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 checkPattern, -- HsExp -> P HsPat
44 checkPatterns, -- SrcLoc -> [HsExp] -> P [HsPat]
45 checkDo, -- [Stmt] -> P [Stmt]
46 checkMDo, -- [Stmt] -> P [Stmt]
47 checkValDef, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl
48 checkValSig, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl
49 parseError, -- String -> Pa
52 #include "HsVersions.h"
54 import HsSyn -- Lots of it
55 import RdrName ( RdrName, isRdrTyVar, mkUnqual, rdrNameOcc,
56 isRdrDataCon, isUnqual, getRdrName, isQual,
58 import BasicTypes ( maxPrecedence, Activation, InlineSpec(..), alwaysInlineSpec, neverInlineSpec )
59 import Lexer ( P, failSpanMsgP, extension, bangPatEnabled )
60 import TysWiredIn ( unitTyCon )
61 import ForeignCall ( CCallConv, Safety, CCallTarget(..), CExportSpec(..),
62 DNCallSpec(..), DNKind(..), CLabelString )
63 import OccName ( srcDataName, varName, isDataOcc, isTcOcc,
66 import OrdList ( OrdList, fromOL )
67 import Bag ( Bag, emptyBag, snocBag, consBag, foldrBag )
72 import List ( isSuffixOf, nubBy )
73 import Monad ( unless )
77 %************************************************************************
79 \subsection{A few functions over HsSyn at RdrName}
81 %************************************************************************
83 extractHsTyRdrNames finds the free variables of a HsType
84 It's used when making the for-alls explicit.
87 extractHsTyRdrTyVars :: LHsType RdrName -> [Located RdrName]
88 extractHsTyRdrTyVars ty = nubBy eqLocated (extract_lty ty [])
90 extractHsRhoRdrTyVars :: LHsContext RdrName -> LHsType RdrName -> [Located RdrName]
91 -- This one takes the context and tau-part of a
92 -- sigma type and returns their free type variables
93 extractHsRhoRdrTyVars ctxt ty
94 = nubBy eqLocated $ extract_lctxt ctxt (extract_lty ty [])
96 extract_lctxt ctxt acc = foldr (extract_pred . unLoc) acc (unLoc ctxt)
98 extract_pred (HsClassP cls tys) acc = foldr extract_lty acc tys
99 extract_pred (HsIParam n ty) acc = extract_lty ty acc
101 extract_lty (L loc ty) acc
103 HsTyVar tv -> extract_tv loc tv acc
104 HsBangTy _ ty -> extract_lty ty acc
105 HsAppTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc)
106 HsListTy ty -> extract_lty ty acc
107 HsPArrTy ty -> extract_lty ty acc
108 HsTupleTy _ tys -> foldr extract_lty acc tys
109 HsFunTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc)
110 HsPredTy p -> extract_pred p acc
111 HsOpTy ty1 (L loc tv) ty2 -> extract_tv loc tv (extract_lty ty1 (extract_lty ty2 acc))
112 HsParTy ty -> extract_lty ty acc
114 HsSpliceTy _ -> acc -- Type splices mention no type variables
115 HsKindSig ty k -> extract_lty ty acc
116 HsForAllTy exp [] cx ty -> extract_lctxt cx (extract_lty ty acc)
117 HsForAllTy exp tvs cx ty -> acc ++ (filter ((`notElem` locals) . unLoc) $
118 extract_lctxt cx (extract_lty ty []))
120 locals = hsLTyVarNames tvs
122 extract_tv :: SrcSpan -> RdrName -> [Located RdrName] -> [Located RdrName]
123 extract_tv loc tv acc | isRdrTyVar tv = L loc tv : acc
126 extractGenericPatTyVars :: LHsBinds RdrName -> [Located RdrName]
127 -- Get the type variables out of the type patterns in a bunch of
128 -- possibly-generic bindings in a class declaration
129 extractGenericPatTyVars binds
130 = nubBy eqLocated (foldrBag get [] binds)
132 get (L _ (FunBind { fun_matches = MatchGroup ms _ })) acc = foldr (get_m.unLoc) acc ms
135 get_m (Match (L _ (TypePat ty) : _) _ _) acc = extract_lty ty acc
136 get_m other acc = acc
140 %************************************************************************
142 \subsection{Construction functions for Rdr stuff}
144 %************************************************************************
146 mkClassDecl builds a RdrClassDecl, filling in the names for tycon and datacon
147 by deriving them from the name of the class. We fill in the names for the
148 tycon and datacon corresponding to the class, by deriving them from the
149 name of the class itself. This saves recording the names in the interface
150 file (which would be equally good).
152 Similarly for mkConDecl, mkClassOpSig and default-method names.
154 *** See "THE NAMING STORY" in HsDecls ****
157 mkClassDecl (cxt, cname, tyvars) fds sigs mbinds ats
158 = ClassDecl { tcdCtxt = cxt, tcdLName = cname, tcdTyVars = tyvars,
165 mkTyData new_or_data (context, tname, tyvars, typats) ksig data_cons maybe_deriv
166 = TyData { tcdND = new_or_data, tcdCtxt = context, tcdLName = tname,
167 tcdTyVars = tyvars, tcdTyPats = typats, tcdCons = data_cons,
168 tcdKindSig = ksig, tcdDerivs = maybe_deriv }
172 mkHsNegApp :: LHsExpr RdrName -> HsExpr RdrName
173 -- RdrName If the type checker sees (negate 3#) it will barf, because negate
174 -- can't take an unboxed arg. But that is exactly what it will see when
175 -- we write "-3#". So we have to do the negation right now!
176 mkHsNegApp (L loc e) = f e
177 where f (HsLit (HsIntPrim i)) = HsLit (HsIntPrim (-i))
178 f (HsLit (HsFloatPrim i)) = HsLit (HsFloatPrim (-i))
179 f (HsLit (HsDoublePrim i)) = HsLit (HsDoublePrim (-i))
180 f expr = NegApp (L loc e) noSyntaxExpr
183 %************************************************************************
185 \subsection[cvBinds-etc]{Converting to @HsBinds@, etc.}
187 %************************************************************************
189 Function definitions are restructured here. Each is assumed to be recursive
190 initially, and non recursive definitions are discovered by the dependency
195 -- | Groups together bindings for a single function
196 cvTopDecls :: OrdList (LHsDecl RdrName) -> [LHsDecl RdrName]
197 cvTopDecls decls = go (fromOL decls)
199 go :: [LHsDecl RdrName] -> [LHsDecl RdrName]
201 go (L l (ValD b) : ds) = L l' (ValD b') : go ds'
202 where (L l' b', ds') = getMonoBind (L l b) ds
203 go (d : ds) = d : go ds
205 -- Declaration list may only contain value bindings and signatures
207 cvBindGroup :: OrdList (LHsDecl RdrName) -> HsValBinds RdrName
209 = case cvBindsAndSigs binding of
210 (mbs, sigs, []) -> -- list of type decls *always* empty
213 cvBindsAndSigs :: OrdList (LHsDecl RdrName)
214 -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName])
215 -- Input decls contain just value bindings and signatures
216 -- and in case of class or instance declarations also
217 -- associated type declarations
218 cvBindsAndSigs fb = go (fromOL fb)
220 go [] = (emptyBag, [], [])
221 go (L l (SigD s) : ds) = (bs, L l s : ss, ts)
222 where (bs, ss, ts) = go ds
223 go (L l (ValD b) : ds) = (b' `consBag` bs, ss, ts)
224 where (b', ds') = getMonoBind (L l b) ds
225 (bs, ss, ts) = go ds'
226 go (L l (TyClD t): ds) = (bs, ss, L l t : ts)
227 where (bs, ss, ts) = go ds
229 -----------------------------------------------------------------------------
230 -- Group function bindings into equation groups
232 getMonoBind :: LHsBind RdrName -> [LHsDecl RdrName]
233 -> (LHsBind RdrName, [LHsDecl RdrName])
234 -- Suppose (b',ds') = getMonoBind b ds
235 -- ds is a list of parsed bindings
236 -- b is a MonoBinds that has just been read off the front
238 -- Then b' is the result of grouping more equations from ds that
239 -- belong with b into a single MonoBinds, and ds' is the depleted
240 -- list of parsed bindings.
242 -- No AndMonoBinds or EmptyMonoBinds here; just single equations
244 getMonoBind (L loc1 bind@(FunBind { fun_id = fun_id1@(L _ f1), fun_infix = is_infix1,
245 fun_matches = MatchGroup mtchs1 _ })) binds
247 = go is_infix1 mtchs1 loc1 binds
249 go is_infix mtchs loc
250 (L loc2 (ValD (FunBind { fun_id = L _ f2, fun_infix = is_infix2,
251 fun_matches = MatchGroup mtchs2 _ })) : binds)
252 | f1 == f2 = go (is_infix || is_infix2) (mtchs2 ++ mtchs)
253 (combineSrcSpans loc loc2) binds
254 go is_infix mtchs loc binds
255 = (L loc (makeFunBind fun_id1 is_infix (reverse mtchs)), binds)
256 -- Reverse the final matches, to get it back in the right order
258 getMonoBind bind binds = (bind, binds)
260 has_args ((L _ (Match args _ _)) : _) = not (null args)
261 -- Don't group together FunBinds if they have
262 -- no arguments. This is necessary now that variable bindings
263 -- with no arguments are now treated as FunBinds rather
264 -- than pattern bindings (tests/rename/should_fail/rnfail002).
268 findSplice :: [LHsDecl a] -> (HsGroup a, Maybe (SpliceDecl a, [LHsDecl a]))
269 findSplice ds = addl emptyRdrGroup ds
271 mkGroup :: [LHsDecl a] -> HsGroup a
272 mkGroup ds = addImpDecls emptyRdrGroup ds
274 addImpDecls :: HsGroup a -> [LHsDecl a] -> HsGroup a
275 -- The decls are imported, and should not have a splice
276 addImpDecls group decls = case addl group decls of
277 (group', Nothing) -> group'
278 other -> panic "addImpDecls"
280 addl :: HsGroup a -> [LHsDecl a] -> (HsGroup a, Maybe (SpliceDecl a, [LHsDecl a]))
281 -- This stuff reverses the declarations (again) but it doesn't matter
284 addl gp [] = (gp, Nothing)
285 addl gp (L l d : ds) = add gp l d ds
288 add :: HsGroup a -> SrcSpan -> HsDecl a -> [LHsDecl a]
289 -> (HsGroup a, Maybe (SpliceDecl a, [LHsDecl a]))
291 add gp l (SpliceD e) ds = (gp, Just (e, ds))
293 -- Class declarations: pull out the fixity signatures to the top
294 add gp@(HsGroup {hs_tyclds = ts, hs_fixds = fs}) l (TyClD d) ds
296 let fsigs = [ L l f | L l (FixSig f) <- tcdSigs d ] in
297 addl (gp { hs_tyclds = L l d : ts, hs_fixds = fsigs ++ fs }) ds
299 addl (gp { hs_tyclds = L l d : ts }) ds
301 -- Signatures: fixity sigs go a different place than all others
302 add gp@(HsGroup {hs_fixds = ts}) l (SigD (FixSig f)) ds
303 = addl (gp {hs_fixds = L l f : ts}) ds
304 add gp@(HsGroup {hs_valds = ts}) l (SigD d) ds
305 = addl (gp {hs_valds = add_sig (L l d) ts}) ds
307 -- Value declarations: use add_bind
308 add gp@(HsGroup {hs_valds = ts}) l (ValD d) ds
309 = addl (gp { hs_valds = add_bind (L l d) ts }) ds
311 -- The rest are routine
312 add gp@(HsGroup {hs_instds = ts}) l (InstD d) ds
313 = addl (gp { hs_instds = L l d : ts }) ds
314 add gp@(HsGroup {hs_defds = ts}) l (DefD d) ds
315 = addl (gp { hs_defds = L l d : ts }) ds
316 add gp@(HsGroup {hs_fords = ts}) l (ForD d) ds
317 = addl (gp { hs_fords = L l d : ts }) ds
318 add gp@(HsGroup {hs_depds = ts}) l (DeprecD d) ds
319 = addl (gp { hs_depds = L l d : ts }) ds
320 add gp@(HsGroup {hs_ruleds = ts}) l (RuleD d) ds
321 = addl (gp { hs_ruleds = L l d : ts }) ds
323 add_bind b (ValBindsIn bs sigs) = ValBindsIn (bs `snocBag` b) sigs
324 add_sig s (ValBindsIn bs sigs) = ValBindsIn bs (s:sigs)
327 %************************************************************************
329 \subsection[PrefixToHS-utils]{Utilities for conversion}
331 %************************************************************************
335 -----------------------------------------------------------------------------
338 -- When parsing data declarations, we sometimes inadvertently parse
339 -- a constructor application as a type (eg. in data T a b = C a b `D` E a b)
340 -- This function splits up the type application, adds any pending
341 -- arguments, and converts the type constructor back into a data constructor.
343 mkPrefixCon :: LHsType RdrName -> [LBangType RdrName]
344 -> P (Located RdrName, HsConDetails RdrName (LBangType RdrName))
348 split (L _ (HsAppTy t u)) ts = split t (u : ts)
349 split (L l (HsTyVar tc)) ts = do data_con <- tyConToDataCon l tc
350 return (data_con, PrefixCon ts)
351 split (L l _) _ = parseError l "parse error in data/newtype declaration"
353 mkRecCon :: Located RdrName -> [([Located RdrName], LBangType RdrName)]
354 -> P (Located RdrName, HsConDetails RdrName (LBangType RdrName))
355 mkRecCon (L loc con) fields
356 = do data_con <- tyConToDataCon loc con
357 return (data_con, RecCon [ (l,t) | (ls,t) <- fields, l <- ls ])
359 tyConToDataCon :: SrcSpan -> RdrName -> P (Located RdrName)
360 tyConToDataCon loc tc
361 | isTcOcc (rdrNameOcc tc)
362 = return (L loc (setRdrNameSpace tc srcDataName))
364 = parseError loc (showSDoc (text "Not a constructor:" <+> quotes (ppr tc)))
366 ----------------------------------------------------------------------------
367 -- Various Syntactic Checks
369 checkInstType :: LHsType RdrName -> P (LHsType RdrName)
370 checkInstType (L l t)
372 HsForAllTy exp tvs ctxt ty -> do
373 dict_ty <- checkDictTy ty
374 return (L l (HsForAllTy exp tvs ctxt dict_ty))
376 HsParTy ty -> checkInstType ty
378 ty -> do dict_ty <- checkDictTy (L l ty)
379 return (L l (HsForAllTy Implicit [] (noLoc []) dict_ty))
381 -- Check whether the given list of type parameters are all type variables
382 -- (possibly with a kind signature). If the second argument is `False',
383 -- only type variables are allowed and we raise an error on encountering a
384 -- non-variable; otherwise, we allow non-variable arguments and return the
385 -- entire list of parameters.
387 checkTyVars :: [LHsType RdrName] -> P ()
388 checkTyVars tparms = mapM_ chk tparms
390 -- Check that the name space is correct!
391 chk (L l (HsKindSig (L _ (HsTyVar tv)) k))
392 | isRdrTyVar tv = return ()
393 chk (L l (HsTyVar tv))
394 | isRdrTyVar tv = return ()
396 parseError l "Type found where type variable expected"
398 -- Check whether the type arguments in a type synonym head are simply
399 -- variables. If not, we have a type equation of a type function and return
400 -- all patterns. If yes, we return 'Nothing' as the third component to
401 -- indicate a vanilla type synonym.
403 checkSynHdr :: LHsType RdrName
404 -> Bool -- is type instance?
405 -> P (Located RdrName, -- head symbol
406 [LHsTyVarBndr RdrName], -- parameters
407 [LHsType RdrName]) -- type patterns
408 checkSynHdr ty isTyInst =
409 do { (_, tc, tvs, tparms) <- checkTyClHdr (noLoc []) ty
410 ; unless isTyInst $ checkTyVars tparms
411 ; return (tc, tvs, tparms) }
414 -- Well-formedness check and decomposition of type and class heads.
416 checkTyClHdr :: LHsContext RdrName -> LHsType RdrName
417 -> P (LHsContext RdrName, -- the type context
418 Located RdrName, -- the head symbol (type or class name)
419 [LHsTyVarBndr RdrName], -- free variables of the non-context part
420 [LHsType RdrName]) -- parameters of head symbol
421 -- The header of a type or class decl should look like
422 -- (C a, D b) => T a b
426 -- With associated types, we can also have non-variable parameters; ie,
428 -- The unaltered parameter list is returned in the fourth component of the
432 -- ('()', 'T', ['a'], ['Int', '[a]'])
433 checkTyClHdr (L l cxt) ty
434 = do (tc, tvs, parms) <- gol ty []
436 return (L l cxt, tc, tvs, parms)
438 gol (L l ty) acc = go l ty acc
440 go l (HsTyVar tc) acc
441 | not (isRdrTyVar tc) = do
442 tvs <- extractTyVars acc
443 return (L l tc, tvs, acc)
444 go l (HsOpTy t1 tc t2) acc = do
445 tvs <- extractTyVars (t1:t2:acc)
446 return (tc, tvs, acc)
447 go l (HsParTy ty) acc = gol ty acc
448 go l (HsAppTy t1 t2) acc = gol t1 (t2:acc)
450 parseError l "Malformed head of type or class declaration"
452 -- The predicates in a type or class decl must all
453 -- be HsClassPs. They need not all be type variables,
454 -- even in Haskell 98. E.g. class (Monad m, Monad (t m)) => MonadT t m
455 chk_pred (L l (HsClassP _ args)) = return ()
457 = parseError l "Malformed context in type or class declaration"
459 -- Extract the type variables of a list of type parameters.
461 -- * Type arguments can be complex type terms (needed for associated type
464 extractTyVars :: [LHsType RdrName] -> P [LHsTyVarBndr RdrName]
465 extractTyVars tvs = collects [] tvs
467 -- Collect all variables (1st arg serves as an accumulator)
468 collect tvs (L l (HsForAllTy _ _ _ _)) =
469 parseError l "Forall type not allowed as type parameter"
470 collect tvs (L l (HsTyVar tv))
471 | isRdrTyVar tv = return $ L l (UserTyVar tv) : tvs
472 | otherwise = return tvs
473 collect tvs (L l (HsBangTy _ _ )) =
474 parseError l "Bang-style type annotations not allowed as type parameter"
475 collect tvs (L l (HsAppTy t1 t2 )) = do
476 tvs' <- collect tvs t2
478 collect tvs (L l (HsFunTy t1 t2 )) = do
479 tvs' <- collect tvs t2
481 collect tvs (L l (HsListTy t )) = collect tvs t
482 collect tvs (L l (HsPArrTy t )) = collect tvs t
483 collect tvs (L l (HsTupleTy _ ts )) = collects tvs ts
484 collect tvs (L l (HsOpTy t1 _ t2 )) = do
485 tvs' <- collect tvs t2
487 collect tvs (L l (HsParTy t )) = collect tvs t
488 collect tvs (L l (HsNumTy t )) = return tvs
489 collect tvs (L l (HsPredTy t )) =
490 parseError l "Predicate not allowed as type parameter"
491 collect tvs (L l (HsKindSig (L _ (HsTyVar tv)) k))
493 return $ L l (KindedTyVar tv k) : tvs
495 parseError l "Kind signature only allowed for type variables"
496 collect tvs (L l (HsSpliceTy t )) =
497 parseError l "Splice not allowed as type parameter"
499 -- Collect all variables of a list of types
500 collects tvs [] = return tvs
501 collects tvs (t:ts) = do
502 tvs' <- collects tvs ts
505 -- Check that associated type declarations of a class are all kind signatures.
507 checkKindSigs :: [LTyClDecl RdrName] -> P ()
508 checkKindSigs = mapM_ check
511 | isKindSigDecl tydecl
512 || isSynDecl tydecl = return ()
514 parseError l "Type declaration in a class must be a kind signature or synonym default"
516 checkContext :: LHsType RdrName -> P (LHsContext RdrName)
520 check (HsTupleTy _ ts) -- (Eq a, Ord b) shows up as a tuple type
521 = do ctx <- mapM checkPred ts
524 check (HsParTy ty) -- to be sure HsParTy doesn't get into the way
527 check (HsTyVar t) -- Empty context shows up as a unit type ()
528 | t == getRdrName unitTyCon = return (L l [])
531 = do p <- checkPred (L l t)
535 checkPred :: LHsType RdrName -> P (LHsPred RdrName)
536 -- Watch out.. in ...deriving( Show )... we use checkPred on
537 -- the list of partially applied predicates in the deriving,
538 -- so there can be zero args.
539 checkPred (L spn (HsPredTy (HsIParam n ty)))
540 = return (L spn (HsIParam n ty))
544 checkl (L l ty) args = check l ty args
546 check _loc (HsTyVar t) args | not (isRdrTyVar t)
547 = return (L spn (HsClassP t args))
548 check _loc (HsAppTy l r) args = checkl l (r:args)
549 check _loc (HsOpTy l (L loc tc) r) args = check loc (HsTyVar tc) (l:r:args)
550 check _loc (HsParTy t) args = checkl t args
551 check loc _ _ = parseError loc "malformed class assertion"
553 checkDictTy :: LHsType RdrName -> P (LHsType RdrName)
554 checkDictTy (L spn ty) = check ty []
556 check (HsTyVar t) args | not (isRdrTyVar t)
557 = return (L spn (HsPredTy (HsClassP t args)))
558 check (HsAppTy l r) args = check (unLoc l) (r:args)
559 check (HsParTy t) args = check (unLoc t) args
560 check _ _ = parseError spn "Malformed context in instance header"
562 ---------------------------------------------------------------------------
563 -- Checking statements in a do-expression
564 -- We parse do { e1 ; e2 ; }
565 -- as [ExprStmt e1, ExprStmt e2]
566 -- checkDo (a) checks that the last thing is an ExprStmt
567 -- (b) returns it separately
568 -- same comments apply for mdo as well
570 checkDo = checkDoMDo "a " "'do'"
571 checkMDo = checkDoMDo "an " "'mdo'"
573 checkDoMDo :: String -> String -> SrcSpan -> [LStmt RdrName] -> P ([LStmt RdrName], LHsExpr RdrName)
574 checkDoMDo pre nm loc [] = parseError loc ("Empty " ++ nm ++ " construct")
575 checkDoMDo pre nm loc ss = do
578 check [L l (ExprStmt e _ _)] = return ([], e)
579 check [L l _] = parseError l ("The last statement in " ++ pre ++ nm ++
580 " construct must be an expression")
585 -- -------------------------------------------------------------------------
586 -- Checking Patterns.
588 -- We parse patterns as expressions and check for valid patterns below,
589 -- converting the expression into a pattern at the same time.
591 checkPattern :: LHsExpr RdrName -> P (LPat RdrName)
592 checkPattern e = checkLPat e
594 checkPatterns :: [LHsExpr RdrName] -> P [LPat RdrName]
595 checkPatterns es = mapM checkPattern es
597 checkLPat :: LHsExpr RdrName -> P (LPat RdrName)
598 checkLPat e@(L l _) = checkPat l e []
600 checkPat :: SrcSpan -> LHsExpr RdrName -> [LPat RdrName] -> P (LPat RdrName)
601 checkPat loc (L l (HsVar c)) args
602 | isRdrDataCon c = return (L loc (ConPatIn (L l c) (PrefixCon args)))
603 checkPat loc e args -- OK to let this happen even if bang-patterns
604 -- are not enabled, because there is no valid
605 -- non-bang-pattern parse of (C ! e)
606 | Just (e', args') <- splitBang e
607 = do { args'' <- checkPatterns args'
608 ; checkPat loc e' (args'' ++ args) }
609 checkPat loc (L _ (HsApp f x)) args
610 = do { x <- checkLPat x; checkPat loc f (x:args) }
611 checkPat loc (L _ e) []
612 = do { p <- checkAPat loc e; return (L loc p) }
613 checkPat loc pat _some_args
616 checkAPat loc e = case e of
617 EWildPat -> return (WildPat placeHolderType)
618 HsVar x | isQual x -> parseError loc ("Qualified variable in pattern: "
620 | otherwise -> return (VarPat x)
621 HsLit l -> return (LitPat l)
623 -- Overloaded numeric patterns (e.g. f 0 x = x)
624 -- Negation is recorded separately, so that the literal is zero or +ve
625 -- NB. Negative *primitive* literals are already handled by
626 -- RdrHsSyn.mkHsNegApp
627 HsOverLit pos_lit -> return (mkNPat pos_lit Nothing)
628 NegApp (L _ (HsOverLit pos_lit)) _
629 -> return (mkNPat pos_lit (Just noSyntaxExpr))
631 SectionR (L _ (HsVar bang)) e -- (! x)
633 -> do { bang_on <- extension bangPatEnabled
634 ; if bang_on then checkLPat e >>= (return . BangPat)
635 else parseError loc "Illegal bang-pattern (use -fbang-patterns)" }
637 ELazyPat e -> checkLPat e >>= (return . LazyPat)
638 EAsPat n e -> checkLPat e >>= (return . AsPat n)
639 ExprWithTySig e t -> checkLPat e >>= \e ->
640 -- Pattern signatures are parsed as sigtypes,
641 -- but they aren't explicit forall points. Hence
642 -- we have to remove the implicit forall here.
644 L _ (HsForAllTy Implicit _ (L _ []) ty) -> ty
647 return (SigPatIn e t')
650 OpApp (L nloc (HsVar n)) (L _ (HsVar plus)) _
651 (L _ (HsOverLit lit@(HsIntegral _ _)))
653 -> return (mkNPlusKPat (L nloc n) lit)
655 OpApp l op fix r -> checkLPat l >>= \l ->
656 checkLPat r >>= \r ->
658 L cl (HsVar c) | isDataOcc (rdrNameOcc c)
659 -> return (ConPatIn (L cl c) (InfixCon l r))
662 HsPar e -> checkLPat e >>= (return . ParPat)
663 ExplicitList _ es -> mapM (\e -> checkLPat e) es >>= \ps ->
664 return (ListPat ps placeHolderType)
665 ExplicitPArr _ es -> mapM (\e -> checkLPat e) es >>= \ps ->
666 return (PArrPat ps placeHolderType)
668 ExplicitTuple es b -> mapM (\e -> checkLPat e) es >>= \ps ->
669 return (TuplePat ps b placeHolderType)
671 RecordCon c _ fs -> mapM checkPatField fs >>= \fs ->
672 return (ConPatIn c (RecCon fs))
674 HsType ty -> return (TypePat ty)
677 plus_RDR, bang_RDR :: RdrName
678 plus_RDR = mkUnqual varName FSLIT("+") -- Hack
679 bang_RDR = mkUnqual varName FSLIT("!") -- Hack
681 checkPatField :: (Located RdrName, LHsExpr RdrName) -> P (Located RdrName, LPat RdrName)
682 checkPatField (n,e) = do
686 patFail loc = parseError loc "Parse error in pattern"
689 ---------------------------------------------------------------------------
690 -- Check Equation Syntax
692 checkValDef :: LHsExpr RdrName
693 -> Maybe (LHsType RdrName)
694 -> Located (GRHSs RdrName)
695 -> P (HsBind RdrName)
697 checkValDef lhs (Just sig) grhss
698 -- x :: ty = rhs parses as a *pattern* binding
699 = checkPatBind (L (combineLocs lhs sig) (ExprWithTySig lhs sig)) grhss
701 checkValDef lhs opt_sig grhss
702 = do { mb_fun <- isFunLhs lhs
704 Just (fun, is_infix, pats) -> checkFunBind (getLoc lhs)
705 fun is_infix pats opt_sig grhss
706 Nothing -> checkPatBind lhs grhss }
708 checkFunBind lhs_loc fun is_infix pats opt_sig (L rhs_span grhss)
710 = parseError (getLoc fun) ("Qualified name in function definition: " ++
711 showRdrName (unLoc fun))
713 = do ps <- checkPatterns pats
714 let match_span = combineSrcSpans lhs_loc rhs_span
715 return (makeFunBind fun is_infix [L match_span (Match ps opt_sig grhss)])
716 -- The span of the match covers the entire equation.
717 -- That isn't quite right, but it'll do for now.
719 makeFunBind :: Located id -> Bool -> [LMatch id] -> HsBind id
720 -- Like HsUtils.mkFunBind, but we need to be able to set the fixity too
721 makeFunBind fn is_infix ms
722 = FunBind { fun_id = fn, fun_infix = is_infix, fun_matches = mkMatchGroup ms,
723 fun_co_fn = idCoercion, bind_fvs = placeHolderNames }
725 checkPatBind lhs (L _ grhss)
726 = do { lhs <- checkPattern lhs
727 ; return (PatBind lhs grhss placeHolderType placeHolderNames) }
733 checkValSig (L l (HsVar v)) ty
734 | isUnqual v && not (isDataOcc (rdrNameOcc v))
735 = return (TypeSig (L l v) ty)
736 checkValSig (L l other) ty
737 = parseError l "Invalid type signature"
739 mkGadtDecl :: Located RdrName
740 -> LHsType RdrName -- assuming HsType
742 mkGadtDecl name (L _ (HsForAllTy _ qvars cxt ty)) = mk_gadt_con name qvars cxt ty
743 mkGadtDecl name ty = mk_gadt_con name [] (noLoc []) ty
745 mk_gadt_con name qvars cxt ty
746 = ConDecl { con_name = name
747 , con_explicit = Implicit
750 , con_details = PrefixCon []
751 , con_res = ResTyGADT ty }
752 -- NB: we put the whole constr type into the ResTyGADT for now;
753 -- the renamer will unravel it once it has sorted out
756 -- A variable binding is parsed as a FunBind.
759 -- The parser left-associates, so there should
760 -- not be any OpApps inside the e's
761 splitBang :: LHsExpr RdrName -> Maybe (LHsExpr RdrName, [LHsExpr RdrName])
762 -- Splits (f ! g a b) into (f, [(! g), a, g])
763 splitBang (L loc (OpApp l_arg bang@(L loc' (HsVar op)) _ r_arg))
764 | op == bang_RDR = Just (l_arg, L loc (SectionR bang arg1) : argns)
766 (arg1,argns) = split_bang r_arg []
767 split_bang (L _ (HsApp f e)) es = split_bang f (e:es)
768 split_bang e es = (e,es)
769 splitBang other = Nothing
771 isFunLhs :: LHsExpr RdrName
772 -> P (Maybe (Located RdrName, Bool, [LHsExpr RdrName]))
773 -- Just (fun, is_infix, arg_pats) if e is a function LHS
776 go (L loc (HsVar f)) es
777 | not (isRdrDataCon f) = return (Just (L loc f, False, es))
778 go (L _ (HsApp f e)) es = go f (e:es)
779 go (L _ (HsPar e)) es@(_:_) = go e es
781 -- For infix function defns, there should be only one infix *function*
782 -- (though there may be infix *datacons* involved too). So we don't
783 -- need fixity info to figure out which function is being defined.
784 -- a `K1` b `op` c `K2` d
786 -- (a `K1` b) `op` (c `K2` d)
787 -- The renamer checks later that the precedences would yield such a parse.
789 -- There is a complication to deal with bang patterns.
791 -- ToDo: what about this?
792 -- x + 1 `op` y = ...
794 go e@(L loc (OpApp l (L loc' (HsVar op)) fix r)) es
795 | Just (e',es') <- splitBang e
796 = do { bang_on <- extension bangPatEnabled
797 ; if bang_on then go e' (es' ++ es)
798 else return (Just (L loc' op, True, (l:r:es))) }
799 -- No bangs; behave just like the next case
800 | not (isRdrDataCon op) -- We have found the function!
801 = return (Just (L loc' op, True, (l:r:es)))
802 | otherwise -- Infix data con; keep going
803 = do { mb_l <- go l es
805 Just (op', True, j : k : es')
806 -> return (Just (op', True, j : op_app : es'))
808 op_app = L loc (OpApp k (L loc' (HsVar op)) fix r)
809 _ -> return Nothing }
810 go _ _ = return Nothing
812 ---------------------------------------------------------------------------
813 -- Miscellaneous utilities
815 checkPrecP :: Located Int -> P Int
817 | 0 <= i && i <= maxPrecedence = return i
818 | otherwise = parseError l "Precedence out of range"
823 -> HsRecordBinds RdrName
824 -> P (HsExpr RdrName)
826 mkRecConstrOrUpdate (L l (HsVar c)) loc fs | isRdrDataCon c
827 = return (RecordCon (L l c) noPostTcExpr fs)
828 mkRecConstrOrUpdate exp loc fs@(_:_)
829 = return (RecordUpd exp fs placeHolderType placeHolderType)
830 mkRecConstrOrUpdate _ loc []
831 = parseError loc "Empty record update"
833 mkInlineSpec :: Maybe Activation -> Bool -> InlineSpec
834 -- The Maybe is becuase the user can omit the activation spec (and usually does)
835 mkInlineSpec Nothing True = alwaysInlineSpec -- INLINE
836 mkInlineSpec Nothing False = neverInlineSpec -- NOINLINE
837 mkInlineSpec (Just act) inl = Inline act inl
840 -----------------------------------------------------------------------------
841 -- utilities for foreign declarations
843 -- supported calling conventions
845 data CallConv = CCall CCallConv -- ccall or stdcall
848 -- construct a foreign import declaration
852 -> (Located FastString, Located RdrName, LHsType RdrName)
853 -> P (HsDecl RdrName)
854 mkImport (CCall cconv) safety (entity, v, ty) = do
855 importSpec <- parseCImport entity cconv safety v
856 return (ForD (ForeignImport v ty importSpec))
857 mkImport (DNCall ) _ (entity, v, ty) = do
858 spec <- parseDImport entity
859 return $ ForD (ForeignImport v ty (DNImport spec))
861 -- parse the entity string of a foreign import declaration for the `ccall' or
862 -- `stdcall' calling convention'
864 parseCImport :: Located FastString
869 parseCImport (L loc entity) cconv safety v
870 -- FIXME: we should allow white space around `dynamic' and `wrapper' -=chak
871 | entity == FSLIT ("dynamic") =
872 return $ CImport cconv safety nilFS nilFS (CFunction DynamicTarget)
873 | entity == FSLIT ("wrapper") =
874 return $ CImport cconv safety nilFS nilFS CWrapper
875 | otherwise = parse0 (unpackFS entity)
877 -- using the static keyword?
878 parse0 (' ': rest) = parse0 rest
879 parse0 ('s':'t':'a':'t':'i':'c':rest) = parse1 rest
880 parse0 rest = parse1 rest
881 -- check for header file name
882 parse1 "" = parse4 "" nilFS False nilFS
883 parse1 (' ':rest) = parse1 rest
884 parse1 str@('&':_ ) = parse2 str nilFS
885 parse1 str@('[':_ ) = parse3 str nilFS False
887 | ".h" `isSuffixOf` first = parse2 rest (mkFastString first)
888 | otherwise = parse4 str nilFS False nilFS
890 (first, rest) = break (\c -> c == ' ' || c == '&' || c == '[') str
891 -- check for address operator (indicating a label import)
892 parse2 "" header = parse4 "" header False nilFS
893 parse2 (' ':rest) header = parse2 rest header
894 parse2 ('&':rest) header = parse3 rest header True
895 parse2 str@('[':_ ) header = parse3 str header False
896 parse2 str header = parse4 str header False nilFS
897 -- check for library object name
898 parse3 (' ':rest) header isLbl = parse3 rest header isLbl
899 parse3 ('[':rest) header isLbl =
900 case break (== ']') rest of
901 (lib, ']':rest) -> parse4 rest header isLbl (mkFastString lib)
902 _ -> parseError loc "Missing ']' in entity"
903 parse3 str header isLbl = parse4 str header isLbl nilFS
904 -- check for name of C function
905 parse4 "" header isLbl lib = build (mkExtName (unLoc v)) header isLbl lib
906 parse4 (' ':rest) header isLbl lib = parse4 rest header isLbl lib
907 parse4 str header isLbl lib
908 | all (== ' ') rest = build (mkFastString first) header isLbl lib
909 | otherwise = parseError loc "Malformed entity string"
911 (first, rest) = break (== ' ') str
913 build cid header False lib = return $
914 CImport cconv safety header lib (CFunction (StaticTarget cid))
915 build cid header True lib = return $
916 CImport cconv safety header lib (CLabel cid )
919 -- Unravel a dotnet spec string.
921 parseDImport :: Located FastString -> P DNCallSpec
922 parseDImport (L loc entity) = parse0 comps
924 comps = words (unpackFS entity)
928 | x == "static" = parse1 True xs
929 | otherwise = parse1 False (x:xs)
932 parse1 isStatic (x:xs)
933 | x == "method" = parse2 isStatic DNMethod xs
934 | x == "field" = parse2 isStatic DNField xs
935 | x == "ctor" = parse2 isStatic DNConstructor xs
936 parse1 isStatic xs = parse2 isStatic DNMethod xs
939 parse2 isStatic kind (('[':x):xs) =
942 vs | last vs == ']' -> parse3 isStatic kind (init vs) xs
943 parse2 isStatic kind xs = parse3 isStatic kind "" xs
945 parse3 isStatic kind assem [x] =
946 return (DNCallSpec isStatic kind assem x
947 -- these will be filled in once known.
948 (error "FFI-dotnet-args")
949 (error "FFI-dotnet-result"))
950 parse3 _ _ _ _ = d'oh
952 d'oh = parseError loc "Malformed entity string"
954 -- construct a foreign export declaration
957 -> (Located FastString, Located RdrName, LHsType RdrName)
958 -> P (HsDecl RdrName)
959 mkExport (CCall cconv) (L loc entity, v, ty) = return $
960 ForD (ForeignExport v ty (CExport (CExportStatic entity' cconv)))
962 entity' | nullFS entity = mkExtName (unLoc v)
964 mkExport DNCall (L loc entity, v, ty) =
965 parseError (getLoc v){-TODO: not quite right-}
966 "Foreign export is not yet supported for .NET"
968 -- Supplying the ext_name in a foreign decl is optional; if it
969 -- isn't there, the Haskell name is assumed. Note that no transformation
970 -- of the Haskell name is then performed, so if you foreign export (++),
971 -- it's external name will be "++". Too bad; it's important because we don't
972 -- want z-encoding (e.g. names with z's in them shouldn't be doubled)
974 mkExtName :: RdrName -> CLabelString
975 mkExtName rdrNm = mkFastString (occNameString (rdrNameOcc rdrNm))
979 -----------------------------------------------------------------------------
983 showRdrName :: RdrName -> String
984 showRdrName r = showSDoc (ppr r)
986 parseError :: SrcSpan -> String -> P a
987 parseError span s = failSpanMsgP span s