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(..), FoImport(..), FoExport(..), FoType(..),
14 ConDecl(..), ConDetails(..),
15 BangType(..), getBangType, getBangStrictness, unbangedType,
16 DeprecDecl(..), DeprecTxt,
17 hsDeclName, instDeclName,
18 tyClDeclName, tyClDeclNames, tyClDeclSysNames, tyClDeclTyVars,
19 isClassDecl, isSynDecl, isDataDecl, isIfaceSigDecl, countTyClDecls,
20 mkClassDeclSysNames, isSourceInstDecl, ifaceRuleDeclName,
21 getClassDeclSysNames, conDetailsTys,
25 #include "HsVersions.h"
28 import HsBinds ( HsBinds, MonoBinds, Sig(..), FixitySig(..) )
29 import HsExpr ( HsExpr )
30 import HsImpExp ( ppr_var )
32 import PprCore ( pprCoreRule )
33 import HsCore ( UfExpr, UfBinder, HsIdInfo, pprHsIdInfo,
34 eq_ufBinders, eq_ufExpr, pprUfExpr
36 import CoreSyn ( CoreRule(..), RuleName )
37 import BasicTypes ( NewOrData(..), StrictnessMark(..), Activation(..) )
38 import ForeignCall ( CExportSpec, CCallSpec, DNCallSpec, CCallConv )
41 import Name ( NamedThing )
42 import FunDeps ( pprFundeps )
43 import Class ( FunDep, DefMeth(..) )
44 import CStrings ( CLabelString )
46 import Util ( eqListBy, count )
47 import SrcLoc ( SrcLoc )
50 import Maybe ( isNothing, fromJust )
54 %************************************************************************
56 \subsection[HsDecl]{Declarations}
58 %************************************************************************
62 = TyClD (TyClDecl name pat)
63 | InstD (InstDecl name pat)
64 | DefD (DefaultDecl name)
65 | ValD (HsBinds name pat)
66 | ForD (ForeignDecl name)
67 | FixD (FixitySig name)
68 | DeprecD (DeprecDecl name)
69 | RuleD (RuleDecl name pat)
71 -- NB: all top-level fixity decls are contained EITHER
73 -- OR in the ClassDecls in TyClDs
76 -- a) data constructors
77 -- b) class methods (but they can be also done in the
78 -- signatures of class decls)
79 -- c) imported functions (that have an IfacSig)
82 -- The latter is for class methods only
87 hsDeclName :: (NamedThing name, Outputable name, Outputable pat)
88 => HsDecl name pat -> name
90 hsDeclName (TyClD decl) = tyClDeclName decl
91 hsDeclName (InstD decl) = instDeclName decl
92 hsDeclName (ForD decl) = forDeclName decl
93 hsDeclName (FixD (FixitySig name _ _)) = name
94 -- Others don't make sense
96 hsDeclName x = pprPanic "HsDecls.hsDeclName" (ppr x)
100 instDeclName :: InstDecl name pat -> name
101 instDeclName (InstDecl _ _ _ (Just name) _) = name
106 instance (NamedThing name, Outputable name, Outputable pat)
107 => Outputable (HsDecl name pat) where
109 ppr (TyClD dcl) = ppr dcl
110 ppr (ValD binds) = ppr binds
111 ppr (DefD def) = ppr def
112 ppr (InstD inst) = ppr inst
113 ppr (ForD fd) = ppr fd
114 ppr (FixD fd) = ppr fd
115 ppr (RuleD rd) = ppr rd
116 ppr (DeprecD dd) = ppr dd
120 %************************************************************************
122 \subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
124 %************************************************************************
126 --------------------------------
128 --------------------------------
130 Here is the story about the implicit names that go with type, class, and instance
131 decls. It's a bit tricky, so pay attention!
133 "Implicit" (or "system") binders
134 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
135 Each data type decl defines
136 a worker name for each constructor
137 to-T and from-T convertors
138 Each class decl defines
139 a tycon for the class
140 a data constructor for that tycon
141 the worker for that constructor
142 a selector for each superclass
144 All have occurrence names that are derived uniquely from their parent declaration.
146 None of these get separate definitions in an interface file; they are
147 fully defined by the data or class decl. But they may *occur* in
148 interface files, of course. Any such occurrence must haul in the
149 relevant type or class decl.
152 - Make up their occurrence names immediately
153 This is done in RdrHsSyn.mkClassDecl, mkTyDecl, mkConDecl
155 - Ensure they "point to" the parent data/class decl
156 when loading that decl from an interface file
157 (See RnHiFiles.getTyClDeclSysNames)
159 - When renaming the decl look them up in the name cache,
160 ensure correct module and provenance is set
164 - Occurrence name is derived uniquely from the method name
167 - If there is a default method name at all, it's recorded in
168 the ClassOpSig (in HsBinds), in the DefMeth field.
169 (DefMeth is defined in Class.lhs)
171 Source-code class decls and interface-code class decls are treated subtly
172 differently, which has given me a great deal of confusion over the years.
173 Here's the deal. (We distinguish the two cases because source-code decls
174 have (Just binds) in the tcdMeths field, whereas interface decls have Nothing.
176 In *source-code* class declarations:
177 - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName
178 This is done by RdrHsSyn.mkClassOpSigDM
180 - The renamer renames it to a Name
182 - During typechecking, we generate a binding for each $dm for
183 which there's a programmer-supplied default method:
188 We generate a binding for $dmop1 but not for $dmop2.
189 The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1.
190 The Name for $dmop2 is simply discarded.
192 In *interface-file* class declarations:
193 - When parsing, we see if there's an explicit programmer-supplied default method
194 because there's an '=' sign to indicate it:
196 op1 = :: <type> -- NB the '='
198 We use this info to generate a DefMeth with a suitable RdrName for op1,
199 and a NoDefMeth for op2
200 - The interface file has a separate definition for $dmop1, with unfolding etc.
201 - The renamer renames it to a Name.
202 - The renamer treats $dmop1 as a free variable of the declaration, so that
203 the binding for $dmop1 will be sucked in. (See RnHsSyn.tyClDeclFVs)
204 This doesn't happen for source code class decls, because they *bind* the default method.
208 Each instance declaration gives rise to one dictionary function binding.
210 The type checker makes up new source-code instance declarations
211 (e.g. from 'deriving' or generic default methods --- see
212 TcInstDcls.tcInstDecls1). So we can't generate the names for
213 dictionary functions in advance (we don't know how many we need).
215 On the other hand for interface-file instance declarations, the decl
216 specifies the name of the dictionary function, and it has a binding elsewhere
217 in the interface file:
218 instance {Eq Int} = dEqInt
219 dEqInt :: {Eq Int} <pragma info>
221 So again we treat source code and interface file code slightly differently.
224 - Source code instance decls have a Nothing in the (Maybe name) field
225 (see data InstDecl below)
227 - The typechecker makes up a Local name for the dict fun for any source-code
228 instance decl, whether it comes from a source-code instance decl, or whether
229 the instance decl is derived from some other construct (e.g. 'deriving').
231 - The occurrence name it chooses is derived from the instance decl (just for
232 documentation really) --- e.g. dNumInt. Two dict funs may share a common
233 occurrence name, but will have different uniques. E.g.
234 instance Foo [Int] where ...
235 instance Foo [Bool] where ...
236 These might both be dFooList
238 - The CoreTidy phase globalises the name, and ensures the occurrence name is
239 unique (this isn't special to dict funs). So we'd get dFooList and dFooList1.
241 - We can take this relaxed approach (changing the occurrence name later)
242 because dict fun Ids are not captured in a TyCon or Class (unlike default
243 methods, say). Instead, they are kept separately in the InstEnv. This
244 makes it easy to adjust them after compiling a module. (Once we've finished
245 compiling that module, they don't change any more.)
249 - The instance decl gives the dict fun name, so the InstDecl has a (Just name)
250 in the (Maybe name) field.
252 - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
253 suck in the dfun binding
257 -- TyClDecls are precisely the kind of declarations that can
258 -- appear in interface files; or (internally) in GHC's interface
259 -- for a module. That's why (despite the misnomer) IfaceSig and ForeignType
260 -- are both in TyClDecl
262 data TyClDecl name pat
263 = IfaceSig { tcdName :: name, -- It may seem odd to classify an interface-file signature
264 tcdType :: HsType name, -- as a 'TyClDecl', but it's very convenient.
265 tcdIdInfo :: [HsIdInfo name],
269 | ForeignType { tcdName :: name, -- See remarks about IfaceSig above
270 tcdExtName :: Maybe FastString,
274 | TyData { tcdND :: NewOrData,
275 tcdCtxt :: HsContext name, -- context
276 tcdName :: name, -- type constructor
277 tcdTyVars :: [HsTyVarBndr name], -- type variables
278 tcdCons :: [ConDecl name], -- data constructors (empty if abstract)
279 tcdNCons :: Int, -- Number of data constructors (valid even if type is abstract)
280 tcdDerivs :: Maybe (HsContext name), -- derivings; Nothing => not specified
281 -- Just [] => derive exactly what is asked
282 tcdSysNames :: DataSysNames name, -- Generic converter functions
286 | TySynonym { tcdName :: name, -- type constructor
287 tcdTyVars :: [HsTyVarBndr name], -- type variables
288 tcdSynRhs :: HsType name, -- synonym expansion
292 | ClassDecl { tcdCtxt :: HsContext name, -- Context...
293 tcdName :: name, -- Name of the class
294 tcdTyVars :: [HsTyVarBndr name], -- The class type variables
295 tcdFDs :: [FunDep name], -- Functional dependencies
296 tcdSigs :: [Sig name], -- Methods' signatures
297 tcdMeths :: Maybe (MonoBinds name pat), -- Default methods
298 -- Nothing for imported class decls
299 -- Just bs for source class decls
300 tcdSysNames :: ClassSysNames name,
308 isIfaceSigDecl, isDataDecl, isSynDecl, isClassDecl :: TyClDecl name pat -> Bool
310 isIfaceSigDecl (IfaceSig {}) = True
311 isIfaceSigDecl other = False
313 isSynDecl (TySynonym {}) = True
314 isSynDecl other = False
316 isDataDecl (TyData {}) = True
317 isDataDecl other = False
319 isClassDecl (ClassDecl {}) = True
320 isClassDecl other = False
326 --------------------------------
327 tyClDeclName :: TyClDecl name pat -> name
328 tyClDeclName tycl_decl = tcdName tycl_decl
330 --------------------------------
331 tyClDeclNames :: Eq name => TyClDecl name pat -> [(name, SrcLoc)]
332 -- Returns all the *binding* names of the decl, along with their SrcLocs
333 -- The first one is guaranteed to be the name of the decl
334 -- For record fields, the first one counts as the SrcLoc
335 -- We use the equality to filter out duplicate field names
337 tyClDeclNames (TySynonym {tcdName = name, tcdLoc = loc}) = [(name,loc)]
338 tyClDeclNames (IfaceSig {tcdName = name, tcdLoc = loc}) = [(name,loc)]
339 tyClDeclNames (ForeignType {tcdName = name, tcdLoc = loc}) = [(name,loc)]
341 tyClDeclNames (ClassDecl {tcdName = cls_name, tcdSigs = sigs, tcdLoc = loc})
342 = (cls_name,loc) : [(n,loc) | ClassOpSig n _ _ loc <- sigs]
344 tyClDeclNames (TyData {tcdName = tc_name, tcdCons = cons, tcdLoc = loc})
345 = (tc_name,loc) : conDeclsNames cons
348 tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
349 tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs
350 tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
351 tyClDeclTyVars (ForeignType {}) = []
352 tyClDeclTyVars (IfaceSig {}) = []
355 --------------------------------
356 -- The "system names" are extra implicit names *bound* by the decl.
357 -- They are kept in a list rather than a tuple
358 -- to make the renamer easier.
360 type ClassSysNames name = [name]
361 -- For class decls they are:
362 -- [tycon, datacon wrapper, datacon worker,
363 -- superclass selector 1, ..., superclass selector n]
365 type DataSysNames name = [name]
366 -- For data decls they are
368 -- where from :: T -> Tring
371 tyClDeclSysNames :: TyClDecl name pat -> [(name, SrcLoc)]
372 -- Similar to tyClDeclNames, but returns the "implicit"
373 -- or "system" names of the declaration
375 tyClDeclSysNames (ClassDecl {tcdSysNames = names, tcdLoc = loc})
376 = [(n,loc) | n <- names]
377 tyClDeclSysNames (TyData {tcdCons = cons, tcdSysNames = names, tcdLoc = loc})
378 = [(n,loc) | n <- names] ++
379 [(wkr_name,loc) | ConDecl _ wkr_name _ _ _ loc <- cons]
380 tyClDeclSysNames decl = []
383 mkClassDeclSysNames :: (name, name, name, [name]) -> [name]
384 getClassDeclSysNames :: [name] -> (name, name, name, [name])
385 mkClassDeclSysNames (a,b,c,ds) = a:b:c:ds
386 getClassDeclSysNames (a:b:c:ds) = (a,b,c,ds)
390 instance (NamedThing name, Ord name) => Eq (TyClDecl name pat) where
391 -- Used only when building interface files
392 (==) d1@(IfaceSig {}) d2@(IfaceSig {})
393 = tcdName d1 == tcdName d2 &&
394 tcdType d1 == tcdType d2 &&
395 tcdIdInfo d1 == tcdIdInfo d2
397 (==) d1@(ForeignType {}) d2@(ForeignType {})
398 = tcdName d1 == tcdName d2 &&
399 tcdFoType d1 == tcdFoType d2
401 (==) d1@(TyData {}) d2@(TyData {})
402 = tcdName d1 == tcdName d2 &&
403 tcdND d1 == tcdND d2 &&
404 eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
405 eq_hsContext env (tcdCtxt d1) (tcdCtxt d2) &&
406 eqListBy (eq_ConDecl env) (tcdCons d1) (tcdCons d2)
409 (==) d1@(TySynonym {}) d2@(TySynonym {})
410 = tcdName d1 == tcdName d2 &&
411 eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
412 eq_hsType env (tcdSynRhs d1) (tcdSynRhs d2)
415 (==) d1@(ClassDecl {}) d2@(ClassDecl {})
416 = tcdName d1 == tcdName d2 &&
417 eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
418 eq_hsContext env (tcdCtxt d1) (tcdCtxt d2) &&
419 eqListBy (eq_hsFD env) (tcdFDs d1) (tcdFDs d2) &&
420 eqListBy (eq_cls_sig env) (tcdSigs d1) (tcdSigs d2)
423 (==) _ _ = False -- default case
425 eq_hsFD env (ns1,ms1) (ns2,ms2)
426 = eqListBy (eq_hsVar env) ns1 ns2 && eqListBy (eq_hsVar env) ms1 ms2
428 eq_cls_sig env (ClassOpSig n1 dm1 ty1 _) (ClassOpSig n2 dm2 ty2 _)
429 = n1==n2 && dm1 `eq_dm` dm2 && eq_hsType env ty1 ty2
431 -- Ignore the name of the default method for (DefMeth id)
432 -- This is used for comparing declarations before putting
433 -- them into interface files, and the name of the default
434 -- method isn't relevant
435 NoDefMeth `eq_dm` NoDefMeth = True
436 GenDefMeth `eq_dm` GenDefMeth = True
437 DefMeth _ `eq_dm` DefMeth _ = True
438 dm1 `eq_dm` dm2 = False
444 countTyClDecls :: [TyClDecl name pat] -> (Int, Int, Int, Int, Int)
445 -- class, data, newtype, synonym decls
447 = (count isClassDecl decls,
448 count isSynDecl decls,
449 count isIfaceSigDecl decls,
450 count isDataTy decls,
453 isDataTy TyData{tcdND=DataType} = True
456 isNewTy TyData{tcdND=NewType} = True
461 instance (NamedThing name, Outputable name, Outputable pat)
462 => Outputable (TyClDecl name pat) where
464 ppr (IfaceSig {tcdName = var, tcdType = ty, tcdIdInfo = info})
465 = getPprStyle $ \ sty ->
466 hsep [ if ifaceStyle sty then ppr var else ppr_var var,
467 dcolon, ppr ty, pprHsIdInfo info
470 ppr (ForeignType {tcdName = tycon})
471 = hsep [ptext SLIT("foreign import type dotnet"), ppr tycon]
473 ppr (TySynonym {tcdName = tycon, tcdTyVars = tyvars, tcdSynRhs = mono_ty})
474 = hang (ptext SLIT("type") <+> pp_decl_head [] tycon tyvars <+> equals)
477 ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdName = tycon,
478 tcdTyVars = tyvars, tcdCons = condecls, tcdNCons = ncons,
479 tcdDerivs = derivings})
480 = pp_tydecl (ptext keyword <+> pp_decl_head context tycon tyvars)
481 (pp_condecls condecls ncons)
484 keyword = case new_or_data of
485 NewType -> SLIT("newtype")
486 DataType -> SLIT("data")
488 ppr (ClassDecl {tcdCtxt = context, tcdName = clas, tcdTyVars = tyvars, tcdFDs = fds,
489 tcdSigs = sigs, tcdMeths = methods})
490 | null sigs -- No "where" part
493 | otherwise -- Laid out
494 = sep [hsep [top_matter, ptext SLIT("where {")],
495 nest 4 (sep [sep (map ppr_sig sigs), pp_methods, char '}'])]
497 top_matter = ptext SLIT("class") <+> pp_decl_head context clas tyvars <+> pprFundeps fds
498 ppr_sig sig = ppr sig <> semi
500 pp_methods = getPprStyle $ \ sty ->
501 if ifaceStyle sty || isNothing methods
503 else ppr (fromJust methods)
505 pp_decl_head :: Outputable name => HsContext name -> name -> [HsTyVarBndr name] -> SDoc
506 pp_decl_head context thing tyvars = hsep [pprHsContext context, ppr thing, interppSP tyvars]
508 pp_condecls [] ncons = ptext SLIT("{- abstract with") <+> int ncons <+> ptext SLIT("constructors -}")
509 pp_condecls (c:cs) ncons = equals <+> sep (ppr c : map (\ c -> ptext SLIT("|") <+> ppr c) cs)
511 pp_tydecl pp_head pp_decl_rhs derivings
512 = hang pp_head 4 (sep [
516 Just ds -> hsep [ptext SLIT("deriving"), ppr_hs_context ds]
521 %************************************************************************
523 \subsection[ConDecl]{A data-constructor declaration}
525 %************************************************************************
529 = ConDecl name -- Constructor name; this is used for the
530 -- DataCon itself, and for the user-callable wrapper Id
532 name -- Name of the constructor's 'worker Id'
533 -- Filled in as the ConDecl is built
535 [HsTyVarBndr name] -- Existentially quantified type variables
536 (HsContext name) -- ...and context
537 -- If both are empty then there are no existentials
543 = VanillaCon -- prefix-style con decl
546 | InfixCon -- infix-style con decl
550 | RecCon -- record-style con decl
551 [([name], BangType name)] -- list of "fields"
555 conDeclsNames :: Eq name => [ConDecl name] -> [(name,SrcLoc)]
556 -- See tyClDeclNames for what this does
557 -- The function is boringly complicated because of the records
558 -- And since we only have equality, we have to be a little careful
560 = snd (foldl do_one ([], []) cons)
562 do_one (flds_seen, acc) (ConDecl name _ _ _ details loc)
563 = do_details ((name,loc):acc) details
565 do_details acc (RecCon flds) = foldl do_fld (flds_seen, acc) flds
566 do_details acc other = (flds_seen, acc)
568 do_fld acc (flds, _) = foldl do_fld1 acc flds
570 do_fld1 (flds_seen, acc) fld
571 | fld `elem` flds_seen = (flds_seen,acc)
572 | otherwise = (fld:flds_seen, (fld,loc):acc)
576 conDetailsTys :: ConDetails name -> [HsType name]
577 conDetailsTys (VanillaCon btys) = map getBangType btys
578 conDetailsTys (InfixCon bty1 bty2) = [getBangType bty1, getBangType bty2]
579 conDetailsTys (RecCon fields) = [getBangType bty | (_, bty) <- fields]
582 eq_ConDecl env (ConDecl n1 _ tvs1 cxt1 cds1 _)
583 (ConDecl n2 _ tvs2 cxt2 cds2 _)
585 (eq_hsTyVars env tvs1 tvs2 $ \ env ->
586 eq_hsContext env cxt1 cxt2 &&
587 eq_ConDetails env cds1 cds2)
589 eq_ConDetails env (VanillaCon bts1) (VanillaCon bts2)
590 = eqListBy (eq_btype env) bts1 bts2
591 eq_ConDetails env (InfixCon bta1 btb1) (InfixCon bta2 btb2)
592 = eq_btype env bta1 bta2 && eq_btype env btb1 btb2
593 eq_ConDetails env (RecCon fs1) (RecCon fs2)
594 = eqListBy (eq_fld env) fs1 fs2
595 eq_ConDetails env _ _ = False
597 eq_fld env (ns1,bt1) (ns2, bt2) = ns1==ns2 && eq_btype env bt1 bt2
601 data BangType name = BangType StrictnessMark (HsType name)
603 getBangType (BangType _ ty) = ty
604 getBangStrictness (BangType s _) = s
606 unbangedType ty = BangType NotMarkedStrict ty
608 eq_btype env (BangType s1 t1) (BangType s2 t2) = s1==s2 && eq_hsType env t1 t2
612 instance (Outputable name) => Outputable (ConDecl name) where
613 ppr (ConDecl con _ tvs cxt con_details loc)
614 = sep [pprHsForAll tvs cxt, ppr_con_details con con_details]
616 ppr_con_details con (InfixCon ty1 ty2)
617 = hsep [ppr_bang ty1, ppr con, ppr_bang ty2]
619 -- ConDecls generated by MkIface.ifaceTyThing always have a VanillaCon, even
620 -- if the constructor is an infix one. This is because in an interface file
621 -- we don't distinguish between the two. Hence when printing these for the
622 -- user, we need to parenthesise infix constructor names.
623 ppr_con_details con (VanillaCon tys)
624 = getPprStyle $ \ sty ->
625 hsep ((if ifaceStyle sty then ppr con else ppr_var con)
626 : map (ppr_bang) tys)
628 ppr_con_details con (RecCon fields)
629 = ppr con <+> braces (sep (punctuate comma (map ppr_field fields)))
631 ppr_field (ns, ty) = hsep (map (ppr) ns) <+>
635 instance Outputable name => Outputable (BangType name) where
638 ppr_bang (BangType s ty) = ppr s <> pprParendHsType ty
642 %************************************************************************
644 \subsection[InstDecl]{An instance declaration
646 %************************************************************************
649 data InstDecl name pat
650 = InstDecl (HsType name) -- Context => Class Instance-type
651 -- Using a polytype means that the renamer conveniently
652 -- figures out the quantified type variables for us.
656 [Sig name] -- User-supplied pragmatic info
658 (Maybe name) -- Name for the dictionary function
659 -- Nothing for source-file instance decls
663 isSourceInstDecl :: InstDecl name pat -> Bool
664 isSourceInstDecl (InstDecl _ _ _ maybe_dfun _) = isNothing maybe_dfun
668 instance (Outputable name, Outputable pat)
669 => Outputable (InstDecl name pat) where
671 ppr (InstDecl inst_ty binds uprags maybe_dfun_name src_loc)
672 = getPprStyle $ \ sty ->
673 if ifaceStyle sty then
674 hsep [ptext SLIT("instance"), ppr inst_ty, equals, pp_dfun]
676 vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
680 pp_dfun = case maybe_dfun_name of
686 instance Ord name => Eq (InstDecl name pat) where
687 -- Used for interface comparison only, so don't compare bindings
688 (==) (InstDecl inst_ty1 _ _ dfun1 _) (InstDecl inst_ty2 _ _ dfun2 _)
689 = inst_ty1 == inst_ty2 && dfun1 == dfun2
693 %************************************************************************
695 \subsection[DefaultDecl]{A @default@ declaration}
697 %************************************************************************
699 There can only be one default declaration per module, but it is hard
700 for the parser to check that; we pass them all through in the abstract
701 syntax, and that restriction must be checked in the front end.
704 data DefaultDecl name
705 = DefaultDecl [HsType name]
708 instance (Outputable name)
709 => Outputable (DefaultDecl name) where
711 ppr (DefaultDecl tys src_loc)
712 = ptext SLIT("default") <+> parens (interpp'SP tys)
715 %************************************************************************
717 \subsection{Foreign function interface declaration}
719 %************************************************************************
722 data ForeignDecl name
723 = ForeignImport name (HsType name) FoImport SrcLoc
724 | ForeignExport name (HsType name) FoExport SrcLoc
726 forDeclName (ForeignImport n _ _ _) = n
727 forDeclName (ForeignExport n _ _ _) = n
730 = LblImport CLabelString -- foreign label
731 | CImport CCallSpec -- foreign import
732 | CDynImport CCallConv -- foreign export dynamic
733 | DNImport DNCallSpec -- foreign import dotnet
735 data FoExport = CExport CExportSpec
737 data FoType = DNType -- In due course we'll add subtype stuff
738 deriving( Eq ) -- Used for equality instance for TyClDecl
740 instance Outputable name => Outputable (ForeignDecl name) where
741 ppr (ForeignImport nm ty (LblImport lbl) src_loc)
742 = ptext SLIT("foreign label") <+> ppr lbl <+> ppr nm <+> dcolon <+> ppr ty
743 ppr (ForeignImport nm ty decl src_loc)
744 = ptext SLIT("foreign import") <+> ppr decl <+> ppr nm <+> dcolon <+> ppr ty
745 ppr (ForeignExport nm ty decl src_loc)
746 = ptext SLIT("foreign export") <+> ppr decl <+> ppr nm <+> dcolon <+> ppr ty
748 instance Outputable FoImport where
749 ppr (CImport d) = ppr d
750 ppr (CDynImport conv) = text "dynamic" <+> ppr conv
751 ppr (DNImport d) = ptext SLIT("dotnet") <+> ppr d
752 ppr (LblImport l) = ptext SLIT("label") <+> ppr l
754 instance Outputable FoExport where
755 ppr (CExport d) = ppr d
757 instance Outputable FoType where
758 ppr DNType = ptext SLIT("type dotnet")
762 %************************************************************************
764 \subsection{Transformation rules}
766 %************************************************************************
769 data RuleDecl name pat
770 = HsRule -- Source rule
771 RuleName -- Rule name
773 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
774 (HsExpr name pat) -- LHS
775 (HsExpr name pat) -- RHS
778 | IfaceRule -- One that's come in from an interface file; pre-typecheck
781 [UfBinder name] -- Tyvars and term vars
783 [UfExpr name] -- Args of LHS
784 (UfExpr name) -- Pre typecheck
787 | IfaceRuleOut -- Post typecheck
791 ifaceRuleDeclName :: RuleDecl name pat -> name
792 ifaceRuleDeclName (IfaceRule _ _ _ n _ _ _) = n
793 ifaceRuleDeclName (IfaceRuleOut n r) = n
794 ifaceRuleDeclName (HsRule fs _ _ _ _ _) = pprPanic "ifaceRuleDeclName" (ppr fs)
798 | RuleBndrSig name (HsType name)
800 collectRuleBndrSigTys :: [RuleBndr name] -> [HsType name]
801 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
803 instance (NamedThing name, Ord name) => Eq (RuleDecl name pat) where
804 -- Works for IfaceRules only; used when comparing interface file versions
805 (IfaceRule n1 a1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 a2 bs2 f2 es2 rhs2 _)
806 = n1==n2 && f1 == f2 && a1==a2 &&
807 eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
808 eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
810 instance (NamedThing name, Outputable name, Outputable pat)
811 => Outputable (RuleDecl name pat) where
812 ppr (HsRule name act ns lhs rhs loc)
813 = sep [text "{-# RULES" <+> doubleQuotes (ptext name) <+> ppr act,
814 pp_forall, ppr lhs, equals <+> ppr rhs,
817 pp_forall | null ns = empty
818 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
820 ppr (IfaceRule name act tpl_vars fn tpl_args rhs loc)
821 = hsep [ doubleQuotes (ptext name), ppr act,
822 ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
823 ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
824 ptext SLIT("=") <+> ppr rhs
827 ppr (IfaceRuleOut fn rule) = pprCoreRule (ppr fn) rule
829 instance Outputable name => Outputable (RuleBndr name) where
830 ppr (RuleBndr name) = ppr name
831 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
835 %************************************************************************
837 \subsection[DeprecDecl]{Deprecations}
839 %************************************************************************
841 We use exported entities for things to deprecate.
844 data DeprecDecl name = Deprecation name DeprecTxt SrcLoc
846 type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
848 instance Outputable name => Outputable (DeprecDecl name) where
849 ppr (Deprecation thing txt _)
850 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]