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
233 instance Eq OccName where
234 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
236 instance Ord OccName where
237 -- Compares lexicographically, *not* by Unique of the string
238 compare (OccName sp1 s1) (OccName sp2 s2)
239 = (s1 `compare` s2) `thenCmp` (sp1 `compare` sp2)
241 instance Data OccName where
243 toConstr _ = abstractConstr "OccName"
244 gunfold _ _ = error "gunfold"
245 dataTypeOf _ = mkNoRepType "OccName"
249 %************************************************************************
251 \subsection{Printing}
253 %************************************************************************
256 instance Outputable OccName where
259 pprOccName :: OccName -> SDoc
260 pprOccName (OccName sp occ)
261 = getPprStyle $ \ sty ->
263 then ftext (zEncodeFS occ)
264 else pp_occ <> pp_debug sty
266 pp_debug sty | debugStyle sty = braces (pprNameSpaceBrief sp)
269 pp_occ | opt_SuppressUniques = text (strip_th_unique (unpackFS occ))
270 | otherwise = ftext occ
272 -- See Note [Suppressing uniques in OccNames]
273 strip_th_unique ('[' : c : _) | isAlphaNum c = []
274 strip_th_unique (c : cs) = c : strip_th_unique cs
275 strip_th_unique [] = []
278 Note [Suppressing uniques in OccNames]
279 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
280 This is a hack to de-wobblify the OccNames that contain uniques from
281 Template Haskell that have been turned into a string in the OccName.
282 See Note [Unique OccNames from Template Haskell] in Convert.hs
284 %************************************************************************
286 \subsection{Construction}
288 %************************************************************************
291 mkOccName :: NameSpace -> String -> OccName
292 mkOccName occ_sp str = OccName occ_sp (mkFastString str)
294 mkOccNameFS :: NameSpace -> FastString -> OccName
295 mkOccNameFS occ_sp fs = OccName occ_sp fs
297 mkVarOcc :: String -> OccName
298 mkVarOcc s = mkOccName varName s
300 mkVarOccFS :: FastString -> OccName
301 mkVarOccFS fs = mkOccNameFS varName fs
303 mkDataOcc :: String -> OccName
304 mkDataOcc = mkOccName dataName
306 mkDataOccFS :: FastString -> OccName
307 mkDataOccFS = mkOccNameFS dataName
309 mkTyVarOcc :: String -> OccName
310 mkTyVarOcc = mkOccName tvName
312 mkTyVarOccFS :: FastString -> OccName
313 mkTyVarOccFS fs = mkOccNameFS tvName fs
315 mkTcOcc :: String -> OccName
316 mkTcOcc = mkOccName tcName
318 mkTcOccFS :: FastString -> OccName
319 mkTcOccFS = mkOccNameFS tcName
321 mkClsOcc :: String -> OccName
322 mkClsOcc = mkOccName clsName
324 mkClsOccFS :: FastString -> OccName
325 mkClsOccFS = mkOccNameFS clsName
329 %************************************************************************
333 %************************************************************************
335 OccEnvs are used mainly for the envts in ModIfaces.
337 Note [The Unique of an OccName]
338 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
339 They are efficient, because FastStrings have unique Int# keys. We assume
340 this key is less than 2^24, and indeed FastStrings are allocated keys
341 sequentially starting at 0.
343 So we can make a Unique using
344 mkUnique ns key :: Unique
345 where 'ns' is a Char reprsenting the name space. This in turn makes it
346 easy to build an OccEnv.
349 instance Uniquable OccName where
350 -- See Note [The Unique of an OccName]
351 getUnique (OccName (VarName depth) fs) = mkVarOccUnique fs depth
352 getUnique (OccName DataName fs) = mkDataOccUnique fs
353 getUnique (OccName TvName fs) = mkTvOccUnique fs
354 getUnique (OccName TcClsName fs) = mkTcOccUnique fs
356 newtype OccEnv a = A (UniqFM a)
358 emptyOccEnv :: OccEnv a
359 unitOccEnv :: OccName -> a -> OccEnv a
360 extendOccEnv :: OccEnv a -> OccName -> a -> OccEnv a
361 extendOccEnvList :: OccEnv a -> [(OccName, a)] -> OccEnv a
362 lookupOccEnv :: OccEnv a -> OccName -> Maybe a
363 mkOccEnv :: [(OccName,a)] -> OccEnv a
364 mkOccEnv_C :: (a -> a -> a) -> [(OccName,a)] -> OccEnv a
365 elemOccEnv :: OccName -> OccEnv a -> Bool
366 foldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b
367 occEnvElts :: OccEnv a -> [a]
368 extendOccEnv_C :: (a->a->a) -> OccEnv a -> OccName -> a -> OccEnv a
369 extendOccEnv_Acc :: (a->b->b) -> (a->b) -> OccEnv b -> OccName -> a -> OccEnv b
370 plusOccEnv :: OccEnv a -> OccEnv a -> OccEnv a
371 plusOccEnv_C :: (a->a->a) -> OccEnv a -> OccEnv a -> OccEnv a
372 mapOccEnv :: (a->b) -> OccEnv a -> OccEnv b
373 delFromOccEnv :: OccEnv a -> OccName -> OccEnv a
374 delListFromOccEnv :: OccEnv a -> [OccName] -> OccEnv a
375 filterOccEnv :: (elt -> Bool) -> OccEnv elt -> OccEnv elt
377 emptyOccEnv = A emptyUFM
378 unitOccEnv x y = A $ unitUFM x y
379 extendOccEnv (A x) y z = A $ addToUFM x y z
380 extendOccEnvList (A x) l = A $ addListToUFM x l
381 lookupOccEnv (A x) y = lookupUFM x y
382 mkOccEnv l = A $ listToUFM l
383 elemOccEnv x (A y) = elemUFM x y
384 foldOccEnv a b (A c) = foldUFM a b c
385 occEnvElts (A x) = eltsUFM x
386 plusOccEnv (A x) (A y) = A $ plusUFM x y
387 plusOccEnv_C f (A x) (A y) = A $ plusUFM_C f x y
388 extendOccEnv_C f (A x) y z = A $ addToUFM_C f x y z
389 extendOccEnv_Acc f g (A x) y z = A $ addToUFM_Acc f g x y z
390 mapOccEnv f (A x) = A $ mapUFM f x
391 mkOccEnv_C comb l = A $ addListToUFM_C comb emptyUFM l
392 delFromOccEnv (A x) y = A $ delFromUFM x y
393 delListFromOccEnv (A x) y = A $ delListFromUFM x y
394 filterOccEnv x (A y) = A $ filterUFM x y
396 instance Outputable a => Outputable (OccEnv a) where
399 type OccSet = UniqSet OccName
401 emptyOccSet :: OccSet
402 unitOccSet :: OccName -> OccSet
403 mkOccSet :: [OccName] -> OccSet
404 extendOccSet :: OccSet -> OccName -> OccSet
405 extendOccSetList :: OccSet -> [OccName] -> OccSet
406 unionOccSets :: OccSet -> OccSet -> OccSet
407 unionManyOccSets :: [OccSet] -> OccSet
408 minusOccSet :: OccSet -> OccSet -> OccSet
409 elemOccSet :: OccName -> OccSet -> Bool
410 occSetElts :: OccSet -> [OccName]
411 foldOccSet :: (OccName -> b -> b) -> b -> OccSet -> b
412 isEmptyOccSet :: OccSet -> Bool
413 intersectOccSet :: OccSet -> OccSet -> OccSet
414 intersectsOccSet :: OccSet -> OccSet -> Bool
416 emptyOccSet = emptyUniqSet
417 unitOccSet = unitUniqSet
419 extendOccSet = addOneToUniqSet
420 extendOccSetList = addListToUniqSet
421 unionOccSets = unionUniqSets
422 unionManyOccSets = unionManyUniqSets
423 minusOccSet = minusUniqSet
424 elemOccSet = elementOfUniqSet
425 occSetElts = uniqSetToList
426 foldOccSet = foldUniqSet
427 isEmptyOccSet = isEmptyUniqSet
428 intersectOccSet = intersectUniqSets
429 intersectsOccSet s1 s2 = not (isEmptyOccSet (s1 `intersectOccSet` s2))
433 %************************************************************************
435 \subsection{Predicates and taking them apart}
437 %************************************************************************
440 occNameString :: OccName -> String
441 occNameString (OccName _ s) = unpackFS s
443 setOccNameSpace :: NameSpace -> OccName -> OccName
444 setOccNameSpace sp (OccName _ occ) = OccName sp occ
446 isVarOcc, isTvOcc, isTcOcc, isDataOcc :: OccName -> Bool
448 isVarOcc (OccName (VarName _) _) = True
451 isTvOcc (OccName TvName _) = True
454 isTcOcc (OccName TcClsName _) = True
457 -- | /Value/ 'OccNames's are those that are either in
458 -- the variable or data constructor namespaces
459 isValOcc :: OccName -> Bool
460 isValOcc (OccName (VarName _) _) = True
461 isValOcc (OccName DataName _) = True
464 isDataOcc (OccName DataName _) = True
465 isDataOcc (OccName (VarName _) s)
466 | isLexCon s = pprPanic "isDataOcc: check me" (ppr s)
467 -- Jan06: I don't think this should happen
470 -- | Test if the 'OccName' is a data constructor that starts with
471 -- a symbol (e.g. @:@, or @[]@)
472 isDataSymOcc :: OccName -> Bool
473 isDataSymOcc (OccName DataName s) = isLexConSym s
474 isDataSymOcc (OccName (VarName _) s)
475 | isLexConSym s = pprPanic "isDataSymOcc: check me" (ppr s)
476 -- Jan06: I don't think this should happen
477 isDataSymOcc _ = False
478 -- Pretty inefficient!
480 -- | Test if the 'OccName' is that for any operator (whether
481 -- it is a data constructor or variable or whatever)
482 isSymOcc :: OccName -> Bool
483 isSymOcc (OccName DataName s) = isLexConSym s
484 isSymOcc (OccName TcClsName s) = isLexConSym s
485 isSymOcc (OccName (VarName _) s) = isLexSym s
486 isSymOcc (OccName TvName s) = isLexSym s
487 -- Pretty inefficient!
489 parenSymOcc :: OccName -> SDoc -> SDoc
490 -- ^ Wrap parens around an operator
491 parenSymOcc occ doc | isSymOcc occ = parens doc
497 startsWithUnderscore :: OccName -> Bool
498 -- ^ Haskell 98 encourages compilers to suppress warnings about unsed
499 -- names in a pattern if they start with @_@: this implements that test
500 startsWithUnderscore occ = case occNameString occ of
506 %************************************************************************
508 \subsection{Making system names}
510 %************************************************************************
512 Here's our convention for splitting up the interface file name space:
514 d... dictionary identifiers
515 (local variables, so no name-clash worries)
517 All of these other OccNames contain a mixture of alphabetic
518 and symbolic characters, and hence cannot possibly clash with
519 a user-written type or function name
521 $f... Dict-fun identifiers (from inst decls)
522 $dmop Default method for 'op'
523 $pnC n'th superclass selector for class C
524 $wf Worker for functtoin 'f'
525 $sf.. Specialised version of f
526 T:C Tycon for dictionary for class C
527 D:C Data constructor for dictionary for class C
528 NTCo:T Coercion connecting newtype T with its representation type
529 TFCo:R Coercion connecting a data family to its respresentation type R
531 In encoded form these appear as Zdfxxx etc
533 :... keywords (export:, letrec: etc.)
534 --- I THINK THIS IS WRONG!
536 This knowledge is encoded in the following functions.
538 @mk_deriv@ generates an @OccName@ from the prefix and a string.
539 NB: The string must already be encoded!
542 mk_deriv :: NameSpace
543 -> String -- Distinguishes one sort of derived name from another
547 mk_deriv occ_sp sys_prefix str = mkOccName occ_sp (sys_prefix ++ str)
549 isDerivedOccName :: OccName -> Bool
550 isDerivedOccName occ =
551 case occNameString occ of
552 '$':c:_ | isAlphaNum c -> True
553 ':':c:_ | isAlphaNum c -> True
558 mkDataConWrapperOcc, mkWorkerOcc, mkDefaultMethodOcc, mkDerivedTyConOcc,
559 mkClassTyConOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc,
560 mkSpecOcc, mkForeignExportOcc, mkGenOcc1, mkGenOcc2,
561 mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
562 mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
563 mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
564 mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
565 mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
566 :: OccName -> OccName
568 -- These derived variables have a prefix that no Haskell value could have
569 mkDataConWrapperOcc = mk_simple_deriv varName "$W"
570 mkWorkerOcc = mk_simple_deriv varName "$w"
571 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
572 mkClassOpAuxOcc = mk_simple_deriv varName "$c"
573 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
574 mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
575 mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
576 -- for datacons from classes
577 mkDictOcc = mk_simple_deriv varName "$d"
578 mkIPOcc = mk_simple_deriv varName "$i"
579 mkSpecOcc = mk_simple_deriv varName "$s"
580 mkForeignExportOcc = mk_simple_deriv varName "$f"
581 mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
582 mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
583 mkEqPredCoOcc = mk_simple_deriv tcName "$co"
585 -- used in derived instances
586 mkCon2TagOcc = mk_simple_deriv varName "$con2tag_"
587 mkTag2ConOcc = mk_simple_deriv varName "$tag2con_"
588 mkMaxTagOcc = mk_simple_deriv varName "$maxtag_"
590 -- Generic derivable classes
591 mkGenOcc1 = mk_simple_deriv varName "$gfrom"
592 mkGenOcc2 = mk_simple_deriv varName "$gto"
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 $fx7ClsTy, which get bound to the real
653 -- thing when we compile the mother module. Reason: we don't know exactly
654 -- what the mother module will call it.
656 mkDFunOcc info_str is_boot set
657 = chooseUniqueOcc (VarName 0) (prefix ++ info_str) set
659 prefix | is_boot = "$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
832 put_ bh (VarName depth) = do if depth > 255-4
833 then error "FIXME: no support for serializing VarNames at this syntactic depth"
834 else putByte bh ((fromIntegral ((depth+3) :: Int)))
835 put_ bh DataName = do
839 put_ bh TcClsName = do
844 0 -> do return DataName
845 1 -> do return TvName
846 2 -> do return TcClsName
847 n -> do return (VarName (fromIntegral (n-3)))
849 instance Binary OccName where
850 put_ bh (OccName aa ab) = do
856 return (OccName aa ab)