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, pprGlobalRdrEnv, globalRdrEnvElts,
31 lookupGRE_RdrName, lookupGRE_Name,
33 -- GlobalRdrElt, Provenance, ImportSpec
34 GlobalRdrElt(..), Provenance(..), ImportSpec(..),
39 #include "HsVersions.h"
41 import OccName ( NameSpace, varName,
44 mkOccFS, occNameFlavour,
45 isDataOcc, isTvOcc, isTcOcc,
46 OccEnv, emptyOccEnv, extendOccEnvList, lookupOccEnv,
47 elemOccEnv, plusOccEnv_C, extendOccEnv_C, foldOccEnv,
50 import Module ( Module, mkModuleFS )
51 import Name ( Name, NamedThing(getName), nameModule, nameParent_maybe,
52 nameOccName, isExternalName, nameSrcLoc )
53 import SrcLoc ( isGoodSrcLoc, SrcSpan )
55 import Util ( thenCmp )
59 %************************************************************************
61 \subsection{The main data type}
63 %************************************************************************
68 -- Used for ordinary, unqualified occurrences
71 -- A qualified name written by the user in
72 -- *source* code. The module isn't necessarily
73 -- the module where the thing is defined;
74 -- just the one from which it is imported
77 -- An original name; the module is the *defining* module.
78 -- This is used when GHC generates code that will be fed
79 -- into the renamer (e.g. from deriving clauses), but where
80 -- we want to say "Use Prelude.map dammit".
83 -- We know exactly the Name. This is used
84 -- (a) when the parser parses built-in syntax like "[]"
85 -- and "(,)", but wants a RdrName from it
86 -- (b) when converting names to the RdrNames in IfaceTypes
87 -- Here an Exact RdrName always contains an External Name
88 -- (Internal Names are converted to simple Unquals)
89 -- (c) by Template Haskell, when TH has generated a unique name
93 %************************************************************************
95 \subsection{Simple functions}
97 %************************************************************************
100 rdrNameModule :: RdrName -> Module
101 rdrNameModule (Qual m _) = m
102 rdrNameModule (Orig m _) = m
103 rdrNameModule (Exact n) = nameModule n
104 rdrNameModule (Unqual n) = pprPanic "rdrNameModule" (ppr n)
106 rdrNameOcc :: RdrName -> OccName
107 rdrNameOcc (Qual _ occ) = occ
108 rdrNameOcc (Unqual occ) = occ
109 rdrNameOcc (Orig _ occ) = occ
110 rdrNameOcc (Exact name) = nameOccName name
112 setRdrNameSpace :: RdrName -> NameSpace -> RdrName
113 -- This rather gruesome function is used mainly by the parser
114 -- When parsing data T a = T | T1 Int
115 -- we parse the data constructors as *types* because of parser ambiguities,
116 -- so then we need to change the *type constr* to a *data constr*
118 -- The original-name case *can* occur when parsing
119 -- data [] a = [] | a : [a]
120 -- For the orig-name case we return an unqualified name.
121 setRdrNameSpace (Unqual occ) ns = Unqual (setOccNameSpace ns occ)
122 setRdrNameSpace (Qual m occ) ns = Qual m (setOccNameSpace ns occ)
123 setRdrNameSpace (Orig m occ) ns = Orig m (setOccNameSpace ns occ)
124 setRdrNameSpace (Exact n) ns = Orig (nameModule n)
125 (setOccNameSpace ns (nameOccName n))
129 -- These two are the basic constructors
130 mkRdrUnqual :: OccName -> RdrName
131 mkRdrUnqual occ = Unqual occ
133 mkRdrQual :: Module -> OccName -> RdrName
134 mkRdrQual mod occ = Qual mod occ
136 mkOrig :: Module -> OccName -> RdrName
137 mkOrig mod occ = Orig mod occ
140 mkDerivedRdrName :: Name -> (OccName -> OccName) -> (RdrName)
141 mkDerivedRdrName parent mk_occ
142 = mkOrig (nameModule parent) (mk_occ (nameOccName parent))
145 -- These two are used when parsing source files
146 -- They do encode the module and occurrence names
147 mkUnqual :: NameSpace -> UserFS -> RdrName
148 mkUnqual sp n = Unqual (mkOccFS sp n)
150 mkVarUnqual :: UserFS -> RdrName
151 mkVarUnqual n = Unqual (mkOccFS varName n)
153 mkQual :: NameSpace -> (UserFS, UserFS) -> RdrName
154 mkQual sp (m, n) = Qual (mkModuleFS m) (mkOccFS sp n)
156 getRdrName :: NamedThing thing => thing -> RdrName
157 getRdrName name = nameRdrName (getName name)
159 nameRdrName :: Name -> RdrName
160 nameRdrName name = Exact name
161 -- Keep the Name even for Internal names, so that the
162 -- unique is still there for debug printing, particularly
163 -- of Types (which are converted to IfaceTypes before printing)
165 nukeExact :: Name -> RdrName
167 | isExternalName n = Orig (nameModule n) (nameOccName n)
168 | otherwise = Unqual (nameOccName n)
172 isRdrDataCon rn = isDataOcc (rdrNameOcc rn)
173 isRdrTyVar rn = isTvOcc (rdrNameOcc rn)
174 isRdrTc rn = isTcOcc (rdrNameOcc rn)
176 isSrcRdrName (Unqual _) = True
177 isSrcRdrName (Qual _ _) = True
178 isSrcRdrName _ = False
180 isUnqual (Unqual _) = True
181 isUnqual other = False
183 isQual (Qual _ _) = True
186 isOrig (Orig _ _) = True
189 isOrig_maybe (Orig m n) = Just (m,n)
190 isOrig_maybe _ = Nothing
192 isExact (Exact _) = True
193 isExact other = False
195 isExact_maybe (Exact n) = Just n
196 isExact_maybe other = Nothing
200 %************************************************************************
202 \subsection{Instances}
204 %************************************************************************
207 instance Outputable RdrName where
208 ppr (Exact name) = ppr name
209 ppr (Unqual occ) = ppr occ <+> ppr_name_space occ
210 ppr (Qual mod occ) = ppr mod <> dot <> ppr occ <+> ppr_name_space occ
211 ppr (Orig mod occ) = ppr mod <> dot <> ppr occ <+> ppr_name_space occ
213 ppr_name_space occ = ifPprDebug (parens (occNameFlavour occ))
215 instance OutputableBndr RdrName where
217 | isTvOcc (rdrNameOcc n) = char '@' <+> ppr n
220 instance Eq RdrName where
221 (Exact n1) == (Exact n2) = n1==n2
222 -- Convert exact to orig
223 (Exact n1) == r2@(Orig _ _) = nukeExact n1 == r2
224 r1@(Orig _ _) == (Exact n2) = r1 == nukeExact n2
226 (Orig m1 o1) == (Orig m2 o2) = m1==m2 && o1==o2
227 (Qual m1 o1) == (Qual m2 o2) = m1==m2 && o1==o2
228 (Unqual o1) == (Unqual o2) = o1==o2
231 instance Ord RdrName where
232 a <= b = case (a `compare` b) of { LT -> True; EQ -> True; GT -> False }
233 a < b = case (a `compare` b) of { LT -> True; EQ -> False; GT -> False }
234 a >= b = case (a `compare` b) of { LT -> False; EQ -> True; GT -> True }
235 a > b = case (a `compare` b) of { LT -> False; EQ -> False; GT -> True }
237 -- Exact < Unqual < Qual < Orig
238 -- [Note: Apr 2004] We used to use nukeExact to convert Exact to Orig
239 -- before comparing so that Prelude.map == the exact Prelude.map, but
240 -- that meant that we reported duplicates when renaming bindings
241 -- generated by Template Haskell; e.g
242 -- do { n1 <- newName "foo"; n2 <- newName "foo";
243 -- <decl involving n1,n2> }
244 -- I think we can do without this conversion
245 compare (Exact n1) (Exact n2) = n1 `compare` n2
246 compare (Exact n1) n2 = LT
248 compare (Unqual _) (Exact _) = GT
249 compare (Unqual o1) (Unqual o2) = o1 `compare` o2
250 compare (Unqual _) _ = LT
252 compare (Qual _ _) (Exact _) = GT
253 compare (Qual _ _) (Unqual _) = GT
254 compare (Qual m1 o1) (Qual m2 o2) = (o1 `compare` o2) `thenCmp` (m1 `compare` m2)
255 compare (Qual _ _) (Orig _ _) = LT
257 compare (Orig m1 o1) (Orig m2 o2) = (o1 `compare` o2) `thenCmp` (m1 `compare` m2)
258 compare (Orig _ _) _ = GT
263 %************************************************************************
267 %************************************************************************
269 A LocalRdrEnv is used for local bindings (let, where, lambda, case)
270 It is keyed by OccName, because we never use it for qualified names.
273 type LocalRdrEnv = OccEnv Name
275 emptyLocalRdrEnv = emptyOccEnv
277 extendLocalRdrEnv :: LocalRdrEnv -> [Name] -> LocalRdrEnv
278 extendLocalRdrEnv env names
279 = extendOccEnvList env [(nameOccName n, n) | n <- names]
281 lookupLocalRdrEnv :: LocalRdrEnv -> RdrName -> Maybe Name
282 lookupLocalRdrEnv env (Exact name) = Just name
283 lookupLocalRdrEnv env (Unqual occ) = lookupOccEnv env occ
284 lookupLocalRdrEnv env other = Nothing
286 elemLocalRdrEnv :: RdrName -> LocalRdrEnv -> Bool
287 elemLocalRdrEnv rdr_name env
288 | isUnqual rdr_name = rdrNameOcc rdr_name `elemOccEnv` env
293 %************************************************************************
297 %************************************************************************
300 type GlobalRdrEnv = OccEnv [GlobalRdrElt]
301 -- Keyed by OccName; when looking up a qualified name
302 -- we look up the OccName part, and then check the Provenance
303 -- to see if the appropriate qualification is valid. This
304 -- saves routinely doubling the size of the env by adding both
305 -- qualified and unqualified names to the domain.
307 -- The list in the range is reqd because there may be name clashes
308 -- These only get reported on lookup, not on construction
310 -- INVARIANT: All the members of the list have distinct
311 -- gre_name fields; that is, no duplicate Names
313 emptyGlobalRdrEnv = emptyOccEnv
315 globalRdrEnvElts :: GlobalRdrEnv -> [GlobalRdrElt]
316 globalRdrEnvElts env = foldOccEnv (++) [] env
319 = GRE { gre_name :: Name,
320 gre_prov :: Provenance -- Why it's in scope
323 instance Outputable GlobalRdrElt where
324 ppr gre = ppr name <+> pp_parent (nameParent_maybe name)
325 <+> parens (pprNameProvenance gre)
328 pp_parent (Just p) = brackets (text "parent:" <+> ppr p)
329 pp_parent Nothing = empty
331 pprGlobalRdrEnv :: GlobalRdrEnv -> SDoc
333 = vcat (map pp (occEnvElts env))
335 pp gres = ppr (nameOccName (gre_name (head gres))) <> colon <+>
336 vcat [ ppr (gre_name gre) <+> pprNameProvenance gre
341 lookupGlobalRdrEnv :: GlobalRdrEnv -> OccName -> [GlobalRdrElt]
342 lookupGlobalRdrEnv env rdr_name = case lookupOccEnv env rdr_name of
346 lookupGRE_RdrName :: RdrName -> GlobalRdrEnv -> [GlobalRdrElt]
347 lookupGRE_RdrName rdr_name env
348 = case lookupOccEnv env occ of
350 Just gres | isUnqual rdr_name -> filter unQualOK gres
351 | otherwise -> filter (hasQual mod) gres
353 mod = rdrNameModule rdr_name
354 occ = rdrNameOcc rdr_name
356 lookupGRE_Name :: GlobalRdrEnv -> Name -> [GlobalRdrElt]
357 lookupGRE_Name env name
358 = [ gre | gre <- lookupGlobalRdrEnv env (nameOccName name),
359 gre_name gre == name ]
362 isLocalGRE :: GlobalRdrElt -> Bool
363 isLocalGRE (GRE {gre_prov = LocalDef _}) = True
364 isLocalGRE other = False
366 unQualOK :: GlobalRdrElt -> Bool
367 -- An unqualifed version of this thing is in scope
368 unQualOK (GRE {gre_prov = LocalDef _}) = True
369 unQualOK (GRE {gre_prov = Imported is _}) = not (all is_qual is)
371 hasQual :: Module -> GlobalRdrElt -> Bool
372 -- A qualified version of this thing is in scope
373 hasQual mod (GRE {gre_prov = LocalDef m}) = m == mod
374 hasQual mod (GRE {gre_prov = Imported is _}) = any ((== mod) . is_as) is
376 plusGlobalRdrEnv :: GlobalRdrEnv -> GlobalRdrEnv -> GlobalRdrEnv
377 plusGlobalRdrEnv env1 env2 = plusOccEnv_C (foldr insertGRE) env1 env2
379 mkGlobalRdrEnv :: [GlobalRdrElt] -> GlobalRdrEnv
381 = foldr add emptyGlobalRdrEnv gres
383 add gre env = extendOccEnv_C (foldr insertGRE) env
384 (nameOccName (gre_name gre))
387 insertGRE :: GlobalRdrElt -> [GlobalRdrElt] -> [GlobalRdrElt]
388 insertGRE new_g [] = [new_g]
389 insertGRE new_g (old_g : old_gs)
390 | gre_name new_g == gre_name old_g
391 = new_g `plusGRE` old_g : old_gs
393 = old_g : insertGRE new_g old_gs
395 plusGRE :: GlobalRdrElt -> GlobalRdrElt -> GlobalRdrElt
396 -- Used when the gre_name fields match
398 = GRE { gre_name = gre_name g1,
399 gre_prov = gre_prov g1 `plusProv` gre_prov g2 }
403 %************************************************************************
407 %************************************************************************
409 The "provenance" of something says how it came to be in scope.
413 = LocalDef -- Defined locally
416 | Imported -- Imported
417 [ImportSpec] -- INVARIANT: non-empty
418 Bool -- True iff the thing was named *explicitly*
419 -- in *any* of the import specs rather than being
420 -- imported as part of a group;
424 -- Here, everything imported by B, and the constructors of T
425 -- are not named explicitly; only T is named explicitly.
426 -- This info is used when warning of unused names.
428 data ImportSpec -- Describes a particular import declaration
429 -- Shared among all the Provenaces for a particular
430 -- import declaration
432 is_mod :: Module, -- 'import Muggle'
433 -- Note the Muggle may well not be
434 -- the defining module for this thing!
435 is_as :: Module, -- 'as M' (or 'Muggle' if there is no 'as' clause)
436 is_qual :: Bool, -- True <=> qualified (only)
437 is_loc :: SrcSpan } -- Location of import statment
439 -- Comparison of provenance is just used for grouping
440 -- error messages (in RnEnv.warnUnusedBinds)
441 instance Eq Provenance where
442 p1 == p2 = case p1 `compare` p2 of EQ -> True; _ -> False
444 instance Eq ImportSpec where
445 p1 == p2 = case p1 `compare` p2 of EQ -> True; _ -> False
447 instance Ord Provenance where
448 compare (LocalDef _) (LocalDef _) = EQ
449 compare (LocalDef _) (Imported _ _) = LT
450 compare (Imported _ _) (LocalDef _) = GT
451 compare (Imported is1 _) (Imported is2 _) = compare (head is1) (head is2)
453 instance Ord ImportSpec where
454 compare is1 is2 = (is_mod is1 `compare` is_mod is2) `thenCmp`
455 (is_loc is1 `compare` is_loc is2)
459 plusProv :: Provenance -> Provenance -> Provenance
460 -- Choose LocalDef over Imported
461 -- There is an obscure bug lurking here; in the presence
462 -- of recursive modules, something can be imported *and* locally
463 -- defined, and one might refer to it with a qualified name from
464 -- the import -- but I'm going to ignore that because it makes
465 -- the isLocalGRE predicate so much nicer this way
466 plusProv (LocalDef m1) (LocalDef m2)
467 = pprPanic "plusProv" (ppr m1 <+> ppr m2)
468 plusProv p1@(LocalDef _) p2 = p1
469 plusProv p1 p2@(LocalDef _) = p2
470 plusProv (Imported is1 ex1) (Imported is2 ex2)
471 = Imported (is1++is2) (ex1 || ex2)
473 pprNameProvenance :: GlobalRdrElt -> SDoc
474 pprNameProvenance (GRE {gre_name = name, gre_prov = LocalDef _})
475 = ptext SLIT("defined at") <+> ppr (nameSrcLoc name)
476 pprNameProvenance (GRE {gre_name = name, gre_prov = Imported (why:whys) _})
477 = sep [ppr why, nest 2 (ppr_defn (nameSrcLoc name))]
479 -- If we know the exact definition point (which we may do with GHCi)
480 -- then show that too. But not if it's just "imported from X".
481 ppr_defn loc | isGoodSrcLoc loc = parens (ptext SLIT("defined at") <+> ppr loc)
484 instance Outputable ImportSpec where
486 = ptext SLIT("imported from") <+> ppr (is_mod imp_spec)
487 <+> ptext SLIT("at") <+> ppr (is_loc imp_spec)