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,
52 mkDerivedTyConOcc, mkNewTyCoOcc, mkClassOpAuxOcc,
53 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
54 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
55 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
56 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc,
57 mkSuperDictSelOcc, mkLocalOcc, mkMethodOcc, mkInstTyTcOcc,
58 mkInstTyCoOcc, mkEqPredCoOcc,
59 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
60 mkPDataTyConOcc, mkPDataDataConOcc,
65 occNameFS, occNameString, occNameSpace,
67 isVarOcc, isTvOcc, isTcOcc, isDataOcc, isDataSymOcc, isSymOcc, isValOcc,
68 parenSymOcc, startsWithUnderscore,
70 isTcClsNameSpace, isTvNameSpace, isDataConNameSpace, isVarNameSpace, isValNameSpace,
74 -- * The 'OccEnv' type
75 OccEnv, emptyOccEnv, unitOccEnv, extendOccEnv, mapOccEnv,
76 lookupOccEnv, mkOccEnv, mkOccEnv_C, extendOccEnvList, elemOccEnv,
77 occEnvElts, foldOccEnv, plusOccEnv, plusOccEnv_C, extendOccEnv_C,
78 extendOccEnv_Acc, filterOccEnv, delListFromOccEnv, delFromOccEnv,
80 -- * The 'OccSet' type
81 OccSet, emptyOccSet, unitOccSet, mkOccSet, extendOccSet,
83 unionOccSets, unionManyOccSets, minusOccSet, elemOccSet, occSetElts,
84 foldOccSet, isEmptyOccSet, intersectOccSet, intersectsOccSet,
87 TidyOccEnv, emptyTidyOccEnv, tidyOccName, initTidyOccEnv,
89 -- * Lexical characteristics of Haskell names
90 isLexCon, isLexVar, isLexId, isLexSym,
91 isLexConId, isLexConSym, isLexVarId, isLexVarSym,
92 startsVarSym, startsVarId, startsConSym, startsConId
105 import StaticFlags( opt_SuppressUniques )
110 %************************************************************************
112 \subsection{Name space}
114 %************************************************************************
117 data NameSpace = VarName Int -- Variables, including "real" data constructors; Int is the syntactic HetMet bracket depth
118 | DataName -- "Source" data constructors
119 | TvName -- Type variables
120 | TcClsName -- Type constructors and classes; Haskell has them
121 -- in the same name space for now.
123 {-! derive: Binary !-}
125 -- Note [Data Constructors]
126 -- see also: Note [Data Constructor Naming] in DataCon.lhs
128 -- $real_vs_source_data_constructors
129 -- There are two forms of data constructor:
131 -- [Source data constructors] The data constructors mentioned in Haskell source code
133 -- [Real data constructors] The data constructors of the representation type, which may not be the same as the source type
137 -- > data T = T !(Int, Int)
139 -- The source datacon has type @(Int, Int) -> T@
140 -- The real datacon has type @Int -> Int -> T@
142 -- GHC chooses a representation based on the strictness etc.
144 tcName, clsName, tcClsName :: NameSpace
145 dataName, srcDataName :: NameSpace
146 tvName, varName :: NameSpace
147 varNameDepth :: Int -> 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 varNameDepth = VarName
164 getOccNameDepth :: OccName -> Int
165 getOccNameDepth name =
166 case occNameSpace name of
169 setOccNameDepth :: Int -> OccName -> OccName
170 setOccNameDepth depth name =
171 case occNameSpace name of
172 (VarName _) -> name{ occNameSpace = VarName depth }
175 else error ("tried to change the depth of a name in namespace " ++ (showSDoc $ ppr name))
177 isDataConNameSpace :: NameSpace -> Bool
178 isDataConNameSpace DataName = True
179 isDataConNameSpace _ = False
181 isTcClsNameSpace :: NameSpace -> Bool
182 isTcClsNameSpace TcClsName = True
183 isTcClsNameSpace _ = False
185 isTvNameSpace :: NameSpace -> Bool
186 isTvNameSpace TvName = True
187 isTvNameSpace _ = False
189 isVarNameSpace :: NameSpace -> Bool -- Variables or type variables, but not constructors
190 isVarNameSpace TvName = True
191 isVarNameSpace (VarName _) = True
192 isVarNameSpace _ = False
194 isValNameSpace :: NameSpace -> Bool
195 isValNameSpace DataName = True
196 isValNameSpace (VarName _) = True
197 isValNameSpace _ = False
199 pprNameSpace :: NameSpace -> SDoc
200 pprNameSpace DataName = ptext (sLit "data constructor")
201 pprNameSpace (VarName _) = ptext (sLit "variable")
202 pprNameSpace TvName = ptext (sLit "type variable")
203 pprNameSpace TcClsName = ptext (sLit "type constructor or class")
205 pprNonVarNameSpace :: NameSpace -> SDoc
206 pprNonVarNameSpace (VarName _) = empty
207 pprNonVarNameSpace ns = pprNameSpace ns
209 pprNameSpaceBrief :: NameSpace -> SDoc
210 pprNameSpaceBrief DataName = char 'd'
211 pprNameSpaceBrief (VarName _) = char 'v'
212 pprNameSpaceBrief TvName = ptext (sLit "tv")
213 pprNameSpaceBrief TcClsName = ptext (sLit "tc")
217 %************************************************************************
219 \subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
221 %************************************************************************
224 data OccName = OccName
225 { occNameSpace :: !NameSpace
226 , occNameFS :: !FastString
232 instance Eq OccName where
233 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
235 instance Ord OccName where
236 -- Compares lexicographically, *not* by Unique of the string
237 compare (OccName sp1 s1) (OccName sp2 s2)
238 = (s1 `compare` s2) `thenCmp` (sp1 `compare` sp2)
240 INSTANCE_TYPEABLE0(OccName,occNameTc,"OccName")
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, mkDerivedTyConOcc,
560 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
561 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
562 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
563 mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
564 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
565 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
566 mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
567 :: OccName -> OccName
569 -- These derived variables have a prefix that no Haskell value could have
570 mkDataConWrapperOcc = mk_simple_deriv varName "$W"
571 mkWorkerOcc = mk_simple_deriv varName "$w"
572 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
573 mkClassOpAuxOcc = mk_simple_deriv varName "$c"
574 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
575 mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
576 mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
577 -- for datacons from classes
578 mkDictOcc = mk_simple_deriv varName "$d"
579 mkIPOcc = mk_simple_deriv varName "$i"
580 mkSpecOcc = mk_simple_deriv varName "$s"
581 mkForeignExportOcc = mk_simple_deriv varName "$f"
582 mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
583 mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
584 mkEqPredCoOcc = mk_simple_deriv tcName "$co"
586 -- used in derived instances
587 mkCon2TagOcc = mk_simple_deriv varName "$con2tag_"
588 mkTag2ConOcc = mk_simple_deriv varName "$tag2con_"
589 mkMaxTagOcc = mk_simple_deriv varName "$maxtag_"
591 -- Generic derivable classes
592 mkGenOcc1 = mk_simple_deriv varName "$gfrom"
593 mkGenOcc2 = mk_simple_deriv varName "$gto"
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 $fx7ClsTy, which get bound to the real
654 -- thing when we compile the mother module. Reason: we don't know exactly
655 -- what the mother module will call it.
657 mkDFunOcc info_str is_boot set
658 = chooseUniqueOcc (VarName 0) (prefix ++ info_str) set
660 prefix | is_boot = "$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
833 put_ bh (VarName depth) = do if depth > 255-4
834 then error "FIXME: no support for serializing VarNames at this syntactic depth"
835 else putByte bh ((fromIntegral ((depth+3) :: Int)))
836 put_ bh DataName = do
840 put_ bh TcClsName = do
845 0 -> do return DataName
846 1 -> do return TvName
847 2 -> do return TcClsName
848 n -> do return (VarName (fromIntegral (n-3)))
850 instance Binary OccName where
851 put_ bh (OccName aa ab) = do
857 return (OccName aa ab)