2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[HsDecls]{Abstract syntax: global declarations}
6 Definitions for: @TyDecl@ and @ConDecl@, @ClassDecl@,
7 @InstDecl@, @DefaultDecl@ and @ForeignDecl@.
11 HsDecl(..), TyClDecl(..), InstDecl(..), RuleDecl(..), RuleBndr(..),
12 DefaultDecl(..), ForeignDecl(..), ForKind(..),
13 ExtName(..), isDynamicExtName, extNameStatic,
14 ConDecl(..), ConDetails(..), BangType(..),
15 IfaceSig(..), SpecDataSig(..),
16 DeprecDecl(..), DeprecTxt,
17 hsDeclName, tyClDeclName, isClassDecl, isSynDecl, isDataDecl, countTyClDecls, toHsRule
20 #include "HsVersions.h"
23 import HsBinds ( HsBinds, MonoBinds, Sig(..), FixitySig(..), nullMonoBinds )
24 import HsExpr ( HsExpr )
25 import HsPragmas ( DataPragmas, ClassPragmas )
26 import HsImpExp ( IE(..) )
28 import PprCore ( pprCoreRule )
29 import HsCore ( UfExpr(UfVar), UfBinder, IfaceSig(..), eq_ufBinders, eq_ufExpr, pprUfExpr, toUfExpr, toUfBndr )
30 import CoreSyn ( CoreRule(..) )
31 import BasicTypes ( Fixity, NewOrData(..) )
32 import CallConv ( CallConv, pprCallConv )
33 import Var ( TyVar, Id )
34 import Name ( toRdrName )
38 import FunDeps ( pprFundeps )
39 import Class ( FunDep )
40 import CStrings ( CLabelString, pprCLabelString )
42 import SrcLoc ( SrcLoc, noSrcLoc )
47 %************************************************************************
49 \subsection[HsDecl]{Declarations}
51 %************************************************************************
55 = TyClD (TyClDecl name pat)
56 | InstD (InstDecl name pat)
57 | DefD (DefaultDecl name)
58 | ValD (HsBinds name pat)
59 | ForD (ForeignDecl name)
60 | SigD (IfaceSig name)
61 | FixD (FixitySig name)
62 | DeprecD (DeprecDecl name)
63 | RuleD (RuleDecl name pat)
65 -- NB: all top-level fixity decls are contained EITHER
67 -- OR in the ClassDecls in TyClDs
70 -- a) data constructors
71 -- b) class methods (but they can be also done in the
72 -- signatures of class decls)
73 -- c) imported functions (that have an IfacSig)
76 -- The latter is for class methods only
81 hsDeclName :: (Outputable name, Outputable pat)
82 => HsDecl name pat -> name
84 hsDeclName (TyClD decl) = tyClDeclName decl
85 hsDeclName (SigD (IfaceSig name _ _ _)) = name
86 hsDeclName (InstD (InstDecl _ _ _ name _)) = name
87 hsDeclName (ForD (ForeignDecl name _ _ _ _ _)) = name
88 hsDeclName (FixD (FixitySig name _ _)) = name
89 -- Others don't make sense
91 hsDeclName x = pprPanic "HsDecls.hsDeclName" (ppr x)
94 tyClDeclName :: TyClDecl name pat -> name
95 tyClDeclName (TyData _ _ name _ _ _ _ _ _) = name
96 tyClDeclName (TySynonym name _ _ _) = name
97 tyClDeclName (ClassDecl _ name _ _ _ _ _ _ _ _ _ _) = name
101 instance (Outputable name, Outputable pat)
102 => Outputable (HsDecl name pat) where
104 ppr (TyClD dcl) = ppr dcl
105 ppr (SigD sig) = ppr sig
106 ppr (ValD binds) = ppr binds
107 ppr (DefD def) = ppr def
108 ppr (InstD inst) = ppr inst
109 ppr (ForD fd) = ppr fd
110 ppr (FixD fd) = ppr fd
111 ppr (RuleD rd) = ppr rd
112 ppr (DeprecD dd) = ppr dd
116 instance Ord name => Eq (HsDecl name pat) where
117 -- Used only when comparing interfaces,
118 -- at which time only signature and type/class decls
119 (SigD s1) == (SigD s2) = s1 == s2
120 (TyClD d1) == (TyClD d2) = d1 == d2
124 %************************************************************************
126 \subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
128 %************************************************************************
131 data TyClDecl name pat
133 (HsContext name) -- context
134 name -- type constructor
135 [HsTyVarBndr name] -- type variables
136 [ConDecl name] -- data constructors (empty if abstract)
137 Int -- Number of data constructors (valid even if type is abstract)
138 (Maybe [name]) -- derivings; Nothing => not specified
139 -- (i.e., derive default); Just [] => derive
140 -- *nothing*; Just <list> => as you would
145 | TySynonym name -- type constructor
146 [HsTyVarBndr name] -- type variables
147 (HsType name) -- synonym expansion
150 | ClassDecl (HsContext name) -- context...
151 name -- name of the class
152 [HsTyVarBndr name] -- the class type variables
153 [FunDep name] -- functional dependencies
154 [Sig name] -- methods' signatures
155 (MonoBinds name pat) -- default methods
157 name name name [name] -- The names of the tycon, datacon wrapper, datacon worker,
158 -- and superclass selectors for this class.
159 -- These are filled in as the ClassDecl is made.
162 instance Ord name => Eq (TyClDecl name pat) where
163 -- Used only when building interface files
164 (==) (TyData nd1 cxt1 n1 tvs1 cons1 _ _ _ _)
165 (TyData nd2 cxt2 n2 tvs2 cons2 _ _ _ _)
168 eqWithHsTyVars tvs1 tvs2 (\ env ->
169 eq_hsContext env cxt1 cxt2 &&
170 eqListBy (eq_ConDecl env) cons1 cons2
173 (==) (TySynonym n1 tvs1 ty1 _)
174 (TySynonym n2 tvs2 ty2 _)
176 eqWithHsTyVars tvs1 tvs2 (\ env -> eq_hsType env ty1 ty2)
178 (==) (ClassDecl cxt1 n1 tvs1 fds1 sigs1 _ _ _ _ _ _ _)
179 (ClassDecl cxt2 n2 tvs2 fds2 sigs2 _ _ _ _ _ _ _)
181 eqWithHsTyVars tvs1 tvs2 (\ env ->
182 eq_hsContext env cxt1 cxt2 &&
183 eqListBy (eq_hsFD env) fds1 fds2 &&
184 eqListBy (eq_cls_sig env) sigs1 sigs2
187 eq_hsFD env (ns1,ms1) (ns2,ms2)
188 = eqListBy (eq_hsVar env) ns1 ns2 && eqListBy (eq_hsVar env) ms1 ms2
190 eq_cls_sig env (ClassOpSig n1 _ b1 ty1 _) (ClassOpSig n2 _ b2 ty2 _)
191 = n1==n2 && b1==b2 && eq_hsType env ty1 ty2
195 countTyClDecls :: [TyClDecl name pat] -> (Int, Int, Int, Int)
196 -- class, data, newtype, synonym decls
198 = (length [() | ClassDecl _ _ _ _ _ _ _ _ _ _ _ _ <- decls],
199 length [() | TyData DataType _ _ _ _ _ _ _ _ <- decls],
200 length [() | TyData NewType _ _ _ _ _ _ _ _ <- decls],
201 length [() | TySynonym _ _ _ _ <- decls])
203 isDataDecl, isSynDecl, isClassDecl :: TyClDecl name pat -> Bool
205 isSynDecl (TySynonym _ _ _ _) = True
206 isSynDecl other = False
208 isDataDecl (TyData _ _ _ _ _ _ _ _ _) = True
209 isDataDecl other = False
211 isClassDecl (ClassDecl _ _ _ _ _ _ _ _ _ _ _ _) = True
212 isClassDecl other = False
216 instance (Outputable name, Outputable pat)
217 => Outputable (TyClDecl name pat) where
219 ppr (TySynonym tycon tyvars mono_ty src_loc)
220 = hang (ptext SLIT("type") <+> pp_decl_head [] tycon tyvars <+> equals)
223 ppr (TyData new_or_data context tycon tyvars condecls ncons derivings pragmas src_loc)
225 (ptext keyword <+> pp_decl_head context tycon tyvars <+> equals)
226 (pp_condecls condecls ncons)
229 keyword = case new_or_data of
230 NewType -> SLIT("newtype")
231 DataType -> SLIT("data")
233 ppr (ClassDecl context clas tyvars fds sigs methods pragmas _ _ _ _ src_loc)
234 | null sigs -- No "where" part
237 | otherwise -- Laid out
238 = sep [hsep [top_matter, ptext SLIT("where {")],
239 nest 4 (sep [sep (map ppr_sig sigs), pp_methods, char '}'])]
241 top_matter = ptext SLIT("class") <+> pp_decl_head context clas tyvars <+> pprFundeps fds
242 ppr_sig sig = ppr sig <> semi
243 pp_methods = getPprStyle $ \ sty ->
244 if ifaceStyle sty then empty else ppr methods
247 pp_decl_head :: Outputable name => HsContext name -> name -> [HsTyVarBndr name] -> SDoc
248 pp_decl_head context thing tyvars = hsep [pprHsContext context, ppr thing, interppSP tyvars]
250 pp_condecls [] ncons = ptext SLIT("{- abstract with") <+> int ncons <+> ptext SLIT("constructors -}")
251 pp_condecls (c:cs) ncons = sep (ppr c : map (\ c -> ptext SLIT("|") <+> ppr c) cs)
253 pp_tydecl pp_head pp_decl_rhs derivings
254 = hang pp_head 4 (sep [
258 Just ds -> hsep [ptext SLIT("deriving"), parens (interpp'SP ds)]
262 A type for recording what types a datatype should be specialised to.
263 It's called a ``Sig'' because it's sort of like a ``type signature''
264 for an datatype declaration.
267 data SpecDataSig name
268 = SpecDataSig name -- tycon to specialise
272 instance (Outputable name)
273 => Outputable (SpecDataSig name) where
275 ppr (SpecDataSig tycon ty _)
276 = hsep [text "{-# SPECIALIZE data", ppr ty, text "#-}"]
279 %************************************************************************
281 \subsection[ConDecl]{A data-constructor declaration}
283 %************************************************************************
287 = ConDecl name -- Constructor name; this is used for the
288 -- DataCon itself, and for the user-callable wrapper Id
290 name -- Name of the constructor's 'worker Id'
291 -- Filled in as the ConDecl is built
293 [HsTyVarBndr name] -- Existentially quantified type variables
294 (HsContext name) -- ...and context
295 -- If both are empty then there are no existentials
301 = VanillaCon -- prefix-style con decl
304 | InfixCon -- infix-style con decl
308 | RecCon -- record-style con decl
309 [([name], BangType name)] -- list of "fields"
311 | NewCon -- newtype con decl, possibly with a labelled field.
313 (Maybe name) -- Just x => labelled field 'x'
316 = Banged (HsType name) -- HsType: to allow Haskell extensions
317 | Unbanged (HsType name) -- (MonoType only needed for straight Haskell)
318 | Unpacked (HsType name) -- Field is strict and to be unpacked if poss.
321 eq_ConDecl env (ConDecl n1 _ tvs1 cxt1 cds1 _)
322 (ConDecl n2 _ tvs2 cxt2 cds2 _)
324 (eqWithHsTyVars tvs1 tvs2 $ \ env ->
325 eq_hsContext env cxt1 cxt2 &&
326 eq_ConDetails env cds1 cds2)
328 eq_ConDetails env (VanillaCon bts1) (VanillaCon bts2)
329 = eqListBy (eq_btype env) bts1 bts2
330 eq_ConDetails env (InfixCon bta1 btb1) (InfixCon bta2 btb2)
331 = eq_btype env bta1 bta2 && eq_btype env btb1 btb2
332 eq_ConDetails env (RecCon fs1) (RecCon fs2)
333 = eqListBy (eq_fld env) fs1 fs2
334 eq_ConDetails env (NewCon t1 mn1) (NewCon t2 mn2)
335 = eq_hsType env t1 t2 && mn1 == mn2
336 eq_ConDetails env _ _ = False
338 eq_fld env (ns1,bt1) (ns2, bt2) = ns1==ns2 && eq_btype env bt1 bt2
340 eq_btype env (Banged t1) (Banged t2) = eq_hsType env t1 t2
341 eq_btype env (Unbanged t1) (Unbanged t2) = eq_hsType env t1 t2
342 eq_btype env (Unpacked t1) (Unpacked t2) = eq_hsType env t1 t2
346 instance (Outputable name) => Outputable (ConDecl name) where
347 ppr (ConDecl con _ tvs cxt con_details loc)
348 = sep [pprHsForAll tvs cxt, ppr_con_details con con_details]
350 ppr_con_details con (InfixCon ty1 ty2)
351 = hsep [ppr_bang ty1, ppr con, ppr_bang ty2]
353 ppr_con_details con (VanillaCon tys)
354 = ppr con <+> hsep (map (ppr_bang) tys)
356 ppr_con_details con (NewCon ty Nothing)
357 = ppr con <+> pprParendHsType ty
359 ppr_con_details con (NewCon ty (Just x))
360 = ppr con <+> braces pp_field
362 pp_field = ppr x <+> dcolon <+> pprParendHsType ty
364 ppr_con_details con (RecCon fields)
365 = ppr con <+> braces (hsep (punctuate comma (map ppr_field fields)))
367 ppr_field (ns, ty) = hsep (map (ppr) ns) <+>
371 instance Outputable name => Outputable (BangType name) where
374 ppr_bang (Banged ty) = ptext SLIT("!") <> pprParendHsType ty
375 ppr_bang (Unbanged ty) = pprParendHsType ty
376 ppr_bang (Unpacked ty) = ptext SLIT("! !") <> pprParendHsType ty
380 %************************************************************************
382 \subsection[InstDecl]{An instance declaration
384 %************************************************************************
387 data InstDecl name pat
388 = InstDecl (HsType name) -- Context => Class Instance-type
389 -- Using a polytype means that the renamer conveniently
390 -- figures out the quantified type variables for us.
394 [Sig name] -- User-supplied pragmatic info
396 name -- Name for the dictionary function
402 instance (Outputable name, Outputable pat)
403 => Outputable (InstDecl name pat) where
405 ppr (InstDecl inst_ty binds uprags dfun_name src_loc)
406 = getPprStyle $ \ sty ->
407 if ifaceStyle sty then
408 hsep [ptext SLIT("instance"), ppr inst_ty, equals, ppr dfun_name]
410 vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
416 instance Ord name => Eq (InstDecl name pat) where
417 -- Used for interface comparison only, so don't compare bindings
418 (==) (InstDecl inst_ty1 _ _ dfun1 _) (InstDecl inst_ty2 _ _ dfun2 _)
419 = inst_ty1 == inst_ty2 && dfun1 == dfun2
423 %************************************************************************
425 \subsection[DefaultDecl]{A @default@ declaration}
427 %************************************************************************
429 There can only be one default declaration per module, but it is hard
430 for the parser to check that; we pass them all through in the abstract
431 syntax, and that restriction must be checked in the front end.
434 data DefaultDecl name
435 = DefaultDecl [HsType name]
438 instance (Outputable name)
439 => Outputable (DefaultDecl name) where
441 ppr (DefaultDecl tys src_loc)
442 = ptext SLIT("default") <+> parens (interpp'SP tys)
445 %************************************************************************
447 \subsection{Foreign function interface declaration}
449 %************************************************************************
452 data ForeignDecl name =
461 instance (Outputable name)
462 => Outputable (ForeignDecl name) where
464 ppr (ForeignDecl nm imp_exp ty ext_name cconv src_loc)
465 = ptext SLIT("foreign") <+> ppr_imp_exp <+> pprCallConv cconv <+>
466 ppr ext_name <+> ppr_unsafe <+> ppr nm <+> dcolon <+> ppr ty
468 (ppr_imp_exp, ppr_unsafe) =
470 FoLabel -> (ptext SLIT("label"), empty)
471 FoExport -> (ptext SLIT("export"), empty)
473 | us -> (ptext SLIT("import"), ptext SLIT("unsafe"))
474 | otherwise -> (ptext SLIT("import"), empty)
479 | FoImport Bool -- True => unsafe call.
483 | ExtName CLabelString -- The external name of the foreign thing,
484 (Maybe CLabelString) -- and optionally its DLL or module name
485 -- Both of these are completely unencoded;
486 -- we just print them as they are
488 isDynamicExtName :: ExtName -> Bool
489 isDynamicExtName Dynamic = True
490 isDynamicExtName _ = False
492 extNameStatic :: ExtName -> CLabelString
493 extNameStatic (ExtName f _) = f
494 extNameStatic Dynamic = panic "staticExtName: Dynamic - shouldn't ever happen."
496 instance Outputable ExtName where
497 ppr Dynamic = ptext SLIT("dynamic")
498 ppr (ExtName nm mb_mod) =
499 case mb_mod of { Nothing -> empty; Just m -> doubleQuotes (ptext m) } <+>
500 doubleQuotes (pprCLabelString nm)
503 %************************************************************************
505 \subsection{Transformation rules}
507 %************************************************************************
510 data RuleDecl name pat
511 = HsRule -- Source rule
512 FAST_STRING -- Rule name
513 [name] -- Forall'd tyvars, filled in by the renamer with
514 -- tyvars mentioned in sigs; then filled out by typechecker
515 [RuleBndr name] -- Forall'd term vars
516 (HsExpr name pat) -- LHS
517 (HsExpr name pat) -- RHS
520 | IfaceRule -- One that's come in from an interface file; pre-typecheck
522 [UfBinder name] -- Tyvars and term vars
524 [UfExpr name] -- Args of LHS
525 (UfExpr name) -- Pre typecheck
528 | IfaceRuleOut -- Post typecheck
535 | RuleBndrSig name (HsType name)
537 instance Ord name => Eq (RuleDecl name pat) where
538 -- Works for IfaceRules only; used when comparing interface file versions
539 (IfaceRule n1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 bs2 f2 es2 rhs2 _)
540 = n1==n2 && f1 == f2 &&
541 eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
542 eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
544 instance (Outputable name, Outputable pat)
545 => Outputable (RuleDecl name pat) where
546 ppr (HsRule name tvs ns lhs rhs loc)
547 = sep [text "{-# RULES" <+> doubleQuotes (ptext name),
548 pp_forall, ppr lhs, equals <+> ppr rhs,
551 pp_forall | null tvs && null ns = empty
552 | otherwise = text "forall" <+>
553 fsep (map ppr tvs ++ map ppr ns)
556 ppr (IfaceRule name tpl_vars fn tpl_args rhs loc)
557 = hsep [ doubleQuotes (ptext name),
558 ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
559 ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
560 ptext SLIT("=") <+> ppr rhs
563 ppr (IfaceRuleOut fn rule) = pprCoreRule (ppr fn) rule
565 instance Outputable name => Outputable (RuleBndr name) where
566 ppr (RuleBndr name) = ppr name
567 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
569 toHsRule id (BuiltinRule _)
570 = pprTrace "toHsRule: builtin" (ppr id) (bogusIfaceRule id)
572 toHsRule id (Rule name bndrs args rhs)
573 = IfaceRule name (map toUfBndr bndrs) (toRdrName id)
574 (map toUfExpr args) (toUfExpr rhs) noSrcLoc
577 = IfaceRule SLIT("bogus") [] (toRdrName id) [] (UfVar (toRdrName id)) noSrcLoc
581 %************************************************************************
583 \subsection[DeprecDecl]{Deprecations}
585 %************************************************************************
587 We use exported entities for things to deprecate. Cunning trick (hack?):
588 `IEModuleContents undefined' is used for module deprecation.
591 data DeprecDecl name = Deprecation (IE name) DeprecTxt SrcLoc
593 type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
595 instance Outputable name => Outputable (DeprecDecl name) where
596 ppr (Deprecation (IEModuleContents _) txt _)
597 = hsep [text "{-# DEPRECATED", doubleQuotes (ppr txt), text "#-}"]
598 ppr (Deprecation thing txt _)
599 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]