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(..),
42 CImportSpec(..), FoType(..),
43 -- ** Data-constructor declarations
44 ConDecl(..), LConDecl, ResType(..), ConDeclField(..),
45 HsConDeclDetails, hsConDeclArgTys,
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 id]
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,
409 | -- | @type/data/newtype family T :: *->*@
410 TyFamily { tcdFlavour:: FamilyFlavour, -- type, new, or data
411 tcdLName :: Located name, -- type constructor
412 tcdTyVars :: [LHsTyVarBndr name], -- type variables
413 tcdKind :: Maybe Kind -- result kind
417 | -- | Declares a data type or newtype, giving its construcors
419 -- data/newtype T a = <constrs>
420 -- data/newtype instance T [a] = <constrs>
422 TyData { tcdND :: NewOrData,
423 tcdCtxt :: LHsContext name, -- ^ Context
424 tcdLName :: Located name, -- ^ Type constructor
426 tcdTyVars :: [LHsTyVarBndr name], -- ^ Type variables
428 tcdTyPats :: Maybe [LHsType name],
431 -- @Just [t1..tn]@ for @data instance T t1..tn = ...@
432 -- in this case @tcdTyVars = fv( tcdTyPats )@.
433 -- @Nothing@ for everything else.
435 tcdKindSig:: Maybe Kind,
436 -- ^ Optional kind signature.
438 -- @(Just k)@ for a GADT-style @data@, or @data
439 -- instance@ decl with explicit kind sig
441 tcdCons :: [LConDecl name],
442 -- ^ Data constructors
444 -- For @data T a = T1 | T2 a@
445 -- the 'LConDecl's all have 'ResTyH98'.
446 -- For @data T a where { T1 :: T a }@
447 -- the 'LConDecls' all have 'ResTyGADT'.
449 tcdDerivs :: Maybe [LHsType name]
450 -- ^ Derivings; @Nothing@ => not specified,
451 -- @Just []@ => derive exactly what is asked
453 -- These "types" must be of form
455 -- forall ab. C ty1 ty2
457 -- Typically the foralls and ty args are empty, but they
458 -- are non-empty for the newtype-deriving case
461 | TySynonym { tcdLName :: Located name, -- ^ type constructor
462 tcdTyVars :: [LHsTyVarBndr name], -- ^ type variables
463 tcdTyPats :: Maybe [LHsType name], -- ^ Type patterns
464 -- See comments for tcdTyPats in TyData
465 -- 'Nothing' => vanilla type synonym
467 tcdSynRhs :: LHsType name -- ^ synonym expansion
470 | ClassDecl { tcdCtxt :: LHsContext name, -- ^ Context...
471 tcdLName :: Located name, -- ^ Name of the class
472 tcdTyVars :: [LHsTyVarBndr name], -- ^ Class type variables
473 tcdFDs :: [Located (FunDep name)], -- ^ Functional deps
474 tcdSigs :: [LSig name], -- ^ Methods' signatures
475 tcdMeths :: LHsBinds name, -- ^ Default methods
476 tcdATs :: [LTyClDecl name], -- ^ Associated types; ie
477 -- only 'TyFamily' and
479 -- latter for defaults
480 tcdDocs :: [LDocDecl name] -- ^ Haddock docs
484 = NewType -- ^ @newtype Blah ...@
485 | DataType -- ^ @data Blah ...@
486 deriving( Eq ) -- Needed because Demand derives Eq
489 = TypeFamily -- ^ @type family ...@
490 | DataFamily -- ^ @data family ...@
496 -- | @True@ <=> argument is a @data@\/@newtype@ or @data@\/@newtype instance@
498 isDataDecl :: TyClDecl name -> Bool
499 isDataDecl (TyData {}) = True
500 isDataDecl _other = False
502 -- | type or type instance declaration
503 isTypeDecl :: TyClDecl name -> Bool
504 isTypeDecl (TySynonym {}) = True
505 isTypeDecl _other = False
507 -- | vanilla Haskell type synonym (ie, not a type instance)
508 isSynDecl :: TyClDecl name -> Bool
509 isSynDecl (TySynonym {tcdTyPats = Nothing}) = True
510 isSynDecl _other = False
513 isClassDecl :: TyClDecl name -> Bool
514 isClassDecl (ClassDecl {}) = True
515 isClassDecl _ = False
517 -- | type family declaration
518 isFamilyDecl :: TyClDecl name -> Bool
519 isFamilyDecl (TyFamily {}) = True
520 isFamilyDecl _other = False
522 -- | family instance (types, newtypes, and data types)
523 isFamInstDecl :: TyClDecl name -> Bool
526 || isDataDecl tydecl = isJust (tcdTyPats tydecl)
533 tcdName :: TyClDecl name -> name
534 tcdName decl = unLoc (tcdLName decl)
536 tyClDeclNames :: Eq name => TyClDecl name -> [Located name]
537 -- Returns all the *binding* names of the decl, along with their SrcLocs
538 -- The first one is guaranteed to be the name of the decl
539 -- For record fields, the first one counts as the SrcLoc
540 -- We use the equality to filter out duplicate field names
542 tyClDeclNames (TyFamily {tcdLName = name}) = [name]
543 tyClDeclNames (TySynonym {tcdLName = name}) = [name]
544 tyClDeclNames (ForeignType {tcdLName = name}) = [name]
546 tyClDeclNames (ClassDecl {tcdLName = cls_name, tcdSigs = sigs, tcdATs = ats})
548 concatMap (tyClDeclNames . unLoc) ats ++ [n | L _ (TypeSig n _) <- sigs]
550 tyClDeclNames (TyData {tcdLName = tc_name, tcdCons = cons})
551 = tc_name : conDeclsNames (map unLoc cons)
553 tyClDeclTyVars :: TyClDecl name -> [LHsTyVarBndr name]
554 tyClDeclTyVars (TyFamily {tcdTyVars = tvs}) = tvs
555 tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
556 tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs
557 tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
558 tyClDeclTyVars (ForeignType {}) = []
562 countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int, Int, Int)
563 -- class, synonym decls, data, newtype, family decls, family instances
565 = (count isClassDecl decls,
566 count isSynDecl decls, -- excluding...
567 count isDataTy decls, -- ...family...
568 count isNewTy decls, -- ...instances
569 count isFamilyDecl decls,
570 count isFamInstDecl decls)
572 isDataTy TyData{tcdND = DataType, tcdTyPats = Nothing} = True
575 isNewTy TyData{tcdND = NewType, tcdTyPats = Nothing} = True
580 instance OutputableBndr name
581 => Outputable (TyClDecl name) where
583 ppr (ForeignType {tcdLName = ltycon})
584 = hsep [ptext (sLit "foreign import type dotnet"), ppr ltycon]
586 ppr (TyFamily {tcdFlavour = flavour, tcdLName = ltycon,
587 tcdTyVars = tyvars, tcdKind = mb_kind})
588 = pp_flavour <+> pp_decl_head [] ltycon tyvars Nothing <+> pp_kind
590 pp_flavour = case flavour of
591 TypeFamily -> ptext (sLit "type family")
592 DataFamily -> ptext (sLit "data family")
594 pp_kind = case mb_kind of
596 Just kind -> dcolon <+> pprKind kind
598 ppr (TySynonym {tcdLName = ltycon, tcdTyVars = tyvars, tcdTyPats = typats,
599 tcdSynRhs = mono_ty})
600 = hang (ptext (sLit "type") <+>
601 (if isJust typats then ptext (sLit "instance") else empty) <+>
602 pp_decl_head [] ltycon tyvars typats <+>
606 ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = ltycon,
607 tcdTyVars = tyvars, tcdTyPats = typats, tcdKindSig = mb_sig,
608 tcdCons = condecls, tcdDerivs = derivings})
609 = pp_tydecl (null condecls && isJust mb_sig)
611 (if isJust typats then ptext (sLit "instance") else empty) <+>
612 pp_decl_head (unLoc context) ltycon tyvars typats <+>
614 (pp_condecls condecls)
617 ppr_sig Nothing = empty
618 ppr_sig (Just kind) = dcolon <+> pprKind kind
620 ppr (ClassDecl {tcdCtxt = context, tcdLName = lclas, tcdTyVars = tyvars,
622 tcdSigs = sigs, tcdMeths = methods, tcdATs = ats})
623 | null sigs && null ats -- No "where" part
626 | otherwise -- Laid out
627 = sep [hsep [top_matter, ptext (sLit "where {")],
628 nest 4 (sep [ sep (map ppr_semi ats)
629 , sep (map ppr_semi sigs)
630 , pprLHsBinds methods
633 top_matter = ptext (sLit "class")
634 <+> pp_decl_head (unLoc context) lclas tyvars Nothing
635 <+> pprFundeps (map unLoc fds)
636 ppr_semi decl = ppr decl <> semi
638 pp_decl_head :: OutputableBndr name
641 -> [LHsTyVarBndr name]
642 -> Maybe [LHsType name]
644 pp_decl_head context thing tyvars Nothing -- no explicit type patterns
645 = hsep [pprHsContext context, ppr thing, interppSP tyvars]
646 pp_decl_head context thing _ (Just typats) -- explicit type patterns
647 = hsep [ pprHsContext context, ppr thing
648 , hsep (map (pprParendHsType.unLoc) typats)]
650 pp_condecls :: OutputableBndr name => [LConDecl name] -> SDoc
651 pp_condecls cs@(L _ ConDecl{ con_res = ResTyGADT _ } : _) -- In GADT syntax
652 = hang (ptext (sLit "where")) 2 (vcat (map ppr cs))
653 pp_condecls cs -- In H98 syntax
654 = equals <+> sep (punctuate (ptext (sLit " |")) (map ppr cs))
656 pp_tydecl :: OutputableBndr name => Bool -> SDoc -> SDoc -> Maybe [LHsType name] -> SDoc
657 pp_tydecl True pp_head _ _
659 pp_tydecl False pp_head pp_decl_rhs derivings
660 = hang pp_head 4 (sep [
664 Just ds -> hsep [ptext (sLit "deriving"), parens (interpp'SP ds)]
667 instance Outputable NewOrData where
668 ppr NewType = ptext (sLit "newtype")
669 ppr DataType = ptext (sLit "data")
673 %************************************************************************
675 \subsection[ConDecl]{A data-constructor declaration}
677 %************************************************************************
680 type LConDecl name = Located (ConDecl name)
682 -- data T b = forall a. Eq a => MkT a b
683 -- MkT :: forall b a. Eq a => MkT a b
686 -- MkT1 :: Int -> T Int
688 -- data T = Int `MkT` Int
692 -- Int `MkT` Int :: T Int
696 { con_name :: Located name -- Constructor name; this is used for the
697 -- DataCon itself, and for the user-callable wrapper Id
699 , con_explicit :: HsExplicitForAll -- Is there an user-written forall? (cf. HStypes.HsForAllTy)
701 , con_qvars :: [LHsTyVarBndr name] -- ResTyH98: the constructor's existential type variables
702 -- ResTyGADT: all the constructor's quantified type variables
704 , con_cxt :: LHsContext name -- The context. This *does not* include the
705 -- "stupid theta" which lives only in the TyData decl
707 , con_details :: HsConDeclDetails name -- The main payload
709 , con_res :: ResType name -- Result type of the constructor
711 , con_doc :: Maybe (LHsDoc name) -- A possible Haddock comment
714 type HsConDeclDetails name = HsConDetails (LBangType name) [ConDeclField name]
716 hsConDeclArgTys :: HsConDeclDetails name -> [LBangType name]
717 hsConDeclArgTys (PrefixCon tys) = tys
718 hsConDeclArgTys (InfixCon ty1 ty2) = [ty1,ty2]
719 hsConDeclArgTys (RecCon flds) = map cd_fld_type flds
721 data ConDeclField name -- Record fields have Haddoc docs on them
722 = ConDeclField { cd_fld_name :: Located name,
723 cd_fld_type :: LBangType name,
724 cd_fld_doc :: Maybe (LHsDoc name) }
727 = ResTyH98 -- Constructor was declared using Haskell 98 syntax
728 | ResTyGADT (LHsType name) -- Constructor was declared using GADT-style syntax,
729 -- and here is its result type
733 conDeclsNames :: (Eq name) => [ConDecl name] -> [Located name]
734 -- See tyClDeclNames for what this does
735 -- The function is boringly complicated because of the records
736 -- And since we only have equality, we have to be a little careful
738 = snd (foldl do_one ([], []) cons)
740 do_one (flds_seen, acc) (ConDecl { con_name = lname, con_details = RecCon flds })
741 = (map unLoc new_flds ++ flds_seen, lname : new_flds ++ acc)
743 new_flds = filterOut (\f -> unLoc f `elem` flds_seen)
744 (map cd_fld_name flds)
746 do_one (flds_seen, acc) c
747 = (flds_seen, (con_name c):acc)
752 instance (OutputableBndr name) => Outputable (ConDecl name) where
755 pprConDecl :: OutputableBndr name => ConDecl name -> SDoc
756 pprConDecl (ConDecl con expl tvs cxt details ResTyH98 doc)
757 = sep [ppr_mbDoc doc, pprHsForAll expl tvs cxt, ppr_details con details]
759 ppr_details con (InfixCon t1 t2) = hsep [ppr t1, pprHsInfix con, ppr t2]
760 ppr_details con (PrefixCon tys) = hsep (pprHsVar con : map ppr tys)
761 ppr_details con (RecCon fields) = ppr con <+> ppr_fields fields
763 pprConDecl (ConDecl con expl tvs cxt (PrefixCon arg_tys) (ResTyGADT res_ty) _)
764 = ppr con <+> dcolon <+>
765 sep [pprHsForAll expl tvs cxt, ppr (foldr mk_fun_ty res_ty arg_tys)]
767 mk_fun_ty a b = noLoc (HsFunTy a b)
769 pprConDecl (ConDecl con expl tvs cxt (RecCon fields) (ResTyGADT res_ty) _)
770 = sep [pprHsForAll expl tvs cxt, ppr con <+> ppr_fields fields <+> dcolon <+> ppr res_ty]
772 pprConDecl (ConDecl con _expl _tvs _cxt (InfixCon _ _) (ResTyGADT _res_ty) _)
773 = pprPanic "pprConDecl" (ppr con)
774 -- In GADT syntax we don't allow infix constructors
777 ppr_fields :: OutputableBndr name => [ConDeclField name] -> SDoc
778 ppr_fields fields = braces (sep (punctuate comma (map ppr_fld fields)))
780 ppr_fld (ConDeclField { cd_fld_name = n, cd_fld_type = ty,
782 = ppr n <+> dcolon <+> ppr ty <+> ppr_mbDoc doc
785 %************************************************************************
787 \subsection[InstDecl]{An instance declaration
789 %************************************************************************
792 type LInstDecl name = Located (InstDecl name)
795 = InstDecl (LHsType name) -- Context => Class Instance-type
796 -- Using a polytype means that the renamer conveniently
797 -- figures out the quantified type variables for us.
799 [LSig name] -- User-supplied pragmatic info
800 [LTyClDecl name]-- Associated types (ie, 'TyData' and
803 instance (OutputableBndr name) => Outputable (InstDecl name) where
805 ppr (InstDecl inst_ty binds uprags ats)
806 = vcat [hsep [ptext (sLit "instance"), ppr inst_ty, ptext (sLit "where")]
807 , nest 4 $ vcat (map ppr ats)
808 , nest 4 $ vcat (map ppr uprags)
809 , nest 4 $ pprLHsBinds binds ]
811 -- Extract the declarations of associated types from an instance
813 instDeclATs :: InstDecl name -> [LTyClDecl name]
814 instDeclATs (InstDecl _ _ _ ats) = ats
817 %************************************************************************
819 \subsection[DerivDecl]{A stand-alone instance deriving declaration
821 %************************************************************************
824 type LDerivDecl name = Located (DerivDecl name)
826 data DerivDecl name = DerivDecl (LHsType name)
828 instance (OutputableBndr name) => Outputable (DerivDecl name) where
830 = hsep [ptext (sLit "derived instance"), ppr ty]
833 %************************************************************************
835 \subsection[DefaultDecl]{A @default@ declaration}
837 %************************************************************************
839 There can only be one default declaration per module, but it is hard
840 for the parser to check that; we pass them all through in the abstract
841 syntax, and that restriction must be checked in the front end.
844 type LDefaultDecl name = Located (DefaultDecl name)
846 data DefaultDecl name
847 = DefaultDecl [LHsType name]
849 instance (OutputableBndr name)
850 => Outputable (DefaultDecl name) where
852 ppr (DefaultDecl tys)
853 = ptext (sLit "default") <+> parens (interpp'SP tys)
856 %************************************************************************
858 \subsection{Foreign function interface declaration}
860 %************************************************************************
864 -- foreign declarations are distinguished as to whether they define or use a
867 -- * the Boolean value indicates whether the pre-standard deprecated syntax
870 type LForeignDecl name = Located (ForeignDecl name)
872 data ForeignDecl name
873 = ForeignImport (Located name) (LHsType name) ForeignImport -- defines name
874 | ForeignExport (Located name) (LHsType name) ForeignExport -- uses name
876 -- Specification Of an imported external entity in dependence on the calling
879 data ForeignImport = -- import of a C entity
881 -- * the two strings specifying a header file or library
882 -- may be empty, which indicates the absence of a
883 -- header or object specification (both are not used
884 -- in the case of `CWrapper' and when `CFunction'
885 -- has a dynamic target)
887 -- * the calling convention is irrelevant for code
888 -- generation in the case of `CLabel', but is needed
889 -- for pretty printing
891 -- * `Safety' is irrelevant for `CLabel' and `CWrapper'
893 CImport CCallConv -- ccall or stdcall
894 Safety -- safe or unsafe
895 FastString -- name of C header
896 FastString -- name of library object
897 CImportSpec -- details of the C entity
899 -- import of a .NET function
901 | DNImport DNCallSpec
903 -- details of an external C entity
905 data CImportSpec = CLabel CLabelString -- import address of a C label
906 | CFunction CCallTarget -- static or dynamic function
907 | CWrapper -- wrapper to expose closures
910 -- specification of an externally exported entity in dependence on the calling
913 data ForeignExport = CExport CExportSpec -- contains the calling convention
914 | DNExport -- presently unused
916 -- abstract type imported from .NET
918 data FoType = DNType -- In due course we'll add subtype stuff
919 deriving (Eq) -- Used for equality instance for TyClDecl
922 -- pretty printing of foreign declarations
925 instance OutputableBndr name => Outputable (ForeignDecl name) where
926 ppr (ForeignImport n ty fimport) =
927 hang (ptext (sLit "foreign import") <+> ppr fimport <+> ppr n)
928 2 (dcolon <+> ppr ty)
929 ppr (ForeignExport n ty fexport) =
930 hang (ptext (sLit "foreign export") <+> ppr fexport <+> ppr n)
931 2 (dcolon <+> ppr ty)
933 instance Outputable ForeignImport where
934 ppr (DNImport spec) =
935 ptext (sLit "dotnet") <+> ppr spec
936 ppr (CImport cconv safety header lib spec) =
937 ppr cconv <+> ppr safety <+>
938 char '"' <> pprCEntity header lib spec <> char '"'
940 pprCEntity header lib (CLabel lbl) =
941 ptext (sLit "static") <+> ftext header <+> char '&' <>
942 pprLib lib <> ppr lbl
943 pprCEntity header lib (CFunction (StaticTarget lbl)) =
944 ptext (sLit "static") <+> ftext header <+> char '&' <>
945 pprLib lib <> ppr lbl
946 pprCEntity _ _ (CFunction (DynamicTarget)) =
947 ptext (sLit "dynamic")
948 pprCEntity _ _ (CWrapper) = ptext (sLit "wrapper")
950 pprLib lib | nullFS lib = empty
951 | otherwise = char '[' <> ppr lib <> char ']'
953 instance Outputable ForeignExport where
954 ppr (CExport (CExportStatic lbl cconv)) =
955 ppr cconv <+> char '"' <> ppr lbl <> char '"'
957 ptext (sLit "dotnet") <+> ptext (sLit "\"<unused>\"")
959 instance Outputable FoType where
960 ppr DNType = ptext (sLit "type dotnet")
964 %************************************************************************
966 \subsection{Transformation rules}
968 %************************************************************************
971 type LRuleDecl name = Located (RuleDecl name)
974 = HsRule -- Source rule
975 RuleName -- Rule name
977 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
978 (Located (HsExpr name)) -- LHS
979 NameSet -- Free-vars from the LHS
980 (Located (HsExpr name)) -- RHS
981 NameSet -- Free-vars from the RHS
984 = RuleBndr (Located name)
985 | RuleBndrSig (Located name) (LHsType name)
987 collectRuleBndrSigTys :: [RuleBndr name] -> [LHsType name]
988 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
990 instance OutputableBndr name => Outputable (RuleDecl name) where
991 ppr (HsRule name act ns lhs _fv_lhs rhs _fv_rhs)
992 = sep [text "{-# RULES" <+> doubleQuotes (ftext name) <+> ppr act,
993 nest 4 (pp_forall <+> pprExpr (unLoc lhs)),
994 nest 4 (equals <+> pprExpr (unLoc rhs) <+> text "#-}") ]
996 pp_forall | null ns = empty
997 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
999 instance OutputableBndr name => Outputable (RuleBndr name) where
1000 ppr (RuleBndr name) = ppr name
1001 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
1004 %************************************************************************
1006 \subsection[DocDecl]{Document comments}
1008 %************************************************************************
1012 type LDocDecl name = Located (DocDecl name)
1015 = DocCommentNext (HsDoc name)
1016 | DocCommentPrev (HsDoc name)
1017 | DocCommentNamed String (HsDoc name)
1018 | DocGroup Int (HsDoc name)
1020 -- Okay, I need to reconstruct the document comments, but for now:
1021 instance Outputable (DocDecl name) where
1022 ppr _ = text "<document comment>"
1024 docDeclDoc :: DocDecl name -> HsDoc name
1025 docDeclDoc (DocCommentNext d) = d
1026 docDeclDoc (DocCommentPrev d) = d
1027 docDeclDoc (DocCommentNamed _ d) = d
1028 docDeclDoc (DocGroup _ d) = d
1032 %************************************************************************
1034 \subsection[DeprecDecl]{Deprecations}
1036 %************************************************************************
1038 We use exported entities for things to deprecate.
1041 type LWarnDecl name = Located (WarnDecl name)
1043 data WarnDecl name = Warning name WarningTxt
1045 instance OutputableBndr name => Outputable (WarnDecl name) where
1046 ppr (Warning thing txt)
1047 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]
1050 %************************************************************************
1052 \subsection[AnnDecl]{Annotations}
1054 %************************************************************************
1057 type LAnnDecl name = Located (AnnDecl name)
1059 data AnnDecl name = HsAnnotation (AnnProvenance name) (Located (HsExpr name))
1061 instance (OutputableBndr name) => Outputable (AnnDecl name) where
1062 ppr (HsAnnotation provenance expr)
1063 = hsep [text "{-#", pprAnnProvenance provenance, pprExpr (unLoc expr), text "#-}"]
1066 data AnnProvenance name = ValueAnnProvenance name
1067 | TypeAnnProvenance name
1068 | ModuleAnnProvenance
1070 annProvenanceName_maybe :: AnnProvenance name -> Maybe name
1071 annProvenanceName_maybe (ValueAnnProvenance name) = Just name
1072 annProvenanceName_maybe (TypeAnnProvenance name) = Just name
1073 annProvenanceName_maybe ModuleAnnProvenance = Nothing
1075 -- TODO: Replace with Traversable instance when GHC bootstrap version rises high enough
1076 modifyAnnProvenanceNameM :: Monad m => (before -> m after) -> AnnProvenance before -> m (AnnProvenance after)
1077 modifyAnnProvenanceNameM fm prov =
1079 ValueAnnProvenance name -> liftM ValueAnnProvenance (fm name)
1080 TypeAnnProvenance name -> liftM TypeAnnProvenance (fm name)
1081 ModuleAnnProvenance -> return ModuleAnnProvenance
1083 pprAnnProvenance :: OutputableBndr name => AnnProvenance name -> SDoc
1084 pprAnnProvenance ModuleAnnProvenance = ptext (sLit "ANN module")
1085 pprAnnProvenance (ValueAnnProvenance name) = ptext (sLit "ANN") <+> ppr name
1086 pprAnnProvenance (TypeAnnProvenance name) = ptext (sLit "ANN type") <+> ppr name