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, mkGenC, mkGenS, mkGenR0, mkGenR0Co,
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"
584 mkGenC occ m = mk_deriv tcName ("C1_" ++ show m) (occNameString occ)
585 mkGenS occ m n = mk_deriv tcName ("S1_" ++ show m ++ "_" ++ show n)
588 mkGenR0 = mk_simple_deriv tcName "Rep0_"
589 mkGenR0Co = mk_simple_deriv tcName "CoRep0_"
591 -- data T = MkT ... deriving( Data ) needs defintions for
592 -- $tT :: Data.Generics.Basics.DataType
593 -- $cMkT :: Data.Generics.Basics.Constr
594 mkDataTOcc = mk_simple_deriv varName "$t"
595 mkDataCOcc = mk_simple_deriv varName "$c"
598 mkVectOcc = mk_simple_deriv varName "$v_"
599 mkVectTyConOcc = mk_simple_deriv tcName ":V_"
600 mkVectDataConOcc = mk_simple_deriv dataName ":VD_"
601 mkVectIsoOcc = mk_simple_deriv varName "$VI_"
602 mkPDataTyConOcc = mk_simple_deriv tcName ":VP_"
603 mkPDataDataConOcc = mk_simple_deriv dataName ":VPD_"
604 mkPReprTyConOcc = mk_simple_deriv tcName ":VR_"
605 mkPADFunOcc = mk_simple_deriv varName "$PA_"
607 mk_simple_deriv :: NameSpace -> String -> OccName -> OccName
608 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
610 -- Data constructor workers are made by setting the name space
611 -- of the data constructor OccName (which should be a DataName)
613 mkDataConWorkerOcc datacon_occ = setOccNameSpace varName datacon_occ
617 mkSuperDictSelOcc :: Int -- ^ Index of superclass, e.g. 3
618 -> OccName -- ^ Class, e.g. @Ord@
619 -> OccName -- ^ Derived 'Occname', e.g. @$p3Ord@
620 mkSuperDictSelOcc index cls_occ
621 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
623 mkLocalOcc :: Unique -- ^ Unique to combine with the 'OccName'
624 -> OccName -- ^ Local name, e.g. @sat@
625 -> OccName -- ^ Nice unique version, e.g. @$L23sat@
627 = mk_deriv varName ("$L" ++ show uniq) (occNameString occ)
628 -- The Unique might print with characters
629 -- that need encoding (e.g. 'z'!)
633 -- | Derive a name for the representation type constructor of a
634 -- @data@\/@newtype@ instance.
635 mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@
636 -> OccSet -- ^ avoid these Occs
637 -> OccName -- ^ @R:Map@
638 mkInstTyTcOcc str set =
639 chooseUniqueOcc tcName ('R' : ':' : str) set
643 mkDFunOcc :: String -- ^ Typically the class and type glommed together e.g. @OrdMaybe@.
644 -- Only used in debug mode, for extra clarity
645 -> Bool -- ^ Is this a hs-boot instance DFun?
646 -> OccSet -- ^ avoid these Occs
647 -> OccName -- ^ E.g. @$f3OrdMaybe@
649 -- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real
650 -- thing when we compile the mother module. Reason: we don't know exactly
651 -- what the mother module will call it.
653 mkDFunOcc info_str is_boot set
654 = chooseUniqueOcc VarName (prefix ++ info_str) set
656 prefix | is_boot = "$fx"
660 Sometimes we need to pick an OccName that has not already been used,
661 given a set of in-use OccNames.
664 chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName
665 chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int)
668 | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1)
672 We used to add a '$m' to indicate a method, but that gives rise to bad
673 error messages from the type checker when we print the function name or pattern
674 of an instance-decl binding. Why? Because the binding is zapped
675 to use the method name in place of the selector name.
676 (See TcClassDcl.tcMethodBind)
678 The way it is now, -ddump-xx output may look confusing, but
679 you can always say -dppr-debug to get the uniques.
681 However, we *do* have to zap the first character to be lower case,
682 because overloaded constructors (blarg) generate methods too.
683 And convert to VarName space
685 e.g. a call to constructor MkFoo where
686 data (Ord a) => Foo a = MkFoo a
688 If this is necessary, we do it by prefixing '$m'. These
689 guys never show up in error messages. What a hack.
692 mkMethodOcc :: OccName -> OccName
693 mkMethodOcc occ@(OccName VarName _) = occ
694 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
698 %************************************************************************
700 \subsection{Tidying them up}
702 %************************************************************************
704 Before we print chunks of code we like to rename it so that
705 we don't have to print lots of silly uniques in it. But we mustn't
706 accidentally introduce name clashes! So the idea is that we leave the
707 OccName alone unless it accidentally clashes with one that is already
708 in scope; if so, we tack on '1' at the end and try again, then '2', and
709 so on till we find a unique one.
711 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
712 because that isn't a single lexeme. So we encode it to 'lle' and *then*
713 tack on the '1', if necessary.
716 type TidyOccEnv = OccEnv Int -- The in-scope OccNames
717 -- Range gives a plausible starting point for new guesses
719 emptyTidyOccEnv :: TidyOccEnv
720 emptyTidyOccEnv = emptyOccEnv
722 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
723 initTidyOccEnv = foldl (\env occ -> extendOccEnv env occ 1) emptyTidyOccEnv
725 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
727 tidyOccName in_scope occ@(OccName occ_sp fs)
728 = case lookupOccEnv in_scope occ of
729 Nothing -> -- Not already used: make it used
730 (extendOccEnv in_scope occ 1, occ)
732 Just n -> -- Already used: make a new guess,
733 -- change the guess base, and try again
734 tidyOccName (extendOccEnv in_scope occ (n+1))
735 (mkOccName occ_sp (base_occ ++ show n))
737 base_occ = reverse (dropWhile isDigit (reverse (unpackFS fs)))
740 %************************************************************************
742 Stuff for dealing with tuples
744 %************************************************************************
747 mkTupleOcc :: NameSpace -> Boxity -> Arity -> OccName
748 mkTupleOcc ns bx ar = OccName ns (mkFastString str)
750 -- no need to cache these, the caching is done in the caller
751 -- (TysWiredIn.mk_tuple)
753 Boxed -> '(' : commas ++ ")"
754 Unboxed -> '(' : '#' : commas ++ "#)"
756 commas = take (ar-1) (repeat ',')
758 isTupleOcc_maybe :: OccName -> Maybe (NameSpace, Boxity, Arity)
759 -- Tuples are special, because there are so many of them!
760 isTupleOcc_maybe (OccName ns fs)
761 = case unpackFS fs of
762 '(':'#':',':rest -> Just (ns, Unboxed, 2 + count_commas rest)
763 '(':',':rest -> Just (ns, Boxed, 2 + count_commas rest)
766 count_commas (',':rest) = 1 + count_commas rest
770 %************************************************************************
772 \subsection{Lexical categories}
774 %************************************************************************
776 These functions test strings to see if they fit the lexical categories
777 defined in the Haskell report.
780 isLexCon, isLexVar, isLexId, isLexSym :: FastString -> Bool
781 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FastString -> Bool
783 isLexCon cs = isLexConId cs || isLexConSym cs
784 isLexVar cs = isLexVarId cs || isLexVarSym cs
786 isLexId cs = isLexConId cs || isLexVarId cs
787 isLexSym cs = isLexConSym cs || isLexVarSym cs
791 isLexConId cs -- Prefix type or data constructors
792 | nullFS cs = False -- e.g. "Foo", "[]", "(,)"
793 | cs == (fsLit "[]") = True
794 | otherwise = startsConId (headFS cs)
796 isLexVarId cs -- Ordinary prefix identifiers
797 | nullFS cs = False -- e.g. "x", "_x"
798 | otherwise = startsVarId (headFS cs)
800 isLexConSym cs -- Infix type or data constructors
801 | nullFS cs = False -- e.g. ":-:", ":", "->"
802 | cs == (fsLit "->") = True
803 | otherwise = startsConSym (headFS cs)
805 isLexVarSym cs -- Infix identifiers
806 | nullFS cs = False -- e.g. "+"
807 | otherwise = startsVarSym (headFS cs)
810 startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
811 startsVarSym c = isSymbolASCII c || (ord c > 0x7f && isSymbol c) -- Infix Ids
812 startsConSym c = c == ':' -- Infix data constructors
813 startsVarId c = isLower c || c == '_' -- Ordinary Ids
814 startsConId c = isUpper c || c == '(' -- Ordinary type constructors and data constructors
816 isSymbolASCII :: Char -> Bool
817 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
820 %************************************************************************
823 Here rather than BinIface because OccName is abstract
825 %************************************************************************
828 instance Binary NameSpace where
831 put_ bh DataName = do
835 put_ bh TcClsName = do
840 0 -> do return VarName
841 1 -> do return DataName
842 2 -> do return TvName
843 _ -> do return TcClsName
845 instance Binary OccName where
846 put_ bh (OccName aa ab) = do
852 return (OccName aa ab)