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, varNameDepth,
29 tvName, srcDataName, setOccNameDepth, getOccNameDepth,
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, mkGenDefMethodOcc,
52 mkDerivedTyConOcc, mkNewTyCoOcc, mkClassOpAuxOcc,
53 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
54 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
55 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
56 mkGenD, mkGenR, mkGenRCo, mkGenC, mkGenS,
57 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc,
58 mkSuperDictSelOcc, mkLocalOcc, mkMethodOcc, mkInstTyTcOcc,
59 mkInstTyCoOcc, mkEqPredCoOcc,
60 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
61 mkPDataTyConOcc, mkPDataDataConOcc,
66 occNameFS, occNameString, occNameSpace,
68 isVarOcc, isTvOcc, isTcOcc, isDataOcc, isDataSymOcc, isSymOcc, isValOcc,
69 parenSymOcc, startsWithUnderscore,
71 isTcClsNameSpace, isTvNameSpace, isDataConNameSpace, isVarNameSpace, isValNameSpace,
75 -- * The 'OccEnv' type
76 OccEnv, emptyOccEnv, unitOccEnv, extendOccEnv, mapOccEnv,
77 lookupOccEnv, mkOccEnv, mkOccEnv_C, extendOccEnvList, elemOccEnv,
78 occEnvElts, foldOccEnv, plusOccEnv, plusOccEnv_C, extendOccEnv_C,
79 extendOccEnv_Acc, filterOccEnv, delListFromOccEnv, delFromOccEnv,
81 -- * The 'OccSet' type
82 OccSet, emptyOccSet, unitOccSet, mkOccSet, extendOccSet,
84 unionOccSets, unionManyOccSets, minusOccSet, elemOccSet, occSetElts,
85 foldOccSet, isEmptyOccSet, intersectOccSet, intersectsOccSet,
88 TidyOccEnv, emptyTidyOccEnv, tidyOccName, initTidyOccEnv,
90 -- * Lexical characteristics of Haskell names
91 isLexCon, isLexVar, isLexId, isLexSym,
92 isLexConId, isLexConSym, isLexVarId, isLexVarSym,
93 startsVarSym, startsVarId, startsConSym, startsConId
106 import StaticFlags( opt_SuppressUniques )
111 %************************************************************************
113 \subsection{Name space}
115 %************************************************************************
118 data NameSpace = VarName Int -- Variables, including "real" data constructors; Int is the syntactic HetMet bracket depth
119 | DataName -- "Source" data constructors
120 | TvName -- Type variables
121 | TcClsName -- Type constructors and classes; Haskell has them
122 -- in the same name space for now.
124 {-! derive: Binary !-}
126 -- Note [Data Constructors]
127 -- see also: Note [Data Constructor Naming] in DataCon.lhs
129 -- $real_vs_source_data_constructors
130 -- There are two forms of data constructor:
132 -- [Source data constructors] The data constructors mentioned in Haskell source code
134 -- [Real data constructors] The data constructors of the representation type, which may not be the same as the source type
138 -- > data T = T !(Int, Int)
140 -- The source datacon has type @(Int, Int) -> T@
141 -- The real datacon has type @Int -> Int -> T@
143 -- GHC chooses a representation based on the strictness etc.
145 tcName, clsName, tcClsName :: NameSpace
146 dataName, srcDataName :: NameSpace
147 tvName, varName :: NameSpace
148 varNameDepth :: Int -> NameSpace
150 -- Though type constructors and classes are in the same name space now,
151 -- the NameSpace type is abstract, so we can easily separate them later
152 tcName = TcClsName -- Type constructors
153 clsName = TcClsName -- Classes
154 tcClsName = TcClsName -- Not sure which!
157 srcDataName = DataName -- Haskell-source data constructors should be
158 -- in the Data name space
163 varNameDepth = VarName
165 getOccNameDepth :: OccName -> Int
166 getOccNameDepth name =
167 case occNameSpace name of
170 setOccNameDepth :: Int -> OccName -> OccName
171 setOccNameDepth depth name =
172 case occNameSpace name of
173 (VarName _) -> name{ occNameSpace = VarName depth }
176 else error ("tried to change the depth of a name in namespace " ++ (showSDoc $ ppr name))
178 isDataConNameSpace :: NameSpace -> Bool
179 isDataConNameSpace DataName = True
180 isDataConNameSpace _ = False
182 isTcClsNameSpace :: NameSpace -> Bool
183 isTcClsNameSpace TcClsName = True
184 isTcClsNameSpace _ = False
186 isTvNameSpace :: NameSpace -> Bool
187 isTvNameSpace TvName = True
188 isTvNameSpace _ = False
190 isVarNameSpace :: NameSpace -> Bool -- Variables or type variables, but not constructors
191 isVarNameSpace TvName = True
192 isVarNameSpace (VarName _) = True
193 isVarNameSpace _ = False
195 isValNameSpace :: NameSpace -> Bool
196 isValNameSpace DataName = True
197 isValNameSpace (VarName _) = True
198 isValNameSpace _ = False
200 pprNameSpace :: NameSpace -> SDoc
201 pprNameSpace DataName = ptext (sLit "data constructor")
202 pprNameSpace (VarName _) = ptext (sLit "variable")
203 pprNameSpace TvName = ptext (sLit "type variable")
204 pprNameSpace TcClsName = ptext (sLit "type constructor or class")
206 pprNonVarNameSpace :: NameSpace -> SDoc
207 pprNonVarNameSpace (VarName _) = empty
208 pprNonVarNameSpace ns = pprNameSpace ns
210 pprNameSpaceBrief :: NameSpace -> SDoc
211 pprNameSpaceBrief DataName = char 'd'
212 pprNameSpaceBrief (VarName _) = char 'v'
213 pprNameSpaceBrief TvName = ptext (sLit "tv")
214 pprNameSpaceBrief TcClsName = ptext (sLit "tc")
218 %************************************************************************
220 \subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
222 %************************************************************************
225 data OccName = OccName
226 { occNameSpace :: !NameSpace
227 , occNameFS :: !FastString
234 instance Eq OccName where
235 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
237 instance Ord OccName where
238 -- Compares lexicographically, *not* by Unique of the string
239 compare (OccName sp1 s1) (OccName sp2 s2)
240 = (s1 `compare` s2) `thenCmp` (sp1 `compare` sp2)
242 instance Data OccName where
244 toConstr _ = abstractConstr "OccName"
245 gunfold _ _ = error "gunfold"
246 dataTypeOf _ = mkNoRepType "OccName"
250 %************************************************************************
252 \subsection{Printing}
254 %************************************************************************
257 instance Outputable OccName where
260 pprOccName :: OccName -> SDoc
261 pprOccName (OccName sp occ)
262 = getPprStyle $ \ sty ->
264 then ftext (zEncodeFS occ)
265 else pp_occ <> pp_debug sty
267 pp_debug sty | debugStyle sty = braces (pprNameSpaceBrief sp)
270 pp_occ | opt_SuppressUniques = text (strip_th_unique (unpackFS occ))
271 | otherwise = ftext occ
273 -- See Note [Suppressing uniques in OccNames]
274 strip_th_unique ('[' : c : _) | isAlphaNum c = []
275 strip_th_unique (c : cs) = c : strip_th_unique cs
276 strip_th_unique [] = []
279 Note [Suppressing uniques in OccNames]
280 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
281 This is a hack to de-wobblify the OccNames that contain uniques from
282 Template Haskell that have been turned into a string in the OccName.
283 See Note [Unique OccNames from Template Haskell] in Convert.hs
285 %************************************************************************
287 \subsection{Construction}
289 %************************************************************************
292 mkOccName :: NameSpace -> String -> OccName
293 mkOccName occ_sp str = OccName occ_sp (mkFastString str)
295 mkOccNameFS :: NameSpace -> FastString -> OccName
296 mkOccNameFS occ_sp fs = OccName occ_sp fs
298 mkVarOcc :: String -> OccName
299 mkVarOcc s = mkOccName varName s
301 mkVarOccFS :: FastString -> OccName
302 mkVarOccFS fs = mkOccNameFS varName fs
304 mkDataOcc :: String -> OccName
305 mkDataOcc = mkOccName dataName
307 mkDataOccFS :: FastString -> OccName
308 mkDataOccFS = mkOccNameFS dataName
310 mkTyVarOcc :: String -> OccName
311 mkTyVarOcc = mkOccName tvName
313 mkTyVarOccFS :: FastString -> OccName
314 mkTyVarOccFS fs = mkOccNameFS tvName fs
316 mkTcOcc :: String -> OccName
317 mkTcOcc = mkOccName tcName
319 mkTcOccFS :: FastString -> OccName
320 mkTcOccFS = mkOccNameFS tcName
322 mkClsOcc :: String -> OccName
323 mkClsOcc = mkOccName clsName
325 mkClsOccFS :: FastString -> OccName
326 mkClsOccFS = mkOccNameFS clsName
330 %************************************************************************
334 %************************************************************************
336 OccEnvs are used mainly for the envts in ModIfaces.
338 Note [The Unique of an OccName]
339 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
340 They are efficient, because FastStrings have unique Int# keys. We assume
341 this key is less than 2^24, and indeed FastStrings are allocated keys
342 sequentially starting at 0.
344 So we can make a Unique using
345 mkUnique ns key :: Unique
346 where 'ns' is a Char reprsenting the name space. This in turn makes it
347 easy to build an OccEnv.
350 instance Uniquable OccName where
351 -- See Note [The Unique of an OccName]
352 getUnique (OccName (VarName depth) fs) = mkVarOccUnique fs depth
353 getUnique (OccName DataName fs) = mkDataOccUnique fs
354 getUnique (OccName TvName fs) = mkTvOccUnique fs
355 getUnique (OccName TcClsName fs) = mkTcOccUnique fs
357 newtype OccEnv a = A (UniqFM a)
359 emptyOccEnv :: OccEnv a
360 unitOccEnv :: OccName -> a -> OccEnv a
361 extendOccEnv :: OccEnv a -> OccName -> a -> OccEnv a
362 extendOccEnvList :: OccEnv a -> [(OccName, a)] -> OccEnv a
363 lookupOccEnv :: OccEnv a -> OccName -> Maybe a
364 mkOccEnv :: [(OccName,a)] -> OccEnv a
365 mkOccEnv_C :: (a -> a -> a) -> [(OccName,a)] -> OccEnv a
366 elemOccEnv :: OccName -> OccEnv a -> Bool
367 foldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b
368 occEnvElts :: OccEnv a -> [a]
369 extendOccEnv_C :: (a->a->a) -> OccEnv a -> OccName -> a -> OccEnv a
370 extendOccEnv_Acc :: (a->b->b) -> (a->b) -> OccEnv b -> OccName -> a -> OccEnv b
371 plusOccEnv :: OccEnv a -> OccEnv a -> OccEnv a
372 plusOccEnv_C :: (a->a->a) -> OccEnv a -> OccEnv a -> OccEnv a
373 mapOccEnv :: (a->b) -> OccEnv a -> OccEnv b
374 delFromOccEnv :: OccEnv a -> OccName -> OccEnv a
375 delListFromOccEnv :: OccEnv a -> [OccName] -> OccEnv a
376 filterOccEnv :: (elt -> Bool) -> OccEnv elt -> OccEnv elt
378 emptyOccEnv = A emptyUFM
379 unitOccEnv x y = A $ unitUFM x y
380 extendOccEnv (A x) y z = A $ addToUFM x y z
381 extendOccEnvList (A x) l = A $ addListToUFM x l
382 lookupOccEnv (A x) y = lookupUFM x y
383 mkOccEnv l = A $ listToUFM l
384 elemOccEnv x (A y) = elemUFM x y
385 foldOccEnv a b (A c) = foldUFM a b c
386 occEnvElts (A x) = eltsUFM x
387 plusOccEnv (A x) (A y) = A $ plusUFM x y
388 plusOccEnv_C f (A x) (A y) = A $ plusUFM_C f x y
389 extendOccEnv_C f (A x) y z = A $ addToUFM_C f x y z
390 extendOccEnv_Acc f g (A x) y z = A $ addToUFM_Acc f g x y z
391 mapOccEnv f (A x) = A $ mapUFM f x
392 mkOccEnv_C comb l = A $ addListToUFM_C comb emptyUFM l
393 delFromOccEnv (A x) y = A $ delFromUFM x y
394 delListFromOccEnv (A x) y = A $ delListFromUFM x y
395 filterOccEnv x (A y) = A $ filterUFM x y
397 instance Outputable a => Outputable (OccEnv a) where
400 type OccSet = UniqSet OccName
402 emptyOccSet :: OccSet
403 unitOccSet :: OccName -> OccSet
404 mkOccSet :: [OccName] -> OccSet
405 extendOccSet :: OccSet -> OccName -> OccSet
406 extendOccSetList :: OccSet -> [OccName] -> OccSet
407 unionOccSets :: OccSet -> OccSet -> OccSet
408 unionManyOccSets :: [OccSet] -> OccSet
409 minusOccSet :: OccSet -> OccSet -> OccSet
410 elemOccSet :: OccName -> OccSet -> Bool
411 occSetElts :: OccSet -> [OccName]
412 foldOccSet :: (OccName -> b -> b) -> b -> OccSet -> b
413 isEmptyOccSet :: OccSet -> Bool
414 intersectOccSet :: OccSet -> OccSet -> OccSet
415 intersectsOccSet :: OccSet -> OccSet -> Bool
417 emptyOccSet = emptyUniqSet
418 unitOccSet = unitUniqSet
420 extendOccSet = addOneToUniqSet
421 extendOccSetList = addListToUniqSet
422 unionOccSets = unionUniqSets
423 unionManyOccSets = unionManyUniqSets
424 minusOccSet = minusUniqSet
425 elemOccSet = elementOfUniqSet
426 occSetElts = uniqSetToList
427 foldOccSet = foldUniqSet
428 isEmptyOccSet = isEmptyUniqSet
429 intersectOccSet = intersectUniqSets
430 intersectsOccSet s1 s2 = not (isEmptyOccSet (s1 `intersectOccSet` s2))
434 %************************************************************************
436 \subsection{Predicates and taking them apart}
438 %************************************************************************
441 occNameString :: OccName -> String
442 occNameString (OccName _ s) = unpackFS s
444 setOccNameSpace :: NameSpace -> OccName -> OccName
445 setOccNameSpace sp (OccName _ occ) = OccName sp occ
447 isVarOcc, isTvOcc, isTcOcc, isDataOcc :: OccName -> Bool
449 isVarOcc (OccName (VarName _) _) = True
452 isTvOcc (OccName TvName _) = True
455 isTcOcc (OccName TcClsName _) = True
458 -- | /Value/ 'OccNames's are those that are either in
459 -- the variable or data constructor namespaces
460 isValOcc :: OccName -> Bool
461 isValOcc (OccName (VarName _) _) = True
462 isValOcc (OccName DataName _) = True
465 isDataOcc (OccName DataName _) = True
466 isDataOcc (OccName (VarName _) s)
467 | isLexCon s = pprPanic "isDataOcc: check me" (ppr s)
468 -- Jan06: I don't think this should happen
471 -- | Test if the 'OccName' is a data constructor that starts with
472 -- a symbol (e.g. @:@, or @[]@)
473 isDataSymOcc :: OccName -> Bool
474 isDataSymOcc (OccName DataName s) = isLexConSym s
475 isDataSymOcc (OccName (VarName _) s)
476 | isLexConSym s = pprPanic "isDataSymOcc: check me" (ppr s)
477 -- Jan06: I don't think this should happen
478 isDataSymOcc _ = False
479 -- Pretty inefficient!
481 -- | Test if the 'OccName' is that for any operator (whether
482 -- it is a data constructor or variable or whatever)
483 isSymOcc :: OccName -> Bool
484 isSymOcc (OccName DataName s) = isLexConSym s
485 isSymOcc (OccName TcClsName s) = isLexConSym s
486 isSymOcc (OccName (VarName _) s) = isLexSym s
487 isSymOcc (OccName TvName s) = isLexSym s
488 -- Pretty inefficient!
490 parenSymOcc :: OccName -> SDoc -> SDoc
491 -- ^ Wrap parens around an operator
492 parenSymOcc occ doc | isSymOcc occ = parens doc
498 startsWithUnderscore :: OccName -> Bool
499 -- ^ Haskell 98 encourages compilers to suppress warnings about unsed
500 -- names in a pattern if they start with @_@: this implements that test
501 startsWithUnderscore occ = case occNameString occ of
507 %************************************************************************
509 \subsection{Making system names}
511 %************************************************************************
513 Here's our convention for splitting up the interface file name space:
515 d... dictionary identifiers
516 (local variables, so no name-clash worries)
518 All of these other OccNames contain a mixture of alphabetic
519 and symbolic characters, and hence cannot possibly clash with
520 a user-written type or function name
522 $f... Dict-fun identifiers (from inst decls)
523 $dmop Default method for 'op'
524 $pnC n'th superclass selector for class C
525 $wf Worker for functtoin 'f'
526 $sf.. Specialised version of f
527 T:C Tycon for dictionary for class C
528 D:C Data constructor for dictionary for class C
529 NTCo:T Coercion connecting newtype T with its representation type
530 TFCo:R Coercion connecting a data family to its respresentation type R
532 In encoded form these appear as Zdfxxx etc
534 :... keywords (export:, letrec: etc.)
535 --- I THINK THIS IS WRONG!
537 This knowledge is encoded in the following functions.
539 @mk_deriv@ generates an @OccName@ from the prefix and a string.
540 NB: The string must already be encoded!
543 mk_deriv :: NameSpace
544 -> String -- Distinguishes one sort of derived name from another
548 mk_deriv occ_sp sys_prefix str = mkOccName occ_sp (sys_prefix ++ str)
550 isDerivedOccName :: OccName -> Bool
551 isDerivedOccName occ =
552 case occNameString occ of
553 '$':c:_ | isAlphaNum c -> True
554 ':':c:_ | isAlphaNum c -> True
559 mkDataConWrapperOcc, mkWorkerOcc, mkDefaultMethodOcc, mkGenDefMethodOcc,
560 mkDerivedTyConOcc, mkClassTyConOcc, mkClassDataConOcc, mkDictOcc,
561 mkIPOcc, mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
562 mkGenD, mkGenR, mkGenRCo,
563 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
564 mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
565 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
566 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
567 mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
568 :: OccName -> OccName
570 -- These derived variables have a prefix that no Haskell value could have
571 mkDataConWrapperOcc = mk_simple_deriv varName "$W"
572 mkWorkerOcc = mk_simple_deriv varName "$w"
573 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
574 mkGenDefMethodOcc = mk_simple_deriv varName "$gdm"
575 mkClassOpAuxOcc = mk_simple_deriv varName "$c"
576 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
577 mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
578 mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
579 -- for datacons from classes
580 mkDictOcc = mk_simple_deriv varName "$d"
581 mkIPOcc = mk_simple_deriv varName "$i"
582 mkSpecOcc = mk_simple_deriv varName "$s"
583 mkForeignExportOcc = mk_simple_deriv varName "$f"
584 mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
585 mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
586 mkEqPredCoOcc = mk_simple_deriv tcName "$co"
588 -- used in derived instances
589 mkCon2TagOcc = mk_simple_deriv varName "$con2tag_"
590 mkTag2ConOcc = mk_simple_deriv varName "$tag2con_"
591 mkMaxTagOcc = mk_simple_deriv varName "$maxtag_"
593 -- Generic derivable classes (old)
594 mkGenOcc1 = mk_simple_deriv varName "$gfrom"
595 mkGenOcc2 = mk_simple_deriv varName "$gto"
597 -- Generic deriving mechanism (new)
598 mkGenD = mk_simple_deriv tcName "D1"
600 mkGenC :: OccName -> Int -> OccName
601 mkGenC occ m = mk_deriv tcName ("C1_" ++ show m) (occNameString occ)
603 mkGenS :: OccName -> Int -> Int -> OccName
604 mkGenS occ m n = mk_deriv tcName ("S1_" ++ show m ++ "_" ++ show n)
607 mkGenR = mk_simple_deriv tcName "Rep_"
608 mkGenRCo = mk_simple_deriv tcName "CoRep_"
610 -- data T = MkT ... deriving( Data ) needs defintions for
611 -- $tT :: Data.Generics.Basics.DataType
612 -- $cMkT :: Data.Generics.Basics.Constr
613 mkDataTOcc = mk_simple_deriv varName "$t"
614 mkDataCOcc = mk_simple_deriv varName "$c"
617 mkVectOcc = mk_simple_deriv varName "$v_"
618 mkVectTyConOcc = mk_simple_deriv tcName ":V_"
619 mkVectDataConOcc = mk_simple_deriv dataName ":VD_"
620 mkVectIsoOcc = mk_simple_deriv varName "$VI_"
621 mkPDataTyConOcc = mk_simple_deriv tcName ":VP_"
622 mkPDataDataConOcc = mk_simple_deriv dataName ":VPD_"
623 mkPReprTyConOcc = mk_simple_deriv tcName ":VR_"
624 mkPADFunOcc = mk_simple_deriv varName "$PA_"
626 mk_simple_deriv :: NameSpace -> String -> OccName -> OccName
627 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
629 -- Data constructor workers are made by setting the name space
630 -- of the data constructor OccName (which should be a DataName)
632 mkDataConWorkerOcc datacon_occ = setOccNameSpace varName datacon_occ
636 mkSuperDictSelOcc :: Int -- ^ Index of superclass, e.g. 3
637 -> OccName -- ^ Class, e.g. @Ord@
638 -> OccName -- ^ Derived 'Occname', e.g. @$p3Ord@
639 mkSuperDictSelOcc index cls_occ
640 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
642 mkLocalOcc :: Unique -- ^ Unique to combine with the 'OccName'
643 -> OccName -- ^ Local name, e.g. @sat@
644 -> OccName -- ^ Nice unique version, e.g. @$L23sat@
646 = mk_deriv varName ("$L" ++ show uniq) (occNameString occ)
647 -- The Unique might print with characters
648 -- that need encoding (e.g. 'z'!)
652 -- | Derive a name for the representation type constructor of a
653 -- @data@\/@newtype@ instance.
654 mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@
655 -> OccSet -- ^ avoid these Occs
656 -> OccName -- ^ @R:Map@
657 mkInstTyTcOcc str set =
658 chooseUniqueOcc tcName ('R' : ':' : str) set
662 mkDFunOcc :: String -- ^ Typically the class and type glommed together e.g. @OrdMaybe@.
663 -- Only used in debug mode, for extra clarity
664 -> Bool -- ^ Is this a hs-boot instance DFun?
665 -> OccSet -- ^ avoid these Occs
666 -> OccName -- ^ E.g. @$f3OrdMaybe@
668 -- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real
669 -- thing when we compile the mother module. Reason: we don't know exactly
670 -- what the mother module will call it.
672 mkDFunOcc info_str is_boot set
673 = chooseUniqueOcc (VarName 0) (prefix ++ info_str) set
675 prefix | is_boot = "$fx"
679 Sometimes we need to pick an OccName that has not already been used,
680 given a set of in-use OccNames.
683 chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName
684 chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int)
687 | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1)
691 We used to add a '$m' to indicate a method, but that gives rise to bad
692 error messages from the type checker when we print the function name or pattern
693 of an instance-decl binding. Why? Because the binding is zapped
694 to use the method name in place of the selector name.
695 (See TcClassDcl.tcMethodBind)
697 The way it is now, -ddump-xx output may look confusing, but
698 you can always say -dppr-debug to get the uniques.
700 However, we *do* have to zap the first character to be lower case,
701 because overloaded constructors (blarg) generate methods too.
702 And convert to VarName space
704 e.g. a call to constructor MkFoo where
705 data (Ord a) => Foo a = MkFoo a
707 If this is necessary, we do it by prefixing '$m'. These
708 guys never show up in error messages. What a hack.
711 mkMethodOcc :: OccName -> OccName
712 mkMethodOcc occ@(OccName (VarName _) _) = occ
713 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
717 %************************************************************************
719 \subsection{Tidying them up}
721 %************************************************************************
723 Before we print chunks of code we like to rename it so that
724 we don't have to print lots of silly uniques in it. But we mustn't
725 accidentally introduce name clashes! So the idea is that we leave the
726 OccName alone unless it accidentally clashes with one that is already
727 in scope; if so, we tack on '1' at the end and try again, then '2', and
728 so on till we find a unique one.
730 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
731 because that isn't a single lexeme. So we encode it to 'lle' and *then*
732 tack on the '1', if necessary.
735 type TidyOccEnv = OccEnv Int -- The in-scope OccNames
736 -- Range gives a plausible starting point for new guesses
738 emptyTidyOccEnv :: TidyOccEnv
739 emptyTidyOccEnv = emptyOccEnv
741 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
742 initTidyOccEnv = foldl (\env occ -> extendOccEnv env occ 1) emptyTidyOccEnv
744 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
746 tidyOccName in_scope occ@(OccName occ_sp fs)
747 = case lookupOccEnv in_scope occ of
748 Nothing -> -- Not already used: make it used
749 (extendOccEnv in_scope occ 1, occ)
751 Just n -> -- Already used: make a new guess,
752 -- change the guess base, and try again
753 tidyOccName (extendOccEnv in_scope occ (n+1))
754 (mkOccName occ_sp (base_occ ++ show n))
756 base_occ = reverse (dropWhile isDigit (reverse (unpackFS fs)))
759 %************************************************************************
761 Stuff for dealing with tuples
763 %************************************************************************
766 mkTupleOcc :: NameSpace -> Boxity -> Arity -> OccName
767 mkTupleOcc ns bx ar = OccName ns (mkFastString str)
769 -- no need to cache these, the caching is done in the caller
770 -- (TysWiredIn.mk_tuple)
772 Boxed -> '(' : commas ++ ")"
773 Unboxed -> '(' : '#' : commas ++ "#)"
775 commas = take (ar-1) (repeat ',')
777 isTupleOcc_maybe :: OccName -> Maybe (NameSpace, Boxity, Arity)
778 -- Tuples are special, because there are so many of them!
779 isTupleOcc_maybe (OccName ns fs)
780 = case unpackFS fs of
781 '(':'#':',':rest -> Just (ns, Unboxed, 2 + count_commas rest)
782 '(':',':rest -> Just (ns, Boxed, 2 + count_commas rest)
785 count_commas (',':rest) = 1 + count_commas rest
789 %************************************************************************
791 \subsection{Lexical categories}
793 %************************************************************************
795 These functions test strings to see if they fit the lexical categories
796 defined in the Haskell report.
799 isLexCon, isLexVar, isLexId, isLexSym :: FastString -> Bool
800 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FastString -> Bool
802 isLexCon cs = isLexConId cs || isLexConSym cs
803 isLexVar cs = isLexVarId cs || isLexVarSym cs
805 isLexId cs = isLexConId cs || isLexVarId cs
806 isLexSym cs = isLexConSym cs || isLexVarSym cs
810 isLexConId cs -- Prefix type or data constructors
811 | nullFS cs = False -- e.g. "Foo", "[]", "(,)"
812 | cs == (fsLit "[]") = True
813 | otherwise = startsConId (headFS cs)
815 isLexVarId cs -- Ordinary prefix identifiers
816 | nullFS cs = False -- e.g. "x", "_x"
817 | otherwise = startsVarId (headFS cs)
819 isLexConSym cs -- Infix type or data constructors
820 | nullFS cs = False -- e.g. ":-:", ":", "->"
821 | cs == (fsLit "->") = True
822 | otherwise = startsConSym (headFS cs)
824 isLexVarSym cs -- Infix identifiers
825 | nullFS cs = False -- e.g. "+"
826 | otherwise = startsVarSym (headFS cs)
829 startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
830 startsVarSym c = isSymbolASCII c || (ord c > 0x7f && isSymbol c) -- Infix Ids
831 startsConSym c = c == ':' -- Infix data constructors
832 startsVarId c = isLower c || c == '_' -- Ordinary Ids
833 startsConId c = isUpper c || c == '(' -- Ordinary type constructors and data constructors
835 isSymbolASCII :: Char -> Bool
836 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
839 %************************************************************************
842 Here rather than BinIface because OccName is abstract
844 %************************************************************************
847 instance Binary NameSpace where
848 put_ bh (VarName depth) = do if depth > 255-4
849 then error "FIXME: no support for serializing VarNames at this syntactic depth"
850 else putByte bh ((fromIntegral ((depth+3) :: Int)))
851 put_ bh DataName = do
855 put_ bh TcClsName = do
860 0 -> do return DataName
861 1 -> do return TvName
862 2 -> do return TcClsName
863 n -> do return (VarName (fromIntegral (n-3)))
865 instance Binary OccName where
866 put_ bh (OccName aa ab) = do
872 return (OccName aa ab)