2 % (c) The University of Glasgow, 1996-2003
4 Functions over HsSyn specialised to RdrName.
9 extractHsRhoRdrTyVars, extractGenericPatTyVars,
11 mkHsOpApp, mkClassDecl,
12 mkHsNegApp, mkHsIntegral, mkHsFractional,
14 mkTyData, mkPrefixCon, mkRecCon, mkInlineSpec,
15 mkRecConstrOrUpdate, -- HsExp -> [HsFieldUpdate] -> P HsExp
22 -- Stuff to do with Foreign declarations
24 mkImport, -- CallConv -> Safety
25 -- -> (FastString, RdrName, RdrNameHsType)
28 -- -> (FastString, RdrName, RdrNameHsType)
30 mkExtName, -- RdrName -> CLabelString
31 mkGadtDecl, -- Located RdrName -> LHsType RdrName -> ConDecl RdrName
33 -- Bunch of functions in the parser monad for
34 -- checking and constructing values
35 checkPrecP, -- Int -> P Int
36 checkContext, -- HsType -> P HsContext
37 checkPred, -- HsType -> P HsPred
38 checkTyClHdr, -- LHsContext RdrName -> LHsType RdrName -> P (LHsContext RdrName, Located RdrName, [LHsTyVarBndr RdrName], [LHsType RdrName])
39 checkTyVars, -- [LHsType RdrName] -> P ()
40 checkSynHdr, -- LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName], [LHsType RdrName])
41 checkKindSigs, -- [LTyClDecl RdrName] -> P ()
42 checkInstType, -- HsType -> P HsType
43 checkDerivDecl, -- LDerivDecl RdrName -> P (LDerivDecl RdrName)
44 checkPattern, -- HsExp -> P HsPat
46 checkPatterns, -- SrcLoc -> [HsExp] -> P [HsPat]
47 checkDo, -- [Stmt] -> P [Stmt]
48 checkMDo, -- [Stmt] -> P [Stmt]
49 checkValDef, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl
50 checkValSig, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl
51 parseError, -- String -> Pa
54 #include "HsVersions.h"
56 import HsSyn -- Lots of it
57 import RdrName ( RdrName, isRdrTyVar, mkUnqual, rdrNameOcc,
58 isRdrDataCon, isUnqual, getRdrName, isQual,
60 import BasicTypes ( maxPrecedence, Activation, InlineSpec(..), alwaysInlineSpec, neverInlineSpec )
61 import Lexer ( P, failSpanMsgP, extension, glaExtsEnabled, bangPatEnabled )
62 import TysWiredIn ( unitTyCon )
63 import ForeignCall ( CCallConv, Safety, CCallTarget(..), CExportSpec(..),
64 DNCallSpec(..), DNKind(..), CLabelString )
65 import OccName ( srcDataName, varName, isDataOcc, isTcOcc,
68 import OrdList ( OrdList, fromOL )
69 import Bag ( Bag, emptyBag, snocBag, consBag, foldrBag )
74 import List ( isSuffixOf, nubBy )
75 import Monad ( unless )
79 %************************************************************************
81 \subsection{A few functions over HsSyn at RdrName}
83 %************************************************************************
85 extractHsTyRdrNames finds the free variables of a HsType
86 It's used when making the for-alls explicit.
89 extractHsTyRdrTyVars :: LHsType RdrName -> [Located RdrName]
90 extractHsTyRdrTyVars ty = nubBy eqLocated (extract_lty ty [])
92 extractHsRhoRdrTyVars :: LHsContext RdrName -> LHsType RdrName -> [Located RdrName]
93 -- This one takes the context and tau-part of a
94 -- sigma type and returns their free type variables
95 extractHsRhoRdrTyVars ctxt ty
96 = nubBy eqLocated $ extract_lctxt ctxt (extract_lty ty [])
98 extract_lctxt ctxt acc = foldr (extract_pred . unLoc) acc (unLoc ctxt)
100 extract_pred (HsClassP cls tys) acc = foldr extract_lty acc tys
101 extract_pred (HsEqualP ty1 ty2) acc = extract_lty ty1 (extract_lty ty2 acc)
102 extract_pred (HsIParam n ty ) acc = extract_lty ty acc
104 extract_lty (L loc ty) acc
106 HsTyVar tv -> extract_tv loc tv acc
107 HsBangTy _ ty -> extract_lty ty acc
108 HsAppTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc)
109 HsListTy ty -> extract_lty ty acc
110 HsPArrTy ty -> extract_lty ty acc
111 HsTupleTy _ tys -> foldr extract_lty acc tys
112 HsFunTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc)
113 HsPredTy p -> extract_pred p acc
114 HsOpTy ty1 (L loc tv) ty2 -> extract_tv loc tv (extract_lty ty1 (extract_lty ty2 acc))
115 HsParTy ty -> extract_lty ty acc
117 HsSpliceTy _ -> acc -- Type splices mention no type variables
118 HsKindSig ty k -> extract_lty ty acc
119 HsForAllTy exp [] cx ty -> extract_lctxt cx (extract_lty ty acc)
120 HsForAllTy exp tvs cx ty -> acc ++ (filter ((`notElem` locals) . unLoc) $
121 extract_lctxt cx (extract_lty ty []))
123 locals = hsLTyVarNames tvs
124 HsDocTy ty doc -> extract_lty ty acc
126 extract_tv :: SrcSpan -> RdrName -> [Located RdrName] -> [Located RdrName]
127 extract_tv loc tv acc | isRdrTyVar tv = L loc tv : acc
130 extractGenericPatTyVars :: LHsBinds RdrName -> [Located RdrName]
131 -- Get the type variables out of the type patterns in a bunch of
132 -- possibly-generic bindings in a class declaration
133 extractGenericPatTyVars binds
134 = nubBy eqLocated (foldrBag get [] binds)
136 get (L _ (FunBind { fun_matches = MatchGroup ms _ })) acc = foldr (get_m.unLoc) acc ms
139 get_m (Match (L _ (TypePat ty) : _) _ _) acc = extract_lty ty acc
140 get_m other acc = acc
144 %************************************************************************
146 \subsection{Construction functions for Rdr stuff}
148 %************************************************************************
150 mkClassDecl builds a RdrClassDecl, filling in the names for tycon and datacon
151 by deriving them from the name of the class. We fill in the names for the
152 tycon and datacon corresponding to the class, by deriving them from the
153 name of the class itself. This saves recording the names in the interface
154 file (which would be equally good).
156 Similarly for mkConDecl, mkClassOpSig and default-method names.
158 *** See "THE NAMING STORY" in HsDecls ****
161 mkClassDecl (cxt, cname, tyvars) fds sigs mbinds ats docs
162 = ClassDecl { tcdCtxt = cxt, tcdLName = cname, tcdTyVars = tyvars,
170 mkTyData new_or_data (context, tname, tyvars, typats) ksig data_cons maybe_deriv
171 = TyData { tcdND = new_or_data, tcdCtxt = context, tcdLName = tname,
172 tcdTyVars = tyvars, tcdTyPats = typats, tcdCons = data_cons,
173 tcdKindSig = ksig, tcdDerivs = maybe_deriv }
177 mkHsNegApp :: LHsExpr RdrName -> HsExpr RdrName
178 -- RdrName If the type checker sees (negate 3#) it will barf, because negate
179 -- can't take an unboxed arg. But that is exactly what it will see when
180 -- we write "-3#". So we have to do the negation right now!
181 mkHsNegApp (L loc e) = f e
182 where f (HsLit (HsIntPrim i)) = HsLit (HsIntPrim (-i))
183 f (HsLit (HsFloatPrim i)) = HsLit (HsFloatPrim (-i))
184 f (HsLit (HsDoublePrim i)) = HsLit (HsDoublePrim (-i))
185 f expr = NegApp (L loc e) noSyntaxExpr
188 %************************************************************************
190 \subsection[cvBinds-etc]{Converting to @HsBinds@, etc.}
192 %************************************************************************
194 Function definitions are restructured here. Each is assumed to be recursive
195 initially, and non recursive definitions are discovered by the dependency
200 -- | Groups together bindings for a single function
201 cvTopDecls :: OrdList (LHsDecl RdrName) -> [LHsDecl RdrName]
202 cvTopDecls decls = go (fromOL decls)
204 go :: [LHsDecl RdrName] -> [LHsDecl RdrName]
206 go (L l (ValD b) : ds) = L l' (ValD b') : go ds'
207 where (L l' b', ds') = getMonoBind (L l b) ds
208 go (d : ds) = d : go ds
210 -- Declaration list may only contain value bindings and signatures.
211 cvBindGroup :: OrdList (LHsDecl RdrName) -> HsValBinds RdrName
213 = case cvBindsAndSigs binding of
214 (mbs, sigs, [], _) -> -- list of type decls *always* empty
217 cvBindsAndSigs :: OrdList (LHsDecl RdrName)
218 -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName], [LDocDecl RdrName])
219 -- Input decls contain just value bindings and signatures
220 -- and in case of class or instance declarations also
221 -- associated type declarations. They might also contain Haddock comments.
222 cvBindsAndSigs fb = go (fromOL fb)
224 go [] = (emptyBag, [], [], [])
225 go (L l x@(SigD s) : ds) = (bs, L l s : ss, ts, docs)
226 where (bs, ss, ts, docs) = go ds
227 go (L l x@(ValD b) : ds) = (b' `consBag` bs, ss, ts, docs)
228 where (b', ds') = getMonoBind (L l b) ds
229 (bs, ss, ts, docs) = go ds'
230 go (L l (TyClD t): ds) = (bs, ss, L l t : ts, docs)
231 where (bs, ss, ts, docs) = go ds
232 go (L l (DocD d) : ds) = (bs, ss, ts, (L l d) : docs)
233 where (bs, ss, ts, docs) = go ds
235 -----------------------------------------------------------------------------
236 -- Group function bindings into equation groups
238 getMonoBind :: LHsBind RdrName -> [LHsDecl RdrName]
239 -> (LHsBind RdrName, [LHsDecl RdrName])
240 -- Suppose (b',ds') = getMonoBind b ds
241 -- ds is a list of parsed bindings
242 -- b is a MonoBinds that has just been read off the front
244 -- Then b' is the result of grouping more equations from ds that
245 -- belong with b into a single MonoBinds, and ds' is the depleted
246 -- list of parsed bindings.
248 -- All Haddock comments between equations inside the group are
251 -- No AndMonoBinds or EmptyMonoBinds here; just single equations
253 getMonoBind (L loc1 bind@(FunBind { fun_id = fun_id1@(L _ f1), fun_infix = is_infix1,
254 fun_matches = MatchGroup mtchs1 _ })) binds
256 = go is_infix1 mtchs1 loc1 binds []
258 go is_infix mtchs loc
259 (L loc2 (ValD (FunBind { fun_id = L _ f2, fun_infix = is_infix2,
260 fun_matches = MatchGroup mtchs2 _ })) : binds) _
261 | f1 == f2 = go (is_infix || is_infix2) (mtchs2 ++ mtchs)
262 (combineSrcSpans loc loc2) binds []
263 go is_infix mtchs loc (doc_decl@(L loc2 (DocD _)) : binds) doc_decls
264 = let doc_decls' = doc_decl : doc_decls
265 in go is_infix mtchs (combineSrcSpans loc loc2) binds doc_decls'
266 go is_infix mtchs loc binds doc_decls
267 = (L loc (makeFunBind fun_id1 is_infix (reverse mtchs)), (reverse doc_decls) ++ binds)
268 -- Reverse the final matches, to get it back in the right order
269 -- Do the same thing with the trailing doc comments
271 getMonoBind bind binds = (bind, binds)
273 has_args ((L _ (Match args _ _)) : _) = not (null args)
274 -- Don't group together FunBinds if they have
275 -- no arguments. This is necessary now that variable bindings
276 -- with no arguments are now treated as FunBinds rather
277 -- than pattern bindings (tests/rename/should_fail/rnfail002).
281 findSplice :: [LHsDecl a] -> (HsGroup a, Maybe (SpliceDecl a, [LHsDecl a]))
282 findSplice ds = addl emptyRdrGroup ds
284 mkGroup :: [LHsDecl a] -> HsGroup a
285 mkGroup ds = addImpDecls emptyRdrGroup ds
287 addImpDecls :: HsGroup a -> [LHsDecl a] -> HsGroup a
288 -- The decls are imported, and should not have a splice
289 addImpDecls group decls = case addl group decls of
290 (group', Nothing) -> group'
291 other -> panic "addImpDecls"
293 addl :: HsGroup a -> [LHsDecl a] -> (HsGroup a, Maybe (SpliceDecl a, [LHsDecl a]))
294 -- This stuff reverses the declarations (again) but it doesn't matter
297 addl gp [] = (gp, Nothing)
298 addl gp (L l d : ds) = add gp l d ds
301 add :: HsGroup a -> SrcSpan -> HsDecl a -> [LHsDecl a]
302 -> (HsGroup a, Maybe (SpliceDecl a, [LHsDecl a]))
304 add gp l (SpliceD e) ds = (gp, Just (e, ds))
306 -- Class declarations: pull out the fixity signatures to the top
307 add gp@(HsGroup {hs_tyclds = ts, hs_fixds = fs})
310 let fsigs = [ L l f | L l (FixSig f) <- tcdSigs d ] in
311 addl (gp { hs_tyclds = L l d : ts, hs_fixds = fsigs ++ fs}) ds
313 addl (gp { hs_tyclds = L l d : ts }) ds
315 addl (gp { hs_tyclds = L l d : ts }) ds
317 -- Signatures: fixity sigs go a different place than all others
318 add gp@(HsGroup {hs_fixds = ts}) l (SigD (FixSig f)) ds
319 = addl (gp {hs_fixds = L l f : ts}) ds
320 add gp@(HsGroup {hs_valds = ts}) l (SigD d) ds
321 = addl (gp {hs_valds = add_sig (L l d) ts}) ds
323 -- Value declarations: use add_bind
324 add gp@(HsGroup {hs_valds = ts}) l (ValD d) ds
325 = addl (gp { hs_valds = add_bind (L l d) ts }) ds
327 -- The rest are routine
328 add gp@(HsGroup {hs_instds = ts}) l (InstD d) ds
329 = addl (gp { hs_instds = L l d : ts }) ds
330 add gp@(HsGroup {hs_derivds = ts}) l (DerivD d) ds
331 = addl (gp { hs_derivds = L l d : ts }) ds
332 add gp@(HsGroup {hs_defds = ts}) l (DefD d) ds
333 = addl (gp { hs_defds = L l d : ts }) ds
334 add gp@(HsGroup {hs_fords = ts}) l (ForD d) ds
335 = addl (gp { hs_fords = L l d : ts }) ds
336 add gp@(HsGroup {hs_depds = ts}) l (DeprecD d) ds
337 = addl (gp { hs_depds = L l d : ts }) ds
338 add gp@(HsGroup {hs_ruleds = ts}) l (RuleD d) ds
339 = addl (gp { hs_ruleds = L l d : ts }) ds
342 = addl (gp { hs_docs = (L l d) : (hs_docs gp) }) ds
344 add_bind b (ValBindsIn bs sigs) = ValBindsIn (bs `snocBag` b) sigs
345 add_sig s (ValBindsIn bs sigs) = ValBindsIn bs (s:sigs)
348 %************************************************************************
350 \subsection[PrefixToHS-utils]{Utilities for conversion}
352 %************************************************************************
356 -----------------------------------------------------------------------------
359 -- When parsing data declarations, we sometimes inadvertently parse
360 -- a constructor application as a type (eg. in data T a b = C a b `D` E a b)
361 -- This function splits up the type application, adds any pending
362 -- arguments, and converts the type constructor back into a data constructor.
364 mkPrefixCon :: LHsType RdrName -> [LBangType RdrName]
365 -> P (Located RdrName, HsConDetails RdrName (LBangType RdrName))
369 split (L _ (HsAppTy t u)) ts = split t (u : ts)
370 split (L l (HsTyVar tc)) ts = do data_con <- tyConToDataCon l tc
371 return (data_con, PrefixCon ts)
372 split (L l _) _ = parseError l "parse error in data/newtype declaration"
374 mkRecCon :: Located RdrName ->
375 [([Located RdrName], LBangType RdrName, Maybe (LHsDoc RdrName))] ->
376 P (Located RdrName, HsConDetails RdrName (LBangType RdrName))
377 mkRecCon (L loc con) fields
378 = do data_con <- tyConToDataCon loc con
379 return (data_con, RecCon [ (HsRecField l t d) | (ls, t, d) <- fields, l <- ls ])
381 tyConToDataCon :: SrcSpan -> RdrName -> P (Located RdrName)
382 tyConToDataCon loc tc
383 | isTcOcc (rdrNameOcc tc)
384 = return (L loc (setRdrNameSpace tc srcDataName))
386 = parseError loc (showSDoc (text "Not a constructor:" <+> quotes (ppr tc)))
388 ----------------------------------------------------------------------------
389 -- Various Syntactic Checks
391 checkInstType :: LHsType RdrName -> P (LHsType RdrName)
392 checkInstType (L l t)
394 HsForAllTy exp tvs ctxt ty -> do
395 dict_ty <- checkDictTy ty
396 return (L l (HsForAllTy exp tvs ctxt dict_ty))
398 HsParTy ty -> checkInstType ty
400 ty -> do dict_ty <- checkDictTy (L l ty)
401 return (L l (HsForAllTy Implicit [] (noLoc []) dict_ty))
403 checkDictTy :: LHsType RdrName -> P (LHsType RdrName)
404 checkDictTy (L spn ty) = check ty []
406 check (HsTyVar t) args | not (isRdrTyVar t)
407 = return (L spn (HsPredTy (HsClassP t args)))
408 check (HsAppTy l r) args = check (unLoc l) (r:args)
409 check (HsParTy t) args = check (unLoc t) args
410 check _ _ = parseError spn "Malformed instance header"
412 -- Check whether the given list of type parameters are all type variables
413 -- (possibly with a kind signature). If the second argument is `False',
414 -- only type variables are allowed and we raise an error on encountering a
415 -- non-variable; otherwise, we allow non-variable arguments and return the
416 -- entire list of parameters.
418 checkTyVars :: [LHsType RdrName] -> P ()
419 checkTyVars tparms = mapM_ chk tparms
421 -- Check that the name space is correct!
422 chk (L l (HsKindSig (L _ (HsTyVar tv)) k))
423 | isRdrTyVar tv = return ()
424 chk (L l (HsTyVar tv))
425 | isRdrTyVar tv = return ()
427 parseError l "Type found where type variable expected"
429 -- Check whether the type arguments in a type synonym head are simply
430 -- variables. If not, we have a type equation of a type function and return
431 -- all patterns. If yes, we return 'Nothing' as the third component to
432 -- indicate a vanilla type synonym.
434 checkSynHdr :: LHsType RdrName
435 -> Bool -- is type instance?
436 -> P (Located RdrName, -- head symbol
437 [LHsTyVarBndr RdrName], -- parameters
438 [LHsType RdrName]) -- type patterns
439 checkSynHdr ty isTyInst =
440 do { (_, tc, tvs, tparms) <- checkTyClHdr (noLoc []) ty
441 ; unless isTyInst $ checkTyVars tparms
442 ; return (tc, tvs, tparms) }
445 -- Well-formedness check and decomposition of type and class heads.
447 checkTyClHdr :: LHsContext RdrName -> LHsType RdrName
448 -> P (LHsContext RdrName, -- the type context
449 Located RdrName, -- the head symbol (type or class name)
450 [LHsTyVarBndr RdrName], -- free variables of the non-context part
451 [LHsType RdrName]) -- parameters of head symbol
452 -- The header of a type or class decl should look like
453 -- (C a, D b) => T a b
457 -- With associated types, we can also have non-variable parameters; ie,
459 -- The unaltered parameter list is returned in the fourth component of the
463 -- ('()', 'T', ['a'], ['Int', '[a]'])
464 checkTyClHdr (L l cxt) ty
465 = do (tc, tvs, parms) <- gol ty []
467 return (L l cxt, tc, tvs, parms)
469 gol (L l ty) acc = go l ty acc
471 go l (HsTyVar tc) acc
472 | not (isRdrTyVar tc) = do
473 tvs <- extractTyVars acc
474 return (L l tc, tvs, acc)
475 go l (HsOpTy t1 tc t2) acc = do
476 tvs <- extractTyVars (t1:t2:acc)
477 return (tc, tvs, acc)
478 go l (HsParTy ty) acc = gol ty acc
479 go l (HsAppTy t1 t2) acc = gol t1 (t2:acc)
481 parseError l "Malformed head of type or class declaration"
483 -- The predicates in a type or class decl must be class predicates or
484 -- equational constraints. They need not all have variable-only
485 -- arguments, even in Haskell 98.
486 -- E.g. class (Monad m, Monad (t m)) => MonadT t m
487 chk_pred (L l (HsClassP _ _)) = return ()
488 chk_pred (L l (HsEqualP _ _)) = return ()
490 = parseError l "Malformed context in type or class declaration"
492 -- Extract the type variables of a list of type parameters.
494 -- * Type arguments can be complex type terms (needed for associated type
497 extractTyVars :: [LHsType RdrName] -> P [LHsTyVarBndr RdrName]
498 extractTyVars tvs = collects [] tvs
500 -- Collect all variables (1st arg serves as an accumulator)
501 collect tvs (L l (HsForAllTy _ _ _ _)) =
502 parseError l "Forall type not allowed as type parameter"
503 collect tvs (L l (HsTyVar tv))
504 | isRdrTyVar tv = return $ L l (UserTyVar tv) : tvs
505 | otherwise = return tvs
506 collect tvs (L l (HsBangTy _ _ )) =
507 parseError l "Bang-style type annotations not allowed as type parameter"
508 collect tvs (L l (HsAppTy t1 t2 )) = do
509 tvs' <- collect tvs t2
511 collect tvs (L l (HsFunTy t1 t2 )) = do
512 tvs' <- collect tvs t2
514 collect tvs (L l (HsListTy t )) = collect tvs t
515 collect tvs (L l (HsPArrTy t )) = collect tvs t
516 collect tvs (L l (HsTupleTy _ ts )) = collects tvs ts
517 collect tvs (L l (HsOpTy t1 _ t2 )) = do
518 tvs' <- collect tvs t2
520 collect tvs (L l (HsParTy t )) = collect tvs t
521 collect tvs (L l (HsNumTy t )) = return tvs
522 collect tvs (L l (HsPredTy t )) =
523 parseError l "Predicate not allowed as type parameter"
524 collect tvs (L l (HsKindSig (L _ (HsTyVar tv)) k))
526 return $ L l (KindedTyVar tv k) : tvs
528 parseError l "Kind signature only allowed for type variables"
529 collect tvs (L l (HsSpliceTy t )) =
530 parseError l "Splice not allowed as type parameter"
532 -- Collect all variables of a list of types
533 collects tvs [] = return tvs
534 collects tvs (t:ts) = do
535 tvs' <- collects tvs ts
538 -- Check that associated type declarations of a class are all kind signatures.
540 checkKindSigs :: [LTyClDecl RdrName] -> P ()
541 checkKindSigs = mapM_ check
544 | isFamilyDecl tydecl
545 || isSynDecl tydecl = return ()
547 parseError l "Type declaration in a class must be a kind signature or synonym default"
549 checkContext :: LHsType RdrName -> P (LHsContext RdrName)
553 check (HsTupleTy _ ts) -- (Eq a, Ord b) shows up as a tuple type
554 = do ctx <- mapM checkPred ts
557 check (HsParTy ty) -- to be sure HsParTy doesn't get into the way
560 check (HsTyVar t) -- Empty context shows up as a unit type ()
561 | t == getRdrName unitTyCon = return (L l [])
564 = do p <- checkPred (L l t)
568 checkPred :: LHsType RdrName -> P (LHsPred RdrName)
569 -- Watch out.. in ...deriving( Show )... we use checkPred on
570 -- the list of partially applied predicates in the deriving,
571 -- so there can be zero args.
572 checkPred (L spn (HsPredTy (HsIParam n ty)))
573 = return (L spn (HsIParam n ty))
577 checkl (L l ty) args = check l ty args
579 check _loc (HsPredTy pred@(HsEqualP _ _))
581 = return $ L spn pred
582 check _loc (HsTyVar t) args | not (isRdrTyVar t)
583 = return (L spn (HsClassP t args))
584 check _loc (HsAppTy l r) args = checkl l (r:args)
585 check _loc (HsOpTy l (L loc tc) r) args = check loc (HsTyVar tc) (l:r:args)
586 check _loc (HsParTy t) args = checkl t args
587 check loc _ _ = parseError loc
588 "malformed class assertion"
590 ---------------------------------------------------------------------------
591 -- Checking stand-alone deriving declarations
593 checkDerivDecl :: LDerivDecl RdrName -> P (LDerivDecl RdrName)
594 checkDerivDecl d@(L loc _) =
595 do glaExtOn <- extension glaExtsEnabled
596 if glaExtOn then return d
597 else parseError loc "Illegal stand-alone deriving declaration (use -fglasgow-exts)"
599 ---------------------------------------------------------------------------
600 -- Checking statements in a do-expression
601 -- We parse do { e1 ; e2 ; }
602 -- as [ExprStmt e1, ExprStmt e2]
603 -- checkDo (a) checks that the last thing is an ExprStmt
604 -- (b) returns it separately
605 -- same comments apply for mdo as well
607 checkDo = checkDoMDo "a " "'do'"
608 checkMDo = checkDoMDo "an " "'mdo'"
610 checkDoMDo :: String -> String -> SrcSpan -> [LStmt RdrName] -> P ([LStmt RdrName], LHsExpr RdrName)
611 checkDoMDo pre nm loc [] = parseError loc ("Empty " ++ nm ++ " construct")
612 checkDoMDo pre nm loc ss = do
615 check [L l (ExprStmt e _ _)] = return ([], e)
616 check [L l _] = parseError l ("The last statement in " ++ pre ++ nm ++
617 " construct must be an expression")
622 -- -------------------------------------------------------------------------
623 -- Checking Patterns.
625 -- We parse patterns as expressions and check for valid patterns below,
626 -- converting the expression into a pattern at the same time.
628 checkPattern :: LHsExpr RdrName -> P (LPat RdrName)
629 checkPattern e = checkLPat e
631 checkPatterns :: [LHsExpr RdrName] -> P [LPat RdrName]
632 checkPatterns es = mapM checkPattern es
634 checkLPat :: LHsExpr RdrName -> P (LPat RdrName)
635 checkLPat e@(L l _) = checkPat l e []
637 checkPat :: SrcSpan -> LHsExpr RdrName -> [LPat RdrName] -> P (LPat RdrName)
638 checkPat loc (L l (HsVar c)) args
639 | isRdrDataCon c = return (L loc (ConPatIn (L l c) (PrefixCon args)))
640 checkPat loc e args -- OK to let this happen even if bang-patterns
641 -- are not enabled, because there is no valid
642 -- non-bang-pattern parse of (C ! e)
643 | Just (e', args') <- splitBang e
644 = do { args'' <- checkPatterns args'
645 ; checkPat loc e' (args'' ++ args) }
646 checkPat loc (L _ (HsApp f x)) args
647 = do { x <- checkLPat x; checkPat loc f (x:args) }
648 checkPat loc (L _ e) []
649 = do { p <- checkAPat loc e; return (L loc p) }
650 checkPat loc pat _some_args
653 checkAPat loc e = case e of
654 EWildPat -> return (WildPat placeHolderType)
655 HsVar x | isQual x -> parseError loc ("Qualified variable in pattern: "
657 | otherwise -> return (VarPat x)
658 HsLit l -> return (LitPat l)
660 -- Overloaded numeric patterns (e.g. f 0 x = x)
661 -- Negation is recorded separately, so that the literal is zero or +ve
662 -- NB. Negative *primitive* literals are already handled by
663 -- RdrHsSyn.mkHsNegApp
664 HsOverLit pos_lit -> return (mkNPat pos_lit Nothing)
665 NegApp (L _ (HsOverLit pos_lit)) _
666 -> return (mkNPat pos_lit (Just noSyntaxExpr))
668 SectionR (L _ (HsVar bang)) e -- (! x)
670 -> do { bang_on <- extension bangPatEnabled
671 ; if bang_on then checkLPat e >>= (return . BangPat)
672 else parseError loc "Illegal bang-pattern (use -fbang-patterns)" }
674 ELazyPat e -> checkLPat e >>= (return . LazyPat)
675 EAsPat n e -> checkLPat e >>= (return . AsPat n)
676 ExprWithTySig e t -> checkLPat e >>= \e ->
677 -- Pattern signatures are parsed as sigtypes,
678 -- but they aren't explicit forall points. Hence
679 -- we have to remove the implicit forall here.
681 L _ (HsForAllTy Implicit _ (L _ []) ty) -> ty
684 return (SigPatIn e t')
687 OpApp (L nloc (HsVar n)) (L _ (HsVar plus)) _
688 (L _ (HsOverLit lit@(HsIntegral _ _)))
690 -> return (mkNPlusKPat (L nloc n) lit)
692 OpApp l op fix r -> checkLPat l >>= \l ->
693 checkLPat r >>= \r ->
695 L cl (HsVar c) | isDataOcc (rdrNameOcc c)
696 -> return (ConPatIn (L cl c) (InfixCon l r))
699 HsPar e -> checkLPat e >>= (return . ParPat)
700 ExplicitList _ es -> mapM (\e -> checkLPat e) es >>= \ps ->
701 return (ListPat ps placeHolderType)
702 ExplicitPArr _ es -> mapM (\e -> checkLPat e) es >>= \ps ->
703 return (PArrPat ps placeHolderType)
705 ExplicitTuple es b -> mapM (\e -> checkLPat e) es >>= \ps ->
706 return (TuplePat ps b placeHolderType)
708 RecordCon c _ fs -> mapM checkPatField fs >>= \fs ->
709 return (ConPatIn c (RecCon (map (uncurry mkRecField) fs)))
711 HsType ty -> return (TypePat ty)
714 plus_RDR, bang_RDR :: RdrName
715 plus_RDR = mkUnqual varName FSLIT("+") -- Hack
716 bang_RDR = mkUnqual varName FSLIT("!") -- Hack
718 checkPatField :: (Located RdrName, LHsExpr RdrName) -> P (Located RdrName, LPat RdrName)
719 checkPatField (n,e) = do
723 patFail loc = parseError loc "Parse error in pattern"
726 ---------------------------------------------------------------------------
727 -- Check Equation Syntax
729 checkValDef :: LHsExpr RdrName
730 -> Maybe (LHsType RdrName)
731 -> Located (GRHSs RdrName)
732 -> P (HsBind RdrName)
734 checkValDef lhs (Just sig) grhss
735 -- x :: ty = rhs parses as a *pattern* binding
736 = checkPatBind (L (combineLocs lhs sig) (ExprWithTySig lhs sig)) grhss
738 checkValDef lhs opt_sig grhss
739 = do { mb_fun <- isFunLhs lhs
741 Just (fun, is_infix, pats) -> checkFunBind (getLoc lhs)
742 fun is_infix pats opt_sig grhss
743 Nothing -> checkPatBind lhs grhss }
745 checkFunBind lhs_loc fun is_infix pats opt_sig (L rhs_span grhss)
747 = parseError (getLoc fun) ("Qualified name in function definition: " ++
748 showRdrName (unLoc fun))
750 = do ps <- checkPatterns pats
751 let match_span = combineSrcSpans lhs_loc rhs_span
752 return (makeFunBind fun is_infix [L match_span (Match ps opt_sig grhss)])
753 -- The span of the match covers the entire equation.
754 -- That isn't quite right, but it'll do for now.
756 makeFunBind :: Located id -> Bool -> [LMatch id] -> HsBind id
757 -- Like HsUtils.mkFunBind, but we need to be able to set the fixity too
758 makeFunBind fn is_infix ms
759 = FunBind { fun_id = fn, fun_infix = is_infix, fun_matches = mkMatchGroup ms,
760 fun_co_fn = idHsWrapper, bind_fvs = placeHolderNames, fun_tick = Nothing }
762 checkPatBind lhs (L _ grhss)
763 = do { lhs <- checkPattern lhs
764 ; return (PatBind lhs grhss placeHolderType placeHolderNames) }
770 checkValSig (L l (HsVar v)) ty
771 | isUnqual v && not (isDataOcc (rdrNameOcc v))
772 = return (TypeSig (L l v) ty)
773 checkValSig (L l other) ty
774 = parseError l "Invalid type signature"
776 mkGadtDecl :: Located RdrName
777 -> LHsType RdrName -- assuming HsType
779 mkGadtDecl name (L _ (HsForAllTy _ qvars cxt ty)) = mk_gadt_con name qvars cxt ty
780 mkGadtDecl name ty = mk_gadt_con name [] (noLoc []) ty
782 mk_gadt_con name qvars cxt ty
783 = ConDecl { con_name = name
784 , con_explicit = Implicit
787 , con_details = PrefixCon []
788 , con_res = ResTyGADT ty
789 , con_doc = Nothing }
790 -- NB: we put the whole constr type into the ResTyGADT for now;
791 -- the renamer will unravel it once it has sorted out
794 -- A variable binding is parsed as a FunBind.
797 -- The parser left-associates, so there should
798 -- not be any OpApps inside the e's
799 splitBang :: LHsExpr RdrName -> Maybe (LHsExpr RdrName, [LHsExpr RdrName])
800 -- Splits (f ! g a b) into (f, [(! g), a, b])
801 splitBang (L loc (OpApp l_arg bang@(L loc' (HsVar op)) _ r_arg))
802 | op == bang_RDR = Just (l_arg, L loc (SectionR bang arg1) : argns)
804 (arg1,argns) = split_bang r_arg []
805 split_bang (L _ (HsApp f e)) es = split_bang f (e:es)
806 split_bang e es = (e,es)
807 splitBang other = Nothing
809 isFunLhs :: LHsExpr RdrName
810 -> P (Maybe (Located RdrName, Bool, [LHsExpr RdrName]))
811 -- Just (fun, is_infix, arg_pats) if e is a function LHS
813 -- The whole LHS is parsed as a single expression.
814 -- Any infix operators on the LHS will parse left-associatively
816 -- will parse (rather strangely) as
818 -- It's up to isFunLhs to sort out the mess
824 go (L loc (HsVar f)) es
825 | not (isRdrDataCon f) = return (Just (L loc f, False, es))
826 go (L _ (HsApp f e)) es = go f (e:es)
827 go (L _ (HsPar e)) es@(_:_) = go e es
829 -- For infix function defns, there should be only one infix *function*
830 -- (though there may be infix *datacons* involved too). So we don't
831 -- need fixity info to figure out which function is being defined.
832 -- a `K1` b `op` c `K2` d
834 -- (a `K1` b) `op` (c `K2` d)
835 -- The renamer checks later that the precedences would yield such a parse.
837 -- There is a complication to deal with bang patterns.
839 -- ToDo: what about this?
840 -- x + 1 `op` y = ...
842 go e@(L loc (OpApp l (L loc' (HsVar op)) fix r)) es
843 | Just (e',es') <- splitBang e
844 = do { bang_on <- extension bangPatEnabled
845 ; if bang_on then go e' (es' ++ es)
846 else return (Just (L loc' op, True, (l:r:es))) }
847 -- No bangs; behave just like the next case
848 | not (isRdrDataCon op) -- We have found the function!
849 = return (Just (L loc' op, True, (l:r:es)))
850 | otherwise -- Infix data con; keep going
851 = do { mb_l <- go l es
853 Just (op', True, j : k : es')
854 -> return (Just (op', True, j : op_app : es'))
856 op_app = L loc (OpApp k (L loc' (HsVar op)) fix r)
857 _ -> return Nothing }
858 go _ _ = return Nothing
860 ---------------------------------------------------------------------------
861 -- Miscellaneous utilities
863 checkPrecP :: Located Int -> P Int
865 | 0 <= i && i <= maxPrecedence = return i
866 | otherwise = parseError l "Precedence out of range"
871 -> HsRecordBinds RdrName
872 -> P (HsExpr RdrName)
874 mkRecConstrOrUpdate (L l (HsVar c)) loc fs | isRdrDataCon c
875 = return (RecordCon (L l c) noPostTcExpr fs)
876 mkRecConstrOrUpdate exp loc fs@(_:_)
877 = return (RecordUpd exp fs placeHolderType placeHolderType)
878 mkRecConstrOrUpdate _ loc []
879 = parseError loc "Empty record update"
881 mkInlineSpec :: Maybe Activation -> Bool -> InlineSpec
882 -- The Maybe is becuase the user can omit the activation spec (and usually does)
883 mkInlineSpec Nothing True = alwaysInlineSpec -- INLINE
884 mkInlineSpec Nothing False = neverInlineSpec -- NOINLINE
885 mkInlineSpec (Just act) inl = Inline act inl
888 -----------------------------------------------------------------------------
889 -- utilities for foreign declarations
891 -- supported calling conventions
893 data CallConv = CCall CCallConv -- ccall or stdcall
896 -- construct a foreign import declaration
900 -> (Located FastString, Located RdrName, LHsType RdrName)
901 -> P (HsDecl RdrName)
902 mkImport (CCall cconv) safety (entity, v, ty) = do
903 importSpec <- parseCImport entity cconv safety v
904 return (ForD (ForeignImport v ty importSpec))
905 mkImport (DNCall ) _ (entity, v, ty) = do
906 spec <- parseDImport entity
907 return $ ForD (ForeignImport v ty (DNImport spec))
909 -- parse the entity string of a foreign import declaration for the `ccall' or
910 -- `stdcall' calling convention'
912 parseCImport :: Located FastString
917 parseCImport (L loc entity) cconv safety v
918 -- FIXME: we should allow white space around `dynamic' and `wrapper' -=chak
919 | entity == FSLIT ("dynamic") =
920 return $ CImport cconv safety nilFS nilFS (CFunction DynamicTarget)
921 | entity == FSLIT ("wrapper") =
922 return $ CImport cconv safety nilFS nilFS CWrapper
923 | otherwise = parse0 (unpackFS entity)
925 -- using the static keyword?
926 parse0 (' ': rest) = parse0 rest
927 parse0 ('s':'t':'a':'t':'i':'c':rest) = parse1 rest
928 parse0 rest = parse1 rest
929 -- check for header file name
930 parse1 "" = parse4 "" nilFS False nilFS
931 parse1 (' ':rest) = parse1 rest
932 parse1 str@('&':_ ) = parse2 str nilFS
933 parse1 str@('[':_ ) = parse3 str nilFS False
935 | ".h" `isSuffixOf` first = parse2 rest (mkFastString first)
936 | otherwise = parse4 str nilFS False nilFS
938 (first, rest) = break (\c -> c == ' ' || c == '&' || c == '[') str
939 -- check for address operator (indicating a label import)
940 parse2 "" header = parse4 "" header False nilFS
941 parse2 (' ':rest) header = parse2 rest header
942 parse2 ('&':rest) header = parse3 rest header True
943 parse2 str@('[':_ ) header = parse3 str header False
944 parse2 str header = parse4 str header False nilFS
945 -- check for library object name
946 parse3 (' ':rest) header isLbl = parse3 rest header isLbl
947 parse3 ('[':rest) header isLbl =
948 case break (== ']') rest of
949 (lib, ']':rest) -> parse4 rest header isLbl (mkFastString lib)
950 _ -> parseError loc "Missing ']' in entity"
951 parse3 str header isLbl = parse4 str header isLbl nilFS
952 -- check for name of C function
953 parse4 "" header isLbl lib = build (mkExtName (unLoc v)) header isLbl lib
954 parse4 (' ':rest) header isLbl lib = parse4 rest header isLbl lib
955 parse4 str header isLbl lib
956 | all (== ' ') rest = build (mkFastString first) header isLbl lib
957 | otherwise = parseError loc "Malformed entity string"
959 (first, rest) = break (== ' ') str
961 build cid header False lib = return $
962 CImport cconv safety header lib (CFunction (StaticTarget cid))
963 build cid header True lib = return $
964 CImport cconv safety header lib (CLabel cid )
967 -- Unravel a dotnet spec string.
969 parseDImport :: Located FastString -> P DNCallSpec
970 parseDImport (L loc entity) = parse0 comps
972 comps = words (unpackFS entity)
976 | x == "static" = parse1 True xs
977 | otherwise = parse1 False (x:xs)
980 parse1 isStatic (x:xs)
981 | x == "method" = parse2 isStatic DNMethod xs
982 | x == "field" = parse2 isStatic DNField xs
983 | x == "ctor" = parse2 isStatic DNConstructor xs
984 parse1 isStatic xs = parse2 isStatic DNMethod xs
987 parse2 isStatic kind (('[':x):xs) =
990 vs | last vs == ']' -> parse3 isStatic kind (init vs) xs
991 parse2 isStatic kind xs = parse3 isStatic kind "" xs
993 parse3 isStatic kind assem [x] =
994 return (DNCallSpec isStatic kind assem x
995 -- these will be filled in once known.
996 (error "FFI-dotnet-args")
997 (error "FFI-dotnet-result"))
998 parse3 _ _ _ _ = d'oh
1000 d'oh = parseError loc "Malformed entity string"
1002 -- construct a foreign export declaration
1004 mkExport :: CallConv
1005 -> (Located FastString, Located RdrName, LHsType RdrName)
1006 -> P (HsDecl RdrName)
1007 mkExport (CCall cconv) (L loc entity, v, ty) = return $
1008 ForD (ForeignExport v ty (CExport (CExportStatic entity' cconv)))
1010 entity' | nullFS entity = mkExtName (unLoc v)
1011 | otherwise = entity
1012 mkExport DNCall (L loc entity, v, ty) =
1013 parseError (getLoc v){-TODO: not quite right-}
1014 "Foreign export is not yet supported for .NET"
1016 -- Supplying the ext_name in a foreign decl is optional; if it
1017 -- isn't there, the Haskell name is assumed. Note that no transformation
1018 -- of the Haskell name is then performed, so if you foreign export (++),
1019 -- it's external name will be "++". Too bad; it's important because we don't
1020 -- want z-encoding (e.g. names with z's in them shouldn't be doubled)
1022 mkExtName :: RdrName -> CLabelString
1023 mkExtName rdrNm = mkFastString (occNameString (rdrNameOcc rdrNm))
1027 -----------------------------------------------------------------------------
1031 showRdrName :: RdrName -> String
1032 showRdrName r = showSDoc (ppr r)
1034 parseError :: SrcSpan -> String -> P a
1035 parseError span s = failSpanMsgP span s