2 % (c) The University of Glasgow, 1996-2003
4 Functions over HsSyn specialised to RdrName.
9 extractHsRhoRdrTyVars, extractGenericPatTyVars,
12 mkHsIntegral, mkHsFractional, mkHsIsString,
13 mkHsDo, mkHsSplice, mkTopSpliceDecl,
14 mkClassDecl, mkTyData, mkTyFamily, mkTySynonym,
15 splitCon, mkInlinePragma,
16 mkRecConstrOrUpdate, -- HsExp -> [HsFieldUpdate] -> P HsExp
23 -- Stuff to do with Foreign declarations
27 mkExtName, -- RdrName -> CLabelString
28 mkGadtDecl, -- [Located RdrName] -> LHsType RdrName -> ConDecl RdrName
30 mkDeprecatedGadtRecordDecl,
32 -- Bunch of functions in the parser monad for
33 -- checking and constructing values
34 checkPrecP, -- Int -> P Int
35 checkContext, -- HsType -> P HsContext
36 checkPred, -- HsType -> P HsPred
37 checkTyVars, -- [LHsType RdrName] -> P ()
38 checkKindSigs, -- [LTyClDecl RdrName] -> P ()
39 checkInstType, -- HsType -> P HsType
40 checkPattern, -- HsExp -> P HsPat
42 checkPatterns, -- SrcLoc -> [HsExp] -> P [HsPat]
43 checkDo, -- [Stmt] -> P [Stmt]
44 checkMDo, -- [Stmt] -> P [Stmt]
45 checkValDef, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl
46 checkValSig, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl
52 import HsSyn -- Lots of it
53 import Class ( FunDep )
54 import TypeRep ( Kind )
55 import RdrName ( RdrName, isRdrTyVar, isRdrTc, mkUnqual, rdrNameOcc,
56 isRdrDataCon, isUnqual, getRdrName, setRdrNameSpace )
57 import BasicTypes ( maxPrecedence, Activation(..), RuleMatchInfo,
58 InlinePragma(..), InlineSpec(..) )
60 import TysWiredIn ( unitTyCon )
62 import OccName ( srcDataName, varName, isDataOcc, isTcOcc,
64 import PrelNames ( forall_tv_RDR )
67 import OrdList ( OrdList, fromOL )
68 import Bag ( Bag, emptyBag, consBag, foldrBag )
73 import Control.Applicative ((<$>))
75 import Text.ParserCombinators.ReadP as ReadP
76 import Data.List ( nubBy )
79 #include "HsVersions.h"
83 %************************************************************************
85 \subsection{A few functions over HsSyn at RdrName}
87 %************************************************************************
89 extractHsTyRdrNames finds the free variables of a HsType
90 It's used when making the for-alls explicit.
93 extractHsTyRdrTyVars :: LHsType RdrName -> [Located RdrName]
94 extractHsTyRdrTyVars ty = nubBy eqLocated (extract_lty ty [])
96 extractHsTysRdrTyVars :: [LHsType RdrName] -> [Located RdrName]
97 extractHsTysRdrTyVars ty = nubBy eqLocated (extract_ltys ty [])
99 extractHsRhoRdrTyVars :: LHsContext RdrName -> LHsType RdrName -> [Located RdrName]
100 -- This one takes the context and tau-part of a
101 -- sigma type and returns their free type variables
102 extractHsRhoRdrTyVars ctxt ty
103 = nubBy eqLocated $ extract_lctxt ctxt (extract_lty ty [])
105 extract_lctxt :: Located [LHsPred RdrName] -> [Located RdrName] -> [Located RdrName]
106 extract_lctxt ctxt acc = foldr (extract_pred . unLoc) acc (unLoc ctxt)
108 extract_pred :: HsPred RdrName -> [Located RdrName] -> [Located RdrName]
109 extract_pred (HsClassP _ tys) acc = extract_ltys tys acc
110 extract_pred (HsEqualP ty1 ty2) acc = extract_lty ty1 (extract_lty ty2 acc)
111 extract_pred (HsIParam _ ty ) acc = extract_lty ty acc
113 extract_ltys :: [LHsType RdrName] -> [Located RdrName] -> [Located RdrName]
114 extract_ltys tys acc = foldr extract_lty acc tys
116 extract_lty :: LHsType RdrName -> [Located RdrName] -> [Located RdrName]
117 extract_lty (L loc ty) acc
119 HsTyVar tv -> extract_tv loc tv acc
120 HsBangTy _ ty -> extract_lty ty acc
121 HsRecTy flds -> foldr (extract_lty . cd_fld_type) acc flds
122 HsAppTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc)
123 HsListTy ty -> extract_lty ty acc
124 HsPArrTy ty -> extract_lty ty acc
125 HsTupleTy _ tys -> extract_ltys tys acc
126 HsFunTy ty1 ty2 -> extract_lty ty1 (extract_lty ty2 acc)
127 HsPredTy p -> extract_pred p acc
128 HsOpTy ty1 (L loc tv) ty2 -> extract_tv loc tv (extract_lty ty1 (extract_lty ty2 acc))
129 HsParTy ty -> extract_lty ty acc
130 HsCoreTy {} -> acc -- The type is closed
131 HsQuasiQuoteTy {} -> acc -- Quasi quotes mention no type variables
132 HsSpliceTy {} -> acc -- Type splices mention no type variables
133 HsKindSig ty _ -> extract_lty ty acc
134 HsForAllTy _ [] cx ty -> extract_lctxt cx (extract_lty ty acc)
135 HsForAllTy _ tvs cx ty -> acc ++ (filter ((`notElem` locals) . unLoc) $
136 extract_lctxt cx (extract_lty ty []))
138 locals = hsLTyVarNames tvs
139 HsDocTy ty _ -> extract_lty ty acc
141 extract_tv :: SrcSpan -> RdrName -> [Located RdrName] -> [Located RdrName]
142 extract_tv loc tv acc | isRdrTyVar tv = L loc tv : acc
145 extractGenericPatTyVars :: LHsBinds RdrName -> [Located RdrName]
146 -- Get the type variables out of the type patterns in a bunch of
147 -- possibly-generic bindings in a class declaration
148 extractGenericPatTyVars binds
149 = nubBy eqLocated (foldrBag get [] binds)
151 get (L _ (FunBind { fun_matches = MatchGroup ms _ })) acc = foldr (get_m.unLoc) acc ms
158 %************************************************************************
160 \subsection{Construction functions for Rdr stuff}
162 %************************************************************************
164 mkClassDecl builds a RdrClassDecl, filling in the names for tycon and datacon
165 by deriving them from the name of the class. We fill in the names for the
166 tycon and datacon corresponding to the class, by deriving them from the
167 name of the class itself. This saves recording the names in the interface
168 file (which would be equally good).
170 Similarly for mkConDecl, mkClassOpSig and default-method names.
172 *** See "THE NAMING STORY" in HsDecls ****
175 mkClassDecl :: SrcSpan
176 -> Located (Maybe (LHsContext RdrName), LHsType RdrName)
177 -> Located [Located (FunDep RdrName)]
178 -> Located (OrdList (LHsDecl RdrName))
179 -> P (LTyClDecl RdrName)
181 mkClassDecl loc (L _ (mcxt, tycl_hdr)) fds where_cls
182 = do { let (binds, sigs, ats, docs) = cvBindsAndSigs (unLoc where_cls)
183 ; let cxt = fromMaybe (noLoc []) mcxt
184 ; (cls, tparams) <- checkTyClHdr tycl_hdr
185 ; tyvars <- checkTyVars tparams -- Only type vars allowed
187 ; return (L loc (ClassDecl { tcdCtxt = cxt, tcdLName = cls, tcdTyVars = tyvars,
188 tcdFDs = unLoc fds, tcdSigs = sigs, tcdMeths = binds,
189 tcdATs = ats, tcdDocs = docs })) }
193 -> Bool -- True <=> data family instance
194 -> Located (Maybe (LHsContext RdrName), LHsType RdrName)
196 -> [LConDecl RdrName]
197 -> Maybe [LHsType RdrName]
198 -> P (LTyClDecl RdrName)
199 mkTyData loc new_or_data is_family (L _ (mcxt, tycl_hdr)) ksig data_cons maybe_deriv
200 = do { (tc, tparams) <- checkTyClHdr tycl_hdr
202 ; checkDatatypeContext mcxt
203 ; let cxt = fromMaybe (noLoc []) mcxt
204 ; (tyvars, typats) <- checkTParams is_family tparams
205 ; return (L loc (TyData { tcdND = new_or_data, tcdCtxt = cxt, tcdLName = tc,
206 tcdTyVars = tyvars, tcdTyPats = typats,
208 tcdKindSig = ksig, tcdDerivs = maybe_deriv })) }
210 mkTySynonym :: SrcSpan
211 -> Bool -- True <=> type family instances
212 -> LHsType RdrName -- LHS
213 -> LHsType RdrName -- RHS
214 -> P (LTyClDecl RdrName)
215 mkTySynonym loc is_family lhs rhs
216 = do { (tc, tparams) <- checkTyClHdr lhs
217 ; (tyvars, typats) <- checkTParams is_family tparams
218 ; return (L loc (TySynonym tc tyvars typats rhs)) }
220 mkTyFamily :: SrcSpan
222 -> LHsType RdrName -- LHS
223 -> Maybe Kind -- Optional kind signature
224 -> P (LTyClDecl RdrName)
225 mkTyFamily loc flavour lhs ksig
226 = do { (tc, tparams) <- checkTyClHdr lhs
227 ; tyvars <- checkTyVars tparams
228 ; return (L loc (TyFamily flavour tc tyvars ksig)) }
230 mkTopSpliceDecl :: LHsExpr RdrName -> HsDecl RdrName
232 -- [pads| ... ] then return a QuasiQuoteD
233 -- $(e) then return a SpliceD
234 -- but if she wrote, say,
235 -- f x then behave as if she'd written $(f x)
237 mkTopSpliceDecl (L _ (HsQuasiQuoteE qq)) = QuasiQuoteD qq
238 mkTopSpliceDecl (L _ (HsSpliceE (HsSplice _ expr))) = SpliceD (SpliceDecl expr Explicit)
239 mkTopSpliceDecl other_expr = SpliceD (SpliceDecl other_expr Implicit)
242 %************************************************************************
244 \subsection[cvBinds-etc]{Converting to @HsBinds@, etc.}
246 %************************************************************************
248 Function definitions are restructured here. Each is assumed to be recursive
249 initially, and non recursive definitions are discovered by the dependency
254 -- | Groups together bindings for a single function
255 cvTopDecls :: OrdList (LHsDecl RdrName) -> [LHsDecl RdrName]
256 cvTopDecls decls = go (fromOL decls)
258 go :: [LHsDecl RdrName] -> [LHsDecl RdrName]
260 go (L l (ValD b) : ds) = L l' (ValD b') : go ds'
261 where (L l' b', ds') = getMonoBind (L l b) ds
262 go (d : ds) = d : go ds
264 -- Declaration list may only contain value bindings and signatures.
265 cvBindGroup :: OrdList (LHsDecl RdrName) -> HsValBinds RdrName
267 = case cvBindsAndSigs binding of
268 (mbs, sigs, tydecls, _) -> ASSERT( null tydecls )
271 cvBindsAndSigs :: OrdList (LHsDecl RdrName)
272 -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName], [LDocDecl])
273 -- Input decls contain just value bindings and signatures
274 -- and in case of class or instance declarations also
275 -- associated type declarations. They might also contain Haddock comments.
276 cvBindsAndSigs fb = go (fromOL fb)
278 go [] = (emptyBag, [], [], [])
279 go (L l (SigD s) : ds) = (bs, L l s : ss, ts, docs)
280 where (bs, ss, ts, docs) = go ds
281 go (L l (ValD b) : ds) = (b' `consBag` bs, ss, ts, docs)
282 where (b', ds') = getMonoBind (L l b) ds
283 (bs, ss, ts, docs) = go ds'
284 go (L l (TyClD t): ds) = (bs, ss, L l t : ts, docs)
285 where (bs, ss, ts, docs) = go ds
286 go (L l (DocD d) : ds) = (bs, ss, ts, (L l d) : docs)
287 where (bs, ss, ts, docs) = go ds
288 go (L _ d : _) = pprPanic "cvBindsAndSigs" (ppr d)
290 -----------------------------------------------------------------------------
291 -- Group function bindings into equation groups
293 getMonoBind :: LHsBind RdrName -> [LHsDecl RdrName]
294 -> (LHsBind RdrName, [LHsDecl RdrName])
295 -- Suppose (b',ds') = getMonoBind b ds
296 -- ds is a list of parsed bindings
297 -- b is a MonoBinds that has just been read off the front
299 -- Then b' is the result of grouping more equations from ds that
300 -- belong with b into a single MonoBinds, and ds' is the depleted
301 -- list of parsed bindings.
303 -- All Haddock comments between equations inside the group are
306 -- No AndMonoBinds or EmptyMonoBinds here; just single equations
308 getMonoBind (L loc1 (FunBind { fun_id = fun_id1@(L _ f1), fun_infix = is_infix1,
309 fun_matches = MatchGroup mtchs1 _ })) binds
311 = go is_infix1 mtchs1 loc1 binds []
313 go is_infix mtchs loc
314 (L loc2 (ValD (FunBind { fun_id = L _ f2, fun_infix = is_infix2,
315 fun_matches = MatchGroup mtchs2 _ })) : binds) _
316 | f1 == f2 = go (is_infix || is_infix2) (mtchs2 ++ mtchs)
317 (combineSrcSpans loc loc2) binds []
318 go is_infix mtchs loc (doc_decl@(L loc2 (DocD _)) : binds) doc_decls
319 = let doc_decls' = doc_decl : doc_decls
320 in go is_infix mtchs (combineSrcSpans loc loc2) binds doc_decls'
321 go is_infix mtchs loc binds doc_decls
322 = (L loc (makeFunBind fun_id1 is_infix (reverse mtchs)), (reverse doc_decls) ++ binds)
323 -- Reverse the final matches, to get it back in the right order
324 -- Do the same thing with the trailing doc comments
326 getMonoBind bind binds = (bind, binds)
328 has_args :: [LMatch RdrName] -> Bool
329 has_args [] = panic "RdrHsSyn:has_args"
330 has_args ((L _ (Match args _ _)) : _) = not (null args)
331 -- Don't group together FunBinds if they have
332 -- no arguments. This is necessary now that variable bindings
333 -- with no arguments are now treated as FunBinds rather
334 -- than pattern bindings (tests/rename/should_fail/rnfail002).
337 %************************************************************************
339 \subsection[PrefixToHS-utils]{Utilities for conversion}
341 %************************************************************************
345 -----------------------------------------------------------------------------
348 -- When parsing data declarations, we sometimes inadvertently parse
349 -- a constructor application as a type (eg. in data T a b = C a b `D` E a b)
350 -- This function splits up the type application, adds any pending
351 -- arguments, and converts the type constructor back into a data constructor.
353 splitCon :: LHsType RdrName
354 -> P (Located RdrName, HsConDeclDetails RdrName)
355 -- This gets given a "type" that should look like
357 -- or C { x::Int, y::Bool }
358 -- and returns the pieces
362 split (L _ (HsAppTy t u)) ts = split t (u : ts)
363 split (L l (HsTyVar tc)) ts = do data_con <- tyConToDataCon l tc
364 return (data_con, mk_rest ts)
365 split (L l _) _ = parseErrorSDoc l (text "parse error in constructor in data/newtype declaration:" <+> ppr ty)
367 mk_rest [L _ (HsRecTy flds)] = RecCon flds
368 mk_rest ts = PrefixCon ts
370 mkDeprecatedGadtRecordDecl :: SrcSpan
372 -> [ConDeclField RdrName]
374 -> P (LConDecl RdrName)
375 -- This one uses the deprecated syntax
376 -- C { x,y ::Int } :: T a b
377 -- We give it a RecCon details right away
378 mkDeprecatedGadtRecordDecl loc (L con_loc con) flds res_ty
379 = do { data_con <- tyConToDataCon con_loc con
380 ; return (L loc (ConDecl { con_old_rec = True
381 , con_name = data_con
382 , con_explicit = Implicit
385 , con_details = RecCon flds
386 , con_res = ResTyGADT res_ty
387 , con_doc = Nothing })) }
389 mkSimpleConDecl :: Located RdrName -> [LHsTyVarBndr RdrName]
390 -> LHsContext RdrName -> HsConDeclDetails RdrName
393 mkSimpleConDecl name qvars cxt details
394 = ConDecl { con_old_rec = False
396 , con_explicit = Explicit
399 , con_details = details
401 , con_doc = Nothing }
403 mkGadtDecl :: [Located RdrName]
404 -> LHsType RdrName -- Always a HsForAllTy
406 -- We allow C,D :: ty
407 -- and expand it as if it had been
409 -- (Just like type signatures in general.)
410 mkGadtDecl names (L _ (HsForAllTy imp qvars cxt tau))
411 = [mk_gadt_con name | name <- names]
413 (details, res_ty) -- See Note [Sorting out the result type]
415 L _ (HsFunTy (L _ (HsRecTy flds)) res_ty) -> (RecCon flds, res_ty)
416 _other -> (PrefixCon [], tau)
419 = ConDecl { con_old_rec = False
424 , con_details = details
425 , con_res = ResTyGADT res_ty
426 , con_doc = Nothing }
427 mkGadtDecl _ other_ty = pprPanic "mkGadtDecl" (ppr other_ty)
429 tyConToDataCon :: SrcSpan -> RdrName -> P (Located RdrName)
430 tyConToDataCon loc tc
431 | isTcOcc (rdrNameOcc tc)
432 = return (L loc (setRdrNameSpace tc srcDataName))
434 = parseErrorSDoc loc (msg $$ extra)
436 msg = text "Not a data constructor:" <+> quotes (ppr tc)
437 extra | tc == forall_tv_RDR
438 = text "Perhaps you intended to use -XExistentialQuantification"
442 Note [Sorting out the result type]
443 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
444 In a GADT declaration which is not a record, we put the whole constr
445 type into the ResTyGADT for now; the renamer will unravel it once it
446 has sorted out operator fixities. Consider for example
447 C :: a :*: b -> a :*: b -> a :+: b
448 Initially this type will parse as
449 a :*: (b -> (a :*: (b -> (a :+: b))))
451 so it's hard to split up the arguments until we've done the precedence
452 resolution (in the renamer) On the other hand, for a record
453 { x,y :: Int } -> a :*: b
454 there is no doubt. AND we need to sort records out so that
455 we can bring x,y into scope. So:
456 * For PrefixCon we keep all the args in the ResTyGADT
457 * For RecCon we do not
460 ----------------------------------------------------------------------------
461 -- Various Syntactic Checks
463 checkInstType :: LHsType RdrName -> P (LHsType RdrName)
464 checkInstType (L l t)
466 HsForAllTy exp tvs ctxt ty -> do
467 dict_ty <- checkDictTy ty
468 return (L l (HsForAllTy exp tvs ctxt dict_ty))
470 HsParTy ty -> checkInstType ty
472 ty -> do dict_ty <- checkDictTy (L l ty)
473 return (L l (HsForAllTy Implicit [] (noLoc []) dict_ty))
475 checkDictTy :: LHsType RdrName -> P (LHsType RdrName)
476 checkDictTy (L spn ty) = check ty []
478 check (HsTyVar tc) args | isRdrTc tc = done tc args
479 check (HsOpTy t1 (L _ tc) t2) args | isRdrTc tc = done tc (t1:t2:args)
480 check (HsAppTy l r) args = check (unLoc l) (r:args)
481 check (HsParTy t) args = check (unLoc t) args
482 check _ _ = parseErrorSDoc spn (text "Malformed instance header:" <+> ppr ty)
484 done tc args = return (L spn (HsPredTy (HsClassP tc args)))
486 checkTParams :: Bool -- Type/data family
488 -> P ([LHsTyVarBndr RdrName], Maybe [LHsType RdrName])
489 -- checkTParams checks the type parameters of a data/newtype declaration
490 -- There are two cases:
492 -- a) Vanilla data/newtype decl. In that case
493 -- - the type parameters should all be type variables
494 -- - they may have a kind annotation
496 -- b) Family data/newtype decl. In that case
497 -- - The type parameters may be arbitrary types
498 -- - We find the type-varaible binders by find the
499 -- free type vars of those types
500 -- - We make them all kind-sig-free binders (UserTyVar)
501 -- If there are kind sigs in the type parameters, they
502 -- will fix the binder's kind when we kind-check the
504 checkTParams is_family tparams
505 | not is_family -- Vanilla case (a)
506 = do { tyvars <- checkTyVars tparams
507 ; return (tyvars, Nothing) }
508 | otherwise -- Family case (b)
509 = do { let tyvars = userHsTyVarBndrs (extractHsTysRdrTyVars tparams)
510 ; return (tyvars, Just tparams) }
512 checkTyVars :: [LHsType RdrName] -> P [LHsTyVarBndr RdrName]
513 -- Check whether the given list of type parameters are all type variables
514 -- (possibly with a kind signature). If the second argument is `False',
515 -- only type variables are allowed and we raise an error on encountering a
516 -- non-variable; otherwise, we allow non-variable arguments and return the
517 -- entire list of parameters.
518 checkTyVars tparms = mapM chk tparms
520 -- Check that the name space is correct!
521 chk (L l (HsKindSig (L _ (HsTyVar tv)) k))
522 | isRdrTyVar tv = return (L l (KindedTyVar tv k))
523 chk (L l (HsTyVar tv))
524 | isRdrTyVar tv = return (L l (UserTyVar tv placeHolderKind))
526 parseErrorSDoc l (text "Type found:" <+> ppr t
527 $$ text "where type variable expected, in:" <+>
528 sep (map (pprParendHsType . unLoc) tparms))
530 checkDatatypeContext :: Maybe (LHsContext RdrName) -> P ()
531 checkDatatypeContext Nothing = return ()
532 checkDatatypeContext (Just (L loc c))
533 = do allowed <- extension datatypeContextsEnabled
536 (text "Illegal datatype context (use -XDatatypeContexts):" <+>
539 checkTyClHdr :: LHsType RdrName
540 -> P (Located RdrName, -- the head symbol (type or class name)
541 [LHsType RdrName]) -- parameters of head symbol
542 -- Well-formedness check and decomposition of type and class heads.
543 -- Decomposes T ty1 .. tyn into (T, [ty1, ..., tyn])
544 -- Int :*: Bool into (:*:, [Int, Bool])
545 -- returning the pieces
549 goL (L l ty) acc = go l ty acc
551 go l (HsTyVar tc) acc
552 | isRdrTc tc = return (L l tc, acc)
554 go _ (HsOpTy t1 ltc@(L _ tc) t2) acc
555 | isRdrTc tc = return (ltc, t1:t2:acc)
556 go _ (HsParTy ty) acc = goL ty acc
557 go _ (HsAppTy t1 t2) acc = goL t1 (t2:acc)
558 go l _ _ = parseErrorSDoc l (text "Malformed head of type or class declaration:" <+> ppr ty)
560 -- Check that associated type declarations of a class are all kind signatures.
562 checkKindSigs :: [LTyClDecl RdrName] -> P ()
563 checkKindSigs = mapM_ check
566 | isFamilyDecl tydecl
567 || isSynDecl tydecl = return ()
569 parseErrorSDoc l (text "Type declaration in a class must be a kind signature or synonym default:" $$ ppr tydecl)
571 checkContext :: LHsType RdrName -> P (LHsContext RdrName)
575 check (HsTupleTy _ ts) -- (Eq a, Ord b) shows up as a tuple type
576 = do ctx <- mapM checkPred ts
579 check (HsParTy ty) -- to be sure HsParTy doesn't get into the way
582 check (HsTyVar t) -- Empty context shows up as a unit type ()
583 | t == getRdrName unitTyCon = return (L l [])
586 = do p <- checkPred (L l t)
590 checkPred :: LHsType RdrName -> P (LHsPred RdrName)
591 -- Watch out.. in ...deriving( Show )... we use checkPred on
592 -- the list of partially applied predicates in the deriving,
593 -- so there can be zero args.
594 checkPred (L spn (HsPredTy (HsIParam n ty)))
595 = return (L spn (HsIParam n ty))
599 checkl (L l ty) args = check l ty args
601 check _loc (HsPredTy pred@(HsEqualP _ _))
603 = return $ L spn pred
604 check _loc (HsTyVar t) args | not (isRdrTyVar t)
605 = return (L spn (HsClassP t args))
606 check _loc (HsAppTy l r) args = checkl l (r:args)
607 check _loc (HsOpTy l (L loc tc) r) args = check loc (HsTyVar tc) (l:r:args)
608 check _loc (HsParTy t) args = checkl t args
609 check loc _ _ = parseErrorSDoc loc
610 (text "malformed class assertion:" <+> ppr ty)
612 ---------------------------------------------------------------------------
613 -- Checking statements in a do-expression
614 -- We parse do { e1 ; e2 ; }
615 -- as [ExprStmt e1, ExprStmt e2]
616 -- checkDo (a) checks that the last thing is an ExprStmt
617 -- (b) returns it separately
618 -- same comments apply for mdo as well
620 checkDo, checkMDo :: SrcSpan -> [LStmt RdrName] -> P ([LStmt RdrName], LHsExpr RdrName)
622 checkDo = checkDoMDo "a " "'do'"
623 checkMDo = checkDoMDo "an " "'mdo'"
625 checkDoMDo :: String -> String -> SrcSpan -> [LStmt RdrName] -> P ([LStmt RdrName], LHsExpr RdrName)
626 checkDoMDo _ nm loc [] = parseErrorSDoc loc (text ("Empty " ++ nm ++ " construct"))
627 checkDoMDo pre nm _ ss = do
630 check [] = panic "RdrHsSyn:checkDoMDo"
631 check [L _ (ExprStmt e _ _)] = return ([], e)
632 check [L l e] = parseErrorSDoc l
633 (text ("The last statement in " ++ pre ++ nm ++
634 " construct must be an expression:")
640 -- -------------------------------------------------------------------------
641 -- Checking Patterns.
643 -- We parse patterns as expressions and check for valid patterns below,
644 -- converting the expression into a pattern at the same time.
646 checkPattern :: LHsExpr RdrName -> P (LPat RdrName)
647 checkPattern e = checkLPat e
649 checkPatterns :: [LHsExpr RdrName] -> P [LPat RdrName]
650 checkPatterns es = mapM checkPattern es
652 checkLPat :: LHsExpr RdrName -> P (LPat RdrName)
653 checkLPat e@(L l _) = checkPat l e []
655 checkPat :: SrcSpan -> LHsExpr RdrName -> [LPat RdrName] -> P (LPat RdrName)
656 checkPat loc (L l (HsVar c)) args
657 | isRdrDataCon c = return (L loc (ConPatIn (L l c) (PrefixCon args)))
658 checkPat loc e args -- OK to let this happen even if bang-patterns
659 -- are not enabled, because there is no valid
660 -- non-bang-pattern parse of (C ! e)
661 | Just (e', args') <- splitBang e
662 = do { args'' <- checkPatterns args'
663 ; checkPat loc e' (args'' ++ args) }
664 checkPat loc (L _ (HsApp f x)) args
665 = do { x <- checkLPat x; checkPat loc f (x:args) }
666 checkPat loc (L _ e) []
667 = do { pState <- getPState
668 ; p <- checkAPat (dflags pState) loc e
671 = patFail loc (unLoc e)
673 checkAPat :: DynFlags -> SrcSpan -> HsExpr RdrName -> P (Pat RdrName)
674 checkAPat dynflags loc e0 = case e0 of
675 EWildPat -> return (WildPat placeHolderType)
676 HsVar x -> return (VarPat x)
677 HsLit l -> return (LitPat l)
679 -- Overloaded numeric patterns (e.g. f 0 x = x)
680 -- Negation is recorded separately, so that the literal is zero or +ve
681 -- NB. Negative *primitive* literals are already handled by the lexer
682 HsOverLit pos_lit -> return (mkNPat pos_lit Nothing)
683 NegApp (L _ (HsOverLit pos_lit)) _
684 -> return (mkNPat pos_lit (Just noSyntaxExpr))
686 SectionR (L _ (HsVar bang)) e -- (! x)
688 -> do { bang_on <- extension bangPatEnabled
689 ; if bang_on then checkLPat e >>= (return . BangPat)
690 else parseErrorSDoc loc (text "Illegal bang-pattern (use -XBangPatterns):" $$ ppr e0) }
692 ELazyPat e -> checkLPat e >>= (return . LazyPat)
693 EAsPat n e -> checkLPat e >>= (return . AsPat n)
694 -- view pattern is well-formed if the pattern is
695 EViewPat expr patE -> checkLPat patE >>= (return . (\p -> ViewPat expr p placeHolderType))
696 ExprWithTySig e t -> do e <- checkLPat e
697 -- Pattern signatures are parsed as sigtypes,
698 -- but they aren't explicit forall points. Hence
699 -- we have to remove the implicit forall here.
701 L _ (HsForAllTy Implicit _ (L _ []) ty) -> ty
703 return (SigPatIn e t')
706 OpApp (L nloc (HsVar n)) (L _ (HsVar plus)) _
707 (L _ (HsOverLit lit@(OverLit {ol_val = HsIntegral {}})))
708 | xopt Opt_NPlusKPatterns dynflags && (plus == plus_RDR)
709 -> return (mkNPlusKPat (L nloc n) lit)
711 OpApp l op _fix r -> do l <- checkLPat l
714 L cl (HsVar c) | isDataOcc (rdrNameOcc c)
715 -> return (ConPatIn (L cl c) (InfixCon l r))
718 HsPar e -> checkLPat e >>= (return . ParPat)
719 ExplicitList _ es -> do ps <- mapM checkLPat es
720 return (ListPat ps placeHolderType)
721 ExplicitPArr _ es -> do ps <- mapM checkLPat es
722 return (PArrPat ps placeHolderType)
725 | all tupArgPresent es -> do ps <- mapM checkLPat [e | Present e <- es]
726 return (TuplePat ps b placeHolderType)
727 | otherwise -> parseErrorSDoc loc (text "Illegal tuple section in pattern:" $$ ppr e0)
729 RecordCon c _ (HsRecFields fs dd)
730 -> do fs <- mapM checkPatField fs
731 return (ConPatIn c (RecCon (HsRecFields fs dd)))
732 HsQuasiQuoteE q -> return (QuasiQuotePat q)
735 placeHolderPunRhs :: LHsExpr RdrName
736 -- The RHS of a punned record field will be filled in by the renamer
737 -- It's better not to make it an error, in case we want to print it when debugging
738 placeHolderPunRhs = noLoc (HsVar pun_RDR)
740 plus_RDR, bang_RDR, pun_RDR :: RdrName
741 plus_RDR = mkUnqual varName (fsLit "+") -- Hack
742 bang_RDR = mkUnqual varName (fsLit "!") -- Hack
743 pun_RDR = mkUnqual varName (fsLit "pun-right-hand-side")
745 checkPatField :: HsRecField RdrName (LHsExpr RdrName) -> P (HsRecField RdrName (LPat RdrName))
746 checkPatField fld = do { p <- checkLPat (hsRecFieldArg fld)
747 ; return (fld { hsRecFieldArg = p }) }
749 patFail :: SrcSpan -> HsExpr RdrName -> P a
750 patFail loc e = parseErrorSDoc loc (text "Parse error in pattern:" <+> ppr e)
753 ---------------------------------------------------------------------------
754 -- Check Equation Syntax
756 checkValDef :: LHsExpr RdrName
757 -> Maybe (LHsType RdrName)
758 -> Located (GRHSs RdrName)
759 -> P (HsBind RdrName)
761 checkValDef lhs (Just sig) grhss
762 -- x :: ty = rhs parses as a *pattern* binding
763 = checkPatBind (L (combineLocs lhs sig) (ExprWithTySig lhs sig)) grhss
765 checkValDef lhs opt_sig grhss
766 = do { mb_fun <- isFunLhs lhs
768 Just (fun, is_infix, pats) -> checkFunBind (getLoc lhs)
769 fun is_infix pats opt_sig grhss
770 Nothing -> checkPatBind lhs grhss }
772 checkFunBind :: SrcSpan
776 -> Maybe (LHsType RdrName)
777 -> Located (GRHSs RdrName)
778 -> P (HsBind RdrName)
779 checkFunBind lhs_loc fun is_infix pats opt_sig (L rhs_span grhss)
780 = do ps <- checkPatterns pats
781 let match_span = combineSrcSpans lhs_loc rhs_span
782 return (makeFunBind fun is_infix [L match_span (Match ps opt_sig grhss)])
783 -- The span of the match covers the entire equation.
784 -- That isn't quite right, but it'll do for now.
786 makeFunBind :: Located id -> Bool -> [LMatch id] -> HsBind id
787 -- Like HsUtils.mkFunBind, but we need to be able to set the fixity too
788 makeFunBind fn is_infix ms
789 = FunBind { fun_id = fn, fun_infix = is_infix, fun_matches = mkMatchGroup ms,
790 fun_co_fn = idHsWrapper, bind_fvs = placeHolderNames, fun_tick = Nothing }
792 checkPatBind :: LHsExpr RdrName
793 -> Located (GRHSs RdrName)
794 -> P (HsBind RdrName)
795 checkPatBind lhs (L _ grhss)
796 = do { lhs <- checkPattern lhs
797 ; return (PatBind lhs grhss placeHolderType placeHolderNames) }
803 checkValSig (L l (HsVar v)) ty
804 | isUnqual v && not (isDataOcc (rdrNameOcc v))
805 = return (TypeSig (L l v) ty)
806 checkValSig lhs@(L l _) ty
807 = parseErrorSDoc l ((text "Invalid type signature:" <+>
808 ppr lhs <+> text "::" <+> ppr ty)
811 hint = if foreign_RDR `looks_like` lhs
812 then "Perhaps you meant to use -XForeignFunctionInterface?"
813 else if default_RDR `looks_like` lhs
814 then "Perhaps you meant to use -XDefaultSignatures?"
815 else "Should be of form <variable> :: <type>"
816 -- A common error is to forget the ForeignFunctionInterface flag
817 -- so check for that, and suggest. cf Trac #3805
818 -- Sadly 'foreign import' still barfs 'parse error' because 'import' is a keyword
819 looks_like s (L _ (HsVar v)) = v == s
820 looks_like s (L _ (HsApp lhs _)) = looks_like s lhs
821 looks_like _ _ = False
823 foreign_RDR = mkUnqual varName (fsLit "foreign")
824 default_RDR = mkUnqual varName (fsLit "default")
826 checkDoAndIfThenElse :: LHsExpr RdrName
832 checkDoAndIfThenElse guardExpr semiThen thenExpr semiElse elseExpr
833 | semiThen || semiElse
834 = do pState <- getPState
835 unless (xopt Opt_DoAndIfThenElse (dflags pState)) $ do
836 parseErrorSDoc (combineLocs guardExpr elseExpr)
837 (text "Unexpected semi-colons in conditional:"
839 $$ text "Perhaps you meant to use -XDoAndIfThenElse?")
840 | otherwise = return ()
841 where pprOptSemi True = semi
842 pprOptSemi False = empty
843 expr = text "if" <+> ppr guardExpr <> pprOptSemi semiThen <+>
844 text "then" <+> ppr thenExpr <> pprOptSemi semiElse <+>
845 text "else" <+> ppr elseExpr
850 -- The parser left-associates, so there should
851 -- not be any OpApps inside the e's
852 splitBang :: LHsExpr RdrName -> Maybe (LHsExpr RdrName, [LHsExpr RdrName])
853 -- Splits (f ! g a b) into (f, [(! g), a, b])
854 splitBang (L loc (OpApp l_arg bang@(L _ (HsVar op)) _ r_arg))
855 | op == bang_RDR = Just (l_arg, L loc (SectionR bang arg1) : argns)
857 (arg1,argns) = split_bang r_arg []
858 split_bang (L _ (HsApp f e)) es = split_bang f (e:es)
859 split_bang e es = (e,es)
860 splitBang _ = Nothing
862 isFunLhs :: LHsExpr RdrName
863 -> P (Maybe (Located RdrName, Bool, [LHsExpr RdrName]))
864 -- A variable binding is parsed as a FunBind.
865 -- Just (fun, is_infix, arg_pats) if e is a function LHS
867 -- The whole LHS is parsed as a single expression.
868 -- Any infix operators on the LHS will parse left-associatively
870 -- will parse (rather strangely) as
872 -- It's up to isFunLhs to sort out the mess
878 go (L loc (HsVar f)) es
879 | not (isRdrDataCon f) = return (Just (L loc f, False, es))
880 go (L _ (HsApp f e)) es = go f (e:es)
881 go (L _ (HsPar e)) es@(_:_) = go e es
883 -- For infix function defns, there should be only one infix *function*
884 -- (though there may be infix *datacons* involved too). So we don't
885 -- need fixity info to figure out which function is being defined.
886 -- a `K1` b `op` c `K2` d
888 -- (a `K1` b) `op` (c `K2` d)
889 -- The renamer checks later that the precedences would yield such a parse.
891 -- There is a complication to deal with bang patterns.
893 -- ToDo: what about this?
894 -- x + 1 `op` y = ...
896 go e@(L loc (OpApp l (L loc' (HsVar op)) fix r)) es
897 | Just (e',es') <- splitBang e
898 = do { bang_on <- extension bangPatEnabled
899 ; if bang_on then go e' (es' ++ es)
900 else return (Just (L loc' op, True, (l:r:es))) }
901 -- No bangs; behave just like the next case
902 | not (isRdrDataCon op) -- We have found the function!
903 = return (Just (L loc' op, True, (l:r:es)))
904 | otherwise -- Infix data con; keep going
905 = do { mb_l <- go l es
907 Just (op', True, j : k : es')
908 -> return (Just (op', True, j : op_app : es'))
910 op_app = L loc (OpApp k (L loc' (HsVar op)) fix r)
911 _ -> return Nothing }
912 go _ _ = return Nothing
914 ---------------------------------------------------------------------------
915 -- Miscellaneous utilities
917 checkPrecP :: Located Int -> P Int
919 | 0 <= i && i <= maxPrecedence = return i
921 = parseErrorSDoc l (text ("Precedence out of range: " ++ show i))
926 -> ([HsRecField RdrName (LHsExpr RdrName)], Bool)
927 -> P (HsExpr RdrName)
929 mkRecConstrOrUpdate (L l (HsVar c)) _ (fs,dd) | isRdrDataCon c
930 = return (RecordCon (L l c) noPostTcExpr (mk_rec_fields fs dd))
931 mkRecConstrOrUpdate exp loc (fs,dd)
932 | null fs = parseErrorSDoc loc (text "Empty record update of:" <+> ppr exp)
933 | otherwise = return (RecordUpd exp (mk_rec_fields fs dd) [] [] [])
935 mk_rec_fields :: [HsRecField id arg] -> Bool -> HsRecFields id arg
936 mk_rec_fields fs False = HsRecFields { rec_flds = fs, rec_dotdot = Nothing }
937 mk_rec_fields fs True = HsRecFields { rec_flds = fs, rec_dotdot = Just (length fs) }
939 mkInlinePragma :: (InlineSpec, RuleMatchInfo) -> Maybe Activation -> InlinePragma
940 -- The Maybe is because the user can omit the activation spec (and usually does)
941 mkInlinePragma (inl, match_info) mb_act
942 = InlinePragma { inl_inline = inl
945 , inl_rule = match_info }
949 Nothing -> -- No phase specified
951 NoInline -> NeverActive
952 _other -> AlwaysActive
954 -----------------------------------------------------------------------------
955 -- utilities for foreign declarations
957 -- construct a foreign import declaration
959 mkImport :: CCallConv
961 -> (Located FastString, Located RdrName, LHsType RdrName)
962 -> P (HsDecl RdrName)
963 mkImport cconv safety (L loc entity, v, ty)
964 | cconv == PrimCallConv = do
965 let funcTarget = CFunction (StaticTarget entity Nothing)
966 importSpec = CImport PrimCallConv safety nilFS funcTarget
967 return (ForD (ForeignImport v ty importSpec))
970 case parseCImport cconv safety (mkExtName (unLoc v)) (unpackFS entity) of
971 Nothing -> parseErrorSDoc loc (text "Malformed entity string")
972 Just importSpec -> return (ForD (ForeignImport v ty importSpec))
974 -- the string "foo" is ambigous: either a header or a C identifier. The
975 -- C identifier case comes first in the alternatives below, so we pick
977 parseCImport :: CCallConv -> Safety -> FastString -> String
978 -> Maybe ForeignImport
979 parseCImport cconv safety nm str =
980 listToMaybe $ map fst $ filter (null.snd) $
986 string "dynamic" >> return (mk nilFS (CFunction DynamicTarget)),
987 string "wrapper" >> return (mk nilFS CWrapper),
988 optional (string "static" >> skipSpaces) >>
989 (mk nilFS <$> cimp nm) +++
990 (do h <- munch1 hdr_char; skipSpaces; mk (mkFastString h) <$> cimp nm)
995 mk = CImport cconv safety
997 hdr_char c = not (isSpace c) -- header files are filenames, which can contain
998 -- pretty much any char (depending on the platform),
999 -- so just accept any non-space character
1000 id_char c = isAlphaNum c || c == '_'
1002 cimp nm = (ReadP.char '&' >> skipSpaces >> CLabel <$> cid)
1003 +++ ((\c -> CFunction (StaticTarget c Nothing)) <$> cid)
1006 (do c <- satisfy (\c -> isAlpha c || c == '_')
1007 cs <- many (satisfy id_char)
1008 return (mkFastString (c:cs)))
1011 -- construct a foreign export declaration
1013 mkExport :: CCallConv
1014 -> (Located FastString, Located RdrName, LHsType RdrName)
1015 -> P (HsDecl RdrName)
1016 mkExport cconv (L _ entity, v, ty) = return $
1017 ForD (ForeignExport v ty (CExport (CExportStatic entity' cconv)))
1019 entity' | nullFS entity = mkExtName (unLoc v)
1020 | otherwise = entity
1022 -- Supplying the ext_name in a foreign decl is optional; if it
1023 -- isn't there, the Haskell name is assumed. Note that no transformation
1024 -- of the Haskell name is then performed, so if you foreign export (++),
1025 -- it's external name will be "++". Too bad; it's important because we don't
1026 -- want z-encoding (e.g. names with z's in them shouldn't be doubled)
1028 mkExtName :: RdrName -> CLabelString
1029 mkExtName rdrNm = mkFastString (occNameString (rdrNameOcc rdrNm))
1033 -----------------------------------------------------------------------------
1037 parseError :: SrcSpan -> String -> P a
1038 parseError span s = parseErrorSDoc span (text s)
1040 parseErrorSDoc :: SrcSpan -> SDoc -> P a
1041 parseErrorSDoc span s = failSpanMsgP span s