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 type LTyClDecl name = Located (TyClDecl name)
336 tcdLName :: Located name,
337 tcdExtName :: Maybe FastString,
341 | TyData { tcdND :: NewOrData,
342 tcdCtxt :: LHsContext name, -- Context
343 tcdLName :: Located name, -- Type constructor
344 tcdTyVars :: [LHsTyVarBndr name], -- Type variables
345 tcdTyPats :: Maybe [LHsType name], -- Type patterns
346 tcdKindSig:: Maybe Kind, -- Optional kind sig;
347 -- (only for the 'where' form)
349 tcdCons :: [LConDecl name], -- Data constructors
350 -- For data T a = T1 | T2 a the LConDecls all have ResTyH98
351 -- For data T a where { T1 :: T a } the LConDecls all have ResTyGADT
353 tcdDerivs :: Maybe [LHsType name]
354 -- Derivings; Nothing => not specified
355 -- Just [] => derive exactly what is asked
356 -- These "types" must be of form
357 -- forall ab. C ty1 ty2
358 -- Typically the foralls and ty args are empty, but they
359 -- are non-empty for the newtype-deriving case
362 | TyFunction {tcdLName :: Located name, -- type constructor
363 tcdTyVars :: [LHsTyVarBndr name], -- type variables
364 tcdIso :: Bool, -- injective type?
365 tcdKindSig:: Maybe Kind -- result kind
368 | TySynonym { tcdLName :: Located name, -- type constructor
369 tcdTyVars :: [LHsTyVarBndr name], -- type variables
370 tcdTyPats :: Maybe [LHsType name], -- Type patterns
371 tcdSynRhs :: LHsType name -- synonym expansion
374 | ClassDecl { tcdCtxt :: LHsContext name, -- Context...
375 tcdLName :: Located name, -- Name of the class
376 tcdTyVars :: [LHsTyVarBndr name], -- Class type variables
377 tcdFDs :: [Located (FunDep name)], -- Functional deps
378 tcdSigs :: [LSig name], -- Methods' signatures
379 tcdMeths :: LHsBinds name, -- Default methods
380 tcdATs :: [LTyClDecl name] -- Associated types; ie
386 = NewType -- "newtype Blah ..."
387 | DataType -- "data Blah ..."
388 deriving( Eq ) -- Needed because Demand derives Eq
394 isTFunDecl, isDataDecl, isSynDecl, isTEqnDecl, isClassDecl ::
395 TyClDecl name -> Bool
397 -- type function kind signature
398 isTFunDecl (TyFunction {}) = True
399 isTFunDecl other = False
401 -- vanilla Haskell type synonym
402 isSynDecl (TySynonym {tcdTyPats = Nothing}) = True
403 isSynDecl other = False
405 -- type equation (of a type function)
406 isTEqnDecl (TySynonym {tcdTyPats = Just _}) = True
407 isTEqnDecl other = False
409 isDataDecl (TyData {}) = True
410 isDataDecl other = False
412 isClassDecl (ClassDecl {}) = True
413 isClassDecl other = False
419 tcdName :: TyClDecl name -> name
420 tcdName decl = unLoc (tcdLName decl)
422 tyClDeclNames :: Eq name => TyClDecl name -> [Located name]
423 -- Returns all the *binding* names of the decl, along with their SrcLocs
424 -- The first one is guaranteed to be the name of the decl
425 -- For record fields, the first one counts as the SrcLoc
426 -- We use the equality to filter out duplicate field names
428 tyClDeclNames (TyFunction {tcdLName = name}) = [name]
429 tyClDeclNames (TySynonym {tcdLName = name,
430 tcdTyPats= Nothing}) = [name]
431 tyClDeclNames (TySynonym {} ) = [] -- type equation
432 tyClDeclNames (ForeignType {tcdLName = name}) = [name]
434 tyClDeclNames (ClassDecl {tcdLName = cls_name, tcdSigs = sigs, tcdATs = ats})
436 concatMap (tyClDeclNames . unLoc) ats ++ [n | L _ (TypeSig n _) <- sigs]
438 tyClDeclNames (TyData {tcdLName = tc_name, tcdCons = cons})
439 = tc_name : conDeclsNames (map unLoc cons)
441 tyClDeclTyVars (TyFunction {tcdTyVars = tvs}) = tvs
442 tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
443 tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs
444 tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
445 tyClDeclTyVars (ForeignType {}) = []
449 countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int, Int, Int)
450 -- class, synonym decls, type function signatures,
451 -- type function equations, data, newtype
453 = (count isClassDecl decls,
454 count isSynDecl decls,
455 count isTFunDecl decls,
456 count isTEqnDecl decls,
457 count isDataTy decls,
460 isDataTy TyData{tcdND=DataType} = True
463 isNewTy TyData{tcdND=NewType} = True
468 instance OutputableBndr name
469 => Outputable (TyClDecl name) where
471 ppr (ForeignType {tcdLName = ltycon})
472 = hsep [ptext SLIT("foreign import type dotnet"), ppr ltycon]
474 ppr (TyFunction {tcdLName = ltycon, tcdTyVars = tyvars, tcdIso = iso,
475 tcdKindSig = mb_sig})
476 = typeMaybeIso <+> pp_decl_head [] ltycon tyvars Nothing <+>
479 typeMaybeIso = if iso
480 then ptext SLIT("type iso")
481 else ptext SLIT("type")
483 ppr_sig Nothing = empty
484 ppr_sig (Just kind) = dcolon <+> pprKind kind
486 ppr (TySynonym {tcdLName = ltycon, tcdTyVars = tyvars, tcdTyPats = typats,
487 tcdSynRhs = mono_ty})
488 = hang (ptext SLIT("type") <+> pp_decl_head [] ltycon tyvars typats <+>
492 ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = ltycon,
493 tcdTyVars = tyvars, tcdTyPats = typats, tcdKindSig = mb_sig,
494 tcdCons = condecls, tcdDerivs = derivings})
495 = pp_tydecl (ppr new_or_data <+>
496 pp_decl_head (unLoc context) ltycon tyvars typats <+>
498 (pp_condecls condecls)
501 ppr_sig Nothing = empty
502 ppr_sig (Just kind) = dcolon <+> pprKind kind
504 ppr (ClassDecl {tcdCtxt = context, tcdLName = lclas, tcdTyVars = tyvars,
506 tcdSigs = sigs, tcdMeths = methods, tcdATs = ats})
507 | null sigs && null ats -- No "where" part
510 | otherwise -- Laid out
511 = sep [hsep [top_matter, ptext SLIT("where {")],
512 nest 4 (sep [ sep (map ppr_semi ats)
513 , sep (map ppr_semi sigs)
514 , pprLHsBinds methods
517 top_matter = ptext SLIT("class")
518 <+> pp_decl_head (unLoc context) lclas tyvars Nothing
519 <+> pprFundeps (map unLoc fds)
520 ppr_semi decl = ppr decl <> semi
522 pp_decl_head :: OutputableBndr name
525 -> [LHsTyVarBndr name]
526 -> Maybe [LHsType name]
528 pp_decl_head context thing tyvars Nothing -- no explicit type patterns
529 = hsep [pprHsContext context, ppr thing, interppSP tyvars]
530 pp_decl_head context thing _ (Just typats) -- explicit type patterns
531 = hsep [ pprHsContext context, ppr thing
532 , hsep (map (pprParendHsType.unLoc) typats)]
534 pp_condecls cs@(L _ ConDecl{ con_res = ResTyGADT _ } : _) -- In GADT syntax
535 = hang (ptext SLIT("where")) 2 (vcat (map ppr cs))
536 pp_condecls cs -- In H98 syntax
537 = equals <+> sep (punctuate (ptext SLIT(" |")) (map ppr cs))
539 pp_tydecl pp_head pp_decl_rhs derivings
540 = hang pp_head 4 (sep [
544 Just ds -> hsep [ptext SLIT("deriving"), parens (interpp'SP ds)]
547 instance Outputable NewOrData where
548 ppr NewType = ptext SLIT("newtype")
549 ppr DataType = ptext SLIT("data")
553 %************************************************************************
555 \subsection[ConDecl]{A data-constructor declaration}
557 %************************************************************************
560 type LConDecl name = Located (ConDecl name)
562 -- data T b = forall a. Eq a => MkT a b
563 -- MkT :: forall b a. Eq a => MkT a b
566 -- MkT1 :: Int -> T Int
568 -- data T = Int `MkT` Int
572 -- Int `MkT` Int :: T Int
576 { con_name :: Located name -- Constructor name; this is used for the
577 -- DataCon itself, and for the user-callable wrapper Id
579 , con_explicit :: HsExplicitForAll -- Is there an user-written forall? (cf. HStypes.HsForAllTy)
581 , con_qvars :: [LHsTyVarBndr name] -- ResTyH98: the constructor's existential type variables
582 -- ResTyGADT: all the constructor's quantified type variables
584 , con_cxt :: LHsContext name -- The context. This *does not* include the
585 -- "stupid theta" which lives only in the TyData decl
587 , con_details :: HsConDetails name (LBangType name) -- The main payload
589 , con_res :: ResType name -- Result type of the constructor
593 = ResTyH98 -- Constructor was declared using Haskell 98 syntax
594 | ResTyGADT (LHsType name) -- Constructor was declared using GADT-style syntax,
595 -- and here is its result type
599 conDeclsNames :: Eq name => [ConDecl name] -> [Located name]
600 -- See tyClDeclNames for what this does
601 -- The function is boringly complicated because of the records
602 -- And since we only have equality, we have to be a little careful
604 = snd (foldl do_one ([], []) cons)
606 do_one (flds_seen, acc) (ConDecl { con_name = lname, con_details = RecCon flds })
607 = (map unLoc new_flds ++ flds_seen, lname : [f | f <- new_flds] ++ acc)
609 new_flds = [ f | (f,_) <- flds, not (unLoc f `elem` flds_seen) ]
611 do_one (flds_seen, acc) c
612 = (flds_seen, (con_name c):acc)
614 conDetailsTys details = map getBangType (hsConArgs details)
619 instance (OutputableBndr name) => Outputable (ConDecl name) where
622 pprConDecl (ConDecl con expl tvs cxt details ResTyH98)
623 = sep [pprHsForAll expl tvs cxt, ppr_details con details]
625 ppr_details con (InfixCon t1 t2) = hsep [ppr t1, pprHsVar con, ppr t2]
626 ppr_details con (PrefixCon tys) = hsep (pprHsVar con : map ppr tys)
627 ppr_details con (RecCon fields) = ppr con <+> ppr_fields fields
629 pprConDecl (ConDecl con expl tvs cxt (PrefixCon arg_tys) (ResTyGADT res_ty))
630 = ppr con <+> dcolon <+>
631 sep [pprHsForAll expl tvs cxt, ppr (foldr mk_fun_ty res_ty arg_tys)]
633 mk_fun_ty a b = noLoc (HsFunTy a b)
634 pprConDecl (ConDecl con expl tvs cxt (RecCon fields) (ResTyGADT res_ty))
635 = sep [pprHsForAll expl tvs cxt, ppr con <+> ppr fields <+> dcolon <+> ppr res_ty]
637 ppr_fields fields = braces (sep (punctuate comma (map ppr_field fields)))
638 ppr_field (n, ty) = ppr n <+> dcolon <+> ppr ty
641 %************************************************************************
643 \subsection[InstDecl]{An instance declaration
645 %************************************************************************
648 type LInstDecl name = Located (InstDecl name)
651 = InstDecl (LHsType name) -- Context => Class Instance-type
652 -- Using a polytype means that the renamer conveniently
653 -- figures out the quantified type variables for us.
655 [LSig name] -- User-supplied pragmatic info
656 [LTyClDecl name]-- Associated types
658 instance (OutputableBndr name) => Outputable (InstDecl name) where
660 ppr (InstDecl inst_ty binds uprags ats)
661 = vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
664 nest 4 (pprLHsBinds binds) ]
666 -- Extract the declarations of associated types from an instance
668 instDeclATs :: InstDecl name -> [LTyClDecl name]
669 instDeclATs (InstDecl _ _ _ ats) = ats
672 %************************************************************************
674 \subsection[DefaultDecl]{A @default@ declaration}
676 %************************************************************************
678 There can only be one default declaration per module, but it is hard
679 for the parser to check that; we pass them all through in the abstract
680 syntax, and that restriction must be checked in the front end.
683 type LDefaultDecl name = Located (DefaultDecl name)
685 data DefaultDecl name
686 = DefaultDecl [LHsType name]
688 instance (OutputableBndr name)
689 => Outputable (DefaultDecl name) where
691 ppr (DefaultDecl tys)
692 = ptext SLIT("default") <+> parens (interpp'SP tys)
695 %************************************************************************
697 \subsection{Foreign function interface declaration}
699 %************************************************************************
703 -- foreign declarations are distinguished as to whether they define or use a
706 -- * the Boolean value indicates whether the pre-standard deprecated syntax
709 type LForeignDecl name = Located (ForeignDecl name)
711 data ForeignDecl name
712 = ForeignImport (Located name) (LHsType name) ForeignImport -- defines name
713 | ForeignExport (Located name) (LHsType name) ForeignExport -- uses name
715 -- Specification Of an imported external entity in dependence on the calling
718 data ForeignImport = -- import of a C entity
720 -- * the two strings specifying a header file or library
721 -- may be empty, which indicates the absence of a
722 -- header or object specification (both are not used
723 -- in the case of `CWrapper' and when `CFunction'
724 -- has a dynamic target)
726 -- * the calling convention is irrelevant for code
727 -- generation in the case of `CLabel', but is needed
728 -- for pretty printing
730 -- * `Safety' is irrelevant for `CLabel' and `CWrapper'
732 CImport CCallConv -- ccall or stdcall
733 Safety -- safe or unsafe
734 FastString -- name of C header
735 FastString -- name of library object
736 CImportSpec -- details of the C entity
738 -- import of a .NET function
740 | DNImport DNCallSpec
742 -- details of an external C entity
744 data CImportSpec = CLabel CLabelString -- import address of a C label
745 | CFunction CCallTarget -- static or dynamic function
746 | CWrapper -- wrapper to expose closures
749 -- specification of an externally exported entity in dependence on the calling
752 data ForeignExport = CExport CExportSpec -- contains the calling convention
753 | DNExport -- presently unused
755 -- abstract type imported from .NET
757 data FoType = DNType -- In due course we'll add subtype stuff
758 deriving (Eq) -- Used for equality instance for TyClDecl
761 -- pretty printing of foreign declarations
764 instance OutputableBndr name => Outputable (ForeignDecl name) where
765 ppr (ForeignImport n ty fimport) =
766 ptext SLIT("foreign import") <+> ppr fimport <+>
767 ppr n <+> dcolon <+> ppr ty
768 ppr (ForeignExport n ty fexport) =
769 ptext SLIT("foreign export") <+> ppr fexport <+>
770 ppr n <+> dcolon <+> ppr ty
772 instance Outputable ForeignImport where
773 ppr (DNImport spec) =
774 ptext SLIT("dotnet") <+> ppr spec
775 ppr (CImport cconv safety header lib spec) =
776 ppr cconv <+> ppr safety <+>
777 char '"' <> pprCEntity header lib spec <> char '"'
779 pprCEntity header lib (CLabel lbl) =
780 ptext SLIT("static") <+> ftext header <+> char '&' <>
781 pprLib lib <> ppr lbl
782 pprCEntity header lib (CFunction (StaticTarget lbl)) =
783 ptext SLIT("static") <+> ftext header <+> char '&' <>
784 pprLib lib <> ppr lbl
785 pprCEntity header lib (CFunction (DynamicTarget)) =
786 ptext SLIT("dynamic")
787 pprCEntity _ _ (CWrapper) = ptext SLIT("wrapper")
789 pprLib lib | nullFS lib = empty
790 | otherwise = char '[' <> ppr lib <> char ']'
792 instance Outputable ForeignExport where
793 ppr (CExport (CExportStatic lbl cconv)) =
794 ppr cconv <+> char '"' <> ppr lbl <> char '"'
796 ptext SLIT("dotnet") <+> ptext SLIT("\"<unused>\"")
798 instance Outputable FoType where
799 ppr DNType = ptext SLIT("type dotnet")
803 %************************************************************************
805 \subsection{Transformation rules}
807 %************************************************************************
810 type LRuleDecl name = Located (RuleDecl name)
813 = HsRule -- Source rule
814 RuleName -- Rule name
816 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
817 (Located (HsExpr name)) -- LHS
818 NameSet -- Free-vars from the LHS
819 (Located (HsExpr name)) -- RHS
820 NameSet -- Free-vars from the RHS
823 = RuleBndr (Located name)
824 | RuleBndrSig (Located name) (LHsType name)
826 collectRuleBndrSigTys :: [RuleBndr name] -> [LHsType name]
827 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
829 instance OutputableBndr name => Outputable (RuleDecl name) where
830 ppr (HsRule name act ns lhs fv_lhs rhs fv_rhs)
831 = sep [text "{-# RULES" <+> doubleQuotes (ftext name) <+> ppr act,
832 nest 4 (pp_forall <+> pprExpr (unLoc lhs)),
833 nest 4 (equals <+> pprExpr (unLoc rhs) <+> text "#-}") ]
835 pp_forall | null ns = empty
836 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
838 instance OutputableBndr name => Outputable (RuleBndr name) where
839 ppr (RuleBndr name) = ppr name
840 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
844 %************************************************************************
846 \subsection[DeprecDecl]{Deprecations}
848 %************************************************************************
850 We use exported entities for things to deprecate.
853 type LDeprecDecl name = Located (DeprecDecl name)
855 data DeprecDecl name = Deprecation name DeprecTxt
857 instance OutputableBndr name => Outputable (DeprecDecl name) where
858 ppr (Deprecation thing txt)
859 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]