2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
9 -- GHC uses several kinds of name internally:
11 -- * 'OccName.OccName' represents names as strings with just a little more information:
12 -- the \"namespace\" that the name came from, e.g. the namespace of value, type constructors or
15 -- * 'RdrName.RdrName': see "RdrName#name_types"
17 -- * 'Name.Name': see "Name#name_types"
19 -- * 'Id.Id': see "Id#name_types"
21 -- * 'Var.Var': see "Var#name_types"
23 -- * The 'NameSpace' type
24 NameSpace, -- Abstract
27 -- $real_vs_source_data_constructors
28 tcName, clsName, tcClsName, dataName, varName,
32 pprNameSpace, pprNonVarNameSpace, pprNameSpaceBrief,
34 -- * The 'OccName' type
35 OccName, -- Abstract, instance of Outputable
39 mkOccName, mkOccNameFS,
41 mkDataOcc, mkDataOccFS,
42 mkTyVarOcc, mkTyVarOccFS,
49 -- ** Derived 'OccName's
51 mkDataConWrapperOcc, mkWorkerOcc, mkDefaultMethodOcc,
52 mkDerivedTyConOcc, mkNewTyCoOcc, mkClassOpAuxOcc,
53 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
54 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
55 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
56 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc,
57 mkSuperDictSelOcc, mkLocalOcc, mkMethodOcc, mkInstTyTcOcc,
58 mkInstTyCoOcc, mkEqPredCoOcc,
59 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
60 mkPDataTyConOcc, mkPDataDataConOcc,
65 occNameFS, occNameString, occNameSpace,
67 isVarOcc, isTvOcc, isTcOcc, isDataOcc, isDataSymOcc, isSymOcc, isValOcc,
68 parenSymOcc, startsWithUnderscore,
70 isTcClsNameSpace, isTvNameSpace, isDataConNameSpace, isVarNameSpace, isValNameSpace,
74 -- * The 'OccEnv' type
75 OccEnv, emptyOccEnv, unitOccEnv, extendOccEnv, mapOccEnv,
76 lookupOccEnv, mkOccEnv, mkOccEnv_C, extendOccEnvList, elemOccEnv,
77 occEnvElts, foldOccEnv, plusOccEnv, plusOccEnv_C, extendOccEnv_C,
78 extendOccEnv_Acc, filterOccEnv, delListFromOccEnv, delFromOccEnv,
80 -- * The 'OccSet' type
81 OccSet, emptyOccSet, unitOccSet, mkOccSet, extendOccSet,
83 unionOccSets, unionManyOccSets, minusOccSet, elemOccSet, occSetElts,
84 foldOccSet, isEmptyOccSet, intersectOccSet, intersectsOccSet,
87 TidyOccEnv, emptyTidyOccEnv, tidyOccName, initTidyOccEnv,
89 -- * Lexical characteristics of Haskell names
90 isLexCon, isLexVar, isLexId, isLexSym,
91 isLexConId, isLexConSym, isLexVarId, isLexVarSym,
92 startsVarSym, startsVarId, startsConSym, startsConId
105 import StaticFlags( opt_SuppressUniques )
110 %************************************************************************
112 \subsection{Name space}
114 %************************************************************************
117 data NameSpace = VarName -- Variables, including "real" data constructors
118 | DataName -- "Source" data constructors
119 | TvName -- Type variables
120 | TcClsName -- Type constructors and classes; Haskell has them
121 -- in the same name space for now.
123 {-! derive: Binary !-}
125 -- Note [Data Constructors]
126 -- see also: Note [Data Constructor Naming] in DataCon.lhs
128 -- $real_vs_source_data_constructors
129 -- There are two forms of data constructor:
131 -- [Source data constructors] The data constructors mentioned in Haskell source code
133 -- [Real data constructors] The data constructors of the representation type, which may not be the same as the source type
137 -- > data T = T !(Int, Int)
139 -- The source datacon has type @(Int, Int) -> T@
140 -- The real datacon has type @Int -> Int -> T@
142 -- GHC chooses a representation based on the strictness etc.
144 tcName, clsName, tcClsName :: NameSpace
145 dataName, srcDataName :: NameSpace
146 tvName, varName :: NameSpace
148 -- Though type constructors and classes are in the same name space now,
149 -- the NameSpace type is abstract, so we can easily separate them later
150 tcName = TcClsName -- Type constructors
151 clsName = TcClsName -- Classes
152 tcClsName = TcClsName -- Not sure which!
155 srcDataName = DataName -- Haskell-source data constructors should be
156 -- in the Data name space
161 isDataConNameSpace :: NameSpace -> Bool
162 isDataConNameSpace DataName = True
163 isDataConNameSpace _ = False
165 isTcClsNameSpace :: NameSpace -> Bool
166 isTcClsNameSpace TcClsName = True
167 isTcClsNameSpace _ = False
169 isTvNameSpace :: NameSpace -> Bool
170 isTvNameSpace TvName = True
171 isTvNameSpace _ = False
173 isVarNameSpace :: NameSpace -> Bool -- Variables or type variables, but not constructors
174 isVarNameSpace TvName = True
175 isVarNameSpace VarName = True
176 isVarNameSpace _ = False
178 isValNameSpace :: NameSpace -> Bool
179 isValNameSpace DataName = True
180 isValNameSpace VarName = True
181 isValNameSpace _ = False
183 pprNameSpace :: NameSpace -> SDoc
184 pprNameSpace DataName = ptext (sLit "data constructor")
185 pprNameSpace VarName = ptext (sLit "variable")
186 pprNameSpace TvName = ptext (sLit "type variable")
187 pprNameSpace TcClsName = ptext (sLit "type constructor or class")
189 pprNonVarNameSpace :: NameSpace -> SDoc
190 pprNonVarNameSpace VarName = empty
191 pprNonVarNameSpace ns = pprNameSpace ns
193 pprNameSpaceBrief :: NameSpace -> SDoc
194 pprNameSpaceBrief DataName = char 'd'
195 pprNameSpaceBrief VarName = char 'v'
196 pprNameSpaceBrief TvName = ptext (sLit "tv")
197 pprNameSpaceBrief TcClsName = ptext (sLit "tc")
201 %************************************************************************
203 \subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
205 %************************************************************************
208 data OccName = OccName
209 { occNameSpace :: !NameSpace
210 , occNameFS :: !FastString
216 instance Eq OccName where
217 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
219 instance Ord OccName where
220 -- Compares lexicographically, *not* by Unique of the string
221 compare (OccName sp1 s1) (OccName sp2 s2)
222 = (s1 `compare` s2) `thenCmp` (sp1 `compare` sp2)
224 INSTANCE_TYPEABLE0(OccName,occNameTc,"OccName")
226 instance Data OccName where
228 toConstr _ = abstractConstr "OccName"
229 gunfold _ _ = error "gunfold"
230 dataTypeOf _ = mkNoRepType "OccName"
234 %************************************************************************
236 \subsection{Printing}
238 %************************************************************************
241 instance Outputable OccName where
244 pprOccName :: OccName -> SDoc
245 pprOccName (OccName sp occ)
246 = getPprStyle $ \ sty ->
248 then ftext (zEncodeFS occ)
249 else pp_occ <> pp_debug sty
251 pp_debug sty | debugStyle sty = braces (pprNameSpaceBrief sp)
254 pp_occ | opt_SuppressUniques = text (strip_th_unique (unpackFS occ))
255 | otherwise = ftext occ
257 -- See Note [Suppressing uniques in OccNames]
258 strip_th_unique ('[' : c : _) | isAlphaNum c = []
259 strip_th_unique (c : cs) = c : strip_th_unique cs
260 strip_th_unique [] = []
263 Note [Suppressing uniques in OccNames]
264 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
265 This is a hack to de-wobblify the OccNames that contain uniques from
266 Template Haskell that have been turned into a string in the OccName.
267 See Note [Unique OccNames from Template Haskell] in Convert.hs
269 %************************************************************************
271 \subsection{Construction}
273 %************************************************************************
276 mkOccName :: NameSpace -> String -> OccName
277 mkOccName occ_sp str = OccName occ_sp (mkFastString str)
279 mkOccNameFS :: NameSpace -> FastString -> OccName
280 mkOccNameFS occ_sp fs = OccName occ_sp fs
282 mkVarOcc :: String -> OccName
283 mkVarOcc s = mkOccName varName s
285 mkVarOccFS :: FastString -> OccName
286 mkVarOccFS fs = mkOccNameFS varName fs
288 mkDataOcc :: String -> OccName
289 mkDataOcc = mkOccName dataName
291 mkDataOccFS :: FastString -> OccName
292 mkDataOccFS = mkOccNameFS dataName
294 mkTyVarOcc :: String -> OccName
295 mkTyVarOcc = mkOccName tvName
297 mkTyVarOccFS :: FastString -> OccName
298 mkTyVarOccFS fs = mkOccNameFS tvName fs
300 mkTcOcc :: String -> OccName
301 mkTcOcc = mkOccName tcName
303 mkTcOccFS :: FastString -> OccName
304 mkTcOccFS = mkOccNameFS tcName
306 mkClsOcc :: String -> OccName
307 mkClsOcc = mkOccName clsName
309 mkClsOccFS :: FastString -> OccName
310 mkClsOccFS = mkOccNameFS clsName
314 %************************************************************************
318 %************************************************************************
320 OccEnvs are used mainly for the envts in ModIfaces.
322 Note [The Unique of an OccName]
323 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
324 They are efficient, because FastStrings have unique Int# keys. We assume
325 this key is less than 2^24, and indeed FastStrings are allocated keys
326 sequentially starting at 0.
328 So we can make a Unique using
329 mkUnique ns key :: Unique
330 where 'ns' is a Char reprsenting the name space. This in turn makes it
331 easy to build an OccEnv.
334 instance Uniquable OccName where
335 -- See Note [The Unique of an OccName]
336 getUnique (OccName VarName fs) = mkVarOccUnique fs
337 getUnique (OccName DataName fs) = mkDataOccUnique fs
338 getUnique (OccName TvName fs) = mkTvOccUnique fs
339 getUnique (OccName TcClsName fs) = mkTcOccUnique fs
341 newtype OccEnv a = A (UniqFM a)
343 emptyOccEnv :: OccEnv a
344 unitOccEnv :: OccName -> a -> OccEnv a
345 extendOccEnv :: OccEnv a -> OccName -> a -> OccEnv a
346 extendOccEnvList :: OccEnv a -> [(OccName, a)] -> OccEnv a
347 lookupOccEnv :: OccEnv a -> OccName -> Maybe a
348 mkOccEnv :: [(OccName,a)] -> OccEnv a
349 mkOccEnv_C :: (a -> a -> a) -> [(OccName,a)] -> OccEnv a
350 elemOccEnv :: OccName -> OccEnv a -> Bool
351 foldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b
352 occEnvElts :: OccEnv a -> [a]
353 extendOccEnv_C :: (a->a->a) -> OccEnv a -> OccName -> a -> OccEnv a
354 extendOccEnv_Acc :: (a->b->b) -> (a->b) -> OccEnv b -> OccName -> a -> OccEnv b
355 plusOccEnv :: OccEnv a -> OccEnv a -> OccEnv a
356 plusOccEnv_C :: (a->a->a) -> OccEnv a -> OccEnv a -> OccEnv a
357 mapOccEnv :: (a->b) -> OccEnv a -> OccEnv b
358 delFromOccEnv :: OccEnv a -> OccName -> OccEnv a
359 delListFromOccEnv :: OccEnv a -> [OccName] -> OccEnv a
360 filterOccEnv :: (elt -> Bool) -> OccEnv elt -> OccEnv elt
362 emptyOccEnv = A emptyUFM
363 unitOccEnv x y = A $ unitUFM x y
364 extendOccEnv (A x) y z = A $ addToUFM x y z
365 extendOccEnvList (A x) l = A $ addListToUFM x l
366 lookupOccEnv (A x) y = lookupUFM x y
367 mkOccEnv l = A $ listToUFM l
368 elemOccEnv x (A y) = elemUFM x y
369 foldOccEnv a b (A c) = foldUFM a b c
370 occEnvElts (A x) = eltsUFM x
371 plusOccEnv (A x) (A y) = A $ plusUFM x y
372 plusOccEnv_C f (A x) (A y) = A $ plusUFM_C f x y
373 extendOccEnv_C f (A x) y z = A $ addToUFM_C f x y z
374 extendOccEnv_Acc f g (A x) y z = A $ addToUFM_Acc f g x y z
375 mapOccEnv f (A x) = A $ mapUFM f x
376 mkOccEnv_C comb l = A $ addListToUFM_C comb emptyUFM l
377 delFromOccEnv (A x) y = A $ delFromUFM x y
378 delListFromOccEnv (A x) y = A $ delListFromUFM x y
379 filterOccEnv x (A y) = A $ filterUFM x y
381 instance Outputable a => Outputable (OccEnv a) where
384 type OccSet = UniqSet OccName
386 emptyOccSet :: OccSet
387 unitOccSet :: OccName -> OccSet
388 mkOccSet :: [OccName] -> OccSet
389 extendOccSet :: OccSet -> OccName -> OccSet
390 extendOccSetList :: OccSet -> [OccName] -> OccSet
391 unionOccSets :: OccSet -> OccSet -> OccSet
392 unionManyOccSets :: [OccSet] -> OccSet
393 minusOccSet :: OccSet -> OccSet -> OccSet
394 elemOccSet :: OccName -> OccSet -> Bool
395 occSetElts :: OccSet -> [OccName]
396 foldOccSet :: (OccName -> b -> b) -> b -> OccSet -> b
397 isEmptyOccSet :: OccSet -> Bool
398 intersectOccSet :: OccSet -> OccSet -> OccSet
399 intersectsOccSet :: OccSet -> OccSet -> Bool
401 emptyOccSet = emptyUniqSet
402 unitOccSet = unitUniqSet
404 extendOccSet = addOneToUniqSet
405 extendOccSetList = addListToUniqSet
406 unionOccSets = unionUniqSets
407 unionManyOccSets = unionManyUniqSets
408 minusOccSet = minusUniqSet
409 elemOccSet = elementOfUniqSet
410 occSetElts = uniqSetToList
411 foldOccSet = foldUniqSet
412 isEmptyOccSet = isEmptyUniqSet
413 intersectOccSet = intersectUniqSets
414 intersectsOccSet s1 s2 = not (isEmptyOccSet (s1 `intersectOccSet` s2))
418 %************************************************************************
420 \subsection{Predicates and taking them apart}
422 %************************************************************************
425 occNameString :: OccName -> String
426 occNameString (OccName _ s) = unpackFS s
428 setOccNameSpace :: NameSpace -> OccName -> OccName
429 setOccNameSpace sp (OccName _ occ) = OccName sp occ
431 isVarOcc, isTvOcc, isTcOcc, isDataOcc :: OccName -> Bool
433 isVarOcc (OccName VarName _) = True
436 isTvOcc (OccName TvName _) = True
439 isTcOcc (OccName TcClsName _) = True
442 -- | /Value/ 'OccNames's are those that are either in
443 -- the variable or data constructor namespaces
444 isValOcc :: OccName -> Bool
445 isValOcc (OccName VarName _) = True
446 isValOcc (OccName DataName _) = True
449 isDataOcc (OccName DataName _) = True
450 isDataOcc (OccName VarName s)
451 | isLexCon s = pprPanic "isDataOcc: check me" (ppr s)
452 -- Jan06: I don't think this should happen
455 -- | Test if the 'OccName' is a data constructor that starts with
456 -- a symbol (e.g. @:@, or @[]@)
457 isDataSymOcc :: OccName -> Bool
458 isDataSymOcc (OccName DataName s) = isLexConSym s
459 isDataSymOcc (OccName VarName s)
460 | isLexConSym s = pprPanic "isDataSymOcc: check me" (ppr s)
461 -- Jan06: I don't think this should happen
462 isDataSymOcc _ = False
463 -- Pretty inefficient!
465 -- | Test if the 'OccName' is that for any operator (whether
466 -- it is a data constructor or variable or whatever)
467 isSymOcc :: OccName -> Bool
468 isSymOcc (OccName DataName s) = isLexConSym s
469 isSymOcc (OccName TcClsName s) = isLexConSym s
470 isSymOcc (OccName VarName s) = isLexSym s
471 isSymOcc (OccName TvName s) = isLexSym s
472 -- Pretty inefficient!
474 parenSymOcc :: OccName -> SDoc -> SDoc
475 -- ^ Wrap parens around an operator
476 parenSymOcc occ doc | isSymOcc occ = parens doc
482 startsWithUnderscore :: OccName -> Bool
483 -- ^ Haskell 98 encourages compilers to suppress warnings about unsed
484 -- names in a pattern if they start with @_@: this implements that test
485 startsWithUnderscore occ = case occNameString occ of
491 %************************************************************************
493 \subsection{Making system names}
495 %************************************************************************
497 Here's our convention for splitting up the interface file name space:
499 d... dictionary identifiers
500 (local variables, so no name-clash worries)
502 All of these other OccNames contain a mixture of alphabetic
503 and symbolic characters, and hence cannot possibly clash with
504 a user-written type or function name
506 $f... Dict-fun identifiers (from inst decls)
507 $dmop Default method for 'op'
508 $pnC n'th superclass selector for class C
509 $wf Worker for functtoin 'f'
510 $sf.. Specialised version of f
511 T:C Tycon for dictionary for class C
512 D:C Data constructor for dictionary for class C
513 NTCo:T Coercion connecting newtype T with its representation type
514 TFCo:R Coercion connecting a data family to its respresentation type R
516 In encoded form these appear as Zdfxxx etc
518 :... keywords (export:, letrec: etc.)
519 --- I THINK THIS IS WRONG!
521 This knowledge is encoded in the following functions.
523 @mk_deriv@ generates an @OccName@ from the prefix and a string.
524 NB: The string must already be encoded!
527 mk_deriv :: NameSpace
528 -> String -- Distinguishes one sort of derived name from another
532 mk_deriv occ_sp sys_prefix str = mkOccName occ_sp (sys_prefix ++ str)
534 isDerivedOccName :: OccName -> Bool
535 isDerivedOccName occ =
536 case occNameString occ of
537 '$':c:_ | isAlphaNum c -> True
538 ':':c:_ | isAlphaNum c -> True
543 mkDataConWrapperOcc, mkWorkerOcc, mkDefaultMethodOcc, mkDerivedTyConOcc,
544 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
545 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
546 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
547 mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
548 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
549 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
550 mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
551 :: OccName -> OccName
553 -- These derived variables have a prefix that no Haskell value could have
554 mkDataConWrapperOcc = mk_simple_deriv varName "$W"
555 mkWorkerOcc = mk_simple_deriv varName "$w"
556 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
557 mkClassOpAuxOcc = mk_simple_deriv varName "$c"
558 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
559 mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
560 mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
561 -- for datacons from classes
562 mkDictOcc = mk_simple_deriv varName "$d"
563 mkIPOcc = mk_simple_deriv varName "$i"
564 mkSpecOcc = mk_simple_deriv varName "$s"
565 mkForeignExportOcc = mk_simple_deriv varName "$f"
566 mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
567 mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
568 mkEqPredCoOcc = mk_simple_deriv tcName "$co"
570 -- used in derived instances
571 mkCon2TagOcc = mk_simple_deriv varName "$con2tag_"
572 mkTag2ConOcc = mk_simple_deriv varName "$tag2con_"
573 mkMaxTagOcc = mk_simple_deriv varName "$maxtag_"
575 -- Generic derivable classes
576 mkGenOcc1 = mk_simple_deriv varName "$gfrom"
577 mkGenOcc2 = mk_simple_deriv varName "$gto"
579 -- data T = MkT ... deriving( Data ) needs defintions for
580 -- $tT :: Data.Generics.Basics.DataType
581 -- $cMkT :: Data.Generics.Basics.Constr
582 mkDataTOcc = mk_simple_deriv varName "$t"
583 mkDataCOcc = mk_simple_deriv varName "$c"
586 mkVectOcc = mk_simple_deriv varName "$v_"
587 mkVectTyConOcc = mk_simple_deriv tcName ":V_"
588 mkVectDataConOcc = mk_simple_deriv dataName ":VD_"
589 mkVectIsoOcc = mk_simple_deriv varName "$VI_"
590 mkPDataTyConOcc = mk_simple_deriv tcName ":VP_"
591 mkPDataDataConOcc = mk_simple_deriv dataName ":VPD_"
592 mkPReprTyConOcc = mk_simple_deriv tcName ":VR_"
593 mkPADFunOcc = mk_simple_deriv varName "$PA_"
595 mk_simple_deriv :: NameSpace -> String -> OccName -> OccName
596 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
598 -- Data constructor workers are made by setting the name space
599 -- of the data constructor OccName (which should be a DataName)
601 mkDataConWorkerOcc datacon_occ = setOccNameSpace varName datacon_occ
605 mkSuperDictSelOcc :: Int -- ^ Index of superclass, e.g. 3
606 -> OccName -- ^ Class, e.g. @Ord@
607 -> OccName -- ^ Derived 'Occname', e.g. @$p3Ord@
608 mkSuperDictSelOcc index cls_occ
609 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
611 mkLocalOcc :: Unique -- ^ Unique to combine with the 'OccName'
612 -> OccName -- ^ Local name, e.g. @sat@
613 -> OccName -- ^ Nice unique version, e.g. @$L23sat@
615 = mk_deriv varName ("$L" ++ show uniq) (occNameString occ)
616 -- The Unique might print with characters
617 -- that need encoding (e.g. 'z'!)
621 -- | Derive a name for the representation type constructor of a
622 -- @data@\/@newtype@ instance.
623 mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@
624 -> OccSet -- ^ avoid these Occs
625 -> OccName -- ^ @R:Map@
626 mkInstTyTcOcc str set =
627 chooseUniqueOcc tcName ('R' : ':' : str) set
631 mkDFunOcc :: String -- ^ Typically the class and type glommed together e.g. @OrdMaybe@.
632 -- Only used in debug mode, for extra clarity
633 -> Bool -- ^ Is this a hs-boot instance DFun?
634 -> OccSet -- ^ avoid these Occs
635 -> OccName -- ^ E.g. @$f3OrdMaybe@
637 -- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real
638 -- thing when we compile the mother module. Reason: we don't know exactly
639 -- what the mother module will call it.
641 mkDFunOcc info_str is_boot set
642 = chooseUniqueOcc VarName (prefix ++ info_str) set
644 prefix | is_boot = "$fx"
648 Sometimes we need to pick an OccName that has not already been used,
649 given a set of in-use OccNames.
652 chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName
653 chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int)
656 | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1)
660 We used to add a '$m' to indicate a method, but that gives rise to bad
661 error messages from the type checker when we print the function name or pattern
662 of an instance-decl binding. Why? Because the binding is zapped
663 to use the method name in place of the selector name.
664 (See TcClassDcl.tcMethodBind)
666 The way it is now, -ddump-xx output may look confusing, but
667 you can always say -dppr-debug to get the uniques.
669 However, we *do* have to zap the first character to be lower case,
670 because overloaded constructors (blarg) generate methods too.
671 And convert to VarName space
673 e.g. a call to constructor MkFoo where
674 data (Ord a) => Foo a = MkFoo a
676 If this is necessary, we do it by prefixing '$m'. These
677 guys never show up in error messages. What a hack.
680 mkMethodOcc :: OccName -> OccName
681 mkMethodOcc occ@(OccName VarName _) = occ
682 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
686 %************************************************************************
688 \subsection{Tidying them up}
690 %************************************************************************
692 Before we print chunks of code we like to rename it so that
693 we don't have to print lots of silly uniques in it. But we mustn't
694 accidentally introduce name clashes! So the idea is that we leave the
695 OccName alone unless it accidentally clashes with one that is already
696 in scope; if so, we tack on '1' at the end and try again, then '2', and
697 so on till we find a unique one.
699 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
700 because that isn't a single lexeme. So we encode it to 'lle' and *then*
701 tack on the '1', if necessary.
704 type TidyOccEnv = OccEnv Int -- The in-scope OccNames
705 -- Range gives a plausible starting point for new guesses
707 emptyTidyOccEnv :: TidyOccEnv
708 emptyTidyOccEnv = emptyOccEnv
710 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
711 initTidyOccEnv = foldl (\env occ -> extendOccEnv env occ 1) emptyTidyOccEnv
713 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
715 tidyOccName in_scope occ@(OccName occ_sp fs)
716 = case lookupOccEnv in_scope occ of
717 Nothing -> -- Not already used: make it used
718 (extendOccEnv in_scope occ 1, occ)
720 Just n -> -- Already used: make a new guess,
721 -- change the guess base, and try again
722 tidyOccName (extendOccEnv in_scope occ (n+1))
723 (mkOccName occ_sp (base_occ ++ show n))
725 base_occ = reverse (dropWhile isDigit (reverse (unpackFS fs)))
728 %************************************************************************
730 Stuff for dealing with tuples
732 %************************************************************************
735 mkTupleOcc :: NameSpace -> Boxity -> Arity -> OccName
736 mkTupleOcc ns bx ar = OccName ns (mkFastString str)
738 -- no need to cache these, the caching is done in the caller
739 -- (TysWiredIn.mk_tuple)
741 Boxed -> '(' : commas ++ ")"
742 Unboxed -> '(' : '#' : commas ++ "#)"
744 commas = take (ar-1) (repeat ',')
746 isTupleOcc_maybe :: OccName -> Maybe (NameSpace, Boxity, Arity)
747 -- Tuples are special, because there are so many of them!
748 isTupleOcc_maybe (OccName ns fs)
749 = case unpackFS fs of
750 '(':'#':',':rest -> Just (ns, Unboxed, 2 + count_commas rest)
751 '(':',':rest -> Just (ns, Boxed, 2 + count_commas rest)
754 count_commas (',':rest) = 1 + count_commas rest
758 %************************************************************************
760 \subsection{Lexical categories}
762 %************************************************************************
764 These functions test strings to see if they fit the lexical categories
765 defined in the Haskell report.
768 isLexCon, isLexVar, isLexId, isLexSym :: FastString -> Bool
769 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FastString -> Bool
771 isLexCon cs = isLexConId cs || isLexConSym cs
772 isLexVar cs = isLexVarId cs || isLexVarSym cs
774 isLexId cs = isLexConId cs || isLexVarId cs
775 isLexSym cs = isLexConSym cs || isLexVarSym cs
779 isLexConId cs -- Prefix type or data constructors
780 | nullFS cs = False -- e.g. "Foo", "[]", "(,)"
781 | cs == (fsLit "[]") = True
782 | otherwise = startsConId (headFS cs)
784 isLexVarId cs -- Ordinary prefix identifiers
785 | nullFS cs = False -- e.g. "x", "_x"
786 | otherwise = startsVarId (headFS cs)
788 isLexConSym cs -- Infix type or data constructors
789 | nullFS cs = False -- e.g. ":-:", ":", "->"
790 | cs == (fsLit "->") = True
791 | otherwise = startsConSym (headFS cs)
793 isLexVarSym cs -- Infix identifiers
794 | nullFS cs = False -- e.g. "+"
795 | otherwise = startsVarSym (headFS cs)
798 startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
799 startsVarSym c = isSymbolASCII c || (ord c > 0x7f && isSymbol c) -- Infix Ids
800 startsConSym c = c == ':' -- Infix data constructors
801 startsVarId c = isLower c || c == '_' -- Ordinary Ids
802 startsConId c = isUpper c || c == '(' -- Ordinary type constructors and data constructors
804 isSymbolASCII :: Char -> Bool
805 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
808 %************************************************************************
811 Here rather than BinIface because OccName is abstract
813 %************************************************************************
816 instance Binary NameSpace where
819 put_ bh DataName = do
823 put_ bh TcClsName = do
828 0 -> do return VarName
829 1 -> do return DataName
830 2 -> do return TvName
831 _ -> do return TcClsName
833 instance Binary OccName where
834 put_ bh (OccName aa ab) = do
840 return (OccName aa ab)