msg -> Left (msg $$ (ptext SLIT("When converting TH pattern")
66 Right res -> Right res
68 convertToHsType :: SrcSpan -> TH.Type -> Either Message (LHsType RdrName)
69 convertToHsType loc t = initCvt loc (cvtType t)
72 -------------------------------------------------------------------
73 newtype CvtM a = CvtM { unCvtM :: SrcSpan -> Either Message a }
74 -- Push down the source location;
75 -- Can fail, with a single error message
77 -- NB: If the conversion succeeds with (Right x), there should
78 -- be no exception values hiding in x
79 -- Reason: so a (head []) in TH code doesn't subsequently
80 -- make GHC crash when it tries to walk the generated tree
82 -- Use the loc everywhere, for lack of anything better
83 -- In particular, we want it on binding locations, so that variables bound in
84 -- the spliced-in declarations get a location that at least relates to the splice point
86 instance Monad CvtM where
87 return x = CvtM $ \loc -> Right x
88 (CvtM m) >>= k = CvtM $ \loc -> case m loc of
90 Right v -> unCvtM (k v) loc
92 initCvt :: SrcSpan -> CvtM a -> Either Message a
93 initCvt loc (CvtM m) = m loc
96 force a = a `seq` return a
98 failWith :: Message -> CvtM a
99 failWith m = CvtM (\loc -> Left full_msg)
101 full_msg = m $$ ptext SLIT("When splicing generated code into the program")
103 returnL :: a -> CvtM (Located a)
104 returnL x = CvtM (\loc -> Right (L loc x))
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 cvtTop :: TH.Dec -> CvtM (LHsDecl RdrName)
113 cvtTop d@(TH.ValD _ _ _) = do { L loc d' <- cvtBind d; return (L loc $ Hs.ValD d') }
114 cvtTop d@(TH.FunD _ _) = do { L loc d' <- cvtBind d; return (L loc $ Hs.ValD d') }
115 cvtTop (TH.SigD nm typ) = do { nm' <- vNameL nm
117 ; returnL $ Hs.SigD (TypeSig nm' ty') }
119 cvtTop (TySynD tc tvs rhs)
120 = do { tc' <- tconNameL tc
122 ; rhs' <- cvtType rhs
123 ; returnL $ TyClD (TySynonym tc' tvs' Nothing rhs') }
125 cvtTop (DataD ctxt tc tvs constrs derivs)
126 = do { stuff <- cvt_tycl_hdr ctxt tc tvs
127 ; cons' <- mapM cvtConstr constrs
128 ; derivs' <- cvtDerivs derivs
129 ; returnL $ TyClD (mkTyData DataType stuff Nothing cons' derivs') }
132 cvtTop (NewtypeD ctxt tc tvs constr derivs)
133 = do { stuff <- cvt_tycl_hdr ctxt tc tvs
134 ; con' <- cvtConstr constr
135 ; derivs' <- cvtDerivs derivs
136 ; returnL $ TyClD (mkTyData NewType stuff Nothing [con'] derivs') }
138 cvtTop (ClassD ctxt cl tvs fds decs)
139 = do { (cxt', tc', tvs', _) <- cvt_tycl_hdr ctxt cl tvs
140 ; fds' <- mapM cvt_fundep fds
141 ; (binds', sigs') <- cvtBindsAndSigs decs
142 ; returnL $ TyClD $ mkClassDecl (cxt', tc', tvs') fds' sigs' binds' [] []
143 -- no ATs or docs in TH ^^ ^^
146 cvtTop (InstanceD tys ty decs)
147 = do { (binds', sigs') <- cvtBindsAndSigs decs
148 ; ctxt' <- cvtContext tys
149 ; L loc pred' <- cvtPred ty
150 ; inst_ty' <- returnL $ mkImplicitHsForAllTy ctxt' (L loc (HsPredTy pred'))
151 ; returnL $ InstD (InstDecl inst_ty' binds' sigs' [])
155 cvtTop (ForeignD ford) = do { ford' <- cvtForD ford; returnL $ ForD ford' }
157 cvt_tycl_hdr cxt tc tvs
158 = do { cxt' <- cvtContext cxt
159 ; tc' <- tconNameL tc
161 ; return (cxt', tc', tvs', Nothing) }
163 ---------------------------------------------------
165 -- Can't handle GADTs yet
166 ---------------------------------------------------
168 cvtConstr (NormalC c strtys)
169 = do { c' <- cNameL c
171 ; tys' <- mapM cvt_arg strtys
172 ; returnL $ ConDecl c' Explicit noExistentials cxt' (PrefixCon tys') ResTyH98 Nothing }
174 cvtConstr (RecC c varstrtys)
175 = do { c' <- cNameL c
177 ; args' <- mapM cvt_id_arg varstrtys
178 ; returnL $ ConDecl c' Explicit noExistentials cxt' (RecCon args') ResTyH98 Nothing }
180 cvtConstr (InfixC st1 c st2)
181 = do { c' <- cNameL c
183 ; st1' <- cvt_arg st1
184 ; st2' <- cvt_arg st2
185 ; returnL $ ConDecl c' Explicit noExistentials cxt' (InfixCon st1' st2') ResTyH98 Nothing }
187 cvtConstr (ForallC tvs ctxt (ForallC tvs' ctxt' con'))
188 = cvtConstr (ForallC (tvs ++ tvs') (ctxt ++ ctxt') con')
190 cvtConstr (ForallC tvs ctxt con)
191 = do { L _ con' <- cvtConstr con
193 ; ctxt' <- cvtContext ctxt
195 ConDecl l _ [] (L _ []) x ResTyH98 _
196 -> returnL $ ConDecl l Explicit tvs' ctxt' x ResTyH98 Nothing
197 c -> panic "ForallC: Can't happen" }
199 cvt_arg (IsStrict, ty) = do { ty' <- cvtType ty; returnL $ HsBangTy HsStrict ty' }
200 cvt_arg (NotStrict, ty) = cvtType ty
202 cvt_id_arg (i, str, ty)
203 = do { i' <- vNameL i
204 ; ty' <- cvt_arg (str,ty)
205 ; return (ConDeclField { cd_fld_name = i', cd_fld_type = ty', cd_fld_doc = Nothing}) }
207 cvtDerivs [] = return Nothing
208 cvtDerivs cs = do { cs' <- mapM cvt_one cs
209 ; return (Just cs') }
211 cvt_one c = do { c' <- tconName c
212 ; returnL $ HsPredTy $ HsClassP c' [] }
214 cvt_fundep :: FunDep -> CvtM (Located (Class.FunDep RdrName))
215 cvt_fundep (FunDep xs ys) = do { xs' <- mapM tName xs; ys' <- mapM tName ys; returnL (xs', ys') }
219 ------------------------------------------
220 -- Foreign declarations
221 ------------------------------------------
223 cvtForD :: Foreign -> CvtM (ForeignDecl RdrName)
224 cvtForD (ImportF callconv safety from nm ty)
225 | Just (c_header, cis) <- parse_ccall_impent (TH.nameBase nm) from
226 = do { nm' <- vNameL nm
228 ; let i = CImport (cvt_conv callconv) safety' c_header nilFS cis
229 ; return $ ForeignImport nm' ty' i }
232 = failWith $ text (show from)<+> ptext SLIT("is not a valid ccall impent")
234 safety' = case safety of
236 Safe -> PlaySafe False
237 Threadsafe -> PlaySafe True
239 cvtForD (ExportF callconv as nm ty)
240 = do { nm' <- vNameL nm
242 ; let e = CExport (CExportStatic (mkFastString as) (cvt_conv callconv))
243 ; return $ ForeignExport nm' ty' e }
245 cvt_conv TH.CCall = CCallConv
246 cvt_conv TH.StdCall = StdCallConv
248 parse_ccall_impent :: String -> String -> Maybe (FastString, CImportSpec)
249 parse_ccall_impent nm s
250 = case lex_ccall_impent s of
251 Just ["dynamic"] -> Just (nilFS, CFunction DynamicTarget)
252 Just ["wrapper"] -> Just (nilFS, CWrapper)
253 Just ("static":ts) -> parse_ccall_impent_static nm ts
254 Just ts -> parse_ccall_impent_static nm ts
257 parse_ccall_impent_static :: String
259 -> Maybe (FastString, CImportSpec)
260 parse_ccall_impent_static nm ts
261 = let ts' = case ts of
262 [ "&", cid] -> [ cid]
263 [fname, "&" ] -> [fname ]
264 [fname, "&", cid] -> [fname, cid]
267 [ cid] | is_cid cid -> Just (nilFS, mk_cid cid)
268 [fname, cid] | is_cid cid -> Just (mkFastString fname, mk_cid cid)
269 [ ] -> Just (nilFS, mk_cid nm)
270 [fname ] -> Just (mkFastString fname, mk_cid nm)
272 where is_cid :: String -> Bool
273 is_cid x = all (/= '.') x && (isAlpha (head x) || head x == '_')
274 mk_cid :: String -> CImportSpec
275 mk_cid = CFunction . StaticTarget . mkFastString
277 lex_ccall_impent :: String -> Maybe [String]
278 lex_ccall_impent "" = Just []
279 lex_ccall_impent ('&':xs) = fmap ("&":) $ lex_ccall_impent xs
280 lex_ccall_impent (' ':xs) = lex_ccall_impent xs
281 lex_ccall_impent ('\t':xs) = lex_ccall_impent xs
282 lex_ccall_impent xs = case span is_valid xs of
284 (t, xs') -> fmap (t:) $ lex_ccall_impent xs'
285 where is_valid :: Char -> Bool
286 is_valid c = isAscii c && (isAlphaNum c || c `elem` "._")
289 ---------------------------------------------------
291 ---------------------------------------------------
293 cvtDecs :: [TH.Dec] -> CvtM (HsLocalBinds RdrName)
294 cvtDecs [] = return EmptyLocalBinds
295 cvtDecs ds = do { (binds,sigs) <- cvtBindsAndSigs ds
296 ; return (HsValBinds (ValBindsIn binds sigs)) }
299 = do { binds' <- mapM cvtBind binds; sigs' <- mapM cvtSig sigs
300 ; return (listToBag binds', sigs') }
302 (sigs, binds) = partition is_sig ds
304 is_sig (TH.SigD _ _) = True
307 cvtSig (TH.SigD nm ty)
308 = do { nm' <- vNameL nm; ty' <- cvtType ty; returnL (Hs.TypeSig nm' ty') }
310 cvtBind :: TH.Dec -> CvtM (LHsBind RdrName)
311 -- Used only for declarations in a 'let/where' clause,
312 -- not for top level decls
313 cvtBind (TH.ValD (TH.VarP s) body ds)
314 = do { s' <- vNameL s
315 ; cl' <- cvtClause (Clause [] body ds)
316 ; returnL $ mkFunBind s' [cl'] }
318 cvtBind (TH.FunD nm cls)
319 = do { nm' <- vNameL nm
320 ; cls' <- mapM cvtClause cls
321 ; returnL $ mkFunBind nm' cls' }
323 cvtBind (TH.ValD p body ds)
324 = do { p' <- cvtPat p
325 ; g' <- cvtGuard body
327 ; returnL $ PatBind { pat_lhs = p', pat_rhs = GRHSs g' ds',
328 pat_rhs_ty = void, bind_fvs = placeHolderNames } }
331 = failWith (sep [ptext SLIT("Illegal kind of declaration in where clause"),
332 nest 2 (text (TH.pprint d))])
334 cvtClause :: TH.Clause -> CvtM (Hs.LMatch RdrName)
335 cvtClause (Clause ps body wheres)
336 = do { ps' <- cvtPats ps
337 ; g' <- cvtGuard body
338 ; ds' <- cvtDecs wheres
339 ; returnL $ Hs.Match ps' Nothing (GRHSs g' ds') }
342 -------------------------------------------------------------------
344 -------------------------------------------------------------------
346 cvtl :: TH.Exp -> CvtM (LHsExpr RdrName)
347 cvtl e = wrapL (cvt e)
349 cvt (VarE s) = do { s' <- vName s; return $ HsVar s' }
350 cvt (ConE s) = do { s' <- cName s; return $ HsVar s' }
352 | overloadedLit l = do { l' <- cvtOverLit l; return $ HsOverLit l' }
353 | otherwise = do { l' <- cvtLit l; return $ HsLit l' }
355 cvt (AppE x y) = do { x' <- cvtl x; y' <- cvtl y; return $ HsApp x' y' }
356 cvt (LamE ps e) = do { ps' <- cvtPats ps; e' <- cvtl e
357 ; return $ HsLam (mkMatchGroup [mkSimpleMatch ps' e']) }
358 cvt (TupE [e]) = cvt e
359 cvt (TupE es) = do { es' <- mapM cvtl es; return $ ExplicitTuple es' Boxed }
360 cvt (CondE x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z
361 ; return $ HsIf x' y' z' }
362 cvt (LetE ds e) = do { ds' <- cvtDecs ds; e' <- cvtl e; return $ HsLet ds' e' }
363 cvt (CaseE e ms) = do { e' <- cvtl e; ms' <- mapM cvtMatch ms
364 ; return $ HsCase e' (mkMatchGroup ms') }
365 cvt (DoE ss) = cvtHsDo DoExpr ss
366 cvt (CompE ss) = cvtHsDo ListComp ss
367 cvt (ArithSeqE dd) = do { dd' <- cvtDD dd; return $ ArithSeq noPostTcExpr dd' }
368 cvt (ListE xs) = do { xs' <- mapM cvtl xs; return $ ExplicitList void xs' }
369 cvt (InfixE (Just x) s (Just y)) = do { x' <- cvtl x; s' <- cvtl s; y' <- cvtl y
370 ; e' <- returnL $ OpApp x' s' undefined y'
371 ; return $ HsPar e' }
372 cvt (InfixE Nothing s (Just y)) = do { s' <- cvtl s; y' <- cvtl y
373 ; return $ SectionR s' y' }
374 cvt (InfixE (Just x) s Nothing ) = do { x' <- cvtl x; s' <- cvtl s
375 ; return $ SectionL x' s' }
376 cvt (InfixE Nothing s Nothing ) = cvt s -- Can I indicate this is an infix thing?
378 cvt (SigE e t) = do { e' <- cvtl e; t' <- cvtType t
379 ; return $ ExprWithTySig e' t' }
380 cvt (RecConE c flds) = do { c' <- cNameL c
381 ; flds' <- mapM cvtFld flds
382 ; return $ RecordCon c' noPostTcExpr (HsRecFields flds' Nothing)}
383 cvt (RecUpdE e flds) = do { e' <- cvtl e
384 ; flds' <- mapM cvtFld flds
385 ; return $ RecordUpd e' (HsRecFields flds' Nothing) [] [] [] }
388 = do { v' <- vNameL v; e' <- cvtl e
389 ; return (HsRecField { hsRecFieldId = v', hsRecFieldArg = e', hsRecPun = False}) }
391 cvtDD :: Range -> CvtM (ArithSeqInfo RdrName)
392 cvtDD (FromR x) = do { x' <- cvtl x; return $ From x' }
393 cvtDD (FromThenR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromThen x' y' }
394 cvtDD (FromToR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromTo x' y' }
395 cvtDD (FromThenToR x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; return $ FromThenTo x' y' z' }
397 -------------------------------------
398 -- Do notation and statements
399 -------------------------------------
401 cvtHsDo do_or_lc stmts
402 = do { stmts' <- cvtStmts stmts
403 ; let body = case last stmts' of
404 L _ (ExprStmt body _ _) -> body
405 ; return $ HsDo do_or_lc (init stmts') body void }
407 cvtStmts = mapM cvtStmt
409 cvtStmt :: TH.Stmt -> CvtM (Hs.LStmt RdrName)
410 cvtStmt (NoBindS e) = do { e' <- cvtl e; returnL $ mkExprStmt e' }
411 cvtStmt (TH.BindS p e) = do { p' <- cvtPat p; e' <- cvtl e; returnL $ mkBindStmt p' e' }
412 cvtStmt (TH.LetS ds) = do { ds' <- cvtDecs ds; returnL $ LetStmt ds' }
413 cvtStmt (TH.ParS dss) = do { dss' <- mapM cvt_one dss; returnL $ ParStmt dss' }
415 cvt_one ds = do { ds' <- cvtStmts ds; return (ds', undefined) }
417 cvtMatch :: TH.Match -> CvtM (Hs.LMatch RdrName)
418 cvtMatch (TH.Match p body decs)
419 = do { p' <- cvtPat p
420 ; g' <- cvtGuard body
421 ; decs' <- cvtDecs decs
422 ; returnL $ Hs.Match [p'] Nothing (GRHSs g' decs') }
424 cvtGuard :: TH.Body -> CvtM [LGRHS RdrName]
425 cvtGuard (GuardedB pairs) = mapM cvtpair pairs
426 cvtGuard (NormalB e) = do { e' <- cvtl e; g' <- returnL $ GRHS [] e'; return [g'] }
428 cvtpair :: (TH.Guard, TH.Exp) -> CvtM (LGRHS RdrName)
429 cvtpair (NormalG ge,rhs) = do { ge' <- cvtl ge; rhs' <- cvtl rhs
430 ; g' <- returnL $ mkExprStmt ge'
431 ; returnL $ GRHS [g'] rhs' }
432 cvtpair (PatG gs,rhs) = do { gs' <- cvtStmts gs; rhs' <- cvtl rhs
433 ; returnL $ GRHS gs' rhs' }
435 cvtOverLit :: Lit -> CvtM (HsOverLit RdrName)
436 cvtOverLit (IntegerL i) = do { force i; return $ mkHsIntegral i placeHolderType}
437 cvtOverLit (RationalL r) = do { force r; return $ mkHsFractional r placeHolderType}
438 cvtOverLit (StringL s) = do { let { s' = mkFastString s }; force s'; return $ mkHsIsString s' placeHolderType }
439 -- An Integer is like an an (overloaded) '3' in a Haskell source program
440 -- Similarly 3.5 for fractionals
442 cvtLit :: Lit -> CvtM HsLit
443 cvtLit (IntPrimL i) = do { force i; return $ HsIntPrim i }
444 cvtLit (FloatPrimL f) = do { force f; return $ HsFloatPrim f }
445 cvtLit (DoublePrimL f) = do { force f; return $ HsDoublePrim f }
446 cvtLit (CharL c) = do { force c; return $ HsChar c }
447 cvtLit (StringL s) = do { let { s' = mkFastString s }; force s'; return $ HsString s' }
449 cvtPats :: [TH.Pat] -> CvtM [Hs.LPat RdrName]
450 cvtPats pats = mapM cvtPat pats
452 cvtPat :: TH.Pat -> CvtM (Hs.LPat RdrName)
453 cvtPat pat = wrapL (cvtp pat)
455 cvtp :: TH.Pat -> CvtM (Hs.Pat RdrName)
457 | overloadedLit l = do { l' <- cvtOverLit l
458 ; return (mkNPat l' Nothing) }
459 -- Not right for negative patterns;
460 -- need to think about that!
461 | otherwise = do { l' <- cvtLit l; return $ Hs.LitPat l' }
462 cvtp (TH.VarP s) = do { s' <- vName s; return $ Hs.VarPat s' }
463 cvtp (TupP [p]) = cvtp p
464 cvtp (TupP ps) = do { ps' <- cvtPats ps; return $ TuplePat ps' Boxed void }
465 cvtp (ConP s ps) = do { s' <- cNameL s; ps' <- cvtPats ps; return $ ConPatIn s' (PrefixCon ps') }
466 cvtp (InfixP p1 s p2) = do { s' <- cNameL s; p1' <- cvtPat p1; p2' <- cvtPat p2
467 ; return $ ConPatIn s' (InfixCon p1' p2') }
468 cvtp (TildeP p) = do { p' <- cvtPat p; return $ LazyPat p' }
469 cvtp (TH.AsP s p) = do { s' <- vNameL s; p' <- cvtPat p; return $ AsPat s' p' }
470 cvtp TH.WildP = return $ WildPat void
471 cvtp (RecP c fs) = do { c' <- cNameL c; fs' <- mapM cvtPatFld fs
472 ; return $ ConPatIn c' $ Hs.RecCon (HsRecFields fs' Nothing) }
473 cvtp (ListP ps) = do { ps' <- cvtPats ps; return $ ListPat ps' void }
474 cvtp (SigP p t) = do { p' <- cvtPat p; t' <- cvtType t; return $ SigPatIn p' t' }
477 = do { s' <- vNameL s; p' <- cvtPat p
478 ; return (HsRecField { hsRecFieldId = s', hsRecFieldArg = p', hsRecPun = False}) }
480 -----------------------------------------------------------
481 -- Types and type variables
483 cvtTvs :: [TH.Name] -> CvtM [LHsTyVarBndr RdrName]
484 cvtTvs tvs = mapM cvt_tv tvs
486 cvt_tv tv = do { tv' <- tName tv; returnL $ UserTyVar tv' }
488 cvtContext :: Cxt -> CvtM (LHsContext RdrName)
489 cvtContext tys = do { preds' <- mapM cvtPred tys; returnL preds' }
491 cvtPred :: TH.Type -> CvtM (LHsPred RdrName)
493 = do { (head, tys') <- split_ty_app ty
495 ConT tc -> do { tc' <- tconName tc; returnL $ HsClassP tc' tys' }
496 VarT tv -> do { tv' <- tName tv; returnL $ HsClassP tv' tys' }
497 other -> failWith (ptext SLIT("Malformed predicate") <+> text (TH.pprint ty)) }
499 cvtType :: TH.Type -> CvtM (LHsType RdrName)
500 cvtType ty = do { (head, tys') <- split_ty_app ty
502 TupleT n | length tys' == n -> returnL (HsTupleTy Boxed tys')
503 | n == 0 -> mk_apps (HsTyVar (getRdrName unitTyCon)) tys'
504 | otherwise -> mk_apps (HsTyVar (getRdrName (tupleTyCon Boxed n))) tys'
505 ArrowT | [x',y'] <- tys' -> returnL (HsFunTy x' y')
506 ListT | [x'] <- tys' -> returnL (HsListTy x')
507 VarT nm -> do { nm' <- tName nm; mk_apps (HsTyVar nm') tys' }
508 ConT nm -> do { nm' <- tconName nm; mk_apps (HsTyVar nm') tys' }
510 ForallT tvs cxt ty | null tys' -> do { tvs' <- cvtTvs tvs
511 ; cxt' <- cvtContext cxt
513 ; returnL $ mkExplicitHsForAllTy tvs' cxt' ty' }
514 otherwise -> failWith (ptext SLIT("Malformed type") <+> text (show ty))
517 mk_apps head [] = returnL head
518 mk_apps head (ty:tys) = do { head' <- returnL head; mk_apps (HsAppTy head' ty) tys }
520 split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsType RdrName])
521 split_ty_app ty = go ty []
523 go (AppT f a) as' = do { a' <- cvtType a; go f (a':as') }
524 go f as = return (f,as)
526 -----------------------------------------------------------
529 -----------------------------------------------------------
530 -- some useful things
532 truePat = nlConPat (getRdrName trueDataCon) []
534 overloadedLit :: Lit -> Bool
535 -- True for literals that Haskell treats as overloaded
536 overloadedLit (IntegerL l) = True
537 overloadedLit (RationalL l) = True
538 overloadedLit l = False
541 void = placeHolderType
543 --------------------------------------------------------------------
544 -- Turning Name back into RdrName
545 --------------------------------------------------------------------
548 vNameL, cNameL, tconNameL :: TH.Name -> CvtM (Located RdrName)
549 vName, cName, tName, tconName :: TH.Name -> CvtM RdrName
551 vNameL n = wrapL (vName n)
552 vName n = cvtName OccName.varName n
554 -- Constructor function names; this is Haskell source, hence srcDataName
555 cNameL n = wrapL (cName n)
556 cName n = cvtName OccName.dataName n
558 -- Type variable names
559 tName n = cvtName OccName.tvName n
561 -- Type Constructor names
562 tconNameL n = wrapL (tconName n)
563 tconName n = cvtName OccName.tcClsName n
565 cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName
566 cvtName ctxt_ns (TH.Name occ flavour)
567 | not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str)
568 | otherwise = force (thRdrName ctxt_ns occ_str flavour)
570 occ_str = TH.occString occ
572 okOcc :: OccName.NameSpace -> String -> Bool
575 | OccName.isVarName ns = startsVarId c || startsVarSym c
576 | otherwise = startsConId c || startsConSym c || str == "[]"
578 badOcc :: OccName.NameSpace -> String -> SDoc
580 = ptext SLIT("Illegal") <+> pprNameSpace ctxt_ns
581 <+> ptext SLIT("name:") <+> quotes (text occ)
583 thRdrName :: OccName.NameSpace -> String -> TH.NameFlavour -> RdrName
584 -- This turns a Name into a RdrName
585 -- The passed-in name space tells what the context is expecting;
586 -- use it unless the TH name knows what name-space it comes
587 -- from, in which case use the latter
589 -- ToDo: we may generate silly RdrNames, by passing a name space
590 -- that doesn't match the string, like VarName ":+",
591 -- which will give confusing error messages later
593 -- The strict applications ensure that any buried exceptions get forced
594 thRdrName ctxt_ns occ (TH.NameG th_ns pkg mod) = (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! (mk_occ (mk_ghc_ns th_ns) occ)
595 thRdrName ctxt_ns occ (TH.NameL uniq) = nameRdrName $! (((Name.mkInternalName $! (mk_uniq uniq)) $! (mk_occ ctxt_ns occ)) noSrcSpan)
596 thRdrName ctxt_ns occ (TH.NameQ mod) = (mkRdrQual $! (mk_mod mod)) $! (mk_occ ctxt_ns occ)
597 thRdrName ctxt_ns occ (TH.NameU uniq) = mkRdrUnqual $! (mk_uniq_occ ctxt_ns occ uniq)
598 thRdrName ctxt_ns occ TH.NameS
599 | Just name <- isBuiltInOcc ctxt_ns occ = nameRdrName $! name
600 | otherwise = mkRdrUnqual $! (mk_occ ctxt_ns occ)
602 isBuiltInOcc :: OccName.NameSpace -> String -> Maybe Name.Name
603 -- Built in syntax isn't "in scope" so an Unqual RdrName won't do
604 -- We must generate an Exact name, just as the parser does
605 isBuiltInOcc ctxt_ns occ
607 ":" -> Just (Name.getName consDataCon)
608 "[]" -> Just (Name.getName nilDataCon)
609 "()" -> Just (tup_name 0)
610 '(' : ',' : rest -> go_tuple 2 rest
613 go_tuple n ")" = Just (tup_name n)
614 go_tuple n (',' : rest) = go_tuple (n+1) rest
615 go_tuple n other = Nothing
618 | OccName.isTcClsName ctxt_ns = Name.getName (tupleTyCon Boxed n)
619 | otherwise = Name.getName (tupleCon Boxed n)
621 mk_uniq_occ :: OccName.NameSpace -> String -> Int# -> OccName.OccName
622 mk_uniq_occ ns occ uniq
623 = OccName.mkOccName ns (occ ++ '[' : shows (mk_uniq uniq) "]")
624 -- The idea here is to make a name that
625 -- a) the user could not possibly write, and
626 -- b) cannot clash with another NameU
627 -- Previously I generated an Exact RdrName with mkInternalName.
628 -- This works fine for local binders, but does not work at all for
629 -- top-level binders, which must have External Names, since they are
630 -- rapidly baked into data constructors and the like. Baling out
631 -- and generating an unqualified RdrName here is the simple solution
633 -- The packing and unpacking is rather turgid :-(
634 mk_occ :: OccName.NameSpace -> String -> OccName.OccName
635 mk_occ ns occ = OccName.mkOccNameFS ns (mkFastString occ)
637 mk_ghc_ns :: TH.NameSpace -> OccName.NameSpace
638 mk_ghc_ns TH.DataName = OccName.dataName
639 mk_ghc_ns TH.TcClsName = OccName.tcClsName
640 mk_ghc_ns TH.VarName = OccName.varName
642 mk_mod :: TH.ModName -> ModuleName
643 mk_mod mod = mkModuleName (TH.modString mod)
645 mk_pkg :: TH.ModName -> PackageId
646 mk_pkg pkg = stringToPackageId (TH.pkgString pkg)
648 mk_uniq :: Int# -> Unique
649 mk_uniq u = mkUniqueGrimily (I# u)