2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
9 {-# OPTIONS -fno-warn-incomplete-patterns #-}
10 -- The above warning supression flag is a temporary kludge.
11 -- While working on this module you are encouraged to remove it and fix
12 -- any warnings in the module. See
13 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
16 -- | Abstract syntax of global declarations.
18 -- Definitions for: @TyDecl@ and @ConDecl@, @ClassDecl@,
19 -- @InstDecl@, @DefaultDecl@ and @ForeignDecl@.
21 -- * Toplevel declarations
23 -- ** Class or type declarations
24 TyClDecl(..), LTyClDecl,
25 isClassDecl, isSynDecl, isDataDecl, isTypeDecl, isFamilyDecl,
26 isFamInstDecl, tcdName, tyClDeclNames, tyClDeclTyVars,
28 -- ** Instance declarations
29 InstDecl(..), LInstDecl, NewOrData(..), FamilyFlavour(..),
31 -- ** Standalone deriving declarations
32 DerivDecl(..), LDerivDecl,
33 -- ** @RULE@ declarations
34 RuleDecl(..), LRuleDecl, RuleBndr(..),
35 collectRuleBndrSigTys,
36 -- ** @default@ declarations
37 DefaultDecl(..), LDefaultDecl,
38 -- ** Top-level template haskell splice
40 -- ** Foreign function interface declarations
41 ForeignDecl(..), LForeignDecl, ForeignImport(..), ForeignExport(..),
43 -- ** Data-constructor declarations
44 ConDecl(..), LConDecl, ResType(..),
45 HsConDeclDetails, hsConDeclArgTys, hsConDeclsNames,
46 -- ** Document comments
47 DocDecl(..), LDocDecl, docDeclDoc,
49 WarnDecl(..), LWarnDecl,
51 AnnDecl(..), LAnnDecl,
52 AnnProvenance(..), annProvenanceName_maybe, modifyAnnProvenanceNameM,
55 HsGroup(..), emptyRdrGroup, emptyRnGroup, appendGroups
59 import {-# SOURCE #-} HsExpr( HsExpr, pprExpr )
60 -- Because Expr imports Decls via HsBracket
67 import {- Kind parts of -} Type
78 import Control.Monad ( liftM )
79 import Data.Maybe ( isJust )
82 %************************************************************************
84 \subsection[HsDecl]{Declarations}
86 %************************************************************************
89 type LHsDecl id = Located (HsDecl id)
91 -- | A Haskell Declaration
93 = TyClD (TyClDecl id) -- ^ A type or class declaration.
94 | InstD (InstDecl id) -- ^ An instance declaration.
95 | DerivD (DerivDecl id)
98 | DefD (DefaultDecl id)
99 | ForD (ForeignDecl id)
100 | WarningD (WarnDecl id)
102 | RuleD (RuleDecl id)
103 | SpliceD (SpliceDecl id)
107 -- NB: all top-level fixity decls are contained EITHER
109 -- OR in the ClassDecls in TyClDs
112 -- a) data constructors
113 -- b) class methods (but they can be also done in the
114 -- signatures of class decls)
115 -- c) imported functions (that have an IfacSig)
116 -- d) top level decls
118 -- The latter is for class methods only
120 -- | A 'HsDecl' is categorised into a 'HsGroup' before being
121 -- fed to the renamer.
124 hs_valds :: HsValBinds id,
125 hs_tyclds :: [LTyClDecl id],
126 hs_instds :: [LInstDecl id],
127 hs_derivds :: [LDerivDecl id],
129 hs_fixds :: [LFixitySig id],
130 -- Snaffled out of both top-level fixity signatures,
131 -- and those in class declarations
133 hs_defds :: [LDefaultDecl id],
134 hs_fords :: [LForeignDecl id],
135 hs_warnds :: [LWarnDecl id],
136 hs_annds :: [LAnnDecl id],
137 hs_ruleds :: [LRuleDecl id],
139 hs_docs :: [LDocDecl]
142 emptyGroup, emptyRdrGroup, emptyRnGroup :: HsGroup a
143 emptyRdrGroup = emptyGroup { hs_valds = emptyValBindsIn }
144 emptyRnGroup = emptyGroup { hs_valds = emptyValBindsOut }
146 emptyGroup = HsGroup { hs_tyclds = [], hs_instds = [], hs_derivds = [],
147 hs_fixds = [], hs_defds = [], hs_annds = [],
148 hs_fords = [], hs_warnds = [], hs_ruleds = [],
149 hs_valds = error "emptyGroup hs_valds: Can't happen",
152 appendGroups :: HsGroup a -> HsGroup a -> HsGroup a
155 hs_valds = val_groups1,
158 hs_derivds = derivds1,
167 hs_valds = val_groups2,
170 hs_derivds = derivds2,
180 hs_valds = val_groups1 `plusHsValBinds` val_groups2,
181 hs_tyclds = tyclds1 ++ tyclds2,
182 hs_instds = instds1 ++ instds2,
183 hs_derivds = derivds1 ++ derivds2,
184 hs_fixds = fixds1 ++ fixds2,
185 hs_annds = annds1 ++ annds2,
186 hs_defds = defds1 ++ defds2,
187 hs_fords = fords1 ++ fords2,
188 hs_warnds = warnds1 ++ warnds2,
189 hs_ruleds = rulds1 ++ rulds2,
190 hs_docs = docs1 ++ docs2 }
194 instance OutputableBndr name => Outputable (HsDecl name) where
195 ppr (TyClD dcl) = ppr dcl
196 ppr (ValD binds) = ppr binds
197 ppr (DefD def) = ppr def
198 ppr (InstD inst) = ppr inst
199 ppr (DerivD deriv) = ppr deriv
200 ppr (ForD fd) = ppr fd
201 ppr (SigD sd) = ppr sd
202 ppr (RuleD rd) = ppr rd
203 ppr (WarningD wd) = ppr wd
204 ppr (AnnD ad) = ppr ad
205 ppr (SpliceD dd) = ppr dd
206 ppr (DocD doc) = ppr doc
208 instance OutputableBndr name => Outputable (HsGroup name) where
209 ppr (HsGroup { hs_valds = val_decls,
210 hs_tyclds = tycl_decls,
211 hs_instds = inst_decls,
212 hs_derivds = deriv_decls,
213 hs_fixds = fix_decls,
214 hs_warnds = deprec_decls,
215 hs_annds = ann_decls,
216 hs_fords = foreign_decls,
217 hs_defds = default_decls,
218 hs_ruleds = rule_decls })
219 = vcat [ppr_ds fix_decls, ppr_ds default_decls,
220 ppr_ds deprec_decls, ppr_ds ann_decls,
223 ppr_ds tycl_decls, ppr_ds inst_decls,
225 ppr_ds foreign_decls]
228 ppr_ds ds = text "" $$ vcat (map ppr ds)
230 data SpliceDecl id = SpliceDecl (Located (HsExpr id)) -- Top level splice
232 instance OutputableBndr name => Outputable (SpliceDecl name) where
233 ppr (SpliceDecl e) = ptext (sLit "$") <> parens (pprExpr (unLoc e))
237 %************************************************************************
239 \subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
241 %************************************************************************
243 --------------------------------
245 --------------------------------
247 Here is the story about the implicit names that go with type, class,
248 and instance decls. It's a bit tricky, so pay attention!
250 "Implicit" (or "system") binders
251 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
252 Each data type decl defines
253 a worker name for each constructor
254 to-T and from-T convertors
255 Each class decl defines
256 a tycon for the class
257 a data constructor for that tycon
258 the worker for that constructor
259 a selector for each superclass
261 All have occurrence names that are derived uniquely from their parent
264 None of these get separate definitions in an interface file; they are
265 fully defined by the data or class decl. But they may *occur* in
266 interface files, of course. Any such occurrence must haul in the
267 relevant type or class decl.
270 - Ensure they "point to" the parent data/class decl
271 when loading that decl from an interface file
272 (See RnHiFiles.getSysBinders)
274 - When typechecking the decl, we build the implicit TyCons and Ids.
275 When doing so we look them up in the name cache (RnEnv.lookupSysName),
276 to ensure correct module and provenance is set
278 These are the two places that we have to conjure up the magic derived
279 names. (The actual magic is in OccName.mkWorkerOcc, etc.)
283 - Occurrence name is derived uniquely from the method name
286 - If there is a default method name at all, it's recorded in
287 the ClassOpSig (in HsBinds), in the DefMeth field.
288 (DefMeth is defined in Class.lhs)
290 Source-code class decls and interface-code class decls are treated subtly
291 differently, which has given me a great deal of confusion over the years.
292 Here's the deal. (We distinguish the two cases because source-code decls
293 have (Just binds) in the tcdMeths field, whereas interface decls have Nothing.
295 In *source-code* class declarations:
297 - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName
298 This is done by RdrHsSyn.mkClassOpSigDM
300 - The renamer renames it to a Name
302 - During typechecking, we generate a binding for each $dm for
303 which there's a programmer-supplied default method:
308 We generate a binding for $dmop1 but not for $dmop2.
309 The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1.
310 The Name for $dmop2 is simply discarded.
312 In *interface-file* class declarations:
313 - When parsing, we see if there's an explicit programmer-supplied default method
314 because there's an '=' sign to indicate it:
316 op1 = :: <type> -- NB the '='
318 We use this info to generate a DefMeth with a suitable RdrName for op1,
319 and a NoDefMeth for op2
320 - The interface file has a separate definition for $dmop1, with unfolding etc.
321 - The renamer renames it to a Name.
322 - The renamer treats $dmop1 as a free variable of the declaration, so that
323 the binding for $dmop1 will be sucked in. (See RnHsSyn.tyClDeclFVs)
324 This doesn't happen for source code class decls, because they *bind* the default method.
328 Each instance declaration gives rise to one dictionary function binding.
330 The type checker makes up new source-code instance declarations
331 (e.g. from 'deriving' or generic default methods --- see
332 TcInstDcls.tcInstDecls1). So we can't generate the names for
333 dictionary functions in advance (we don't know how many we need).
335 On the other hand for interface-file instance declarations, the decl
336 specifies the name of the dictionary function, and it has a binding elsewhere
337 in the interface file:
338 instance {Eq Int} = dEqInt
339 dEqInt :: {Eq Int} <pragma info>
341 So again we treat source code and interface file code slightly differently.
344 - Source code instance decls have a Nothing in the (Maybe name) field
345 (see data InstDecl below)
347 - The typechecker makes up a Local name for the dict fun for any source-code
348 instance decl, whether it comes from a source-code instance decl, or whether
349 the instance decl is derived from some other construct (e.g. 'deriving').
351 - The occurrence name it chooses is derived from the instance decl (just for
352 documentation really) --- e.g. dNumInt. Two dict funs may share a common
353 occurrence name, but will have different uniques. E.g.
354 instance Foo [Int] where ...
355 instance Foo [Bool] where ...
356 These might both be dFooList
358 - The CoreTidy phase externalises the name, and ensures the occurrence name is
359 unique (this isn't special to dict funs). So we'd get dFooList and dFooList1.
361 - We can take this relaxed approach (changing the occurrence name later)
362 because dict fun Ids are not captured in a TyCon or Class (unlike default
363 methods, say). Instead, they are kept separately in the InstEnv. This
364 makes it easy to adjust them after compiling a module. (Once we've finished
365 compiling that module, they don't change any more.)
369 - The instance decl gives the dict fun name, so the InstDecl has a (Just name)
370 in the (Maybe name) field.
372 - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
373 suck in the dfun binding
377 -- Representation of indexed types
378 -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
379 -- Family kind signatures are represented by the variant `TyFamily'. It
380 -- covers "type family", "newtype family", and "data family" declarations,
381 -- distinguished by the value of the field `tcdFlavour'.
383 -- Indexed types are represented by 'TyData' and 'TySynonym' using the field
384 -- 'tcdTyPats::Maybe [LHsType name]', with the following meaning:
386 -- * If it is 'Nothing', we have a *vanilla* data type declaration or type
387 -- synonym declaration and 'tcdVars' contains the type parameters of the
390 -- * If it is 'Just pats', we have the definition of an indexed type. Then,
391 -- 'pats' are type patterns for the type-indexes of the type constructor
392 -- and 'tcdTyVars' are the variables in those patterns. Hence, the arity of
393 -- the indexed type (ie, the number of indexes) is 'length tcdTyPats' and
394 -- *not* 'length tcdVars'.
396 -- In both cases, 'tcdVars' collects all variables we need to quantify over.
398 type LTyClDecl name = Located (TyClDecl name)
400 -- | A type or class declaration.
403 tcdLName :: Located name,
404 tcdExtName :: Maybe FastString
408 | -- | @type/data family T :: *->*@
409 TyFamily { tcdFlavour:: FamilyFlavour, -- type or data
410 tcdLName :: Located name, -- type constructor
411 tcdTyVars :: [LHsTyVarBndr name], -- type variables
412 tcdKind :: Maybe Kind -- result kind
416 | -- | Declares a data type or newtype, giving its construcors
418 -- data/newtype T a = <constrs>
419 -- data/newtype instance T [a] = <constrs>
421 TyData { tcdND :: NewOrData,
422 tcdCtxt :: LHsContext name, -- ^ Context
423 tcdLName :: Located name, -- ^ Type constructor
425 tcdTyVars :: [LHsTyVarBndr name], -- ^ Type variables
427 tcdTyPats :: Maybe [LHsType name],
430 -- @Just [t1..tn]@ for @data instance T t1..tn = ...@
431 -- in this case @tcdTyVars = fv( tcdTyPats )@.
432 -- @Nothing@ for everything else.
434 tcdKindSig:: Maybe Kind,
435 -- ^ Optional kind signature.
437 -- @(Just k)@ for a GADT-style @data@, or @data
438 -- instance@ decl with explicit kind sig
440 tcdCons :: [LConDecl name],
441 -- ^ Data constructors
443 -- For @data T a = T1 | T2 a@
444 -- the 'LConDecl's all have 'ResTyH98'.
445 -- For @data T a where { T1 :: T a }@
446 -- the 'LConDecls' all have 'ResTyGADT'.
448 tcdDerivs :: Maybe [LHsType name]
449 -- ^ Derivings; @Nothing@ => not specified,
450 -- @Just []@ => derive exactly what is asked
452 -- These "types" must be of form
454 -- forall ab. C ty1 ty2
456 -- Typically the foralls and ty args are empty, but they
457 -- are non-empty for the newtype-deriving case
460 | TySynonym { tcdLName :: Located name, -- ^ type constructor
461 tcdTyVars :: [LHsTyVarBndr name], -- ^ type variables
462 tcdTyPats :: Maybe [LHsType name], -- ^ Type patterns
463 -- See comments for tcdTyPats in TyData
464 -- 'Nothing' => vanilla type synonym
466 tcdSynRhs :: LHsType name -- ^ synonym expansion
469 | ClassDecl { tcdCtxt :: LHsContext name, -- ^ Context...
470 tcdLName :: Located name, -- ^ Name of the class
471 tcdTyVars :: [LHsTyVarBndr name], -- ^ Class type variables
472 tcdFDs :: [Located (FunDep name)], -- ^ Functional deps
473 tcdSigs :: [LSig name], -- ^ Methods' signatures
474 tcdMeths :: LHsBinds name, -- ^ Default methods
475 tcdATs :: [LTyClDecl name], -- ^ Associated types; ie
476 -- only 'TyFamily' and
478 -- latter for defaults
479 tcdDocs :: [LDocDecl] -- ^ Haddock docs
483 = NewType -- ^ @newtype Blah ...@
484 | DataType -- ^ @data Blah ...@
485 deriving( Eq ) -- Needed because Demand derives Eq
488 = TypeFamily -- ^ @type family ...@
489 | DataFamily -- ^ @data family ...@
495 -- | @True@ <=> argument is a @data@\/@newtype@ or @data@\/@newtype instance@
497 isDataDecl :: TyClDecl name -> Bool
498 isDataDecl (TyData {}) = True
499 isDataDecl _other = False
501 -- | type or type instance declaration
502 isTypeDecl :: TyClDecl name -> Bool
503 isTypeDecl (TySynonym {}) = True
504 isTypeDecl _other = False
506 -- | vanilla Haskell type synonym (ie, not a type instance)
507 isSynDecl :: TyClDecl name -> Bool
508 isSynDecl (TySynonym {tcdTyPats = Nothing}) = True
509 isSynDecl _other = False
512 isClassDecl :: TyClDecl name -> Bool
513 isClassDecl (ClassDecl {}) = True
514 isClassDecl _ = False
516 -- | type family declaration
517 isFamilyDecl :: TyClDecl name -> Bool
518 isFamilyDecl (TyFamily {}) = True
519 isFamilyDecl _other = False
521 -- | family instance (types, newtypes, and data types)
522 isFamInstDecl :: TyClDecl name -> Bool
525 || isDataDecl tydecl = isJust (tcdTyPats tydecl)
532 tcdName :: TyClDecl name -> name
533 tcdName decl = unLoc (tcdLName decl)
535 tyClDeclNames :: Eq name => TyClDecl name -> [Located name]
536 -- ^ Returns all the /binding/ names of the decl, along with their SrcLocs.
537 -- The first one is guaranteed to be the name of the decl. For record fields
538 -- mentioned in multiple constructors, the SrcLoc will be from the first
539 -- occurence. We use the equality to filter out duplicate field names
541 tyClDeclNames (TyFamily {tcdLName = name}) = [name]
542 tyClDeclNames (TySynonym {tcdLName = name}) = [name]
543 tyClDeclNames (ForeignType {tcdLName = name}) = [name]
545 tyClDeclNames (ClassDecl {tcdLName = cls_name, tcdSigs = sigs, tcdATs = ats})
547 concatMap (tyClDeclNames . unLoc) ats ++ [n | L _ (TypeSig n _) <- sigs]
549 tyClDeclNames (TyData {tcdLName = tc_name, tcdCons = cons})
550 = tc_name : hsConDeclsNames cons
552 tyClDeclTyVars :: TyClDecl name -> [LHsTyVarBndr name]
553 tyClDeclTyVars (TyFamily {tcdTyVars = tvs}) = tvs
554 tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
555 tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs
556 tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
557 tyClDeclTyVars (ForeignType {}) = []
561 countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int, Int, Int)
562 -- class, synonym decls, data, newtype, family decls, family instances
564 = (count isClassDecl decls,
565 count isSynDecl decls, -- excluding...
566 count isDataTy decls, -- ...family...
567 count isNewTy decls, -- ...instances
568 count isFamilyDecl decls,
569 count isFamInstDecl decls)
571 isDataTy TyData{tcdND = DataType, tcdTyPats = Nothing} = True
574 isNewTy TyData{tcdND = NewType, tcdTyPats = Nothing} = True
579 instance OutputableBndr name
580 => Outputable (TyClDecl name) where
582 ppr (ForeignType {tcdLName = ltycon})
583 = hsep [ptext (sLit "foreign import type dotnet"), ppr ltycon]
585 ppr (TyFamily {tcdFlavour = flavour, tcdLName = ltycon,
586 tcdTyVars = tyvars, tcdKind = mb_kind})
587 = pp_flavour <+> pp_decl_head [] ltycon tyvars Nothing <+> pp_kind
589 pp_flavour = case flavour of
590 TypeFamily -> ptext (sLit "type family")
591 DataFamily -> ptext (sLit "data family")
593 pp_kind = case mb_kind of
595 Just kind -> dcolon <+> pprKind kind
597 ppr (TySynonym {tcdLName = ltycon, tcdTyVars = tyvars, tcdTyPats = typats,
598 tcdSynRhs = mono_ty})
599 = hang (ptext (sLit "type") <+>
600 (if isJust typats then ptext (sLit "instance") else empty) <+>
601 pp_decl_head [] ltycon tyvars typats <+>
605 ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = ltycon,
606 tcdTyVars = tyvars, tcdTyPats = typats, tcdKindSig = mb_sig,
607 tcdCons = condecls, tcdDerivs = derivings})
608 = pp_tydecl (null condecls && isJust mb_sig)
610 (if isJust typats then ptext (sLit "instance") else empty) <+>
611 pp_decl_head (unLoc context) ltycon tyvars typats <+>
613 (pp_condecls condecls)
616 ppr_sig Nothing = empty
617 ppr_sig (Just kind) = dcolon <+> pprKind kind
619 ppr (ClassDecl {tcdCtxt = context, tcdLName = lclas, tcdTyVars = tyvars,
621 tcdSigs = sigs, tcdMeths = methods, tcdATs = ats})
622 | null sigs && null ats -- No "where" part
625 | otherwise -- Laid out
626 = sep [hsep [top_matter, ptext (sLit "where {")],
627 nest 4 (sep [ sep (map ppr_semi ats)
628 , sep (map ppr_semi sigs)
629 , pprLHsBinds methods
632 top_matter = ptext (sLit "class")
633 <+> pp_decl_head (unLoc context) lclas tyvars Nothing
634 <+> pprFundeps (map unLoc fds)
635 ppr_semi decl = ppr decl <> semi
637 pp_decl_head :: OutputableBndr name
640 -> [LHsTyVarBndr name]
641 -> Maybe [LHsType name]
643 pp_decl_head context thing tyvars Nothing -- no explicit type patterns
644 = hsep [pprHsContext context, ppr thing, interppSP tyvars]
645 pp_decl_head context thing _ (Just typats) -- explicit type patterns
646 = hsep [ pprHsContext context, ppr thing
647 , hsep (map (pprParendHsType.unLoc) typats)]
649 pp_condecls :: OutputableBndr name => [LConDecl name] -> SDoc
650 pp_condecls cs@(L _ ConDecl{ con_res = ResTyGADT _ } : _) -- In GADT syntax
651 = hang (ptext (sLit "where")) 2 (vcat (map ppr cs))
652 pp_condecls cs -- In H98 syntax
653 = equals <+> sep (punctuate (ptext (sLit " |")) (map ppr cs))
655 pp_tydecl :: OutputableBndr name => Bool -> SDoc -> SDoc -> Maybe [LHsType name] -> SDoc
656 pp_tydecl True pp_head _ _
658 pp_tydecl False pp_head pp_decl_rhs derivings
659 = hang pp_head 4 (sep [
663 Just ds -> hsep [ptext (sLit "deriving"), parens (interpp'SP ds)]
666 instance Outputable NewOrData where
667 ppr NewType = ptext (sLit "newtype")
668 ppr DataType = ptext (sLit "data")
672 %************************************************************************
674 \subsection[ConDecl]{A data-constructor declaration}
676 %************************************************************************
679 type LConDecl name = Located (ConDecl name)
681 -- data T b = forall a. Eq a => MkT a b
682 -- MkT :: forall b a. Eq a => MkT a b
685 -- MkT1 :: Int -> T Int
687 -- data T = Int `MkT` Int
691 -- Int `MkT` Int :: T Int
695 { con_name :: Located name
696 -- ^ Constructor name. This is used for the DataCon itself, and for
697 -- the user-callable wrapper Id.
699 , con_explicit :: HsExplicitForAll
700 -- ^ Is there an user-written forall? (cf. 'HsTypes.HsForAllTy')
702 , con_qvars :: [LHsTyVarBndr name]
703 -- ^ Type variables. Depending on 'con_res' this describes the
704 -- follewing entities
706 -- - ResTyH98: the constructor's *existential* type variables
707 -- - ResTyGADT: *all* the constructor's quantified type variables
709 , con_cxt :: LHsContext name
710 -- ^ The context. This /does not/ include the \"stupid theta\" which
711 -- lives only in the 'TyData' decl.
713 , con_details :: HsConDeclDetails name
714 -- ^ The main payload
716 , con_res :: ResType name
717 -- ^ Result type of the constructor
719 , con_doc :: Maybe LHsDocString
720 -- ^ A possible Haddock comment.
722 , con_old_rec :: Bool
723 -- ^ TEMPORARY field; True <=> user has employed now-deprecated syntax for
724 -- GADT-style record decl C { blah } :: T a b
725 -- Remove this when we no longer parse this stuff, and hence do not
726 -- need to report decprecated use
729 type HsConDeclDetails name = HsConDetails (LBangType name) [ConDeclField name]
731 hsConDeclArgTys :: HsConDeclDetails name -> [LBangType name]
732 hsConDeclArgTys (PrefixCon tys) = tys
733 hsConDeclArgTys (InfixCon ty1 ty2) = [ty1,ty2]
734 hsConDeclArgTys (RecCon flds) = map cd_fld_type flds
737 = ResTyH98 -- Constructor was declared using Haskell 98 syntax
738 | ResTyGADT (LHsType name) -- Constructor was declared using GADT-style syntax,
739 -- and here is its result type
741 instance OutputableBndr name => Outputable (ResType name) where
743 ppr ResTyH98 = ptext (sLit "ResTyH98")
744 ppr (ResTyGADT ty) = ptext (sLit "ResTyGADT") <+> pprParendHsType (unLoc ty)
748 hsConDeclsNames :: (Eq name) => [LConDecl name] -> [Located name]
749 -- See tyClDeclNames for what this does
750 -- The function is boringly complicated because of the records
751 -- And since we only have equality, we have to be a little careful
753 = snd (foldl do_one ([], []) cons)
755 do_one (flds_seen, acc) (L _ (ConDecl { con_name = lname, con_details = RecCon flds }))
756 = (map unLoc new_flds ++ flds_seen, lname : new_flds ++ acc)
758 new_flds = filterOut (\f -> unLoc f `elem` flds_seen)
759 (map cd_fld_name flds)
761 do_one (flds_seen, acc) (L _ (ConDecl { con_name = lname }))
762 = (flds_seen, lname:acc)
767 instance (OutputableBndr name) => Outputable (ConDecl name) where
770 pprConDecl :: OutputableBndr name => ConDecl name -> SDoc
771 pprConDecl (ConDecl { con_name =con, con_explicit = expl, con_qvars = tvs
772 , con_cxt = cxt, con_details = details
773 , con_res = ResTyH98, con_doc = doc })
774 = sep [ppr_mbDoc doc, pprHsForAll expl tvs cxt, ppr_details con details]
776 ppr_details con (InfixCon t1 t2) = hsep [ppr t1, pprHsInfix con, ppr t2]
777 ppr_details con (PrefixCon tys) = hsep (pprHsVar con : map ppr tys)
778 ppr_details con (RecCon fields) = ppr con <+> pprConDeclFields fields
780 pprConDecl (ConDecl { con_name = con, con_explicit = expl, con_qvars = tvs
781 , con_cxt = cxt, con_details = PrefixCon arg_tys
782 , con_res = ResTyGADT res_ty })
783 = ppr con <+> dcolon <+>
784 sep [pprHsForAll expl tvs cxt, ppr (foldr mk_fun_ty res_ty arg_tys)]
786 mk_fun_ty a b = noLoc (HsFunTy a b)
788 pprConDecl (ConDecl { con_name = con, con_explicit = expl, con_qvars = tvs
789 , con_cxt = cxt, con_details = RecCon fields, con_res = ResTyGADT res_ty })
790 = sep [ppr con <+> dcolon <+> pprHsForAll expl tvs cxt,
791 pprConDeclFields fields <+> arrow <+> ppr res_ty]
793 pprConDecl (ConDecl {con_name = con, con_details = InfixCon {}, con_res = ResTyGADT {} })
794 = pprPanic "pprConDecl" (ppr con)
795 -- In GADT syntax we don't allow infix constructors
798 %************************************************************************
800 \subsection[InstDecl]{An instance declaration
802 %************************************************************************
805 type LInstDecl name = Located (InstDecl name)
808 = InstDecl (LHsType name) -- Context => Class Instance-type
809 -- Using a polytype means that the renamer conveniently
810 -- figures out the quantified type variables for us.
812 [LSig name] -- User-supplied pragmatic info
813 [LTyClDecl name]-- Associated types (ie, 'TyData' and
816 instance (OutputableBndr name) => Outputable (InstDecl name) where
818 ppr (InstDecl inst_ty binds uprags ats)
819 = vcat [hsep [ptext (sLit "instance"), ppr inst_ty, ptext (sLit "where")]
820 , nest 4 $ vcat (map ppr ats)
821 , nest 4 $ vcat (map ppr uprags)
822 , nest 4 $ pprLHsBinds binds ]
824 -- Extract the declarations of associated types from an instance
826 instDeclATs :: InstDecl name -> [LTyClDecl name]
827 instDeclATs (InstDecl _ _ _ ats) = ats
830 %************************************************************************
832 \subsection[DerivDecl]{A stand-alone instance deriving declaration
834 %************************************************************************
837 type LDerivDecl name = Located (DerivDecl name)
839 data DerivDecl name = DerivDecl (LHsType name)
841 instance (OutputableBndr name) => Outputable (DerivDecl name) where
843 = hsep [ptext (sLit "deriving instance"), ppr ty]
846 %************************************************************************
848 \subsection[DefaultDecl]{A @default@ declaration}
850 %************************************************************************
852 There can only be one default declaration per module, but it is hard
853 for the parser to check that; we pass them all through in the abstract
854 syntax, and that restriction must be checked in the front end.
857 type LDefaultDecl name = Located (DefaultDecl name)
859 data DefaultDecl name
860 = DefaultDecl [LHsType name]
862 instance (OutputableBndr name)
863 => Outputable (DefaultDecl name) where
865 ppr (DefaultDecl tys)
866 = ptext (sLit "default") <+> parens (interpp'SP tys)
869 %************************************************************************
871 \subsection{Foreign function interface declaration}
873 %************************************************************************
877 -- foreign declarations are distinguished as to whether they define or use a
880 -- * the Boolean value indicates whether the pre-standard deprecated syntax
883 type LForeignDecl name = Located (ForeignDecl name)
885 data ForeignDecl name
886 = ForeignImport (Located name) (LHsType name) ForeignImport -- defines name
887 | ForeignExport (Located name) (LHsType name) ForeignExport -- uses name
889 -- Specification Of an imported external entity in dependence on the calling
892 data ForeignImport = -- import of a C entity
894 -- * the two strings specifying a header file or library
895 -- may be empty, which indicates the absence of a
896 -- header or object specification (both are not used
897 -- in the case of `CWrapper' and when `CFunction'
898 -- has a dynamic target)
900 -- * the calling convention is irrelevant for code
901 -- generation in the case of `CLabel', but is needed
902 -- for pretty printing
904 -- * `Safety' is irrelevant for `CLabel' and `CWrapper'
906 CImport CCallConv -- ccall or stdcall
907 Safety -- safe or unsafe
908 FastString -- name of C header
909 CImportSpec -- details of the C entity
911 -- details of an external C entity
913 data CImportSpec = CLabel CLabelString -- import address of a C label
914 | CFunction CCallTarget -- static or dynamic function
915 | CWrapper -- wrapper to expose closures
918 -- specification of an externally exported entity in dependence on the calling
921 data ForeignExport = CExport CExportSpec -- contains the calling convention
923 -- pretty printing of foreign declarations
926 instance OutputableBndr name => Outputable (ForeignDecl name) where
927 ppr (ForeignImport n ty fimport) =
928 hang (ptext (sLit "foreign import") <+> ppr fimport <+> ppr n)
929 2 (dcolon <+> ppr ty)
930 ppr (ForeignExport n ty fexport) =
931 hang (ptext (sLit "foreign export") <+> ppr fexport <+> ppr n)
932 2 (dcolon <+> ppr ty)
934 instance Outputable ForeignImport where
935 ppr (CImport cconv safety header spec) =
936 ppr cconv <+> ppr safety <+>
937 char '"' <> pprCEntity spec <> char '"'
939 pp_hdr = if nullFS header then empty else ftext header
941 pprCEntity (CLabel lbl) =
942 ptext (sLit "static") <+> pp_hdr <+> char '&' <> ppr lbl
943 pprCEntity (CFunction (StaticTarget lbl)) =
944 ptext (sLit "static") <+> pp_hdr <+> ppr lbl
945 pprCEntity (CFunction (DynamicTarget)) =
946 ptext (sLit "dynamic")
947 pprCEntity (CWrapper) = ptext (sLit "wrapper")
949 instance Outputable ForeignExport where
950 ppr (CExport (CExportStatic lbl cconv)) =
951 ppr cconv <+> char '"' <> ppr lbl <> char '"'
955 %************************************************************************
957 \subsection{Transformation rules}
959 %************************************************************************
962 type LRuleDecl name = Located (RuleDecl name)
965 = HsRule -- Source rule
966 RuleName -- Rule name
968 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
969 (Located (HsExpr name)) -- LHS
970 NameSet -- Free-vars from the LHS
971 (Located (HsExpr name)) -- RHS
972 NameSet -- Free-vars from the RHS
975 = RuleBndr (Located name)
976 | RuleBndrSig (Located name) (LHsType name)
978 collectRuleBndrSigTys :: [RuleBndr name] -> [LHsType name]
979 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
981 instance OutputableBndr name => Outputable (RuleDecl name) where
982 ppr (HsRule name act ns lhs _fv_lhs rhs _fv_rhs)
983 = sep [text "{-# RULES" <+> doubleQuotes (ftext name) <+> ppr act,
984 nest 4 (pp_forall <+> pprExpr (unLoc lhs)),
985 nest 4 (equals <+> pprExpr (unLoc rhs) <+> text "#-}") ]
987 pp_forall | null ns = empty
988 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
990 instance OutputableBndr name => Outputable (RuleBndr name) where
991 ppr (RuleBndr name) = ppr name
992 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
995 %************************************************************************
997 \subsection[DocDecl]{Document comments}
999 %************************************************************************
1003 type LDocDecl = Located (DocDecl)
1006 = DocCommentNext HsDocString
1007 | DocCommentPrev HsDocString
1008 | DocCommentNamed String HsDocString
1009 | DocGroup Int HsDocString
1011 -- Okay, I need to reconstruct the document comments, but for now:
1012 instance Outputable DocDecl where
1013 ppr _ = text "<document comment>"
1015 docDeclDoc :: DocDecl -> HsDocString
1016 docDeclDoc (DocCommentNext d) = d
1017 docDeclDoc (DocCommentPrev d) = d
1018 docDeclDoc (DocCommentNamed _ d) = d
1019 docDeclDoc (DocGroup _ d) = d
1023 %************************************************************************
1025 \subsection[DeprecDecl]{Deprecations}
1027 %************************************************************************
1029 We use exported entities for things to deprecate.
1032 type LWarnDecl name = Located (WarnDecl name)
1034 data WarnDecl name = Warning name WarningTxt
1036 instance OutputableBndr name => Outputable (WarnDecl name) where
1037 ppr (Warning thing txt)
1038 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]
1041 %************************************************************************
1043 \subsection[AnnDecl]{Annotations}
1045 %************************************************************************
1048 type LAnnDecl name = Located (AnnDecl name)
1050 data AnnDecl name = HsAnnotation (AnnProvenance name) (Located (HsExpr name))
1052 instance (OutputableBndr name) => Outputable (AnnDecl name) where
1053 ppr (HsAnnotation provenance expr)
1054 = hsep [text "{-#", pprAnnProvenance provenance, pprExpr (unLoc expr), text "#-}"]
1057 data AnnProvenance name = ValueAnnProvenance name
1058 | TypeAnnProvenance name
1059 | ModuleAnnProvenance
1061 annProvenanceName_maybe :: AnnProvenance name -> Maybe name
1062 annProvenanceName_maybe (ValueAnnProvenance name) = Just name
1063 annProvenanceName_maybe (TypeAnnProvenance name) = Just name
1064 annProvenanceName_maybe ModuleAnnProvenance = Nothing
1066 -- TODO: Replace with Traversable instance when GHC bootstrap version rises high enough
1067 modifyAnnProvenanceNameM :: Monad m => (before -> m after) -> AnnProvenance before -> m (AnnProvenance after)
1068 modifyAnnProvenanceNameM fm prov =
1070 ValueAnnProvenance name -> liftM ValueAnnProvenance (fm name)
1071 TypeAnnProvenance name -> liftM TypeAnnProvenance (fm name)
1072 ModuleAnnProvenance -> return ModuleAnnProvenance
1074 pprAnnProvenance :: OutputableBndr name => AnnProvenance name -> SDoc
1075 pprAnnProvenance ModuleAnnProvenance = ptext (sLit "ANN module")
1076 pprAnnProvenance (ValueAnnProvenance name) = ptext (sLit "ANN") <+> ppr name
1077 pprAnnProvenance (TypeAnnProvenance name) = ptext (sLit "ANN type") <+> ppr name