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
343 eq_btype env _ _ = False
347 instance (Outputable name) => Outputable (ConDecl name) where
348 ppr (ConDecl con _ tvs cxt con_details loc)
349 = sep [pprHsForAll tvs cxt, ppr_con_details con con_details]
351 ppr_con_details con (InfixCon ty1 ty2)
352 = hsep [ppr_bang ty1, ppr con, ppr_bang ty2]
354 ppr_con_details con (VanillaCon tys)
355 = ppr con <+> hsep (map (ppr_bang) tys)
357 ppr_con_details con (NewCon ty Nothing)
358 = ppr con <+> pprParendHsType ty
360 ppr_con_details con (NewCon ty (Just x))
361 = ppr con <+> braces pp_field
363 pp_field = ppr x <+> dcolon <+> pprParendHsType ty
365 ppr_con_details con (RecCon fields)
366 = ppr con <+> braces (hsep (punctuate comma (map ppr_field fields)))
368 ppr_field (ns, ty) = hsep (map (ppr) ns) <+>
372 instance Outputable name => Outputable (BangType name) where
375 ppr_bang (Banged ty) = ptext SLIT("!") <> pprParendHsType ty
376 ppr_bang (Unbanged ty) = pprParendHsType ty
377 ppr_bang (Unpacked ty) = ptext SLIT("! !") <> pprParendHsType ty
381 %************************************************************************
383 \subsection[InstDecl]{An instance declaration
385 %************************************************************************
388 data InstDecl name pat
389 = InstDecl (HsType name) -- Context => Class Instance-type
390 -- Using a polytype means that the renamer conveniently
391 -- figures out the quantified type variables for us.
395 [Sig name] -- User-supplied pragmatic info
397 name -- Name for the dictionary function
403 instance (Outputable name, Outputable pat)
404 => Outputable (InstDecl name pat) where
406 ppr (InstDecl inst_ty binds uprags dfun_name src_loc)
407 = getPprStyle $ \ sty ->
408 if ifaceStyle sty then
409 hsep [ptext SLIT("instance"), ppr inst_ty, equals, ppr dfun_name]
411 vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
417 instance Ord name => Eq (InstDecl name pat) where
418 -- Used for interface comparison only, so don't compare bindings
419 (==) (InstDecl inst_ty1 _ _ dfun1 _) (InstDecl inst_ty2 _ _ dfun2 _)
420 = inst_ty1 == inst_ty2 && dfun1 == dfun2
424 %************************************************************************
426 \subsection[DefaultDecl]{A @default@ declaration}
428 %************************************************************************
430 There can only be one default declaration per module, but it is hard
431 for the parser to check that; we pass them all through in the abstract
432 syntax, and that restriction must be checked in the front end.
435 data DefaultDecl name
436 = DefaultDecl [HsType name]
439 instance (Outputable name)
440 => Outputable (DefaultDecl name) where
442 ppr (DefaultDecl tys src_loc)
443 = ptext SLIT("default") <+> parens (interpp'SP tys)
446 %************************************************************************
448 \subsection{Foreign function interface declaration}
450 %************************************************************************
453 data ForeignDecl name =
462 instance (Outputable name)
463 => Outputable (ForeignDecl name) where
465 ppr (ForeignDecl nm imp_exp ty ext_name cconv src_loc)
466 = ptext SLIT("foreign") <+> ppr_imp_exp <+> pprCallConv cconv <+>
467 ppr ext_name <+> ppr_unsafe <+> ppr nm <+> dcolon <+> ppr ty
469 (ppr_imp_exp, ppr_unsafe) =
471 FoLabel -> (ptext SLIT("label"), empty)
472 FoExport -> (ptext SLIT("export"), empty)
474 | us -> (ptext SLIT("import"), ptext SLIT("unsafe"))
475 | otherwise -> (ptext SLIT("import"), empty)
480 | FoImport Bool -- True => unsafe call.
484 | ExtName CLabelString -- The external name of the foreign thing,
485 (Maybe CLabelString) -- and optionally its DLL or module name
486 -- Both of these are completely unencoded;
487 -- we just print them as they are
489 isDynamicExtName :: ExtName -> Bool
490 isDynamicExtName Dynamic = True
491 isDynamicExtName _ = False
493 extNameStatic :: ExtName -> CLabelString
494 extNameStatic (ExtName f _) = f
495 extNameStatic Dynamic = panic "staticExtName: Dynamic - shouldn't ever happen."
497 instance Outputable ExtName where
498 ppr Dynamic = ptext SLIT("dynamic")
499 ppr (ExtName nm mb_mod) =
500 case mb_mod of { Nothing -> empty; Just m -> doubleQuotes (ptext m) } <+>
501 doubleQuotes (pprCLabelString nm)
504 %************************************************************************
506 \subsection{Transformation rules}
508 %************************************************************************
511 data RuleDecl name pat
512 = HsRule -- Source rule
513 FAST_STRING -- Rule name
514 [name] -- Forall'd tyvars, filled in by the renamer with
515 -- tyvars mentioned in sigs; then filled out by typechecker
516 [RuleBndr name] -- Forall'd term vars
517 (HsExpr name pat) -- LHS
518 (HsExpr name pat) -- RHS
521 | IfaceRule -- One that's come in from an interface file; pre-typecheck
523 [UfBinder name] -- Tyvars and term vars
525 [UfExpr name] -- Args of LHS
526 (UfExpr name) -- Pre typecheck
529 | IfaceRuleOut -- Post typecheck
536 | RuleBndrSig name (HsType name)
538 instance Ord name => Eq (RuleDecl name pat) where
539 -- Works for IfaceRules only; used when comparing interface file versions
540 (IfaceRule n1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 bs2 f2 es2 rhs2 _)
541 = n1==n2 && f1 == f2 &&
542 eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
543 eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
545 instance (Outputable name, Outputable pat)
546 => Outputable (RuleDecl name pat) where
547 ppr (HsRule name tvs ns lhs rhs loc)
548 = sep [text "{-# RULES" <+> doubleQuotes (ptext name),
549 pp_forall, ppr lhs, equals <+> ppr rhs,
552 pp_forall | null tvs && null ns = empty
553 | otherwise = text "forall" <+>
554 fsep (map ppr tvs ++ map ppr ns)
557 ppr (IfaceRule name tpl_vars fn tpl_args rhs loc)
558 = hsep [ doubleQuotes (ptext name),
559 ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
560 ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
561 ptext SLIT("=") <+> ppr rhs
564 ppr (IfaceRuleOut fn rule) = pprCoreRule (ppr fn) rule
566 instance Outputable name => Outputable (RuleBndr name) where
567 ppr (RuleBndr name) = ppr name
568 ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
570 toHsRule id (BuiltinRule _)
571 = pprTrace "toHsRule: builtin" (ppr id) (bogusIfaceRule id)
573 toHsRule id (Rule name bndrs args rhs)
574 = IfaceRule name (map toUfBndr bndrs) (toRdrName id)
575 (map toUfExpr args) (toUfExpr rhs) noSrcLoc
578 = IfaceRule SLIT("bogus") [] (toRdrName id) [] (UfVar (toRdrName id)) noSrcLoc
582 %************************************************************************
584 \subsection[DeprecDecl]{Deprecations}
586 %************************************************************************
588 We use exported entities for things to deprecate. Cunning trick (hack?):
589 `IEModuleContents undefined' is used for module deprecation.
592 data DeprecDecl name = Deprecation (IE name) DeprecTxt SrcLoc
594 type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
596 instance Outputable name => Outputable (DeprecDecl name) where
597 ppr (Deprecation (IEModuleContents _) txt _)
598 = hsep [text "{-# DEPRECATED", doubleQuotes (ppr txt), text "#-}"]
599 ppr (Deprecation thing txt _)
600 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]