2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[RdrName]{@RdrName@}
9 RdrName(..), -- Constructors exported only to BinIface
12 mkRdrUnqual, mkRdrQual,
13 mkUnqual, mkVarUnqual, mkQual, mkOrig,
14 nameRdrName, getRdrName,
18 rdrNameModule, rdrNameOcc, setRdrNameSpace,
19 isRdrDataCon, isRdrTyVar, isRdrTc, isQual, isUnqual,
20 isOrig, isOrig_maybe, isExact, isExact_maybe, isSrcRdrName,
22 -- Printing; instance Outputable RdrName
25 LocalRdrEnv, emptyLocalRdrEnv, extendLocalRdrEnv,
26 lookupLocalRdrEnv, elemLocalRdrEnv,
29 GlobalRdrEnv, emptyGlobalRdrEnv, mkGlobalRdrEnv, plusGlobalRdrEnv,
30 lookupGlobalRdrEnv, extendGlobalRdrEnv,
31 pprGlobalRdrEnv, globalRdrEnvElts,
32 lookupGRE_RdrName, lookupGRE_Name,
34 -- GlobalRdrElt, Provenance, ImportSpec
35 GlobalRdrElt(..), isLocalGRE, unQualOK,
36 Provenance(..), pprNameProvenance,
37 ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..),
38 importSpecLoc, importSpecModule
41 #include "HsVersions.h"
43 import OccName ( NameSpace, varName,
46 mkOccFS, occNameFlavour,
47 isDataOcc, isTvOcc, isTcOcc,
48 OccEnv, emptyOccEnv, extendOccEnvList, lookupOccEnv,
49 elemOccEnv, plusOccEnv_C, extendOccEnv_C, foldOccEnv,
52 import Module ( Module, mkModuleFS )
53 import Name ( Name, NamedThing(getName), nameModule, nameParent_maybe,
54 nameOccName, isExternalName, nameSrcLoc )
55 import SrcLoc ( isGoodSrcLoc, SrcSpan )
57 import Util ( thenCmp )
61 %************************************************************************
63 \subsection{The main data type}
65 %************************************************************************
70 -- Used for ordinary, unqualified occurrences
73 -- A qualified name written by the user in
74 -- *source* code. The module isn't necessarily
75 -- the module where the thing is defined;
76 -- just the one from which it is imported
79 -- An original name; the module is the *defining* module.
80 -- This is used when GHC generates code that will be fed
81 -- into the renamer (e.g. from deriving clauses), but where
82 -- we want to say "Use Prelude.map dammit".
85 -- We know exactly the Name. This is used
86 -- (a) when the parser parses built-in syntax like "[]"
87 -- and "(,)", but wants a RdrName from it
88 -- (b) when converting names to the RdrNames in IfaceTypes
89 -- Here an Exact RdrName always contains an External Name
90 -- (Internal Names are converted to simple Unquals)
91 -- (c) by Template Haskell, when TH has generated a unique name
95 %************************************************************************
97 \subsection{Simple functions}
99 %************************************************************************
102 rdrNameModule :: RdrName -> Module
103 rdrNameModule (Qual m _) = m
104 rdrNameModule (Orig m _) = m
105 rdrNameModule (Exact n) = nameModule n
106 rdrNameModule (Unqual n) = pprPanic "rdrNameModule" (ppr n)
108 rdrNameOcc :: RdrName -> OccName
109 rdrNameOcc (Qual _ occ) = occ
110 rdrNameOcc (Unqual occ) = occ
111 rdrNameOcc (Orig _ occ) = occ
112 rdrNameOcc (Exact name) = nameOccName name
114 setRdrNameSpace :: RdrName -> NameSpace -> RdrName
115 -- This rather gruesome function is used mainly by the parser
116 -- When parsing data T a = T | T1 Int
117 -- we parse the data constructors as *types* because of parser ambiguities,
118 -- so then we need to change the *type constr* to a *data constr*
120 -- The original-name case *can* occur when parsing
121 -- data [] a = [] | a : [a]
122 -- For the orig-name case we return an unqualified name.
123 setRdrNameSpace (Unqual occ) ns = Unqual (setOccNameSpace ns occ)
124 setRdrNameSpace (Qual m occ) ns = Qual m (setOccNameSpace ns occ)
125 setRdrNameSpace (Orig m occ) ns = Orig m (setOccNameSpace ns occ)
126 setRdrNameSpace (Exact n) ns = Orig (nameModule n)
127 (setOccNameSpace ns (nameOccName n))
131 -- These two are the basic constructors
132 mkRdrUnqual :: OccName -> RdrName
133 mkRdrUnqual occ = Unqual occ
135 mkRdrQual :: Module -> OccName -> RdrName
136 mkRdrQual mod occ = Qual mod occ
138 mkOrig :: Module -> OccName -> RdrName
139 mkOrig mod occ = Orig mod occ
142 mkDerivedRdrName :: Name -> (OccName -> OccName) -> (RdrName)
143 mkDerivedRdrName parent mk_occ
144 = mkOrig (nameModule parent) (mk_occ (nameOccName parent))
147 -- These two are used when parsing source files
148 -- They do encode the module and occurrence names
149 mkUnqual :: NameSpace -> UserFS -> RdrName
150 mkUnqual sp n = Unqual (mkOccFS sp n)
152 mkVarUnqual :: UserFS -> RdrName
153 mkVarUnqual n = Unqual (mkOccFS varName n)
155 mkQual :: NameSpace -> (UserFS, UserFS) -> RdrName
156 mkQual sp (m, n) = Qual (mkModuleFS m) (mkOccFS sp n)
158 getRdrName :: NamedThing thing => thing -> RdrName
159 getRdrName name = nameRdrName (getName name)
161 nameRdrName :: Name -> RdrName
162 nameRdrName name = Exact name
163 -- Keep the Name even for Internal names, so that the
164 -- unique is still there for debug printing, particularly
165 -- of Types (which are converted to IfaceTypes before printing)
167 nukeExact :: Name -> RdrName
169 | isExternalName n = Orig (nameModule n) (nameOccName n)
170 | otherwise = Unqual (nameOccName n)
174 isRdrDataCon rn = isDataOcc (rdrNameOcc rn)
175 isRdrTyVar rn = isTvOcc (rdrNameOcc rn)
176 isRdrTc rn = isTcOcc (rdrNameOcc rn)
178 isSrcRdrName (Unqual _) = True
179 isSrcRdrName (Qual _ _) = True
180 isSrcRdrName _ = False
182 isUnqual (Unqual _) = True
183 isUnqual other = False
185 isQual (Qual _ _) = True
188 isOrig (Orig _ _) = True
191 isOrig_maybe (Orig m n) = Just (m,n)
192 isOrig_maybe _ = Nothing
194 isExact (Exact _) = True
195 isExact other = False
197 isExact_maybe (Exact n) = Just n
198 isExact_maybe other = Nothing
202 %************************************************************************
204 \subsection{Instances}
206 %************************************************************************
209 instance Outputable RdrName where
210 ppr (Exact name) = ppr name
211 ppr (Unqual occ) = ppr occ <+> ppr_name_space occ
212 ppr (Qual mod occ) = ppr mod <> dot <> ppr occ <+> ppr_name_space occ
213 ppr (Orig mod occ) = ppr mod <> dot <> ppr occ <+> ppr_name_space occ
215 ppr_name_space occ = ifPprDebug (parens (occNameFlavour occ))
217 instance OutputableBndr RdrName where
219 | isTvOcc (rdrNameOcc n) = char '@' <+> ppr n
222 instance Eq RdrName where
223 (Exact n1) == (Exact n2) = n1==n2
224 -- Convert exact to orig
225 (Exact n1) == r2@(Orig _ _) = nukeExact n1 == r2
226 r1@(Orig _ _) == (Exact n2) = r1 == nukeExact n2
228 (Orig m1 o1) == (Orig m2 o2) = m1==m2 && o1==o2
229 (Qual m1 o1) == (Qual m2 o2) = m1==m2 && o1==o2
230 (Unqual o1) == (Unqual o2) = o1==o2
233 instance Ord RdrName where
234 a <= b = case (a `compare` b) of { LT -> True; EQ -> True; GT -> False }
235 a < b = case (a `compare` b) of { LT -> True; EQ -> False; GT -> False }
236 a >= b = case (a `compare` b) of { LT -> False; EQ -> True; GT -> True }
237 a > b = case (a `compare` b) of { LT -> False; EQ -> False; GT -> True }
239 -- Exact < Unqual < Qual < Orig
240 -- [Note: Apr 2004] We used to use nukeExact to convert Exact to Orig
241 -- before comparing so that Prelude.map == the exact Prelude.map, but
242 -- that meant that we reported duplicates when renaming bindings
243 -- generated by Template Haskell; e.g
244 -- do { n1 <- newName "foo"; n2 <- newName "foo";
245 -- <decl involving n1,n2> }
246 -- I think we can do without this conversion
247 compare (Exact n1) (Exact n2) = n1 `compare` n2
248 compare (Exact n1) n2 = LT
250 compare (Unqual _) (Exact _) = GT
251 compare (Unqual o1) (Unqual o2) = o1 `compare` o2
252 compare (Unqual _) _ = LT
254 compare (Qual _ _) (Exact _) = GT
255 compare (Qual _ _) (Unqual _) = GT
256 compare (Qual m1 o1) (Qual m2 o2) = (o1 `compare` o2) `thenCmp` (m1 `compare` m2)
257 compare (Qual _ _) (Orig _ _) = LT
259 compare (Orig m1 o1) (Orig m2 o2) = (o1 `compare` o2) `thenCmp` (m1 `compare` m2)
260 compare (Orig _ _) _ = GT
265 %************************************************************************
269 %************************************************************************
271 A LocalRdrEnv is used for local bindings (let, where, lambda, case)
272 It is keyed by OccName, because we never use it for qualified names.
275 type LocalRdrEnv = OccEnv Name
277 emptyLocalRdrEnv = emptyOccEnv
279 extendLocalRdrEnv :: LocalRdrEnv -> [Name] -> LocalRdrEnv
280 extendLocalRdrEnv env names
281 = extendOccEnvList env [(nameOccName n, n) | n <- names]
283 lookupLocalRdrEnv :: LocalRdrEnv -> RdrName -> Maybe Name
284 lookupLocalRdrEnv env (Exact name) = Just name
285 lookupLocalRdrEnv env (Unqual occ) = lookupOccEnv env occ
286 lookupLocalRdrEnv env other = Nothing
288 elemLocalRdrEnv :: RdrName -> LocalRdrEnv -> Bool
289 elemLocalRdrEnv rdr_name env
290 | isUnqual rdr_name = rdrNameOcc rdr_name `elemOccEnv` env
295 %************************************************************************
299 %************************************************************************
302 type GlobalRdrEnv = OccEnv [GlobalRdrElt]
303 -- Keyed by OccName; when looking up a qualified name
304 -- we look up the OccName part, and then check the Provenance
305 -- to see if the appropriate qualification is valid. This
306 -- saves routinely doubling the size of the env by adding both
307 -- qualified and unqualified names to the domain.
309 -- The list in the range is reqd because there may be name clashes
310 -- These only get reported on lookup, not on construction
312 -- INVARIANT: All the members of the list have distinct
313 -- gre_name fields; that is, no duplicate Names
315 emptyGlobalRdrEnv = emptyOccEnv
317 globalRdrEnvElts :: GlobalRdrEnv -> [GlobalRdrElt]
318 globalRdrEnvElts env = foldOccEnv (++) [] env
321 = GRE { gre_name :: Name,
322 gre_prov :: Provenance -- Why it's in scope
325 instance Outputable GlobalRdrElt where
326 ppr gre = ppr name <+> pp_parent (nameParent_maybe name)
327 <+> parens (pprNameProvenance gre)
330 pp_parent (Just p) = brackets (text "parent:" <+> ppr p)
331 pp_parent Nothing = empty
333 pprGlobalRdrEnv :: GlobalRdrEnv -> SDoc
335 = vcat (map pp (occEnvElts env))
337 pp gres = ppr (nameOccName (gre_name (head gres))) <> colon <+>
338 vcat [ ppr (gre_name gre) <+> pprNameProvenance gre
343 lookupGlobalRdrEnv :: GlobalRdrEnv -> OccName -> [GlobalRdrElt]
344 lookupGlobalRdrEnv env rdr_name = case lookupOccEnv env rdr_name of
348 extendGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrElt -> GlobalRdrEnv
349 extendGlobalRdrEnv env gre = extendOccEnv_C add env occ [gre]
351 occ = nameOccName (gre_name gre)
352 add gres _ = gre:gres
354 lookupGRE_RdrName :: RdrName -> GlobalRdrEnv -> [GlobalRdrElt]
355 lookupGRE_RdrName rdr_name env
356 = case lookupOccEnv env occ of
358 Just gres | isUnqual rdr_name -> filter unQualOK gres
359 | otherwise -> filter (hasQual mod) gres
361 mod = rdrNameModule rdr_name
362 occ = rdrNameOcc rdr_name
364 lookupGRE_Name :: GlobalRdrEnv -> Name -> [GlobalRdrElt]
365 lookupGRE_Name env name
366 = [ gre | gre <- lookupGlobalRdrEnv env (nameOccName name),
367 gre_name gre == name ]
370 isLocalGRE :: GlobalRdrElt -> Bool
371 isLocalGRE (GRE {gre_prov = LocalDef _}) = True
372 isLocalGRE other = False
374 unQualOK :: GlobalRdrElt -> Bool
375 -- An unqualifed version of this thing is in scope
376 unQualOK (GRE {gre_prov = LocalDef _}) = True
377 unQualOK (GRE {gre_prov = Imported is}) = not (all (is_qual . is_decl) is)
379 hasQual :: Module -> GlobalRdrElt -> Bool
380 -- A qualified version of this thing is in scope
381 hasQual mod (GRE {gre_prov = LocalDef m}) = m == mod
382 hasQual mod (GRE {gre_prov = Imported is}) = any ((== mod) . is_as . is_decl) is
384 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
385 plusGlobalRdrEnv env1 env2 = plusOccEnv_C (foldr insertGRE) env1 env2
387 mkGlobalRdrEnv :: [GlobalRdrElt] -> GlobalRdrEnv
389 = foldr add emptyGlobalRdrEnv gres
391 add gre env = extendOccEnv_C (foldr insertGRE) env
392 (nameOccName (gre_name gre))
395 insertGRE :: GlobalRdrElt -> [GlobalRdrElt] -> [GlobalRdrElt]
396 insertGRE new_g [] = [new_g]
397 insertGRE new_g (old_g : old_gs)
398 | gre_name new_g == gre_name old_g
399 = new_g `plusGRE` old_g : old_gs
401 = old_g : insertGRE new_g old_gs
403 plusGRE :: GlobalRdrElt -> GlobalRdrElt -> GlobalRdrElt
404 -- Used when the gre_name fields match
406 = GRE { gre_name = gre_name g1,
407 gre_prov = gre_prov g1 `plusProv` gre_prov g2 }
411 %************************************************************************
415 %************************************************************************
417 The "provenance" of something says how it came to be in scope.
418 It's quite elaborate so that we can give accurate unused-name warnings.
422 = LocalDef -- Defined locally
425 | Imported -- Imported
426 [ImportSpec] -- INVARIANT: non-empty
428 data ImportSpec = ImpSpec { is_decl :: ImpDeclSpec,
429 is_item :: ImpItemSpec }
432 data ImpDeclSpec -- Describes a particular import declaration
433 -- Shared among all the Provenaces for that decl
435 is_mod :: Module, -- 'import Muggle'
436 -- Note the Muggle may well not be
437 -- the defining module for this thing!
438 is_as :: Module, -- 'as M' (or 'Muggle' if there is no 'as' clause)
439 is_qual :: Bool, -- True <=> qualified (only)
440 is_dloc :: SrcSpan -- Location of import declaration
443 data ImpItemSpec -- Describes import info a particular Name
444 = ImpAll -- The import had no import list,
445 -- or had a hiding list
447 | ImpSome { -- The import had an import list
449 is_iloc :: SrcSpan -- Location of the import item
451 -- The is_explicit field is True iff the thing was named
452 -- *explicitly* in the import specs rather
453 -- than being imported as part of a "..." group
454 -- e.g. import C( T(..) )
455 -- Here the constructors of T are not named explicitly;
456 -- only T is named explicitly.
458 importSpecLoc :: ImportSpec -> SrcSpan
459 importSpecLoc (ImpSpec decl ImpAll) = is_dloc decl
460 importSpecLoc (ImpSpec _ item) = is_iloc item
462 importSpecModule :: ImportSpec -> Module
463 importSpecModule is = is_mod (is_decl is)
465 -- Note [Comparing provenance]
466 -- Comparison of provenance is just used for grouping
467 -- error messages (in RnEnv.warnUnusedBinds)
468 instance Eq Provenance where
469 p1 == p2 = case p1 `compare` p2 of EQ -> True; _ -> False
471 instance Eq ImpDeclSpec where
472 p1 == p2 = case p1 `compare` p2 of EQ -> True; _ -> False
474 instance Eq ImpItemSpec where
475 p1 == p2 = case p1 `compare` p2 of EQ -> True; _ -> False
477 instance Ord Provenance where
478 compare (LocalDef _) (LocalDef _) = EQ
479 compare (LocalDef _) (Imported _) = LT
480 compare (Imported _ ) (LocalDef _) = GT
481 compare (Imported is1) (Imported is2) = compare (head is1)
482 {- See Note [Comparing provenance] -} (head is2)
484 instance Ord ImpDeclSpec where
485 compare is1 is2 = (is_mod is1 `compare` is_mod is2) `thenCmp`
486 (is_dloc is1 `compare` is_dloc is2)
488 instance Ord ImpItemSpec where
489 compare is1 is2 = is_iloc is1 `compare` is_iloc is2
493 plusProv :: Provenance -> Provenance -> Provenance
494 -- Choose LocalDef over Imported
495 -- There is an obscure bug lurking here; in the presence
496 -- of recursive modules, something can be imported *and* locally
497 -- defined, and one might refer to it with a qualified name from
498 -- the import -- but I'm going to ignore that because it makes
499 -- the isLocalGRE predicate so much nicer this way
500 plusProv (LocalDef m1) (LocalDef m2) = pprPanic "plusProv" (ppr m1 <+> ppr m2)
501 plusProv p1@(LocalDef _) p2 = p1
502 plusProv p1 p2@(LocalDef _) = p2
503 plusProv (Imported is1) (Imported is2) = Imported (is1++is2)
505 pprNameProvenance :: GlobalRdrElt -> SDoc
506 pprNameProvenance (GRE {gre_name = name, gre_prov = LocalDef _})
507 = ptext SLIT("defined at") <+> ppr (nameSrcLoc name)
508 pprNameProvenance (GRE {gre_name = name, gre_prov = Imported (why:whys)})
509 = sep [ppr why, nest 2 (ppr_defn (nameSrcLoc name))]
511 -- If we know the exact definition point (which we may do with GHCi)
512 -- then show that too. But not if it's just "imported from X".
513 ppr_defn loc | isGoodSrcLoc loc = parens (ptext SLIT("defined at") <+> ppr loc)
516 instance Outputable ImportSpec where
517 ppr imp_spec@(ImpSpec imp_decl _)
518 = ptext SLIT("imported from") <+> ppr (is_mod imp_decl)
519 <+> ptext SLIT("at") <+> ppr (importSpecLoc imp_spec)