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, 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 -- 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
218 instance Eq OccName where
219 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
221 instance Ord OccName where
222 -- Compares lexicographically, *not* by Unique of the string
223 compare (OccName sp1 s1) (OccName sp2 s2)
224 = (s1 `compare` s2) `thenCmp` (sp1 `compare` sp2)
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, mkGenDefMethodOcc,
544 mkDerivedTyConOcc, mkClassTyConOcc, mkClassDataConOcc, mkDictOcc,
545 mkIPOcc, mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
546 mkGenD, mkGenR, mkGenRCo,
547 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
548 mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
549 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
550 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
551 mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
552 :: OccName -> OccName
554 -- These derived variables have a prefix that no Haskell value could have
555 mkDataConWrapperOcc = mk_simple_deriv varName "$W"
556 mkWorkerOcc = mk_simple_deriv varName "$w"
557 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
558 mkGenDefMethodOcc = mk_simple_deriv varName "$gdm"
559 mkClassOpAuxOcc = mk_simple_deriv varName "$c"
560 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
561 mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
562 mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
563 -- for datacons from classes
564 mkDictOcc = mk_simple_deriv varName "$d"
565 mkIPOcc = mk_simple_deriv varName "$i"
566 mkSpecOcc = mk_simple_deriv varName "$s"
567 mkForeignExportOcc = mk_simple_deriv varName "$f"
568 mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
569 mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
570 mkEqPredCoOcc = mk_simple_deriv tcName "$co"
572 -- used in derived instances
573 mkCon2TagOcc = mk_simple_deriv varName "$con2tag_"
574 mkTag2ConOcc = mk_simple_deriv varName "$tag2con_"
575 mkMaxTagOcc = mk_simple_deriv varName "$maxtag_"
577 -- Generic derivable classes (old)
578 mkGenOcc1 = mk_simple_deriv varName "$gfrom"
579 mkGenOcc2 = mk_simple_deriv varName "$gto"
581 -- Generic deriving mechanism (new)
582 mkGenD = mk_simple_deriv tcName "D1"
584 mkGenC :: OccName -> Int -> OccName
585 mkGenC occ m = mk_deriv tcName ("C1_" ++ show m) (occNameString occ)
587 mkGenS :: OccName -> Int -> Int -> OccName
588 mkGenS occ m n = mk_deriv tcName ("S1_" ++ show m ++ "_" ++ show n)
591 mkGenR = mk_simple_deriv tcName "Rep_"
592 mkGenRCo = mk_simple_deriv tcName "CoRep_"
594 -- data T = MkT ... deriving( Data ) needs defintions for
595 -- $tT :: Data.Generics.Basics.DataType
596 -- $cMkT :: Data.Generics.Basics.Constr
597 mkDataTOcc = mk_simple_deriv varName "$t"
598 mkDataCOcc = mk_simple_deriv varName "$c"
601 mkVectOcc = mk_simple_deriv varName "$v_"
602 mkVectTyConOcc = mk_simple_deriv tcName ":V_"
603 mkVectDataConOcc = mk_simple_deriv dataName ":VD_"
604 mkVectIsoOcc = mk_simple_deriv varName "$VI_"
605 mkPDataTyConOcc = mk_simple_deriv tcName ":VP_"
606 mkPDataDataConOcc = mk_simple_deriv dataName ":VPD_"
607 mkPReprTyConOcc = mk_simple_deriv tcName ":VR_"
608 mkPADFunOcc = mk_simple_deriv varName "$PA_"
610 mk_simple_deriv :: NameSpace -> String -> OccName -> OccName
611 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
613 -- Data constructor workers are made by setting the name space
614 -- of the data constructor OccName (which should be a DataName)
616 mkDataConWorkerOcc datacon_occ = setOccNameSpace varName datacon_occ
620 mkSuperDictSelOcc :: Int -- ^ Index of superclass, e.g. 3
621 -> OccName -- ^ Class, e.g. @Ord@
622 -> OccName -- ^ Derived 'Occname', e.g. @$p3Ord@
623 mkSuperDictSelOcc index cls_occ
624 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
626 mkLocalOcc :: Unique -- ^ Unique to combine with the 'OccName'
627 -> OccName -- ^ Local name, e.g. @sat@
628 -> OccName -- ^ Nice unique version, e.g. @$L23sat@
630 = mk_deriv varName ("$L" ++ show uniq) (occNameString occ)
631 -- The Unique might print with characters
632 -- that need encoding (e.g. 'z'!)
636 -- | Derive a name for the representation type constructor of a
637 -- @data@\/@newtype@ instance.
638 mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@
639 -> OccSet -- ^ avoid these Occs
640 -> OccName -- ^ @R:Map@
641 mkInstTyTcOcc str set =
642 chooseUniqueOcc tcName ('R' : ':' : str) set
646 mkDFunOcc :: String -- ^ Typically the class and type glommed together e.g. @OrdMaybe@.
647 -- Only used in debug mode, for extra clarity
648 -> Bool -- ^ Is this a hs-boot instance DFun?
649 -> OccSet -- ^ avoid these Occs
650 -> OccName -- ^ E.g. @$f3OrdMaybe@
652 -- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real
653 -- thing when we compile the mother module. Reason: we don't know exactly
654 -- what the mother module will call it.
656 mkDFunOcc info_str is_boot set
657 = chooseUniqueOcc VarName (prefix ++ info_str) set
659 prefix | is_boot = "$fx"
663 Sometimes we need to pick an OccName that has not already been used,
664 given a set of in-use OccNames.
667 chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName
668 chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int)
671 | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1)
675 We used to add a '$m' to indicate a method, but that gives rise to bad
676 error messages from the type checker when we print the function name or pattern
677 of an instance-decl binding. Why? Because the binding is zapped
678 to use the method name in place of the selector name.
679 (See TcClassDcl.tcMethodBind)
681 The way it is now, -ddump-xx output may look confusing, but
682 you can always say -dppr-debug to get the uniques.
684 However, we *do* have to zap the first character to be lower case,
685 because overloaded constructors (blarg) generate methods too.
686 And convert to VarName space
688 e.g. a call to constructor MkFoo where
689 data (Ord a) => Foo a = MkFoo a
691 If this is necessary, we do it by prefixing '$m'. These
692 guys never show up in error messages. What a hack.
695 mkMethodOcc :: OccName -> OccName
696 mkMethodOcc occ@(OccName VarName _) = occ
697 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
701 %************************************************************************
703 \subsection{Tidying them up}
705 %************************************************************************
707 Before we print chunks of code we like to rename it so that
708 we don't have to print lots of silly uniques in it. But we mustn't
709 accidentally introduce name clashes! So the idea is that we leave the
710 OccName alone unless it accidentally clashes with one that is already
711 in scope; if so, we tack on '1' at the end and try again, then '2', and
712 so on till we find a unique one.
714 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
715 because that isn't a single lexeme. So we encode it to 'lle' and *then*
716 tack on the '1', if necessary.
719 type TidyOccEnv = OccEnv Int -- The in-scope OccNames
720 -- Range gives a plausible starting point for new guesses
722 emptyTidyOccEnv :: TidyOccEnv
723 emptyTidyOccEnv = emptyOccEnv
725 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
726 initTidyOccEnv = foldl (\env occ -> extendOccEnv env occ 1) emptyTidyOccEnv
728 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
730 tidyOccName in_scope occ@(OccName occ_sp fs)
731 = case lookupOccEnv in_scope occ of
732 Nothing -> -- Not already used: make it used
733 (extendOccEnv in_scope occ 1, occ)
735 Just n -> -- Already used: make a new guess,
736 -- change the guess base, and try again
737 tidyOccName (extendOccEnv in_scope occ (n+1))
738 (mkOccName occ_sp (base_occ ++ show n))
740 base_occ = reverse (dropWhile isDigit (reverse (unpackFS fs)))
743 %************************************************************************
745 Stuff for dealing with tuples
747 %************************************************************************
750 mkTupleOcc :: NameSpace -> Boxity -> Arity -> OccName
751 mkTupleOcc ns bx ar = OccName ns (mkFastString str)
753 -- no need to cache these, the caching is done in the caller
754 -- (TysWiredIn.mk_tuple)
756 Boxed -> '(' : commas ++ ")"
757 Unboxed -> '(' : '#' : commas ++ "#)"
759 commas = take (ar-1) (repeat ',')
761 isTupleOcc_maybe :: OccName -> Maybe (NameSpace, Boxity, Arity)
762 -- Tuples are special, because there are so many of them!
763 isTupleOcc_maybe (OccName ns fs)
764 = case unpackFS fs of
765 '(':'#':',':rest -> Just (ns, Unboxed, 2 + count_commas rest)
766 '(':',':rest -> Just (ns, Boxed, 2 + count_commas rest)
769 count_commas (',':rest) = 1 + count_commas rest
773 %************************************************************************
775 \subsection{Lexical categories}
777 %************************************************************************
779 These functions test strings to see if they fit the lexical categories
780 defined in the Haskell report.
783 isLexCon, isLexVar, isLexId, isLexSym :: FastString -> Bool
784 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FastString -> Bool
786 isLexCon cs = isLexConId cs || isLexConSym cs
787 isLexVar cs = isLexVarId cs || isLexVarSym cs
789 isLexId cs = isLexConId cs || isLexVarId cs
790 isLexSym cs = isLexConSym cs || isLexVarSym cs
794 isLexConId cs -- Prefix type or data constructors
795 | nullFS cs = False -- e.g. "Foo", "[]", "(,)"
796 | cs == (fsLit "[]") = True
797 | otherwise = startsConId (headFS cs)
799 isLexVarId cs -- Ordinary prefix identifiers
800 | nullFS cs = False -- e.g. "x", "_x"
801 | otherwise = startsVarId (headFS cs)
803 isLexConSym cs -- Infix type or data constructors
804 | nullFS cs = False -- e.g. ":-:", ":", "->"
805 | cs == (fsLit "->") = True
806 | otherwise = startsConSym (headFS cs)
808 isLexVarSym cs -- Infix identifiers
809 | nullFS cs = False -- e.g. "+"
810 | otherwise = startsVarSym (headFS cs)
813 startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
814 startsVarSym c = isSymbolASCII c || (ord c > 0x7f && isSymbol c) -- Infix Ids
815 startsConSym c = c == ':' -- Infix data constructors
816 startsVarId c = isLower c || c == '_' -- Ordinary Ids
817 startsConId c = isUpper c || c == '(' -- Ordinary type constructors and data constructors
819 isSymbolASCII :: Char -> Bool
820 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
823 %************************************************************************
826 Here rather than BinIface because OccName is abstract
828 %************************************************************************
831 instance Binary NameSpace where
834 put_ bh DataName = do
838 put_ bh TcClsName = do
843 0 -> do return VarName
844 1 -> do return DataName
845 2 -> do return TvName
846 _ -> do return TcClsName
848 instance Binary OccName where
849 put_ bh (OccName aa ab) = do
855 return (OccName aa ab)