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, mkGenDefMethodOcc,
52 mkDerivedTyConOcc, mkNewTyCoOcc, mkClassOpAuxOcc,
53 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
54 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
55 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
56 mkGenD, mkGenR0, mkGenR0Co, 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 -- Variables, including "real" data constructors
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
149 -- Though type constructors and classes are in the same name space now,
150 -- the NameSpace type is abstract, so we can easily separate them later
151 tcName = TcClsName -- Type constructors
152 clsName = TcClsName -- Classes
153 tcClsName = TcClsName -- Not sure which!
156 srcDataName = DataName -- Haskell-source data constructors should be
157 -- in the Data name space
162 isDataConNameSpace :: NameSpace -> Bool
163 isDataConNameSpace DataName = True
164 isDataConNameSpace _ = False
166 isTcClsNameSpace :: NameSpace -> Bool
167 isTcClsNameSpace TcClsName = True
168 isTcClsNameSpace _ = False
170 isTvNameSpace :: NameSpace -> Bool
171 isTvNameSpace TvName = True
172 isTvNameSpace _ = False
174 isVarNameSpace :: NameSpace -> Bool -- Variables or type variables, but not constructors
175 isVarNameSpace TvName = True
176 isVarNameSpace VarName = True
177 isVarNameSpace _ = False
179 isValNameSpace :: NameSpace -> Bool
180 isValNameSpace DataName = True
181 isValNameSpace VarName = True
182 isValNameSpace _ = False
184 pprNameSpace :: NameSpace -> SDoc
185 pprNameSpace DataName = ptext (sLit "data constructor")
186 pprNameSpace VarName = ptext (sLit "variable")
187 pprNameSpace TvName = ptext (sLit "type variable")
188 pprNameSpace TcClsName = ptext (sLit "type constructor or class")
190 pprNonVarNameSpace :: NameSpace -> SDoc
191 pprNonVarNameSpace VarName = empty
192 pprNonVarNameSpace ns = pprNameSpace ns
194 pprNameSpaceBrief :: NameSpace -> SDoc
195 pprNameSpaceBrief DataName = char 'd'
196 pprNameSpaceBrief VarName = char 'v'
197 pprNameSpaceBrief TvName = ptext (sLit "tv")
198 pprNameSpaceBrief TcClsName = ptext (sLit "tc")
202 %************************************************************************
204 \subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
206 %************************************************************************
209 data OccName = OccName
210 { occNameSpace :: !NameSpace
211 , occNameFS :: !FastString
217 instance Eq OccName where
218 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
220 instance Ord OccName where
221 -- Compares lexicographically, *not* by Unique of the string
222 compare (OccName sp1 s1) (OccName sp2 s2)
223 = (s1 `compare` s2) `thenCmp` (sp1 `compare` sp2)
225 INSTANCE_TYPEABLE0(OccName,occNameTc,"OccName")
227 instance Data OccName where
229 toConstr _ = abstractConstr "OccName"
230 gunfold _ _ = error "gunfold"
231 dataTypeOf _ = mkNoRepType "OccName"
235 %************************************************************************
237 \subsection{Printing}
239 %************************************************************************
242 instance Outputable OccName where
245 pprOccName :: OccName -> SDoc
246 pprOccName (OccName sp occ)
247 = getPprStyle $ \ sty ->
249 then ftext (zEncodeFS occ)
250 else pp_occ <> pp_debug sty
252 pp_debug sty | debugStyle sty = braces (pprNameSpaceBrief sp)
255 pp_occ | opt_SuppressUniques = text (strip_th_unique (unpackFS occ))
256 | otherwise = ftext occ
258 -- See Note [Suppressing uniques in OccNames]
259 strip_th_unique ('[' : c : _) | isAlphaNum c = []
260 strip_th_unique (c : cs) = c : strip_th_unique cs
261 strip_th_unique [] = []
264 Note [Suppressing uniques in OccNames]
265 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
266 This is a hack to de-wobblify the OccNames that contain uniques from
267 Template Haskell that have been turned into a string in the OccName.
268 See Note [Unique OccNames from Template Haskell] in Convert.hs
270 %************************************************************************
272 \subsection{Construction}
274 %************************************************************************
277 mkOccName :: NameSpace -> String -> OccName
278 mkOccName occ_sp str = OccName occ_sp (mkFastString str)
280 mkOccNameFS :: NameSpace -> FastString -> OccName
281 mkOccNameFS occ_sp fs = OccName occ_sp fs
283 mkVarOcc :: String -> OccName
284 mkVarOcc s = mkOccName varName s
286 mkVarOccFS :: FastString -> OccName
287 mkVarOccFS fs = mkOccNameFS varName fs
289 mkDataOcc :: String -> OccName
290 mkDataOcc = mkOccName dataName
292 mkDataOccFS :: FastString -> OccName
293 mkDataOccFS = mkOccNameFS dataName
295 mkTyVarOcc :: String -> OccName
296 mkTyVarOcc = mkOccName tvName
298 mkTyVarOccFS :: FastString -> OccName
299 mkTyVarOccFS fs = mkOccNameFS tvName fs
301 mkTcOcc :: String -> OccName
302 mkTcOcc = mkOccName tcName
304 mkTcOccFS :: FastString -> OccName
305 mkTcOccFS = mkOccNameFS tcName
307 mkClsOcc :: String -> OccName
308 mkClsOcc = mkOccName clsName
310 mkClsOccFS :: FastString -> OccName
311 mkClsOccFS = mkOccNameFS clsName
315 %************************************************************************
319 %************************************************************************
321 OccEnvs are used mainly for the envts in ModIfaces.
323 Note [The Unique of an OccName]
324 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
325 They are efficient, because FastStrings have unique Int# keys. We assume
326 this key is less than 2^24, and indeed FastStrings are allocated keys
327 sequentially starting at 0.
329 So we can make a Unique using
330 mkUnique ns key :: Unique
331 where 'ns' is a Char reprsenting the name space. This in turn makes it
332 easy to build an OccEnv.
335 instance Uniquable OccName where
336 -- See Note [The Unique of an OccName]
337 getUnique (OccName VarName fs) = mkVarOccUnique fs
338 getUnique (OccName DataName fs) = mkDataOccUnique fs
339 getUnique (OccName TvName fs) = mkTvOccUnique fs
340 getUnique (OccName TcClsName fs) = mkTcOccUnique fs
342 newtype OccEnv a = A (UniqFM a)
344 emptyOccEnv :: OccEnv a
345 unitOccEnv :: OccName -> a -> OccEnv a
346 extendOccEnv :: OccEnv a -> OccName -> a -> OccEnv a
347 extendOccEnvList :: OccEnv a -> [(OccName, a)] -> OccEnv a
348 lookupOccEnv :: OccEnv a -> OccName -> Maybe a
349 mkOccEnv :: [(OccName,a)] -> OccEnv a
350 mkOccEnv_C :: (a -> a -> a) -> [(OccName,a)] -> OccEnv a
351 elemOccEnv :: OccName -> OccEnv a -> Bool
352 foldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b
353 occEnvElts :: OccEnv a -> [a]
354 extendOccEnv_C :: (a->a->a) -> OccEnv a -> OccName -> a -> OccEnv a
355 extendOccEnv_Acc :: (a->b->b) -> (a->b) -> OccEnv b -> OccName -> a -> OccEnv b
356 plusOccEnv :: OccEnv a -> OccEnv a -> OccEnv a
357 plusOccEnv_C :: (a->a->a) -> OccEnv a -> OccEnv a -> OccEnv a
358 mapOccEnv :: (a->b) -> OccEnv a -> OccEnv b
359 delFromOccEnv :: OccEnv a -> OccName -> OccEnv a
360 delListFromOccEnv :: OccEnv a -> [OccName] -> OccEnv a
361 filterOccEnv :: (elt -> Bool) -> OccEnv elt -> OccEnv elt
363 emptyOccEnv = A emptyUFM
364 unitOccEnv x y = A $ unitUFM x y
365 extendOccEnv (A x) y z = A $ addToUFM x y z
366 extendOccEnvList (A x) l = A $ addListToUFM x l
367 lookupOccEnv (A x) y = lookupUFM x y
368 mkOccEnv l = A $ listToUFM l
369 elemOccEnv x (A y) = elemUFM x y
370 foldOccEnv a b (A c) = foldUFM a b c
371 occEnvElts (A x) = eltsUFM x
372 plusOccEnv (A x) (A y) = A $ plusUFM x y
373 plusOccEnv_C f (A x) (A y) = A $ plusUFM_C f x y
374 extendOccEnv_C f (A x) y z = A $ addToUFM_C f x y z
375 extendOccEnv_Acc f g (A x) y z = A $ addToUFM_Acc f g x y z
376 mapOccEnv f (A x) = A $ mapUFM f x
377 mkOccEnv_C comb l = A $ addListToUFM_C comb emptyUFM l
378 delFromOccEnv (A x) y = A $ delFromUFM x y
379 delListFromOccEnv (A x) y = A $ delListFromUFM x y
380 filterOccEnv x (A y) = A $ filterUFM x y
382 instance Outputable a => Outputable (OccEnv a) where
385 type OccSet = UniqSet OccName
387 emptyOccSet :: OccSet
388 unitOccSet :: OccName -> OccSet
389 mkOccSet :: [OccName] -> OccSet
390 extendOccSet :: OccSet -> OccName -> OccSet
391 extendOccSetList :: OccSet -> [OccName] -> OccSet
392 unionOccSets :: OccSet -> OccSet -> OccSet
393 unionManyOccSets :: [OccSet] -> OccSet
394 minusOccSet :: OccSet -> OccSet -> OccSet
395 elemOccSet :: OccName -> OccSet -> Bool
396 occSetElts :: OccSet -> [OccName]
397 foldOccSet :: (OccName -> b -> b) -> b -> OccSet -> b
398 isEmptyOccSet :: OccSet -> Bool
399 intersectOccSet :: OccSet -> OccSet -> OccSet
400 intersectsOccSet :: OccSet -> OccSet -> Bool
402 emptyOccSet = emptyUniqSet
403 unitOccSet = unitUniqSet
405 extendOccSet = addOneToUniqSet
406 extendOccSetList = addListToUniqSet
407 unionOccSets = unionUniqSets
408 unionManyOccSets = unionManyUniqSets
409 minusOccSet = minusUniqSet
410 elemOccSet = elementOfUniqSet
411 occSetElts = uniqSetToList
412 foldOccSet = foldUniqSet
413 isEmptyOccSet = isEmptyUniqSet
414 intersectOccSet = intersectUniqSets
415 intersectsOccSet s1 s2 = not (isEmptyOccSet (s1 `intersectOccSet` s2))
419 %************************************************************************
421 \subsection{Predicates and taking them apart}
423 %************************************************************************
426 occNameString :: OccName -> String
427 occNameString (OccName _ s) = unpackFS s
429 setOccNameSpace :: NameSpace -> OccName -> OccName
430 setOccNameSpace sp (OccName _ occ) = OccName sp occ
432 isVarOcc, isTvOcc, isTcOcc, isDataOcc :: OccName -> Bool
434 isVarOcc (OccName VarName _) = True
437 isTvOcc (OccName TvName _) = True
440 isTcOcc (OccName TcClsName _) = True
443 -- | /Value/ 'OccNames's are those that are either in
444 -- the variable or data constructor namespaces
445 isValOcc :: OccName -> Bool
446 isValOcc (OccName VarName _) = True
447 isValOcc (OccName DataName _) = True
450 isDataOcc (OccName DataName _) = True
451 isDataOcc (OccName VarName s)
452 | isLexCon s = pprPanic "isDataOcc: check me" (ppr s)
453 -- Jan06: I don't think this should happen
456 -- | Test if the 'OccName' is a data constructor that starts with
457 -- a symbol (e.g. @:@, or @[]@)
458 isDataSymOcc :: OccName -> Bool
459 isDataSymOcc (OccName DataName s) = isLexConSym s
460 isDataSymOcc (OccName VarName s)
461 | isLexConSym s = pprPanic "isDataSymOcc: check me" (ppr s)
462 -- Jan06: I don't think this should happen
463 isDataSymOcc _ = False
464 -- Pretty inefficient!
466 -- | Test if the 'OccName' is that for any operator (whether
467 -- it is a data constructor or variable or whatever)
468 isSymOcc :: OccName -> Bool
469 isSymOcc (OccName DataName s) = isLexConSym s
470 isSymOcc (OccName TcClsName s) = isLexConSym s
471 isSymOcc (OccName VarName s) = isLexSym s
472 isSymOcc (OccName TvName s) = isLexSym s
473 -- Pretty inefficient!
475 parenSymOcc :: OccName -> SDoc -> SDoc
476 -- ^ Wrap parens around an operator
477 parenSymOcc occ doc | isSymOcc occ = parens doc
483 startsWithUnderscore :: OccName -> Bool
484 -- ^ Haskell 98 encourages compilers to suppress warnings about unsed
485 -- names in a pattern if they start with @_@: this implements that test
486 startsWithUnderscore occ = case occNameString occ of
492 %************************************************************************
494 \subsection{Making system names}
496 %************************************************************************
498 Here's our convention for splitting up the interface file name space:
500 d... dictionary identifiers
501 (local variables, so no name-clash worries)
503 All of these other OccNames contain a mixture of alphabetic
504 and symbolic characters, and hence cannot possibly clash with
505 a user-written type or function name
507 $f... Dict-fun identifiers (from inst decls)
508 $dmop Default method for 'op'
509 $pnC n'th superclass selector for class C
510 $wf Worker for functtoin 'f'
511 $sf.. Specialised version of f
512 T:C Tycon for dictionary for class C
513 D:C Data constructor for dictionary for class C
514 NTCo:T Coercion connecting newtype T with its representation type
515 TFCo:R Coercion connecting a data family to its respresentation type R
517 In encoded form these appear as Zdfxxx etc
519 :... keywords (export:, letrec: etc.)
520 --- I THINK THIS IS WRONG!
522 This knowledge is encoded in the following functions.
524 @mk_deriv@ generates an @OccName@ from the prefix and a string.
525 NB: The string must already be encoded!
528 mk_deriv :: NameSpace
529 -> String -- Distinguishes one sort of derived name from another
533 mk_deriv occ_sp sys_prefix str = mkOccName occ_sp (sys_prefix ++ str)
535 isDerivedOccName :: OccName -> Bool
536 isDerivedOccName occ =
537 case occNameString occ of
538 '$':c:_ | isAlphaNum c -> True
539 ':':c:_ | isAlphaNum c -> True
544 mkDataConWrapperOcc, mkWorkerOcc, mkDefaultMethodOcc, mkGenDefMethodOcc,
545 mkDerivedTyConOcc, mkClassTyConOcc, mkClassDataConOcc, mkDictOcc,
546 mkIPOcc, mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
547 mkGenD, mkGenR0, mkGenR0Co,
548 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
549 mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
550 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
551 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
552 mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
553 :: OccName -> OccName
555 -- These derived variables have a prefix that no Haskell value could have
556 mkDataConWrapperOcc = mk_simple_deriv varName "$W"
557 mkWorkerOcc = mk_simple_deriv varName "$w"
558 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
559 mkGenDefMethodOcc = mk_simple_deriv varName "$gdm"
560 mkClassOpAuxOcc = mk_simple_deriv varName "$c"
561 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
562 mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
563 mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
564 -- for datacons from classes
565 mkDictOcc = mk_simple_deriv varName "$d"
566 mkIPOcc = mk_simple_deriv varName "$i"
567 mkSpecOcc = mk_simple_deriv varName "$s"
568 mkForeignExportOcc = mk_simple_deriv varName "$f"
569 mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
570 mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
571 mkEqPredCoOcc = mk_simple_deriv tcName "$co"
573 -- used in derived instances
574 mkCon2TagOcc = mk_simple_deriv varName "$con2tag_"
575 mkTag2ConOcc = mk_simple_deriv varName "$tag2con_"
576 mkMaxTagOcc = mk_simple_deriv varName "$maxtag_"
578 -- Generic derivable classes (old)
579 mkGenOcc1 = mk_simple_deriv varName "$gfrom"
580 mkGenOcc2 = mk_simple_deriv varName "$gto"
582 -- Generic deriving mechanism (new)
583 mkGenD = mk_simple_deriv tcName "D1"
585 mkGenC :: OccName -> Int -> OccName
586 mkGenC occ m = mk_deriv tcName ("C1_" ++ show m) (occNameString occ)
588 mkGenS :: OccName -> Int -> Int -> OccName
589 mkGenS occ m n = mk_deriv tcName ("S1_" ++ show m ++ "_" ++ show n)
592 mkGenR0 = mk_simple_deriv tcName "Rep0_"
593 mkGenR0Co = mk_simple_deriv tcName "CoRep0_"
595 -- data T = MkT ... deriving( Data ) needs defintions for
596 -- $tT :: Data.Generics.Basics.DataType
597 -- $cMkT :: Data.Generics.Basics.Constr
598 mkDataTOcc = mk_simple_deriv varName "$t"
599 mkDataCOcc = mk_simple_deriv varName "$c"
602 mkVectOcc = mk_simple_deriv varName "$v_"
603 mkVectTyConOcc = mk_simple_deriv tcName ":V_"
604 mkVectDataConOcc = mk_simple_deriv dataName ":VD_"
605 mkVectIsoOcc = mk_simple_deriv varName "$VI_"
606 mkPDataTyConOcc = mk_simple_deriv tcName ":VP_"
607 mkPDataDataConOcc = mk_simple_deriv dataName ":VPD_"
608 mkPReprTyConOcc = mk_simple_deriv tcName ":VR_"
609 mkPADFunOcc = mk_simple_deriv varName "$PA_"
611 mk_simple_deriv :: NameSpace -> String -> OccName -> OccName
612 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
614 -- Data constructor workers are made by setting the name space
615 -- of the data constructor OccName (which should be a DataName)
617 mkDataConWorkerOcc datacon_occ = setOccNameSpace varName datacon_occ
621 mkSuperDictSelOcc :: Int -- ^ Index of superclass, e.g. 3
622 -> OccName -- ^ Class, e.g. @Ord@
623 -> OccName -- ^ Derived 'Occname', e.g. @$p3Ord@
624 mkSuperDictSelOcc index cls_occ
625 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
627 mkLocalOcc :: Unique -- ^ Unique to combine with the 'OccName'
628 -> OccName -- ^ Local name, e.g. @sat@
629 -> OccName -- ^ Nice unique version, e.g. @$L23sat@
631 = mk_deriv varName ("$L" ++ show uniq) (occNameString occ)
632 -- The Unique might print with characters
633 -- that need encoding (e.g. 'z'!)
637 -- | Derive a name for the representation type constructor of a
638 -- @data@\/@newtype@ instance.
639 mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@
640 -> OccSet -- ^ avoid these Occs
641 -> OccName -- ^ @R:Map@
642 mkInstTyTcOcc str set =
643 chooseUniqueOcc tcName ('R' : ':' : str) set
647 mkDFunOcc :: String -- ^ Typically the class and type glommed together e.g. @OrdMaybe@.
648 -- Only used in debug mode, for extra clarity
649 -> Bool -- ^ Is this a hs-boot instance DFun?
650 -> OccSet -- ^ avoid these Occs
651 -> OccName -- ^ E.g. @$f3OrdMaybe@
653 -- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real
654 -- thing when we compile the mother module. Reason: we don't know exactly
655 -- what the mother module will call it.
657 mkDFunOcc info_str is_boot set
658 = chooseUniqueOcc VarName (prefix ++ info_str) set
660 prefix | is_boot = "$fx"
664 Sometimes we need to pick an OccName that has not already been used,
665 given a set of in-use OccNames.
668 chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName
669 chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int)
672 | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1)
676 We used to add a '$m' to indicate a method, but that gives rise to bad
677 error messages from the type checker when we print the function name or pattern
678 of an instance-decl binding. Why? Because the binding is zapped
679 to use the method name in place of the selector name.
680 (See TcClassDcl.tcMethodBind)
682 The way it is now, -ddump-xx output may look confusing, but
683 you can always say -dppr-debug to get the uniques.
685 However, we *do* have to zap the first character to be lower case,
686 because overloaded constructors (blarg) generate methods too.
687 And convert to VarName space
689 e.g. a call to constructor MkFoo where
690 data (Ord a) => Foo a = MkFoo a
692 If this is necessary, we do it by prefixing '$m'. These
693 guys never show up in error messages. What a hack.
696 mkMethodOcc :: OccName -> OccName
697 mkMethodOcc occ@(OccName VarName _) = occ
698 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
702 %************************************************************************
704 \subsection{Tidying them up}
706 %************************************************************************
708 Before we print chunks of code we like to rename it so that
709 we don't have to print lots of silly uniques in it. But we mustn't
710 accidentally introduce name clashes! So the idea is that we leave the
711 OccName alone unless it accidentally clashes with one that is already
712 in scope; if so, we tack on '1' at the end and try again, then '2', and
713 so on till we find a unique one.
715 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
716 because that isn't a single lexeme. So we encode it to 'lle' and *then*
717 tack on the '1', if necessary.
720 type TidyOccEnv = OccEnv Int -- The in-scope OccNames
721 -- Range gives a plausible starting point for new guesses
723 emptyTidyOccEnv :: TidyOccEnv
724 emptyTidyOccEnv = emptyOccEnv
726 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
727 initTidyOccEnv = foldl (\env occ -> extendOccEnv env occ 1) emptyTidyOccEnv
729 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
731 tidyOccName in_scope occ@(OccName occ_sp fs)
732 = case lookupOccEnv in_scope occ of
733 Nothing -> -- Not already used: make it used
734 (extendOccEnv in_scope occ 1, occ)
736 Just n -> -- Already used: make a new guess,
737 -- change the guess base, and try again
738 tidyOccName (extendOccEnv in_scope occ (n+1))
739 (mkOccName occ_sp (base_occ ++ show n))
741 base_occ = reverse (dropWhile isDigit (reverse (unpackFS fs)))
744 %************************************************************************
746 Stuff for dealing with tuples
748 %************************************************************************
751 mkTupleOcc :: NameSpace -> Boxity -> Arity -> OccName
752 mkTupleOcc ns bx ar = OccName ns (mkFastString str)
754 -- no need to cache these, the caching is done in the caller
755 -- (TysWiredIn.mk_tuple)
757 Boxed -> '(' : commas ++ ")"
758 Unboxed -> '(' : '#' : commas ++ "#)"
760 commas = take (ar-1) (repeat ',')
762 isTupleOcc_maybe :: OccName -> Maybe (NameSpace, Boxity, Arity)
763 -- Tuples are special, because there are so many of them!
764 isTupleOcc_maybe (OccName ns fs)
765 = case unpackFS fs of
766 '(':'#':',':rest -> Just (ns, Unboxed, 2 + count_commas rest)
767 '(':',':rest -> Just (ns, Boxed, 2 + count_commas rest)
770 count_commas (',':rest) = 1 + count_commas rest
774 %************************************************************************
776 \subsection{Lexical categories}
778 %************************************************************************
780 These functions test strings to see if they fit the lexical categories
781 defined in the Haskell report.
784 isLexCon, isLexVar, isLexId, isLexSym :: FastString -> Bool
785 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FastString -> Bool
787 isLexCon cs = isLexConId cs || isLexConSym cs
788 isLexVar cs = isLexVarId cs || isLexVarSym cs
790 isLexId cs = isLexConId cs || isLexVarId cs
791 isLexSym cs = isLexConSym cs || isLexVarSym cs
795 isLexConId cs -- Prefix type or data constructors
796 | nullFS cs = False -- e.g. "Foo", "[]", "(,)"
797 | cs == (fsLit "[]") = True
798 | otherwise = startsConId (headFS cs)
800 isLexVarId cs -- Ordinary prefix identifiers
801 | nullFS cs = False -- e.g. "x", "_x"
802 | otherwise = startsVarId (headFS cs)
804 isLexConSym cs -- Infix type or data constructors
805 | nullFS cs = False -- e.g. ":-:", ":", "->"
806 | cs == (fsLit "->") = True
807 | otherwise = startsConSym (headFS cs)
809 isLexVarSym cs -- Infix identifiers
810 | nullFS cs = False -- e.g. "+"
811 | otherwise = startsVarSym (headFS cs)
814 startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
815 startsVarSym c = isSymbolASCII c || (ord c > 0x7f && isSymbol c) -- Infix Ids
816 startsConSym c = c == ':' -- Infix data constructors
817 startsVarId c = isLower c || c == '_' -- Ordinary Ids
818 startsConId c = isUpper c || c == '(' -- Ordinary type constructors and data constructors
820 isSymbolASCII :: Char -> Bool
821 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
824 %************************************************************************
827 Here rather than BinIface because OccName is abstract
829 %************************************************************************
832 instance Binary NameSpace where
835 put_ bh DataName = do
839 put_ bh TcClsName = do
844 0 -> do return VarName
845 1 -> do return DataName
846 2 -> do return TvName
847 _ -> do return TcClsName
849 instance Binary OccName where
850 put_ bh (OccName aa ab) = do
856 return (OccName aa ab)