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(..), TyClDecl(..), InstDecl(..), RuleDecl(..), RuleBndr(..),
13 ForeignDecl(..), ForeignImport(..), ForeignExport(..),
14 CImportSpec(..), FoType(..),
15 ConDecl(..), ConDetails(..),
16 BangType(..), getBangType, getBangStrictness, unbangedType,
17 DeprecDecl(..), DeprecTxt,
18 hsDeclName, instDeclName,
19 tyClDeclName, tyClDeclNames, tyClDeclSysNames, tyClDeclTyVars,
20 isClassDecl, isSynDecl, isDataDecl, isIfaceSigDecl, countTyClDecls,
21 mkClassDeclSysNames, isSourceInstDecl, ifaceRuleDeclName,
22 getClassDeclSysNames, conDetailsTys,
26 #include "HsVersions.h"
29 import HsBinds ( HsBinds, MonoBinds, Sig(..), FixitySig(..) )
30 import HsExpr ( HsExpr )
31 import HsImpExp ( ppr_var )
33 import PprCore ( pprCoreRule )
34 import HsCore ( UfExpr, UfBinder, HsIdInfo, pprHsIdInfo,
35 eq_ufBinders, eq_ufExpr, pprUfExpr
37 import CoreSyn ( CoreRule(..), RuleName )
38 import BasicTypes ( NewOrData(..), StrictnessMark(..), Activation(..) )
39 import ForeignCall ( CCallTarget(..), DNCallSpec, CCallConv, Safety,
43 import Name ( NamedThing )
44 import FunDeps ( pprFundeps )
45 import TyCon ( DataConDetails(..), visibleDataCons )
46 import Class ( FunDep, DefMeth(..) )
47 import CStrings ( CLabelString )
49 import Util ( eqListBy, count )
50 import SrcLoc ( SrcLoc )
53 import Maybe ( isNothing, fromJust )
57 %************************************************************************
59 \subsection[HsDecl]{Declarations}
61 %************************************************************************
65 = TyClD (TyClDecl name pat)
66 | InstD (InstDecl name pat)
67 | DefD (DefaultDecl name)
68 | ValD (HsBinds name pat)
69 | ForD (ForeignDecl name)
70 | FixD (FixitySig name)
71 | DeprecD (DeprecDecl name)
72 | RuleD (RuleDecl name pat)
74 -- NB: all top-level fixity decls are contained EITHER
76 -- OR in the ClassDecls in TyClDs
79 -- a) data constructors
80 -- b) class methods (but they can be also done in the
81 -- signatures of class decls)
82 -- c) imported functions (that have an IfacSig)
85 -- The latter is for class methods only
90 hsDeclName :: (NamedThing name, Outputable name, Outputable pat)
91 => HsDecl name pat -> name
93 hsDeclName (TyClD decl) = tyClDeclName decl
94 hsDeclName (InstD decl) = instDeclName decl
95 hsDeclName (ForD decl) = foreignDeclName decl
96 hsDeclName (FixD (FixitySig name _ _)) = name
97 -- Others don't make sense
99 hsDeclName x = pprPanic "HsDecls.hsDeclName" (ppr x)
103 instDeclName :: InstDecl name pat -> name
104 instDeclName (InstDecl _ _ _ (Just name) _) = name
109 instance (NamedThing name, Outputable name, Outputable pat)
110 => Outputable (HsDecl name pat) where
112 ppr (TyClD dcl) = ppr dcl
113 ppr (ValD binds) = ppr binds
114 ppr (DefD def) = ppr def
115 ppr (InstD inst) = ppr inst
116 ppr (ForD fd) = ppr fd
117 ppr (FixD fd) = ppr fd
118 ppr (RuleD rd) = ppr rd
119 ppr (DeprecD dd) = ppr dd
123 %************************************************************************
125 \subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
127 %************************************************************************
129 --------------------------------
131 --------------------------------
133 Here is the story about the implicit names that go with type, class, and instance
134 decls. It's a bit tricky, so pay attention!
136 "Implicit" (or "system") binders
137 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
138 Each data type decl defines
139 a worker name for each constructor
140 to-T and from-T convertors
141 Each class decl defines
142 a tycon for the class
143 a data constructor for that tycon
144 the worker for that constructor
145 a selector for each superclass
147 All have occurrence names that are derived uniquely from their parent declaration.
149 None of these get separate definitions in an interface file; they are
150 fully defined by the data or class decl. But they may *occur* in
151 interface files, of course. Any such occurrence must haul in the
152 relevant type or class decl.
155 - Make up their occurrence names immediately
156 This is done in RdrHsSyn.mkClassDecl, mkTyDecl, mkConDecl
158 - Ensure they "point to" the parent data/class decl
159 when loading that decl from an interface file
160 (See RnHiFiles.getTyClDeclSysNames)
162 - When renaming the decl look them up in the name cache,
163 ensure correct module and provenance is set
167 - Occurrence name is derived uniquely from the method name
170 - If there is a default method name at all, it's recorded in
171 the ClassOpSig (in HsBinds), in the DefMeth field.
172 (DefMeth is defined in Class.lhs)
174 Source-code class decls and interface-code class decls are treated subtly
175 differently, which has given me a great deal of confusion over the years.
176 Here's the deal. (We distinguish the two cases because source-code decls
177 have (Just binds) in the tcdMeths field, whereas interface decls have Nothing.
179 In *source-code* class declarations:
180 - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName
181 This is done by RdrHsSyn.mkClassOpSigDM
183 - The renamer renames it to a Name
185 - During typechecking, we generate a binding for each $dm for
186 which there's a programmer-supplied default method:
191 We generate a binding for $dmop1 but not for $dmop2.
192 The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1.
193 The Name for $dmop2 is simply discarded.
195 In *interface-file* class declarations:
196 - When parsing, we see if there's an explicit programmer-supplied default method
197 because there's an '=' sign to indicate it:
199 op1 = :: <type> -- NB the '='
201 We use this info to generate a DefMeth with a suitable RdrName for op1,
202 and a NoDefMeth for op2
203 - The interface file has a separate definition for $dmop1, with unfolding etc.
204 - The renamer renames it to a Name.
205 - The renamer treats $dmop1 as a free variable of the declaration, so that
206 the binding for $dmop1 will be sucked in. (See RnHsSyn.tyClDeclFVs)
207 This doesn't happen for source code class decls, because they *bind* the default method.
211 Each instance declaration gives rise to one dictionary function binding.
213 The type checker makes up new source-code instance declarations
214 (e.g. from 'deriving' or generic default methods --- see
215 TcInstDcls.tcInstDecls1). So we can't generate the names for
216 dictionary functions in advance (we don't know how many we need).
218 On the other hand for interface-file instance declarations, the decl
219 specifies the name of the dictionary function, and it has a binding elsewhere
220 in the interface file:
221 instance {Eq Int} = dEqInt
222 dEqInt :: {Eq Int} <pragma info>
224 So again we treat source code and interface file code slightly differently.
227 - Source code instance decls have a Nothing in the (Maybe name) field
228 (see data InstDecl below)
230 - The typechecker makes up a Local name for the dict fun for any source-code
231 instance decl, whether it comes from a source-code instance decl, or whether
232 the instance decl is derived from some other construct (e.g. 'deriving').
234 - The occurrence name it chooses is derived from the instance decl (just for
235 documentation really) --- e.g. dNumInt. Two dict funs may share a common
236 occurrence name, but will have different uniques. E.g.
237 instance Foo [Int] where ...
238 instance Foo [Bool] where ...
239 These might both be dFooList
241 - The CoreTidy phase globalises the name, and ensures the occurrence name is
242 unique (this isn't special to dict funs). So we'd get dFooList and dFooList1.
244 - We can take this relaxed approach (changing the occurrence name later)
245 because dict fun Ids are not captured in a TyCon or Class (unlike default
246 methods, say). Instead, they are kept separately in the InstEnv. This
247 makes it easy to adjust them after compiling a module. (Once we've finished
248 compiling that module, they don't change any more.)
252 - The instance decl gives the dict fun name, so the InstDecl has a (Just name)
253 in the (Maybe name) field.
255 - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
256 suck in the dfun binding
260 -- TyClDecls are precisely the kind of declarations that can
261 -- appear in interface files; or (internally) in GHC's interface
262 -- for a module. That's why (despite the misnomer) IfaceSig and ForeignType
263 -- are both in TyClDecl
265 data TyClDecl name pat
266 = IfaceSig { tcdName :: name, -- It may seem odd to classify an interface-file signature
267 tcdType :: HsType name, -- as a 'TyClDecl', but it's very convenient.
268 tcdIdInfo :: [HsIdInfo name],
272 | ForeignType { tcdName :: name, -- See remarks about IfaceSig above
273 tcdExtName :: Maybe FastString,
277 | TyData { tcdND :: NewOrData,
278 tcdCtxt :: HsContext name, -- context
279 tcdName :: name, -- type constructor
280 tcdTyVars :: [HsTyVarBndr name], -- type variables
281 tcdCons :: DataConDetails (ConDecl name), -- data constructors (empty if abstract)
282 tcdDerivs :: Maybe (HsContext name), -- derivings; Nothing => not specified
283 -- Just [] => derive exactly what is asked
284 tcdSysNames :: DataSysNames name, -- Generic converter functions
288 | TySynonym { tcdName :: name, -- type constructor
289 tcdTyVars :: [HsTyVarBndr name], -- type variables
290 tcdSynRhs :: HsType name, -- synonym expansion
294 | ClassDecl { tcdCtxt :: HsContext name, -- Context...
295 tcdName :: name, -- Name of the class
296 tcdTyVars :: [HsTyVarBndr name], -- The class type variables
297 tcdFDs :: [FunDep name], -- Functional dependencies
298 tcdSigs :: [Sig name], -- Methods' signatures
299 tcdMeths :: Maybe (MonoBinds name pat), -- Default methods
300 -- Nothing for imported class decls
301 -- Just bs for source class decls
302 tcdSysNames :: ClassSysNames name,
310 isIfaceSigDecl, isDataDecl, isSynDecl, isClassDecl :: TyClDecl name pat -> Bool
312 isIfaceSigDecl (IfaceSig {}) = True
313 isIfaceSigDecl other = False
315 isSynDecl (TySynonym {}) = True
316 isSynDecl other = False
318 isDataDecl (TyData {}) = True
319 isDataDecl other = False
321 isClassDecl (ClassDecl {}) = True
322 isClassDecl other = False
328 --------------------------------
329 tyClDeclName :: TyClDecl name pat -> name
330 tyClDeclName tycl_decl = tcdName tycl_decl
332 --------------------------------
333 tyClDeclNames :: Eq name => TyClDecl name pat -> [(name, SrcLoc)]
334 -- Returns all the *binding* names of the decl, along with their SrcLocs
335 -- The first one is guaranteed to be the name of the decl
336 -- For record fields, the first one counts as the SrcLoc
337 -- We use the equality to filter out duplicate field names
339 tyClDeclNames (TySynonym {tcdName = name, tcdLoc = loc}) = [(name,loc)]
340 tyClDeclNames (IfaceSig {tcdName = name, tcdLoc = loc}) = [(name,loc)]
341 tyClDeclNames (ForeignType {tcdName = name, tcdLoc = loc}) = [(name,loc)]
343 tyClDeclNames (ClassDecl {tcdName = cls_name, tcdSigs = sigs, tcdLoc = loc})
344 = (cls_name,loc) : [(n,loc) | ClassOpSig n _ _ loc <- sigs]
346 tyClDeclNames (TyData {tcdName = tc_name, tcdCons = cons, tcdLoc = loc})
347 = (tc_name,loc) : conDeclsNames cons
350 tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
351 tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs
352 tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
353 tyClDeclTyVars (ForeignType {}) = []
354 tyClDeclTyVars (IfaceSig {}) = []
357 --------------------------------
358 -- The "system names" are extra implicit names *bound* by the decl.
359 -- They are kept in a list rather than a tuple
360 -- to make the renamer easier.
362 type ClassSysNames name = [name]
363 -- For class decls they are:
364 -- [tycon, datacon wrapper, datacon worker,
365 -- superclass selector 1, ..., superclass selector n]
367 type DataSysNames name = [name]
368 -- For data decls they are
370 -- where from :: T -> Tring
373 tyClDeclSysNames :: TyClDecl name pat -> [(name, SrcLoc)]
374 -- Similar to tyClDeclNames, but returns the "implicit"
375 -- or "system" names of the declaration
377 tyClDeclSysNames (ClassDecl {tcdSysNames = names, tcdLoc = loc})
378 = [(n,loc) | n <- names]
379 tyClDeclSysNames (TyData {tcdCons = DataCons cons, tcdSysNames = names, tcdLoc = loc})
380 = [(n,loc) | n <- names] ++
381 [(wkr_name,loc) | ConDecl _ wkr_name _ _ _ loc <- cons]
382 tyClDeclSysNames decl = []
385 mkClassDeclSysNames :: (name, name, name, [name]) -> [name]
386 getClassDeclSysNames :: [name] -> (name, name, name, [name])
387 mkClassDeclSysNames (a,b,c,ds) = a:b:c:ds
388 getClassDeclSysNames (a:b:c:ds) = (a,b,c,ds)
392 instance (NamedThing name, Ord name) => Eq (TyClDecl name pat) where
393 -- Used only when building interface files
394 (==) d1@(IfaceSig {}) d2@(IfaceSig {})
395 = tcdName d1 == tcdName d2 &&
396 tcdType d1 == tcdType d2 &&
397 tcdIdInfo d1 == tcdIdInfo d2
399 (==) d1@(ForeignType {}) d2@(ForeignType {})
400 = tcdName d1 == tcdName d2 &&
401 tcdFoType d1 == tcdFoType d2
403 (==) d1@(TyData {}) d2@(TyData {})
404 = tcdName d1 == tcdName d2 &&
405 tcdND d1 == tcdND d2 &&
406 eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
407 eq_hsContext env (tcdCtxt d1) (tcdCtxt d2) &&
408 eq_hsCD env (tcdCons d1) (tcdCons d2)
411 (==) d1@(TySynonym {}) d2@(TySynonym {})
412 = tcdName d1 == tcdName d2 &&
413 eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
414 eq_hsType env (tcdSynRhs d1) (tcdSynRhs d2)
417 (==) d1@(ClassDecl {}) d2@(ClassDecl {})
418 = tcdName d1 == tcdName d2 &&
419 eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
420 eq_hsContext env (tcdCtxt d1) (tcdCtxt d2) &&
421 eqListBy (eq_hsFD env) (tcdFDs d1) (tcdFDs d2) &&
422 eqListBy (eq_cls_sig env) (tcdSigs d1) (tcdSigs d2)
425 (==) _ _ = False -- default case
427 eq_hsCD env (DataCons c1) (DataCons c2) = eqListBy (eq_ConDecl env) c1 c2
428 eq_hsCD env Unknown Unknown = True
429 eq_hsCD env (HasCons n1) (HasCons n2) = n1 == n2
430 eq_hsCD env d1 d2 = False
432 eq_hsFD env (ns1,ms1) (ns2,ms2)
433 = eqListBy (eq_hsVar env) ns1 ns2 && eqListBy (eq_hsVar env) ms1 ms2
435 eq_cls_sig env (ClassOpSig n1 dm1 ty1 _) (ClassOpSig n2 dm2 ty2 _)
436 = n1==n2 && dm1 `eq_dm` dm2 && eq_hsType env ty1 ty2
438 -- Ignore the name of the default method for (DefMeth id)
439 -- This is used for comparing declarations before putting
440 -- them into interface files, and the name of the default
441 -- method isn't relevant
442 NoDefMeth `eq_dm` NoDefMeth = True
443 GenDefMeth `eq_dm` GenDefMeth = True
444 DefMeth _ `eq_dm` DefMeth _ = True
445 dm1 `eq_dm` dm2 = False
451 countTyClDecls :: [TyClDecl name pat] -> (Int, Int, Int, Int, Int)
452 -- class, data, newtype, synonym decls
454 = (count isClassDecl decls,
455 count isSynDecl decls,
456 count isIfaceSigDecl decls,
457 count isDataTy decls,
460 isDataTy TyData{tcdND=DataType} = True
463 isNewTy TyData{tcdND=NewType} = True
468 instance (NamedThing name, Outputable name, Outputable pat)
469 => Outputable (TyClDecl name pat) where
471 ppr (IfaceSig {tcdName = var, tcdType = ty, tcdIdInfo = info})
472 = getPprStyle $ \ sty ->
473 hsep [ if ifaceStyle sty then ppr var else ppr_var var,
474 dcolon, ppr ty, pprHsIdInfo info
477 ppr (ForeignType {tcdName = tycon})
478 = hsep [ptext SLIT("foreign import type dotnet"), ppr tycon]
480 ppr (TySynonym {tcdName = tycon, tcdTyVars = tyvars, tcdSynRhs = mono_ty})
481 = hang (ptext SLIT("type") <+> pp_decl_head [] tycon tyvars <+> equals)
484 ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdName = tycon,
485 tcdTyVars = tyvars, tcdCons = condecls,
486 tcdDerivs = derivings})
487 = pp_tydecl (ptext keyword <+> pp_decl_head context tycon tyvars)
488 (pp_condecls condecls)
491 keyword = case new_or_data of
492 NewType -> SLIT("newtype")
493 DataType -> SLIT("data")
495 ppr (ClassDecl {tcdCtxt = context, tcdName = clas, tcdTyVars = tyvars, tcdFDs = fds,
496 tcdSigs = sigs, tcdMeths = methods})
497 | null sigs -- No "where" part
500 | otherwise -- Laid out
501 = sep [hsep [top_matter, ptext SLIT("where {")],
502 nest 4 (sep [sep (map ppr_sig sigs), pp_methods, char '}'])]
504 top_matter = ptext SLIT("class") <+> pp_decl_head context clas tyvars <+> pprFundeps fds
505 ppr_sig sig = ppr sig <> semi
507 pp_methods = getPprStyle $ \ sty ->
508 if ifaceStyle sty || isNothing methods
510 else ppr (fromJust methods)
512 pp_decl_head :: Outputable name => HsContext name -> name -> [HsTyVarBndr name] -> SDoc
513 pp_decl_head context thing tyvars = hsep [pprHsContext context, ppr thing, interppSP tyvars]
515 pp_condecls Unknown = ptext SLIT("{- abstract -}")
516 pp_condecls (HasCons n) = ptext SLIT("{- abstract with") <+> int n <+> ptext SLIT("constructors -}")
517 pp_condecls (DataCons cs) = equals <+> sep (punctuate (ptext SLIT(" |")) (map ppr cs))
519 pp_tydecl pp_head pp_decl_rhs derivings
520 = hang pp_head 4 (sep [
524 Just ds -> hsep [ptext SLIT("deriving"), ppr_hs_context ds]
529 %************************************************************************
531 \subsection[ConDecl]{A data-constructor declaration}
533 %************************************************************************
537 = ConDecl name -- Constructor name; this is used for the
538 -- DataCon itself, and for the user-callable wrapper Id
540 name -- Name of the constructor's 'worker Id'
541 -- Filled in as the ConDecl is built
543 [HsTyVarBndr name] -- Existentially quantified type variables
544 (HsContext name) -- ...and context
545 -- If both are empty then there are no existentials
551 = VanillaCon -- prefix-style con decl
554 | InfixCon -- infix-style con decl
558 | RecCon -- record-style con decl
559 [([name], BangType name)] -- list of "fields"
563 conDeclsNames :: Eq name => DataConDetails (ConDecl name) -> [(name,SrcLoc)]
564 -- See tyClDeclNames for what this does
565 -- The function is boringly complicated because of the records
566 -- And since we only have equality, we have to be a little careful
568 = snd (foldl do_one ([], []) (visibleDataCons cons))
570 do_one (flds_seen, acc) (ConDecl name _ _ _ details loc)
571 = do_details ((name,loc):acc) details
573 do_details acc (RecCon flds) = foldl do_fld (flds_seen, acc) flds
574 do_details acc other = (flds_seen, acc)
576 do_fld acc (flds, _) = foldl do_fld1 acc flds
578 do_fld1 (flds_seen, acc) fld
579 | fld `elem` flds_seen = (flds_seen,acc)
580 | otherwise = (fld:flds_seen, (fld,loc):acc)
584 conDetailsTys :: ConDetails name -> [HsType name]
585 conDetailsTys (VanillaCon btys) = map getBangType btys
586 conDetailsTys (InfixCon bty1 bty2) = [getBangType bty1, getBangType bty2]
587 conDetailsTys (RecCon fields) = [getBangType bty | (_, bty) <- fields]
590 eq_ConDecl env (ConDecl n1 _ tvs1 cxt1 cds1 _)
591 (ConDecl n2 _ tvs2 cxt2 cds2 _)
593 (eq_hsTyVars env tvs1 tvs2 $ \ env ->
594 eq_hsContext env cxt1 cxt2 &&
595 eq_ConDetails env cds1 cds2)
597 eq_ConDetails env (VanillaCon bts1) (VanillaCon bts2)
598 = eqListBy (eq_btype env) bts1 bts2
599 eq_ConDetails env (InfixCon bta1 btb1) (InfixCon bta2 btb2)
600 = eq_btype env bta1 bta2 && eq_btype env btb1 btb2
601 eq_ConDetails env (RecCon fs1) (RecCon fs2)
602 = eqListBy (eq_fld env) fs1 fs2
603 eq_ConDetails env _ _ = False
605 eq_fld env (ns1,bt1) (ns2, bt2) = ns1==ns2 && eq_btype env bt1 bt2
609 data BangType name = BangType StrictnessMark (HsType name)
611 getBangType (BangType _ ty) = ty
612 getBangStrictness (BangType s _) = s
614 unbangedType ty = BangType NotMarkedStrict ty
616 eq_btype env (BangType s1 t1) (BangType s2 t2) = s1==s2 && eq_hsType env t1 t2
620 instance (Outputable name) => Outputable (ConDecl name) where
621 ppr (ConDecl con _ tvs cxt con_details loc)
622 = sep [pprHsForAll tvs cxt, ppr_con_details con con_details]
624 ppr_con_details con (InfixCon ty1 ty2)
625 = hsep [ppr_bang ty1, ppr con, ppr_bang ty2]
627 -- ConDecls generated by MkIface.ifaceTyThing always have a VanillaCon, even
628 -- if the constructor is an infix one. This is because in an interface file
629 -- we don't distinguish between the two. Hence when printing these for the
630 -- user, we need to parenthesise infix constructor names.
631 ppr_con_details con (VanillaCon tys)
632 = getPprStyle $ \ sty ->
633 hsep ((if ifaceStyle sty then ppr con else ppr_var con)
634 : map (ppr_bang) tys)
636 ppr_con_details con (RecCon fields)
637 = ppr con <+> braces (sep (punctuate comma (map ppr_field fields)))
639 ppr_field (ns, ty) = hsep (map (ppr) ns) <+>
643 instance Outputable name => Outputable (BangType name) where
646 ppr_bang (BangType s ty) = ppr s <> pprParendHsType ty
650 %************************************************************************
652 \subsection[InstDecl]{An instance declaration
654 %************************************************************************
657 data InstDecl name pat
658 = InstDecl (HsType name) -- Context => Class Instance-type
659 -- Using a polytype means that the renamer conveniently
660 -- figures out the quantified type variables for us.
664 [Sig name] -- User-supplied pragmatic info
666 (Maybe name) -- Name for the dictionary function
667 -- Nothing for source-file instance decls
671 isSourceInstDecl :: InstDecl name pat -> Bool
672 isSourceInstDecl (InstDecl _ _ _ maybe_dfun _) = isNothing maybe_dfun
676 instance (Outputable name, Outputable pat)
677 => Outputable (InstDecl name pat) where
679 ppr (InstDecl inst_ty binds uprags maybe_dfun_name src_loc)
680 = getPprStyle $ \ sty ->
681 if ifaceStyle sty then
682 hsep [ptext SLIT("instance"), ppr inst_ty, equals, pp_dfun]
684 vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
688 pp_dfun = case maybe_dfun_name of
694 instance Ord name => Eq (InstDecl name pat) where
695 -- Used for interface comparison only, so don't compare bindings
696 (==) (InstDecl inst_ty1 _ _ dfun1 _) (InstDecl inst_ty2 _ _ dfun2 _)
697 = inst_ty1 == inst_ty2 && dfun1 == dfun2
701 %************************************************************************
703 \subsection[DefaultDecl]{A @default@ declaration}
705 %************************************************************************
707 There can only be one default declaration per module, but it is hard
708 for the parser to check that; we pass them all through in the abstract
709 syntax, and that restriction must be checked in the front end.
712 data DefaultDecl name
713 = DefaultDecl [HsType name]
716 instance (Outputable name)
717 => Outputable (DefaultDecl name) where
719 ppr (DefaultDecl tys src_loc)
720 = ptext SLIT("default") <+> parens (interpp'SP tys)
723 %************************************************************************
725 \subsection{Foreign function interface declaration}
727 %************************************************************************
731 -- foreign declarations are distinguished as to whether they define or use a
734 -- * the Boolean value indicates whether the pre-standard deprecated syntax
737 data ForeignDecl name
738 = ForeignImport name (HsType name) ForeignImport Bool SrcLoc -- defines name
739 | ForeignExport name (HsType name) ForeignExport Bool SrcLoc -- uses name
741 -- yield the Haskell name defined or used in a foreign declaration
743 foreignDeclName :: ForeignDecl name -> name
744 foreignDeclName (ForeignImport n _ _ _ _) = n
745 foreignDeclName (ForeignExport n _ _ _ _) = n
747 -- specification of an imported external entity in dependence on the calling
750 data ForeignImport = -- import of a C entity
752 -- * the two strings specifying a header file or library
753 -- may be empty, which indicates the absence of a
754 -- header or object specification (both are not used
755 -- in the case of `CWrapper' and when `CFunction'
756 -- has a dynamic target)
758 -- * the calling convention is irrelevant for code
759 -- generation in the case of `CLabel', but is needed
760 -- for pretty printing
762 -- * `Safety' is irrelevant for `CLabel' and `CWrapper'
764 CImport CCallConv -- ccall or stdcall
765 Safety -- safe or unsafe
766 FastString -- name of C header
767 FastString -- name of library object
768 CImportSpec -- details of the C entity
770 -- import of a .NET function
772 | DNImport DNCallSpec
774 -- details of an external C entity
776 data CImportSpec = CLabel CLabelString -- import address of a C label
777 | CFunction CCallTarget -- static or dynamic function
778 | CWrapper -- wrapper to expose closures
781 -- specification of an externally exported entity in dependence on the calling
784 data ForeignExport = CExport CExportSpec -- contains the calling convention
785 | DNExport -- presently unused
787 -- abstract type imported from .NET
789 data FoType = DNType -- In due course we'll add subtype stuff
790 deriving (Eq) -- Used for equality instance for TyClDecl
793 -- pretty printing of foreign declarations
796 instance Outputable name => Outputable (ForeignDecl name) where
797 ppr (ForeignImport n ty fimport _ _) =
798 ptext SLIT("foreign import") <+> ppr fimport <+>
799 ppr n <+> dcolon <+> ppr ty
800 ppr (ForeignExport n ty fexport _ _) =
801 ptext SLIT("foreign export") <+> ppr fexport <+>
802 ppr n <+> dcolon <+> ppr ty
804 instance Outputable ForeignImport where
805 ppr (DNImport spec) =
806 ptext SLIT("dotnet") <+> ppr spec
807 ppr (CImport cconv safety header lib spec) =
808 ppr cconv <+> ppr safety <+>
809 char '"' <> pprCEntity header lib spec <> char '"'
811 pprCEntity header lib (CLabel lbl) =
812 ptext SLIT("static") <+> ptext header <+> char '&' <>
813 pprLib lib <> ppr lbl
814 pprCEntity header lib (CFunction (StaticTarget lbl)) =
815 ptext SLIT("static") <+> ptext header <+> char '&' <>
816 pprLib lib <> ppr lbl
817 pprCEntity header lib (CFunction (DynamicTarget)) =
818 ptext SLIT("dynamic")
819 pprCEntity header lib (CFunction (CasmTarget _)) =
820 panic "HsDecls.pprCEntity: malformed C function target"
821 pprCEntity _ _ (CWrapper) = ptext SLIT("wrapper")
823 pprLib lib | nullFastString lib = empty
824 | otherwise = char '[' <> ppr lib <> char ']'
826 instance Outputable ForeignExport where
827 ppr (CExport (CExportStatic lbl cconv)) =
828 ppr cconv <+> char '"' <> ppr lbl <> char '"'
830 ptext SLIT("dotnet") <+> ptext SLIT("\"<unused>\"")
832 instance Outputable FoType where
833 ppr DNType = ptext SLIT("type dotnet")
837 %************************************************************************
839 \subsection{Transformation rules}
841 %************************************************************************
844 data RuleDecl name pat
845 = HsRule -- Source rule
846 RuleName -- Rule name
848 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
849 (HsExpr name pat) -- LHS
850 (HsExpr name pat) -- RHS
853 | IfaceRule -- One that's come in from an interface file; pre-typecheck
856 [UfBinder name] -- Tyvars and term vars
858 [UfExpr name] -- Args of LHS
859 (UfExpr name) -- Pre typecheck
862 | IfaceRuleOut -- Post typecheck
866 ifaceRuleDeclName :: RuleDecl name pat -> name
867 ifaceRuleDeclName (IfaceRule _ _ _ n _ _ _) = n
868 ifaceRuleDeclName (IfaceRuleOut n r) = n
869 ifaceRuleDeclName (HsRule fs _ _ _ _ _) = pprPanic "ifaceRuleDeclName" (ppr fs)
873 | RuleBndrSig name (HsType name)
875 collectRuleBndrSigTys :: [RuleBndr name] -> [HsType name]
876 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
878 instance (NamedThing name, Ord name) => Eq (RuleDecl name pat) where
879 -- Works for IfaceRules only; used when comparing interface file versions
880 (IfaceRule n1 a1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 a2 bs2 f2 es2 rhs2 _)
881 = n1==n2 && f1 == f2 && a1==a2 &&
882 eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
883 eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
885 instance (NamedThing name, Outputable name, Outputable pat)
886 => Outputable (RuleDecl name pat) where
887 ppr (HsRule name act ns lhs rhs loc)
888 = sep [text "{-# RULES" <+> doubleQuotes (ptext name) <+> ppr act,
889 pp_forall, ppr lhs, equals <+> ppr rhs,
892 pp_forall | null ns = empty
893 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
895 ppr (IfaceRule name act tpl_vars fn tpl_args rhs loc)
896 = hsep [ doubleQuotes (ptext name), ppr act,
897 ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
898 ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
899 ptext SLIT("=") <+> ppr rhs
902 ppr (IfaceRuleOut fn rule) = pprCoreRule (ppr fn) rule
904 instance Outputable name => Outputable (RuleBndr name) where
905 ppr (RuleBndr name) = ppr name
906 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
910 %************************************************************************
912 \subsection[DeprecDecl]{Deprecations}
914 %************************************************************************
916 We use exported entities for things to deprecate.
919 data DeprecDecl name = Deprecation name DeprecTxt SrcLoc
921 type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
923 instance Outputable name => Outputable (DeprecDecl name) where
924 ppr (Deprecation thing txt _)
925 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]