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 Class ( FunDep, DefMeth(..) )
46 import CStrings ( CLabelString )
48 import Util ( eqListBy, count )
49 import SrcLoc ( SrcLoc )
52 import Maybe ( isNothing, fromJust )
56 %************************************************************************
58 \subsection[HsDecl]{Declarations}
60 %************************************************************************
64 = TyClD (TyClDecl name pat)
65 | InstD (InstDecl name pat)
66 | DefD (DefaultDecl name)
67 | ValD (HsBinds name pat)
68 | ForD (ForeignDecl name)
69 | FixD (FixitySig name)
70 | DeprecD (DeprecDecl name)
71 | RuleD (RuleDecl name pat)
73 -- NB: all top-level fixity decls are contained EITHER
75 -- OR in the ClassDecls in TyClDs
78 -- a) data constructors
79 -- b) class methods (but they can be also done in the
80 -- signatures of class decls)
81 -- c) imported functions (that have an IfacSig)
84 -- The latter is for class methods only
89 hsDeclName :: (NamedThing name, Outputable name, Outputable pat)
90 => HsDecl name pat -> name
92 hsDeclName (TyClD decl) = tyClDeclName decl
93 hsDeclName (InstD decl) = instDeclName decl
94 hsDeclName (ForD decl) = foreignDeclName decl
95 hsDeclName (FixD (FixitySig name _ _)) = name
96 -- Others don't make sense
98 hsDeclName x = pprPanic "HsDecls.hsDeclName" (ppr x)
102 instDeclName :: InstDecl name pat -> name
103 instDeclName (InstDecl _ _ _ (Just name) _) = name
108 instance (NamedThing name, Outputable name, Outputable pat)
109 => Outputable (HsDecl name pat) where
111 ppr (TyClD dcl) = ppr dcl
112 ppr (ValD binds) = ppr binds
113 ppr (DefD def) = ppr def
114 ppr (InstD inst) = ppr inst
115 ppr (ForD fd) = ppr fd
116 ppr (FixD fd) = ppr fd
117 ppr (RuleD rd) = ppr rd
118 ppr (DeprecD dd) = ppr dd
122 %************************************************************************
124 \subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
126 %************************************************************************
128 --------------------------------
130 --------------------------------
132 Here is the story about the implicit names that go with type, class, and instance
133 decls. It's a bit tricky, so pay attention!
135 "Implicit" (or "system") binders
136 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
137 Each data type decl defines
138 a worker name for each constructor
139 to-T and from-T convertors
140 Each class decl defines
141 a tycon for the class
142 a data constructor for that tycon
143 the worker for that constructor
144 a selector for each superclass
146 All have occurrence names that are derived uniquely from their parent declaration.
148 None of these get separate definitions in an interface file; they are
149 fully defined by the data or class decl. But they may *occur* in
150 interface files, of course. Any such occurrence must haul in the
151 relevant type or class decl.
154 - Make up their occurrence names immediately
155 This is done in RdrHsSyn.mkClassDecl, mkTyDecl, mkConDecl
157 - Ensure they "point to" the parent data/class decl
158 when loading that decl from an interface file
159 (See RnHiFiles.getTyClDeclSysNames)
161 - When renaming the decl look them up in the name cache,
162 ensure correct module and provenance is set
166 - Occurrence name is derived uniquely from the method name
169 - If there is a default method name at all, it's recorded in
170 the ClassOpSig (in HsBinds), in the DefMeth field.
171 (DefMeth is defined in Class.lhs)
173 Source-code class decls and interface-code class decls are treated subtly
174 differently, which has given me a great deal of confusion over the years.
175 Here's the deal. (We distinguish the two cases because source-code decls
176 have (Just binds) in the tcdMeths field, whereas interface decls have Nothing.
178 In *source-code* class declarations:
179 - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName
180 This is done by RdrHsSyn.mkClassOpSigDM
182 - The renamer renames it to a Name
184 - During typechecking, we generate a binding for each $dm for
185 which there's a programmer-supplied default method:
190 We generate a binding for $dmop1 but not for $dmop2.
191 The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1.
192 The Name for $dmop2 is simply discarded.
194 In *interface-file* class declarations:
195 - When parsing, we see if there's an explicit programmer-supplied default method
196 because there's an '=' sign to indicate it:
198 op1 = :: <type> -- NB the '='
200 We use this info to generate a DefMeth with a suitable RdrName for op1,
201 and a NoDefMeth for op2
202 - The interface file has a separate definition for $dmop1, with unfolding etc.
203 - The renamer renames it to a Name.
204 - The renamer treats $dmop1 as a free variable of the declaration, so that
205 the binding for $dmop1 will be sucked in. (See RnHsSyn.tyClDeclFVs)
206 This doesn't happen for source code class decls, because they *bind* the default method.
210 Each instance declaration gives rise to one dictionary function binding.
212 The type checker makes up new source-code instance declarations
213 (e.g. from 'deriving' or generic default methods --- see
214 TcInstDcls.tcInstDecls1). So we can't generate the names for
215 dictionary functions in advance (we don't know how many we need).
217 On the other hand for interface-file instance declarations, the decl
218 specifies the name of the dictionary function, and it has a binding elsewhere
219 in the interface file:
220 instance {Eq Int} = dEqInt
221 dEqInt :: {Eq Int} <pragma info>
223 So again we treat source code and interface file code slightly differently.
226 - Source code instance decls have a Nothing in the (Maybe name) field
227 (see data InstDecl below)
229 - The typechecker makes up a Local name for the dict fun for any source-code
230 instance decl, whether it comes from a source-code instance decl, or whether
231 the instance decl is derived from some other construct (e.g. 'deriving').
233 - The occurrence name it chooses is derived from the instance decl (just for
234 documentation really) --- e.g. dNumInt. Two dict funs may share a common
235 occurrence name, but will have different uniques. E.g.
236 instance Foo [Int] where ...
237 instance Foo [Bool] where ...
238 These might both be dFooList
240 - The CoreTidy phase globalises the name, and ensures the occurrence name is
241 unique (this isn't special to dict funs). So we'd get dFooList and dFooList1.
243 - We can take this relaxed approach (changing the occurrence name later)
244 because dict fun Ids are not captured in a TyCon or Class (unlike default
245 methods, say). Instead, they are kept separately in the InstEnv. This
246 makes it easy to adjust them after compiling a module. (Once we've finished
247 compiling that module, they don't change any more.)
251 - The instance decl gives the dict fun name, so the InstDecl has a (Just name)
252 in the (Maybe name) field.
254 - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
255 suck in the dfun binding
259 -- TyClDecls are precisely the kind of declarations that can
260 -- appear in interface files; or (internally) in GHC's interface
261 -- for a module. That's why (despite the misnomer) IfaceSig and ForeignType
262 -- are both in TyClDecl
264 data TyClDecl name pat
265 = IfaceSig { tcdName :: name, -- It may seem odd to classify an interface-file signature
266 tcdType :: HsType name, -- as a 'TyClDecl', but it's very convenient.
267 tcdIdInfo :: [HsIdInfo name],
271 | ForeignType { tcdName :: name, -- See remarks about IfaceSig above
272 tcdExtName :: Maybe FastString,
276 | TyData { tcdND :: NewOrData,
277 tcdCtxt :: HsContext name, -- context
278 tcdName :: name, -- type constructor
279 tcdTyVars :: [HsTyVarBndr name], -- type variables
280 tcdCons :: [ConDecl name], -- data constructors (empty if abstract)
281 tcdNCons :: Int, -- Number of data constructors (valid even if type is 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 = 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 eqListBy (eq_ConDecl 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_hsFD env (ns1,ms1) (ns2,ms2)
428 = eqListBy (eq_hsVar env) ns1 ns2 && eqListBy (eq_hsVar env) ms1 ms2
430 eq_cls_sig env (ClassOpSig n1 dm1 ty1 _) (ClassOpSig n2 dm2 ty2 _)
431 = n1==n2 && dm1 `eq_dm` dm2 && eq_hsType env ty1 ty2
433 -- Ignore the name of the default method for (DefMeth id)
434 -- This is used for comparing declarations before putting
435 -- them into interface files, and the name of the default
436 -- method isn't relevant
437 NoDefMeth `eq_dm` NoDefMeth = True
438 GenDefMeth `eq_dm` GenDefMeth = True
439 DefMeth _ `eq_dm` DefMeth _ = True
440 dm1 `eq_dm` dm2 = False
446 countTyClDecls :: [TyClDecl name pat] -> (Int, Int, Int, Int, Int)
447 -- class, data, newtype, synonym decls
449 = (count isClassDecl decls,
450 count isSynDecl decls,
451 count isIfaceSigDecl decls,
452 count isDataTy decls,
455 isDataTy TyData{tcdND=DataType} = True
458 isNewTy TyData{tcdND=NewType} = True
463 instance (NamedThing name, Outputable name, Outputable pat)
464 => Outputable (TyClDecl name pat) where
466 ppr (IfaceSig {tcdName = var, tcdType = ty, tcdIdInfo = info})
467 = getPprStyle $ \ sty ->
468 hsep [ if ifaceStyle sty then ppr var else ppr_var var,
469 dcolon, ppr ty, pprHsIdInfo info
472 ppr (ForeignType {tcdName = tycon})
473 = hsep [ptext SLIT("foreign import type dotnet"), ppr tycon]
475 ppr (TySynonym {tcdName = tycon, tcdTyVars = tyvars, tcdSynRhs = mono_ty})
476 = hang (ptext SLIT("type") <+> pp_decl_head [] tycon tyvars <+> equals)
479 ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdName = tycon,
480 tcdTyVars = tyvars, tcdCons = condecls, tcdNCons = ncons,
481 tcdDerivs = derivings})
482 = pp_tydecl (ptext keyword <+> pp_decl_head context tycon tyvars)
483 (pp_condecls condecls ncons)
486 keyword = case new_or_data of
487 NewType -> SLIT("newtype")
488 DataType -> SLIT("data")
490 ppr (ClassDecl {tcdCtxt = context, tcdName = clas, tcdTyVars = tyvars, tcdFDs = fds,
491 tcdSigs = sigs, tcdMeths = methods})
492 | null sigs -- No "where" part
495 | otherwise -- Laid out
496 = sep [hsep [top_matter, ptext SLIT("where {")],
497 nest 4 (sep [sep (map ppr_sig sigs), pp_methods, char '}'])]
499 top_matter = ptext SLIT("class") <+> pp_decl_head context clas tyvars <+> pprFundeps fds
500 ppr_sig sig = ppr sig <> semi
502 pp_methods = getPprStyle $ \ sty ->
503 if ifaceStyle sty || isNothing methods
505 else ppr (fromJust methods)
507 pp_decl_head :: Outputable name => HsContext name -> name -> [HsTyVarBndr name] -> SDoc
508 pp_decl_head context thing tyvars = hsep [pprHsContext context, ppr thing, interppSP tyvars]
510 pp_condecls [] ncons = ptext SLIT("{- abstract with") <+> int ncons <+> ptext SLIT("constructors -}")
511 pp_condecls (c:cs) ncons = equals <+> sep (ppr c : map (\ c -> ptext SLIT("|") <+> ppr c) cs)
513 pp_tydecl pp_head pp_decl_rhs derivings
514 = hang pp_head 4 (sep [
518 Just ds -> hsep [ptext SLIT("deriving"), ppr_hs_context ds]
523 %************************************************************************
525 \subsection[ConDecl]{A data-constructor declaration}
527 %************************************************************************
531 = ConDecl name -- Constructor name; this is used for the
532 -- DataCon itself, and for the user-callable wrapper Id
534 name -- Name of the constructor's 'worker Id'
535 -- Filled in as the ConDecl is built
537 [HsTyVarBndr name] -- Existentially quantified type variables
538 (HsContext name) -- ...and context
539 -- If both are empty then there are no existentials
545 = VanillaCon -- prefix-style con decl
548 | InfixCon -- infix-style con decl
552 | RecCon -- record-style con decl
553 [([name], BangType name)] -- list of "fields"
557 conDeclsNames :: Eq name => [ConDecl name] -> [(name,SrcLoc)]
558 -- See tyClDeclNames for what this does
559 -- The function is boringly complicated because of the records
560 -- And since we only have equality, we have to be a little careful
562 = snd (foldl do_one ([], []) cons)
564 do_one (flds_seen, acc) (ConDecl name _ _ _ details loc)
565 = do_details ((name,loc):acc) details
567 do_details acc (RecCon flds) = foldl do_fld (flds_seen, acc) flds
568 do_details acc other = (flds_seen, acc)
570 do_fld acc (flds, _) = foldl do_fld1 acc flds
572 do_fld1 (flds_seen, acc) fld
573 | fld `elem` flds_seen = (flds_seen,acc)
574 | otherwise = (fld:flds_seen, (fld,loc):acc)
578 conDetailsTys :: ConDetails name -> [HsType name]
579 conDetailsTys (VanillaCon btys) = map getBangType btys
580 conDetailsTys (InfixCon bty1 bty2) = [getBangType bty1, getBangType bty2]
581 conDetailsTys (RecCon fields) = [getBangType bty | (_, bty) <- fields]
584 eq_ConDecl env (ConDecl n1 _ tvs1 cxt1 cds1 _)
585 (ConDecl n2 _ tvs2 cxt2 cds2 _)
587 (eq_hsTyVars env tvs1 tvs2 $ \ env ->
588 eq_hsContext env cxt1 cxt2 &&
589 eq_ConDetails env cds1 cds2)
591 eq_ConDetails env (VanillaCon bts1) (VanillaCon bts2)
592 = eqListBy (eq_btype env) bts1 bts2
593 eq_ConDetails env (InfixCon bta1 btb1) (InfixCon bta2 btb2)
594 = eq_btype env bta1 bta2 && eq_btype env btb1 btb2
595 eq_ConDetails env (RecCon fs1) (RecCon fs2)
596 = eqListBy (eq_fld env) fs1 fs2
597 eq_ConDetails env _ _ = False
599 eq_fld env (ns1,bt1) (ns2, bt2) = ns1==ns2 && eq_btype env bt1 bt2
603 data BangType name = BangType StrictnessMark (HsType name)
605 getBangType (BangType _ ty) = ty
606 getBangStrictness (BangType s _) = s
608 unbangedType ty = BangType NotMarkedStrict ty
610 eq_btype env (BangType s1 t1) (BangType s2 t2) = s1==s2 && eq_hsType env t1 t2
614 instance (Outputable name) => Outputable (ConDecl name) where
615 ppr (ConDecl con _ tvs cxt con_details loc)
616 = sep [pprHsForAll tvs cxt, ppr_con_details con con_details]
618 ppr_con_details con (InfixCon ty1 ty2)
619 = hsep [ppr_bang ty1, ppr con, ppr_bang ty2]
621 -- ConDecls generated by MkIface.ifaceTyThing always have a VanillaCon, even
622 -- if the constructor is an infix one. This is because in an interface file
623 -- we don't distinguish between the two. Hence when printing these for the
624 -- user, we need to parenthesise infix constructor names.
625 ppr_con_details con (VanillaCon tys)
626 = getPprStyle $ \ sty ->
627 hsep ((if ifaceStyle sty then ppr con else ppr_var con)
628 : map (ppr_bang) tys)
630 ppr_con_details con (RecCon fields)
631 = ppr con <+> braces (sep (punctuate comma (map ppr_field fields)))
633 ppr_field (ns, ty) = hsep (map (ppr) ns) <+>
637 instance Outputable name => Outputable (BangType name) where
640 ppr_bang (BangType s ty) = ppr s <> pprParendHsType ty
644 %************************************************************************
646 \subsection[InstDecl]{An instance declaration
648 %************************************************************************
651 data InstDecl name pat
652 = InstDecl (HsType name) -- Context => Class Instance-type
653 -- Using a polytype means that the renamer conveniently
654 -- figures out the quantified type variables for us.
658 [Sig name] -- User-supplied pragmatic info
660 (Maybe name) -- Name for the dictionary function
661 -- Nothing for source-file instance decls
665 isSourceInstDecl :: InstDecl name pat -> Bool
666 isSourceInstDecl (InstDecl _ _ _ maybe_dfun _) = isNothing maybe_dfun
670 instance (Outputable name, Outputable pat)
671 => Outputable (InstDecl name pat) where
673 ppr (InstDecl inst_ty binds uprags maybe_dfun_name src_loc)
674 = getPprStyle $ \ sty ->
675 if ifaceStyle sty then
676 hsep [ptext SLIT("instance"), ppr inst_ty, equals, pp_dfun]
678 vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
682 pp_dfun = case maybe_dfun_name of
688 instance Ord name => Eq (InstDecl name pat) where
689 -- Used for interface comparison only, so don't compare bindings
690 (==) (InstDecl inst_ty1 _ _ dfun1 _) (InstDecl inst_ty2 _ _ dfun2 _)
691 = inst_ty1 == inst_ty2 && dfun1 == dfun2
695 %************************************************************************
697 \subsection[DefaultDecl]{A @default@ declaration}
699 %************************************************************************
701 There can only be one default declaration per module, but it is hard
702 for the parser to check that; we pass them all through in the abstract
703 syntax, and that restriction must be checked in the front end.
706 data DefaultDecl name
707 = DefaultDecl [HsType name]
710 instance (Outputable name)
711 => Outputable (DefaultDecl name) where
713 ppr (DefaultDecl tys src_loc)
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 data ForeignDecl name
732 = ForeignImport name (HsType name) ForeignImport Bool SrcLoc -- defines name
733 | ForeignExport name (HsType name) ForeignExport Bool SrcLoc -- uses name
735 -- yield the Haskell name defined or used in a foreign declaration
737 foreignDeclName :: ForeignDecl name -> name
738 foreignDeclName (ForeignImport n _ _ _ _) = n
739 foreignDeclName (ForeignExport n _ _ _ _) = n
741 -- specification of an imported external entity in dependence on the calling
744 data ForeignImport = -- import of a C entity
746 -- * the two strings specifying a header file or library
747 -- may be empty, which indicates the absence of a
748 -- header or object specification (both are not used
749 -- in the case of `CWrapper' and when `CFunction'
750 -- has a dynamic target)
752 -- * the calling convention is irrelevant for code
753 -- generation in the case of `CLabel', but is needed
754 -- for pretty printing
756 -- * `Safety' is irrelevant for `CLabel' and `CWrapper'
758 CImport CCallConv -- ccall or stdcall
759 Safety -- safe or unsafe
760 FastString -- name of C header
761 FastString -- name of library object
762 CImportSpec -- details of the C entity
764 -- import of a .NET function
766 | DNImport DNCallSpec
768 -- details of an external C entity
770 data CImportSpec = CLabel CLabelString -- import address of a C label
771 | CFunction CCallTarget -- static or dynamic function
772 | CWrapper -- wrapper to expose closures
775 -- specification of an externally exported entity in dependence on the calling
778 data ForeignExport = CExport CExportSpec -- contains the calling convention
779 | DNExport -- presently unused
781 -- abstract type imported from .NET
783 data FoType = DNType -- In due course we'll add subtype stuff
784 deriving (Eq) -- Used for equality instance for TyClDecl
787 -- pretty printing of foreign declarations
790 instance Outputable name => Outputable (ForeignDecl name) where
791 ppr (ForeignImport n ty fimport _ _) =
792 ptext SLIT("foreign import") <+> ppr fimport <+>
793 ppr n <+> dcolon <+> ppr ty
794 ppr (ForeignExport n ty fexport _ _) =
795 ptext SLIT("foreign export") <+> ppr fexport <+>
796 ppr n <+> dcolon <+> ppr ty
798 instance Outputable ForeignImport where
799 ppr (DNImport spec) =
800 ptext SLIT("dotnet") <+> ppr spec
801 ppr (CImport cconv safety header lib spec) =
802 ppr cconv <+> ppr safety <+>
803 char '"' <> pprCEntity header lib spec <> char '"'
805 pprCEntity header lib (CLabel lbl) =
806 ptext SLIT("static") <+> ptext header <+> char '&' <>
807 pprLib lib <> ppr lbl
808 pprCEntity header lib (CFunction (StaticTarget lbl)) =
809 ptext SLIT("static") <+> ptext header <+> char '&' <>
810 pprLib lib <> ppr lbl
811 pprCEntity header lib (CFunction (DynamicTarget)) =
812 ptext SLIT("dynamic")
813 pprCEntity header lib (CFunction (CasmTarget _)) =
814 panic "HsDecls.pprCEntity: malformed C function target"
815 pprCEntity _ _ (CWrapper) = ptext SLIT("wrapper")
817 pprLib lib | nullFastString lib = empty
818 | otherwise = char '[' <> ppr lib <> char ']'
820 instance Outputable ForeignExport where
821 ppr (CExport (CExportStatic lbl cconv)) =
822 ppr cconv <+> char '"' <> ppr lbl <> char '"'
824 ptext SLIT("dotnet") <+> ptext SLIT("\"<unused>\"")
826 instance Outputable FoType where
827 ppr DNType = ptext SLIT("type dotnet")
831 %************************************************************************
833 \subsection{Transformation rules}
835 %************************************************************************
838 data RuleDecl name pat
839 = HsRule -- Source rule
840 RuleName -- Rule name
842 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
843 (HsExpr name pat) -- LHS
844 (HsExpr name pat) -- RHS
847 | IfaceRule -- One that's come in from an interface file; pre-typecheck
850 [UfBinder name] -- Tyvars and term vars
852 [UfExpr name] -- Args of LHS
853 (UfExpr name) -- Pre typecheck
856 | IfaceRuleOut -- Post typecheck
860 ifaceRuleDeclName :: RuleDecl name pat -> name
861 ifaceRuleDeclName (IfaceRule _ _ _ n _ _ _) = n
862 ifaceRuleDeclName (IfaceRuleOut n r) = n
863 ifaceRuleDeclName (HsRule fs _ _ _ _ _) = pprPanic "ifaceRuleDeclName" (ppr fs)
867 | RuleBndrSig name (HsType name)
869 collectRuleBndrSigTys :: [RuleBndr name] -> [HsType name]
870 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
872 instance (NamedThing name, Ord name) => Eq (RuleDecl name pat) where
873 -- Works for IfaceRules only; used when comparing interface file versions
874 (IfaceRule n1 a1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 a2 bs2 f2 es2 rhs2 _)
875 = n1==n2 && f1 == f2 && a1==a2 &&
876 eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
877 eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
879 instance (NamedThing name, Outputable name, Outputable pat)
880 => Outputable (RuleDecl name pat) where
881 ppr (HsRule name act ns lhs rhs loc)
882 = sep [text "{-# RULES" <+> doubleQuotes (ptext name) <+> ppr act,
883 pp_forall, ppr lhs, equals <+> ppr rhs,
886 pp_forall | null ns = empty
887 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
889 ppr (IfaceRule name act tpl_vars fn tpl_args rhs loc)
890 = hsep [ doubleQuotes (ptext name), ppr act,
891 ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
892 ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
893 ptext SLIT("=") <+> ppr rhs
896 ppr (IfaceRuleOut fn rule) = pprCoreRule (ppr fn) rule
898 instance Outputable name => Outputable (RuleBndr name) where
899 ppr (RuleBndr name) = ppr name
900 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
904 %************************************************************************
906 \subsection[DeprecDecl]{Deprecations}
908 %************************************************************************
910 We use exported entities for things to deprecate.
913 data DeprecDecl name = Deprecation name DeprecTxt SrcLoc
915 type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
917 instance Outputable name => Outputable (DeprecDecl name) where
918 ppr (Deprecation thing txt _)
919 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]