2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[HsDecls]{Abstract syntax: global declarations}
6 Definitions for: @TyDecl@ and @oCnDecl@, @ClassDecl@,
7 @InstDecl@, @DefaultDecl@ and @ForeignDecl@.
11 HsDecl(..), LHsDecl, TyClDecl(..), LTyClDecl,
12 InstDecl(..), LInstDecl, NewOrData(..),
13 RuleDecl(..), LRuleDecl, RuleBndr(..),
14 DefaultDecl(..), LDefaultDecl, SpliceDecl(..),
15 ForeignDecl(..), LForeignDecl, ForeignImport(..), ForeignExport(..),
16 CImportSpec(..), FoType(..),
17 ConDecl(..), ResType(..), LConDecl,
18 DeprecDecl(..), LDeprecDecl,
19 HsGroup(..), emptyRdrGroup, emptyRnGroup, appendGroups,
20 tcdName, tyClDeclNames, tyClDeclTyVars,
21 isClassDecl, isTFunDecl, isSynDecl, isTEqnDecl, isDataDecl,
25 collectRuleBndrSigTys,
28 #include "HsVersions.h"
31 import {-# SOURCE #-} HsExpr( HsExpr, pprExpr )
32 -- Because Expr imports Decls via HsBracket
34 import HsBinds ( HsValBinds(..), HsBind, LHsBinds, plusHsValBinds,
35 Sig(..), LSig, LFixitySig, pprLHsBinds,
36 emptyValBindsIn, emptyValBindsOut )
37 import HsPat ( HsConDetails(..), hsConArgs )
38 import HsImpExp ( pprHsVar )
40 import NameSet ( NameSet )
41 import HscTypes ( DeprecTxt )
42 import CoreSyn ( RuleName )
43 import Kind ( Kind, pprKind )
44 import BasicTypes ( Activation(..) )
45 import ForeignCall ( CCallTarget(..), DNCallSpec, CCallConv, Safety,
46 CExportSpec(..), CLabelString )
49 import FunDeps ( pprFundeps )
50 import Class ( FunDep )
53 import SrcLoc ( Located(..), unLoc, noLoc )
58 %************************************************************************
60 \subsection[HsDecl]{Declarations}
62 %************************************************************************
65 type LHsDecl id = Located (HsDecl id)
72 | DefD (DefaultDecl id)
73 | ForD (ForeignDecl id)
74 | DeprecD (DeprecDecl id)
76 | SpliceD (SpliceDecl id)
78 -- NB: all top-level fixity decls are contained EITHER
80 -- OR in the ClassDecls in TyClDs
83 -- a) data constructors
84 -- b) class methods (but they can be also done in the
85 -- signatures of class decls)
86 -- c) imported functions (that have an IfacSig)
89 -- The latter is for class methods only
91 -- A [HsDecl] is categorised into a HsGroup before being
92 -- fed to the renamer.
95 hs_valds :: HsValBinds id,
96 hs_tyclds :: [LTyClDecl id],
97 hs_instds :: [LInstDecl id],
99 hs_fixds :: [LFixitySig id],
100 -- Snaffled out of both top-level fixity signatures,
101 -- and those in class declarations
103 hs_defds :: [LDefaultDecl id],
104 hs_fords :: [LForeignDecl id],
105 hs_depds :: [LDeprecDecl id],
106 hs_ruleds :: [LRuleDecl id]
109 emptyGroup, emptyRdrGroup, emptyRnGroup :: HsGroup a
110 emptyRdrGroup = emptyGroup { hs_valds = emptyValBindsIn }
111 emptyRnGroup = emptyGroup { hs_valds = emptyValBindsOut }
113 emptyGroup = HsGroup { hs_tyclds = [], hs_instds = [],
114 hs_fixds = [], hs_defds = [], hs_fords = [],
115 hs_depds = [], hs_ruleds = [],
116 hs_valds = error "emptyGroup hs_valds: Can't happen" }
118 appendGroups :: HsGroup a -> HsGroup a -> HsGroup a
121 hs_valds = val_groups1,
130 hs_valds = val_groups2,
140 hs_valds = val_groups1 `plusHsValBinds` val_groups2,
141 hs_tyclds = tyclds1 ++ tyclds2,
142 hs_instds = instds1 ++ instds2,
143 hs_fixds = fixds1 ++ fixds2,
144 hs_defds = defds1 ++ defds2,
145 hs_fords = fords1 ++ fords2,
146 hs_depds = depds1 ++ depds2,
147 hs_ruleds = rulds1 ++ rulds2 }
151 instance OutputableBndr name => Outputable (HsDecl name) where
152 ppr (TyClD dcl) = ppr dcl
153 ppr (ValD binds) = ppr binds
154 ppr (DefD def) = ppr def
155 ppr (InstD inst) = ppr inst
156 ppr (ForD fd) = ppr fd
157 ppr (SigD sd) = ppr sd
158 ppr (RuleD rd) = ppr rd
159 ppr (DeprecD dd) = ppr dd
160 ppr (SpliceD dd) = ppr dd
162 instance OutputableBndr name => Outputable (HsGroup name) where
163 ppr (HsGroup { hs_valds = val_decls,
164 hs_tyclds = tycl_decls,
165 hs_instds = inst_decls,
166 hs_fixds = fix_decls,
167 hs_depds = deprec_decls,
168 hs_fords = foreign_decls,
169 hs_defds = default_decls,
170 hs_ruleds = rule_decls })
171 = vcat [ppr_ds fix_decls, ppr_ds default_decls,
172 ppr_ds deprec_decls, ppr_ds rule_decls,
174 ppr_ds tycl_decls, ppr_ds inst_decls,
175 ppr_ds foreign_decls]
178 ppr_ds ds = text "" $$ vcat (map ppr ds)
180 data SpliceDecl id = SpliceDecl (Located (HsExpr id)) -- Top level splice
182 instance OutputableBndr name => Outputable (SpliceDecl name) where
183 ppr (SpliceDecl e) = ptext SLIT("$") <> parens (pprExpr (unLoc e))
187 %************************************************************************
189 \subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
191 %************************************************************************
193 --------------------------------
195 --------------------------------
197 Here is the story about the implicit names that go with type, class,
198 and instance decls. It's a bit tricky, so pay attention!
200 "Implicit" (or "system") binders
201 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
202 Each data type decl defines
203 a worker name for each constructor
204 to-T and from-T convertors
205 Each class decl defines
206 a tycon for the class
207 a data constructor for that tycon
208 the worker for that constructor
209 a selector for each superclass
211 All have occurrence names that are derived uniquely from their parent
214 None of these get separate definitions in an interface file; they are
215 fully defined by the data or class decl. But they may *occur* in
216 interface files, of course. Any such occurrence must haul in the
217 relevant type or class decl.
220 - Ensure they "point to" the parent data/class decl
221 when loading that decl from an interface file
222 (See RnHiFiles.getSysBinders)
224 - When typechecking the decl, we build the implicit TyCons and Ids.
225 When doing so we look them up in the name cache (RnEnv.lookupSysName),
226 to ensure correct module and provenance is set
228 These are the two places that we have to conjure up the magic derived
229 names. (The actual magic is in OccName.mkWorkerOcc, etc.)
233 - Occurrence name is derived uniquely from the method name
236 - If there is a default method name at all, it's recorded in
237 the ClassOpSig (in HsBinds), in the DefMeth field.
238 (DefMeth is defined in Class.lhs)
240 Source-code class decls and interface-code class decls are treated subtly
241 differently, which has given me a great deal of confusion over the years.
242 Here's the deal. (We distinguish the two cases because source-code decls
243 have (Just binds) in the tcdMeths field, whereas interface decls have Nothing.
245 In *source-code* class declarations:
247 - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName
248 This is done by RdrHsSyn.mkClassOpSigDM
250 - The renamer renames it to a Name
252 - During typechecking, we generate a binding for each $dm for
253 which there's a programmer-supplied default method:
258 We generate a binding for $dmop1 but not for $dmop2.
259 The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1.
260 The Name for $dmop2 is simply discarded.
262 In *interface-file* class declarations:
263 - When parsing, we see if there's an explicit programmer-supplied default method
264 because there's an '=' sign to indicate it:
266 op1 = :: <type> -- NB the '='
268 We use this info to generate a DefMeth with a suitable RdrName for op1,
269 and a NoDefMeth for op2
270 - The interface file has a separate definition for $dmop1, with unfolding etc.
271 - The renamer renames it to a Name.
272 - The renamer treats $dmop1 as a free variable of the declaration, so that
273 the binding for $dmop1 will be sucked in. (See RnHsSyn.tyClDeclFVs)
274 This doesn't happen for source code class decls, because they *bind* the default method.
278 Each instance declaration gives rise to one dictionary function binding.
280 The type checker makes up new source-code instance declarations
281 (e.g. from 'deriving' or generic default methods --- see
282 TcInstDcls.tcInstDecls1). So we can't generate the names for
283 dictionary functions in advance (we don't know how many we need).
285 On the other hand for interface-file instance declarations, the decl
286 specifies the name of the dictionary function, and it has a binding elsewhere
287 in the interface file:
288 instance {Eq Int} = dEqInt
289 dEqInt :: {Eq Int} <pragma info>
291 So again we treat source code and interface file code slightly differently.
294 - Source code instance decls have a Nothing in the (Maybe name) field
295 (see data InstDecl below)
297 - The typechecker makes up a Local name for the dict fun for any source-code
298 instance decl, whether it comes from a source-code instance decl, or whether
299 the instance decl is derived from some other construct (e.g. 'deriving').
301 - The occurrence name it chooses is derived from the instance decl (just for
302 documentation really) --- e.g. dNumInt. Two dict funs may share a common
303 occurrence name, but will have different uniques. E.g.
304 instance Foo [Int] where ...
305 instance Foo [Bool] where ...
306 These might both be dFooList
308 - The CoreTidy phase externalises the name, and ensures the occurrence name is
309 unique (this isn't special to dict funs). So we'd get dFooList and dFooList1.
311 - We can take this relaxed approach (changing the occurrence name later)
312 because dict fun Ids are not captured in a TyCon or Class (unlike default
313 methods, say). Instead, they are kept separately in the InstEnv. This
314 makes it easy to adjust them after compiling a module. (Once we've finished
315 compiling that module, they don't change any more.)
319 - The instance decl gives the dict fun name, so the InstDecl has a (Just name)
320 in the (Maybe name) field.
322 - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
323 suck in the dfun binding
327 -- TyClDecls are precisely the kind of declarations that can
328 -- appear in interface files; or (internally) in GHC's interface
329 -- for a module. That's why (despite the misnomer) IfaceSig and ForeignType
330 -- are both in TyClDecl
332 -- Representation of type functions and associated data types & synonyms
333 -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
334 -- 'TyData' and 'TySynonym' have a field 'tcdPats::Maybe [LHsType name]', with
335 -- the following meaning:
337 -- * If it is 'Nothing', we have a *vanilla* data type declaration or type
338 -- synonym declaration and 'tcdVars' contains the type parameters of the
341 -- * If it is 'Just pats', we have the definition of an associated data type
342 -- or a type function equations (toplevel or nested in an instance
343 -- declarations). Then, 'pats' are type patterns for the type-indexes of
344 -- the type constructor and 'tcdVars' are the variables in those
345 -- patterns. Hence, the arity of the type constructor is 'length tcdPats'
346 -- and *not* 'length tcdVars'.
348 -- In both cases, 'tcdVars' collects all variables we need to quantify over.
350 type LTyClDecl name = Located (TyClDecl name)
354 tcdLName :: Located name,
355 tcdExtName :: Maybe FastString,
359 | TyData { tcdND :: NewOrData,
360 tcdCtxt :: LHsContext name, -- Context
361 tcdLName :: Located name, -- Type constructor
362 tcdTyVars :: [LHsTyVarBndr name], -- Type variables
363 tcdTyPats :: Maybe [LHsType name], -- Type patterns
364 tcdKindSig:: Maybe Kind, -- Optional kind sig;
365 -- (only for the 'where' form)
367 tcdCons :: [LConDecl name], -- Data constructors
368 -- For data T a = T1 | T2 a the LConDecls all have ResTyH98
369 -- For data T a where { T1 :: T a } the LConDecls all have ResTyGADT
371 tcdDerivs :: Maybe [LHsType name]
372 -- Derivings; Nothing => not specified
373 -- Just [] => derive exactly what is asked
374 -- These "types" must be of form
375 -- forall ab. C ty1 ty2
376 -- Typically the foralls and ty args are empty, but they
377 -- are non-empty for the newtype-deriving case
380 | TyFunction {tcdLName :: Located name, -- type constructor
381 tcdTyVars :: [LHsTyVarBndr name], -- type variables
382 tcdIso :: Bool, -- injective type?
383 tcdKindSig:: Maybe Kind -- result kind
386 | TySynonym { tcdLName :: Located name, -- type constructor
387 tcdTyVars :: [LHsTyVarBndr name], -- type variables
388 tcdTyPats :: Maybe [LHsType name], -- Type patterns
389 -- 'Nothing' => vanilla
391 tcdSynRhs :: LHsType name -- synonym expansion
394 | ClassDecl { tcdCtxt :: LHsContext name, -- Context...
395 tcdLName :: Located name, -- Name of the class
396 tcdTyVars :: [LHsTyVarBndr name], -- Class type variables
397 tcdFDs :: [Located (FunDep name)], -- Functional deps
398 tcdSigs :: [LSig name], -- Methods' signatures
399 tcdMeths :: LHsBinds name, -- Default methods
400 tcdATs :: [LTyClDecl name] -- Associated types; ie
407 = NewType -- "newtype Blah ..."
408 | DataType -- "data Blah ..."
409 deriving( Eq ) -- Needed because Demand derives Eq
415 isTFunDecl, isDataDecl, isSynDecl, isTEqnDecl, isClassDecl ::
416 TyClDecl name -> Bool
418 -- type function kind signature
419 isTFunDecl (TyFunction {}) = True
420 isTFunDecl other = False
422 -- vanilla Haskell type synonym
423 isSynDecl (TySynonym {tcdTyPats = Nothing}) = True
424 isSynDecl other = False
426 -- type equation (of a type function)
427 isTEqnDecl (TySynonym {tcdTyPats = Just _}) = True
428 isTEqnDecl other = False
430 isDataDecl (TyData {}) = True
431 isDataDecl other = False
433 isClassDecl (ClassDecl {}) = True
434 isClassDecl other = False
440 tcdName :: TyClDecl name -> name
441 tcdName decl = unLoc (tcdLName decl)
443 tyClDeclNames :: Eq name => TyClDecl name -> [Located name]
444 -- Returns all the *binding* names of the decl, along with their SrcLocs
445 -- The first one is guaranteed to be the name of the decl
446 -- For record fields, the first one counts as the SrcLoc
447 -- We use the equality to filter out duplicate field names
449 tyClDeclNames (TyFunction {tcdLName = name}) = [name]
450 tyClDeclNames (TySynonym {tcdLName = name,
451 tcdTyPats= Nothing}) = [name]
452 tyClDeclNames (TySynonym {} ) = [] -- type equation
453 tyClDeclNames (ForeignType {tcdLName = name}) = [name]
455 tyClDeclNames (ClassDecl {tcdLName = cls_name, tcdSigs = sigs, tcdATs = ats})
457 concatMap (tyClDeclNames . unLoc) ats ++ [n | L _ (TypeSig n _) <- sigs]
459 tyClDeclNames (TyData {tcdLName = tc_name, tcdCons = cons})
460 = tc_name : conDeclsNames (map unLoc cons)
462 tyClDeclTyVars (TyFunction {tcdTyVars = tvs}) = tvs
463 tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
464 tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs
465 tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
466 tyClDeclTyVars (ForeignType {}) = []
470 countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int, Int, Int)
471 -- class, synonym decls, type function signatures,
472 -- type function equations, data, newtype
474 = (count isClassDecl decls,
475 count isSynDecl decls,
476 count isTFunDecl decls,
477 count isTEqnDecl decls,
478 count isDataTy decls,
481 isDataTy TyData{tcdND=DataType} = True
484 isNewTy TyData{tcdND=NewType} = True
489 instance OutputableBndr name
490 => Outputable (TyClDecl name) where
492 ppr (ForeignType {tcdLName = ltycon})
493 = hsep [ptext SLIT("foreign import type dotnet"), ppr ltycon]
495 ppr (TyFunction {tcdLName = ltycon, tcdTyVars = tyvars, tcdIso = iso,
496 tcdKindSig = mb_sig})
497 = typeMaybeIso <+> pp_decl_head [] ltycon tyvars Nothing <+>
500 typeMaybeIso = if iso
501 then ptext SLIT("type iso")
502 else ptext SLIT("type")
504 ppr_sig Nothing = empty
505 ppr_sig (Just kind) = dcolon <+> pprKind kind
507 ppr (TySynonym {tcdLName = ltycon, tcdTyVars = tyvars, tcdTyPats = typats,
508 tcdSynRhs = mono_ty})
509 = hang (ptext SLIT("type") <+> pp_decl_head [] ltycon tyvars typats <+>
513 ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = ltycon,
514 tcdTyVars = tyvars, tcdTyPats = typats, tcdKindSig = mb_sig,
515 tcdCons = condecls, tcdDerivs = derivings})
516 = pp_tydecl (ppr new_or_data <+>
517 pp_decl_head (unLoc context) ltycon tyvars typats <+>
519 (pp_condecls condecls)
522 ppr_sig Nothing = empty
523 ppr_sig (Just kind) = dcolon <+> pprKind kind
525 ppr (ClassDecl {tcdCtxt = context, tcdLName = lclas, tcdTyVars = tyvars,
527 tcdSigs = sigs, tcdMeths = methods, tcdATs = ats})
528 | null sigs && null ats -- No "where" part
531 | otherwise -- Laid out
532 = sep [hsep [top_matter, ptext SLIT("where {")],
533 nest 4 (sep [ sep (map ppr_semi ats)
534 , sep (map ppr_semi sigs)
535 , pprLHsBinds methods
538 top_matter = ptext SLIT("class")
539 <+> pp_decl_head (unLoc context) lclas tyvars Nothing
540 <+> pprFundeps (map unLoc fds)
541 ppr_semi decl = ppr decl <> semi
543 pp_decl_head :: OutputableBndr name
546 -> [LHsTyVarBndr name]
547 -> Maybe [LHsType name]
549 pp_decl_head context thing tyvars Nothing -- no explicit type patterns
550 = hsep [pprHsContext context, ppr thing, interppSP tyvars]
551 pp_decl_head context thing _ (Just typats) -- explicit type patterns
552 = hsep [ pprHsContext context, ppr thing
553 , hsep (map (pprParendHsType.unLoc) typats)]
555 pp_condecls cs@(L _ ConDecl{ con_res = ResTyGADT _ } : _) -- In GADT syntax
556 = hang (ptext SLIT("where")) 2 (vcat (map ppr cs))
557 pp_condecls cs -- In H98 syntax
558 = equals <+> sep (punctuate (ptext SLIT(" |")) (map ppr cs))
560 pp_tydecl pp_head pp_decl_rhs derivings
561 = hang pp_head 4 (sep [
565 Just ds -> hsep [ptext SLIT("deriving"), parens (interpp'SP ds)]
568 instance Outputable NewOrData where
569 ppr NewType = ptext SLIT("newtype")
570 ppr DataType = ptext SLIT("data")
574 %************************************************************************
576 \subsection[ConDecl]{A data-constructor declaration}
578 %************************************************************************
581 type LConDecl name = Located (ConDecl name)
583 -- data T b = forall a. Eq a => MkT a b
584 -- MkT :: forall b a. Eq a => MkT a b
587 -- MkT1 :: Int -> T Int
589 -- data T = Int `MkT` Int
593 -- Int `MkT` Int :: T Int
597 { con_name :: Located name -- Constructor name; this is used for the
598 -- DataCon itself, and for the user-callable wrapper Id
600 , con_explicit :: HsExplicitForAll -- Is there an user-written forall? (cf. HStypes.HsForAllTy)
602 , con_qvars :: [LHsTyVarBndr name] -- ResTyH98: the constructor's existential type variables
603 -- ResTyGADT: all the constructor's quantified type variables
605 , con_cxt :: LHsContext name -- The context. This *does not* include the
606 -- "stupid theta" which lives only in the TyData decl
608 , con_details :: HsConDetails name (LBangType name) -- The main payload
610 , con_res :: ResType name -- Result type of the constructor
614 = ResTyH98 -- Constructor was declared using Haskell 98 syntax
615 | ResTyGADT (LHsType name) -- Constructor was declared using GADT-style syntax,
616 -- and here is its result type
620 conDeclsNames :: Eq name => [ConDecl name] -> [Located name]
621 -- See tyClDeclNames for what this does
622 -- The function is boringly complicated because of the records
623 -- And since we only have equality, we have to be a little careful
625 = snd (foldl do_one ([], []) cons)
627 do_one (flds_seen, acc) (ConDecl { con_name = lname, con_details = RecCon flds })
628 = (map unLoc new_flds ++ flds_seen, lname : [f | f <- new_flds] ++ acc)
630 new_flds = [ f | (f,_) <- flds, not (unLoc f `elem` flds_seen) ]
632 do_one (flds_seen, acc) c
633 = (flds_seen, (con_name c):acc)
635 conDetailsTys details = map getBangType (hsConArgs details)
640 instance (OutputableBndr name) => Outputable (ConDecl name) where
643 pprConDecl (ConDecl con expl tvs cxt details ResTyH98)
644 = sep [pprHsForAll expl tvs cxt, ppr_details con details]
646 ppr_details con (InfixCon t1 t2) = hsep [ppr t1, pprHsVar con, ppr t2]
647 ppr_details con (PrefixCon tys) = hsep (pprHsVar con : map ppr tys)
648 ppr_details con (RecCon fields) = ppr con <+> ppr_fields fields
650 pprConDecl (ConDecl con expl tvs cxt (PrefixCon arg_tys) (ResTyGADT res_ty))
651 = ppr con <+> dcolon <+>
652 sep [pprHsForAll expl tvs cxt, ppr (foldr mk_fun_ty res_ty arg_tys)]
654 mk_fun_ty a b = noLoc (HsFunTy a b)
655 pprConDecl (ConDecl con expl tvs cxt (RecCon fields) (ResTyGADT res_ty))
656 = sep [pprHsForAll expl tvs cxt, ppr con <+> ppr fields <+> dcolon <+> ppr res_ty]
658 ppr_fields fields = braces (sep (punctuate comma (map ppr_field fields)))
659 ppr_field (n, ty) = ppr n <+> dcolon <+> ppr ty
662 %************************************************************************
664 \subsection[InstDecl]{An instance declaration
666 %************************************************************************
669 type LInstDecl name = Located (InstDecl name)
672 = InstDecl (LHsType name) -- Context => Class Instance-type
673 -- Using a polytype means that the renamer conveniently
674 -- figures out the quantified type variables for us.
676 [LSig name] -- User-supplied pragmatic info
677 [LTyClDecl name]-- Associated types (ie, 'TyData' and
680 instance (OutputableBndr name) => Outputable (InstDecl name) where
682 ppr (InstDecl inst_ty binds uprags ats)
683 = vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
686 nest 4 (pprLHsBinds binds) ]
688 -- Extract the declarations of associated types from an instance
690 instDeclATs :: InstDecl name -> [LTyClDecl name]
691 instDeclATs (InstDecl _ _ _ ats) = ats
694 %************************************************************************
696 \subsection[DefaultDecl]{A @default@ declaration}
698 %************************************************************************
700 There can only be one default declaration per module, but it is hard
701 for the parser to check that; we pass them all through in the abstract
702 syntax, and that restriction must be checked in the front end.
705 type LDefaultDecl name = Located (DefaultDecl name)
707 data DefaultDecl name
708 = DefaultDecl [LHsType name]
710 instance (OutputableBndr name)
711 => Outputable (DefaultDecl name) where
713 ppr (DefaultDecl tys)
714 = ptext SLIT("default") <+> parens (interpp'SP tys)
717 %************************************************************************
719 \subsection{Foreign function interface declaration}
721 %************************************************************************
725 -- foreign declarations are distinguished as to whether they define or use a
728 -- * the Boolean value indicates whether the pre-standard deprecated syntax
731 type LForeignDecl name = Located (ForeignDecl name)
733 data ForeignDecl name
734 = ForeignImport (Located name) (LHsType name) ForeignImport -- defines name
735 | ForeignExport (Located name) (LHsType name) ForeignExport -- uses name
737 -- Specification Of an imported external entity in dependence on the calling
740 data ForeignImport = -- import of a C entity
742 -- * the two strings specifying a header file or library
743 -- may be empty, which indicates the absence of a
744 -- header or object specification (both are not used
745 -- in the case of `CWrapper' and when `CFunction'
746 -- has a dynamic target)
748 -- * the calling convention is irrelevant for code
749 -- generation in the case of `CLabel', but is needed
750 -- for pretty printing
752 -- * `Safety' is irrelevant for `CLabel' and `CWrapper'
754 CImport CCallConv -- ccall or stdcall
755 Safety -- safe or unsafe
756 FastString -- name of C header
757 FastString -- name of library object
758 CImportSpec -- details of the C entity
760 -- import of a .NET function
762 | DNImport DNCallSpec
764 -- details of an external C entity
766 data CImportSpec = CLabel CLabelString -- import address of a C label
767 | CFunction CCallTarget -- static or dynamic function
768 | CWrapper -- wrapper to expose closures
771 -- specification of an externally exported entity in dependence on the calling
774 data ForeignExport = CExport CExportSpec -- contains the calling convention
775 | DNExport -- presently unused
777 -- abstract type imported from .NET
779 data FoType = DNType -- In due course we'll add subtype stuff
780 deriving (Eq) -- Used for equality instance for TyClDecl
783 -- pretty printing of foreign declarations
786 instance OutputableBndr name => Outputable (ForeignDecl name) where
787 ppr (ForeignImport n ty fimport) =
788 ptext SLIT("foreign import") <+> ppr fimport <+>
789 ppr n <+> dcolon <+> ppr ty
790 ppr (ForeignExport n ty fexport) =
791 ptext SLIT("foreign export") <+> ppr fexport <+>
792 ppr n <+> dcolon <+> ppr ty
794 instance Outputable ForeignImport where
795 ppr (DNImport spec) =
796 ptext SLIT("dotnet") <+> ppr spec
797 ppr (CImport cconv safety header lib spec) =
798 ppr cconv <+> ppr safety <+>
799 char '"' <> pprCEntity header lib spec <> char '"'
801 pprCEntity header lib (CLabel lbl) =
802 ptext SLIT("static") <+> ftext header <+> char '&' <>
803 pprLib lib <> ppr lbl
804 pprCEntity header lib (CFunction (StaticTarget lbl)) =
805 ptext SLIT("static") <+> ftext header <+> char '&' <>
806 pprLib lib <> ppr lbl
807 pprCEntity header lib (CFunction (DynamicTarget)) =
808 ptext SLIT("dynamic")
809 pprCEntity _ _ (CWrapper) = ptext SLIT("wrapper")
811 pprLib lib | nullFS lib = empty
812 | otherwise = char '[' <> ppr lib <> char ']'
814 instance Outputable ForeignExport where
815 ppr (CExport (CExportStatic lbl cconv)) =
816 ppr cconv <+> char '"' <> ppr lbl <> char '"'
818 ptext SLIT("dotnet") <+> ptext SLIT("\"<unused>\"")
820 instance Outputable FoType where
821 ppr DNType = ptext SLIT("type dotnet")
825 %************************************************************************
827 \subsection{Transformation rules}
829 %************************************************************************
832 type LRuleDecl name = Located (RuleDecl name)
835 = HsRule -- Source rule
836 RuleName -- Rule name
838 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
839 (Located (HsExpr name)) -- LHS
840 NameSet -- Free-vars from the LHS
841 (Located (HsExpr name)) -- RHS
842 NameSet -- Free-vars from the RHS
845 = RuleBndr (Located name)
846 | RuleBndrSig (Located name) (LHsType name)
848 collectRuleBndrSigTys :: [RuleBndr name] -> [LHsType name]
849 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
851 instance OutputableBndr name => Outputable (RuleDecl name) where
852 ppr (HsRule name act ns lhs fv_lhs rhs fv_rhs)
853 = sep [text "{-# RULES" <+> doubleQuotes (ftext name) <+> ppr act,
854 nest 4 (pp_forall <+> pprExpr (unLoc lhs)),
855 nest 4 (equals <+> pprExpr (unLoc rhs) <+> text "#-}") ]
857 pp_forall | null ns = empty
858 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
860 instance OutputableBndr name => Outputable (RuleBndr name) where
861 ppr (RuleBndr name) = ppr name
862 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
866 %************************************************************************
868 \subsection[DeprecDecl]{Deprecations}
870 %************************************************************************
872 We use exported entities for things to deprecate.
875 type LDeprecDecl name = Located (DeprecDecl name)
877 data DeprecDecl name = Deprecation name DeprecTxt
879 instance OutputableBndr name => Outputable (DeprecDecl name) where
880 ppr (Deprecation thing txt)
881 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]