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, isIfaceRuleDecl, 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 [name], -- derivings; Nothing => not specified
281 -- (i.e., derive default); Just [] => derive
282 -- *nothing*; Just <list> => as you would
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"), parens (interpp'SP 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
667 instance (Outputable name, Outputable pat)
668 => Outputable (InstDecl name pat) where
670 ppr (InstDecl inst_ty binds uprags maybe_dfun_name src_loc)
671 = getPprStyle $ \ sty ->
672 if ifaceStyle sty then
673 hsep [ptext SLIT("instance"), ppr inst_ty, equals, pp_dfun]
675 vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
679 pp_dfun = case maybe_dfun_name of
685 instance Ord name => Eq (InstDecl name pat) where
686 -- Used for interface comparison only, so don't compare bindings
687 (==) (InstDecl inst_ty1 _ _ dfun1 _) (InstDecl inst_ty2 _ _ dfun2 _)
688 = inst_ty1 == inst_ty2 && dfun1 == dfun2
692 %************************************************************************
694 \subsection[DefaultDecl]{A @default@ declaration}
696 %************************************************************************
698 There can only be one default declaration per module, but it is hard
699 for the parser to check that; we pass them all through in the abstract
700 syntax, and that restriction must be checked in the front end.
703 data DefaultDecl name
704 = DefaultDecl [HsType name]
707 instance (Outputable name)
708 => Outputable (DefaultDecl name) where
710 ppr (DefaultDecl tys src_loc)
711 = ptext SLIT("default") <+> parens (interpp'SP tys)
714 %************************************************************************
716 \subsection{Foreign function interface declaration}
718 %************************************************************************
721 data ForeignDecl name
722 = ForeignImport name (HsType name) FoImport SrcLoc
723 | ForeignExport name (HsType name) FoExport SrcLoc
725 forDeclName (ForeignImport n _ _ _) = n
726 forDeclName (ForeignExport n _ _ _) = n
729 = LblImport CLabelString -- foreign label
730 | CImport CCallSpec -- foreign import
731 | CDynImport CCallConv -- foreign export dynamic
732 | DNImport DNCallSpec -- foreign import dotnet
734 data FoExport = CExport CExportSpec
736 data FoType = DNType -- In due course we'll add subtype stuff
737 deriving( Eq ) -- Used for equality instance for TyClDecl
739 instance Outputable name => Outputable (ForeignDecl name) where
740 ppr (ForeignImport nm ty (LblImport lbl) src_loc)
741 = ptext SLIT("foreign label") <+> ppr lbl <+> ppr nm <+> dcolon <+> ppr ty
742 ppr (ForeignImport nm ty decl src_loc)
743 = ptext SLIT("foreign import") <+> ppr decl <+> ppr nm <+> dcolon <+> ppr ty
744 ppr (ForeignExport nm ty decl src_loc)
745 = ptext SLIT("foreign export") <+> ppr decl <+> ppr nm <+> dcolon <+> ppr ty
747 instance Outputable FoImport where
748 ppr (CImport d) = ppr d
749 ppr (CDynImport conv) = text "dynamic" <+> ppr conv
750 ppr (DNImport d) = ptext SLIT("dotnet") <+> ppr d
751 ppr (LblImport l) = ptext SLIT("label") <+> ppr l
753 instance Outputable FoExport where
754 ppr (CExport d) = ppr d
756 instance Outputable FoType where
757 ppr DNType = ptext SLIT("type dotnet")
761 %************************************************************************
763 \subsection{Transformation rules}
765 %************************************************************************
768 data RuleDecl name pat
769 = HsRule -- Source rule
770 RuleName -- Rule name
772 [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars
773 (HsExpr name pat) -- LHS
774 (HsExpr name pat) -- RHS
777 | IfaceRule -- One that's come in from an interface file; pre-typecheck
780 [UfBinder name] -- Tyvars and term vars
782 [UfExpr name] -- Args of LHS
783 (UfExpr name) -- Pre typecheck
786 | IfaceRuleOut -- Post typecheck
790 isIfaceRuleDecl :: RuleDecl name pat -> Bool
791 isIfaceRuleDecl (HsRule _ _ _ _ _ _) = False
792 isIfaceRuleDecl other = True
794 ifaceRuleDeclName :: RuleDecl name pat -> name
795 ifaceRuleDeclName (IfaceRule _ _ _ n _ _ _) = n
796 ifaceRuleDeclName (IfaceRuleOut n r) = n
797 ifaceRuleDeclName (HsRule fs _ _ _ _ _) = pprPanic "ifaceRuleDeclName" (ppr fs)
801 | RuleBndrSig name (HsType name)
803 collectRuleBndrSigTys :: [RuleBndr name] -> [HsType name]
804 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
806 instance (NamedThing name, Ord name) => Eq (RuleDecl name pat) where
807 -- Works for IfaceRules only; used when comparing interface file versions
808 (IfaceRule n1 a1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 a2 bs2 f2 es2 rhs2 _)
809 = n1==n2 && f1 == f2 && a1==a2 &&
810 eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
811 eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
813 instance (NamedThing name, Outputable name, Outputable pat)
814 => Outputable (RuleDecl name pat) where
815 ppr (HsRule name act ns lhs rhs loc)
816 = sep [text "{-# RULES" <+> doubleQuotes (ptext name) <+> ppr act,
817 pp_forall, ppr lhs, equals <+> ppr rhs,
820 pp_forall | null ns = empty
821 | otherwise = text "forall" <+> fsep (map ppr ns) <> dot
823 ppr (IfaceRule name act tpl_vars fn tpl_args rhs loc)
824 = hsep [ doubleQuotes (ptext name), ppr act,
825 ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
826 ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
827 ptext SLIT("=") <+> ppr rhs
830 ppr (IfaceRuleOut fn rule) = pprCoreRule (ppr fn) rule
832 instance Outputable name => Outputable (RuleBndr name) where
833 ppr (RuleBndr name) = ppr name
834 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
838 %************************************************************************
840 \subsection[DeprecDecl]{Deprecations}
842 %************************************************************************
844 We use exported entities for things to deprecate.
847 data DeprecDecl name = Deprecation name DeprecTxt SrcLoc
849 type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
851 instance Outputable name => Outputable (DeprecDecl name) where
852 ppr (Deprecation thing txt _)
853 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]