2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[OccName]{@OccName@}
9 -- The NameSpace type; abstact
10 NameSpace, tcName, clsName, tcClsName, dataName, varName,
11 tvName, nameSpaceString,
14 OccName, -- Abstract, instance of Outputable
17 mkOccFS, mkSysOcc, mkSysOccFS, mkFCallOcc, mkVarOcc, mkKindOccFS,
18 mkSuperDictSelOcc, mkDFunOcc, mkForeignExportOcc,
19 mkDictOcc, mkIPOcc, mkWorkerOcc, mkMethodOcc, mkDefaultMethodOcc,
20 mkDerivedTyConOcc, mkClassTyConOcc, mkClassDataConOcc, mkSpecOcc,
21 mkGenOcc1, mkGenOcc2, mkLocalOcc,
23 isTvOcc, isTcOcc, isDataOcc, isDataSymOcc, isSymOcc, isValOcc,
25 occNameFS, occNameString, occNameUserString, occNameSpace, occNameFlavour,
29 TidyOccEnv, emptyTidyOccEnv, tidyOccName, initTidyOccEnv,
32 EncodedString, EncodedFS, UserString, UserFS, encode, encodeFS, decode, pprEncodedFS,
34 -- The basic form of names
35 isLexCon, isLexVar, isLexId, isLexSym,
36 isLexConId, isLexConSym, isLexVarId, isLexVarSym,
37 isLowerISO, isUpperISO
41 #include "HsVersions.h"
43 import Char ( isDigit, isUpper, isLower, isAlphaNum, ord, chr, digitToInt )
44 import Util ( thenCmp )
45 import Unique ( Unique )
46 import FiniteMap ( FiniteMap, emptyFM, lookupFM, addToFM, elemFM )
51 We hold both module names and identifier names in a 'Z-encoded' form
52 that makes them acceptable both as a C identifier and as a Haskell
55 They can always be decoded again when printing error messages
56 or anything else for the user, but it does make sense for it
57 to be represented here in encoded form, so that when generating
58 code the encoding operation is not performed on each occurrence.
60 These type synonyms help documentation.
63 type UserFS = FAST_STRING -- As the user typed it
64 type EncodedFS = FAST_STRING -- Encoded form
66 type UserString = String -- As the user typed it
67 type EncodedString = String -- Encoded form
70 pprEncodedFS :: EncodedFS -> SDoc
72 = getPprStyle $ \ sty ->
74 -- ptext (decodeFS fs) would needlessly pack the string again
75 then text (decode (_UNPK_ fs))
79 %************************************************************************
81 \subsection{Name space}
83 %************************************************************************
86 data NameSpace = VarName -- Variables
87 | DataName -- Data constructors
88 | TvName -- Type variables
89 | TcClsName -- Type constructors and classes; Haskell has them
90 -- in the same name space for now.
93 -- Though type constructors and classes are in the same name space now,
94 -- the NameSpace type is abstract, so we can easily separate them later
95 tcName = TcClsName -- Type constructors
96 clsName = TcClsName -- Classes
97 tcClsName = TcClsName -- Not sure which!
104 nameSpaceString :: NameSpace -> String
105 nameSpaceString DataName = "Data constructor"
106 nameSpaceString VarName = "Variable"
107 nameSpaceString TvName = "Type variable"
108 nameSpaceString TcClsName = "Type constructor or class"
112 %************************************************************************
114 \subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
116 %************************************************************************
119 data OccName = OccName
126 instance Eq OccName where
127 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
129 instance Ord OccName where
130 compare (OccName sp1 s1) (OccName sp2 s2) = (s1 `compare` s2) `thenCmp`
135 %************************************************************************
137 \subsection{Printing}
139 %************************************************************************
142 instance Outputable OccName where
145 pprOccName :: OccName -> SDoc
146 pprOccName (OccName sp occ) = pprEncodedFS occ
150 %************************************************************************
152 \subsection{Construction}
154 %************************************************************************
156 *Sys* things do no encoding; the caller should ensure that the thing is
160 mkSysOcc :: NameSpace -> EncodedString -> OccName
161 mkSysOcc occ_sp str = ASSERT2( alreadyEncoded str, text str )
162 OccName occ_sp (_PK_ str)
164 mkSysOccFS :: NameSpace -> EncodedFS -> OccName
165 mkSysOccFS occ_sp fs = ASSERT2( alreadyEncodedFS fs, ppr fs )
168 mkFCallOcc :: EncodedString -> OccName
169 -- This version of mkSysOcc doesn't check that the string is already encoded,
170 -- because it will be something like "{__ccall f dyn Int# -> Int#}"
171 -- This encodes a lot into something that then parses like an Id.
172 -- But then alreadyEncoded complains about the braces!
173 mkFCallOcc str = OccName varName (_PK_ str)
175 -- Kind constructors get a special function. Uniquely, they are not encoded,
176 -- so that they have names like '*'. This means that *even in interface files*
177 -- we'll get kinds like (* -> (* -> *)). We can't use mkSysOcc because it
178 -- has an ASSERT that doesn't hold.
179 mkKindOccFS :: NameSpace -> EncodedFS -> OccName
180 mkKindOccFS occ_sp fs = OccName occ_sp fs
183 *Source-code* things are encoded.
186 mkOccFS :: NameSpace -> UserFS -> OccName
187 mkOccFS occ_sp fs = mkSysOccFS occ_sp (encodeFS fs)
189 mkVarOcc :: UserFS -> OccName
190 mkVarOcc fs = mkSysOccFS varName (encodeFS fs)
195 %************************************************************************
197 \subsection{Predicates and taking them apart}
199 %************************************************************************
202 occNameFS :: OccName -> EncodedFS
203 occNameFS (OccName _ s) = s
205 occNameString :: OccName -> EncodedString
206 occNameString (OccName _ s) = _UNPK_ s
208 occNameUserString :: OccName -> UserString
209 occNameUserString occ = decode (occNameString occ)
211 occNameSpace :: OccName -> NameSpace
212 occNameSpace (OccName sp _) = sp
214 setOccNameSpace :: OccName -> NameSpace -> OccName
215 setOccNameSpace (OccName _ occ) sp = OccName sp occ
217 -- occNameFlavour is used only to generate good error messages
218 occNameFlavour :: OccName -> String
219 occNameFlavour (OccName sp _) = nameSpaceString sp
223 isTvOcc, isDataSymOcc, isSymOcc, isTcOcc :: OccName -> Bool
225 isTvOcc (OccName TvName _) = True
226 isTvOcc other = False
228 isTcOcc (OccName TcClsName _) = True
229 isTcOcc other = False
231 isValOcc (OccName VarName _) = True
232 isValOcc (OccName DataName _) = True
233 isValOcc other = False
235 -- Data constructor operator (starts with ':', or '[]')
236 -- Pretty inefficient!
237 isDataSymOcc (OccName DataName s) = isLexConSym (decodeFS s)
238 isDataSymOcc other = False
240 isDataOcc (OccName DataName _) = True
241 isDataOcc other = False
243 -- Any operator (data constructor or variable)
244 -- Pretty inefficient!
245 isSymOcc (OccName DataName s) = isLexConSym (decodeFS s)
246 isSymOcc (OccName VarName s) = isLexSym (decodeFS s)
250 %************************************************************************
252 \subsection{Making system names}
254 %************************************************************************
256 Here's our convention for splitting up the interface file name space:
258 d... dictionary identifiers
259 (local variables, so no name-clash worries)
261 $f... dict-fun identifiers (from inst decls)
262 $dm... default methods
263 $p... superclass selectors
265 :T... compiler-generated tycons for dictionaries
266 :D... ...ditto data cons
267 $sf.. specialised version of f
269 in encoded form these appear as Zdfxxx etc
271 :... keywords (export:, letrec: etc.)
272 --- I THINK THIS IS WRONG!
274 This knowledge is encoded in the following functions.
277 @mk_deriv@ generates an @OccName@ from the prefix and a string.
278 NB: The string must already be encoded!
281 mk_deriv :: NameSpace
282 -> String -- Distinguishes one sort of derived name from another
283 -> EncodedString -- Must be already encoded!! We don't want to encode it a
284 -- second time because encoding isn't idempotent
287 mk_deriv occ_sp sys_prefix str = mkSysOcc occ_sp (encode sys_prefix ++ str)
291 mkDictOcc, mkIPOcc, mkWorkerOcc, mkDefaultMethodOcc,
292 mkClassTyConOcc, mkClassDataConOcc, mkSpecOcc
293 :: OccName -> OccName
295 -- These derived variables have a prefix that no Haskell value could have
296 mkWorkerOcc = mk_simple_deriv varName "$w"
297 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
298 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
299 mkClassTyConOcc = mk_simple_deriv tcName ":T" -- as a tycon/datacon
300 mkClassDataConOcc = mk_simple_deriv dataName ":D" --
301 mkDictOcc = mk_simple_deriv varName "$d"
302 mkIPOcc = mk_simple_deriv varName "$i"
303 mkSpecOcc = mk_simple_deriv varName "$s"
304 mkForeignExportOcc = mk_simple_deriv varName "$f"
305 mkGenOcc1 = mk_simple_deriv varName "$gfrom" -- Generics
306 mkGenOcc2 = mk_simple_deriv varName "$gto" -- Generics
307 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
311 mkSuperDictSelOcc :: Int -- Index of superclass, eg 3
312 -> OccName -- Class, eg "Ord"
313 -> OccName -- eg "$p3Ord"
314 mkSuperDictSelOcc index cls_occ
315 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
317 mkLocalOcc :: Unique -- Unique
318 -> OccName -- Local name (e.g. "sat")
319 -> OccName -- Nice unique version ("$L23sat")
321 = mk_deriv varName ("$L" ++ show uniq) (occNameString occ)
322 -- The Unique might print with characters
323 -- that need encoding (e.g. 'z'!)
328 mkDFunOcc :: EncodedString -- Typically the class and type glommed together e.g. "OrdMaybe"
329 -> OccName -- "$fOrdMaybe"
331 mkDFunOcc string = mk_deriv VarName "$f" string
334 We used to add a '$m' to indicate a method, but that gives rise to bad
335 error messages from the type checker when we print the function name or pattern
336 of an instance-decl binding. Why? Because the binding is zapped
337 to use the method name in place of the selector name.
338 (See TcClassDcl.tcMethodBind)
340 The way it is now, -ddump-xx output may look confusing, but
341 you can always say -dppr-debug to get the uniques.
343 However, we *do* have to zap the first character to be lower case,
344 because overloaded constructors (blarg) generate methods too.
345 And convert to VarName space
347 e.g. a call to constructor MkFoo where
348 data (Ord a) => Foo a = MkFoo a
350 If this is necessary, we do it by prefixing '$m'. These
351 guys never show up in error messages. What a hack.
354 mkMethodOcc :: OccName -> OccName
355 mkMethodOcc occ@(OccName VarName fs) = occ
356 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
360 %************************************************************************
362 \subsection{Tidying them up}
364 %************************************************************************
366 Before we print chunks of code we like to rename it so that
367 we don't have to print lots of silly uniques in it. But we mustn't
368 accidentally introduce name clashes! So the idea is that we leave the
369 OccName alone unless it accidentally clashes with one that is already
370 in scope; if so, we tack on '1' at the end and try again, then '2', and
371 so on till we find a unique one.
373 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
374 because that isn't a single lexeme. So we encode it to 'lle' and *then*
375 tack on the '1', if necessary.
378 type TidyOccEnv = FiniteMap FAST_STRING Int -- The in-scope OccNames
379 emptyTidyOccEnv = emptyFM
381 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
382 initTidyOccEnv = foldl (\env (OccName _ fs) -> addToFM env fs 1) emptyTidyOccEnv
384 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
386 tidyOccName in_scope occ@(OccName occ_sp fs)
387 | not (fs `elemFM` in_scope)
388 = (addToFM in_scope fs 1, occ) -- First occurrence
390 | otherwise -- Already occurs
391 = go in_scope (_UNPK_ fs)
394 go in_scope str = case lookupFM in_scope pk_str of
395 Just n -> go (addToFM in_scope pk_str (n+1)) (str ++ show n)
396 -- Need to go round again, just in case "t3" (say)
397 -- clashes with a "t3" that's already in scope
399 Nothing -> (addToFM in_scope pk_str 1, mkSysOccFS occ_sp pk_str)
406 %************************************************************************
408 \subsection{The 'Z' encoding}
410 %************************************************************************
412 This is the main name-encoding and decoding function. It encodes any
413 string into a string that is acceptable as a C name. This is the name
414 by which things are known right through the compiler.
416 The basic encoding scheme is this.
418 * Tuples (,,,) are coded as Z3T
420 * Alphabetic characters (upper and lower) and digits
421 all translate to themselves;
422 except 'Z', which translates to 'ZZ'
423 and 'z', which translates to 'zz'
424 We need both so that we can preserve the variable/tycon distinction
426 * Most other printable characters translate to 'zx' or 'Zx' for some
427 alphabetic character x
429 * The others translate as 'znnnU' where 'nnn' is the decimal number
433 --------------------------
445 (# #) Z1H unboxed 1-tuple (note the space)
446 (#,,,,#) Z5H unboxed 5-tuple
447 (NB: There is no Z1T nor Z0H.)
450 -- alreadyEncoded is used in ASSERTs to check for encoded
451 -- strings. It isn't fail-safe, of course, because, say 'zh' might
452 -- be encoded or not.
453 alreadyEncoded :: String -> Bool
454 alreadyEncoded s = all ok s
457 -- This is a bit of a lie; if we really wanted spaces
458 -- in names we'd have to encode them. But we do put
459 -- spaces in ccall "occurrences", and we don't want to
461 ok ch = isAlphaNum ch
463 alreadyEncodedFS :: FAST_STRING -> Bool
464 alreadyEncodedFS fs = alreadyEncoded (_UNPK_ fs)
466 encode :: UserString -> EncodedString
467 encode cs = case maybe_tuple cs of
468 Just n -> n -- Tuples go to Z2T etc
472 go (c:cs) = encode_ch c ++ go cs
474 maybe_tuple "(# #)" = Just("Z1H")
475 maybe_tuple ('(' : '#' : cs) = case count_commas (0::Int) cs of
476 (n, '#' : ')' : cs) -> Just ('Z' : shows (n+1) "H")
478 maybe_tuple "()" = Just("Z0T")
479 maybe_tuple ('(' : cs) = case count_commas (0::Int) cs of
480 (n, ')' : cs) -> Just ('Z' : shows (n+1) "T")
482 maybe_tuple other = Nothing
484 count_commas :: Int -> String -> (Int, String)
485 count_commas n (',' : cs) = count_commas (n+1) cs
486 count_commas n cs = (n,cs)
488 encodeFS :: UserFS -> EncodedFS
489 encodeFS fast_str | all unencodedChar str = fast_str
490 | otherwise = _PK_ (encode str)
492 str = _UNPK_ fast_str
494 unencodedChar :: Char -> Bool -- True for chars that don't need encoding
495 unencodedChar 'Z' = False
496 unencodedChar 'z' = False
497 unencodedChar c = c >= 'a' && c <= 'z'
498 || c >= 'A' && c <= 'Z'
499 || c >= '0' && c <= '9'
501 encode_ch :: Char -> EncodedString
502 encode_ch c | unencodedChar c = [c] -- Common case first
505 encode_ch '(' = "ZL" -- Needed for things like (,), and (->)
506 encode_ch ')' = "ZR" -- For symmetry with (
526 encode_ch '\'' = "zq"
527 encode_ch '\\' = "zr"
532 encode_ch c = 'z' : shows (ord c) "U"
535 Decode is used for user printing.
538 decodeFS :: FAST_STRING -> FAST_STRING
539 decodeFS fs = _PK_ (decode (_UNPK_ fs))
541 decode :: EncodedString -> UserString
543 decode ('Z' : rest) = decode_escape rest
544 decode ('z' : rest) = decode_escape rest
545 decode (c : rest) = c : decode rest
547 decode_escape :: EncodedString -> UserString
549 decode_escape ('L' : rest) = '(' : decode rest
550 decode_escape ('R' : rest) = ')' : decode rest
551 decode_escape ('M' : rest) = '[' : decode rest
552 decode_escape ('N' : rest) = ']' : decode rest
553 decode_escape ('C' : rest) = ':' : decode rest
554 decode_escape ('Z' : rest) = 'Z' : decode rest
556 decode_escape ('z' : rest) = 'z' : decode rest
557 decode_escape ('a' : rest) = '&' : decode rest
558 decode_escape ('b' : rest) = '|' : decode rest
559 decode_escape ('c' : rest) = '^' : decode rest
560 decode_escape ('d' : rest) = '$' : decode rest
561 decode_escape ('e' : rest) = '=' : decode rest
562 decode_escape ('g' : rest) = '>' : decode rest
563 decode_escape ('h' : rest) = '#' : decode rest
564 decode_escape ('i' : rest) = '.' : decode rest
565 decode_escape ('l' : rest) = '<' : decode rest
566 decode_escape ('m' : rest) = '-' : decode rest
567 decode_escape ('n' : rest) = '!' : decode rest
568 decode_escape ('p' : rest) = '+' : decode rest
569 decode_escape ('q' : rest) = '\'' : decode rest
570 decode_escape ('r' : rest) = '\\' : decode rest
571 decode_escape ('s' : rest) = '/' : decode rest
572 decode_escape ('t' : rest) = '*' : decode rest
573 decode_escape ('u' : rest) = '_' : decode rest
574 decode_escape ('v' : rest) = '%' : decode rest
576 -- Tuples are coded as Z23T
577 -- Characters not having a specific code are coded as z224U
578 decode_escape (c : rest)
579 | isDigit c = go (digitToInt c) rest
581 go n (c : rest) | isDigit c = go (10*n + digitToInt c) rest
582 go 0 ('T' : rest) = "()" ++ (decode rest)
583 go n ('T' : rest) = '(' : replicate (n-1) ',' ++ ')' : decode rest
584 go 1 ('H' : rest) = "(# #)" ++ (decode rest)
585 go n ('H' : rest) = '(' : '#' : replicate (n-1) ',' ++ '#' : ')' : decode rest
586 go n ('U' : rest) = chr n : decode rest
587 go n other = pprPanic "decode_escape" (ppr n <+> text (c:rest))
589 decode_escape (c : rest) = pprTrace "decode_escape" (char c) (decode rest)
590 decode_escape [] = pprTrace "decode_escape" (text "empty") ""
594 %************************************************************************
596 \subsection{Lexical categories}
598 %************************************************************************
600 These functions test strings to see if they fit the lexical categories
601 defined in the Haskell report.
604 isLexCon, isLexVar, isLexId, isLexSym :: FAST_STRING -> Bool
605 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FAST_STRING -> Bool
607 isLexCon cs = isLexConId cs || isLexConSym cs
608 isLexVar cs = isLexVarId cs || isLexVarSym cs
610 isLexId cs = isLexConId cs || isLexVarId cs
611 isLexSym cs = isLexConSym cs || isLexVarSym cs
615 isLexConId cs -- Prefix type or data constructors
616 | _NULL_ cs = False -- e.g. "Foo", "[]", "(,)"
617 | cs == SLIT("[]") = True
618 | otherwise = startsConId (_HEAD_ cs)
620 isLexVarId cs -- Ordinary prefix identifiers
621 | _NULL_ cs = False -- e.g. "x", "_x"
622 | otherwise = startsVarId (_HEAD_ cs)
624 isLexConSym cs -- Infix type or data constructors
625 | _NULL_ cs = False -- e.g. ":-:", ":", "->"
626 | cs == SLIT("->") = True
627 | otherwise = startsConSym (_HEAD_ cs)
629 isLexVarSym cs -- Infix identifiers
630 | _NULL_ cs = False -- e.g. "+"
631 | otherwise = startsVarSym (_HEAD_ cs)
634 startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
635 startsVarSym c = isSymbolASCII c || isSymbolISO c -- Infix Ids
636 startsConSym c = c == ':' -- Infix data constructors
637 startsVarId c = isLower c || isLowerISO c || c == '_' -- Ordinary Ids
638 startsConId c = isUpper c || isUpperISO c || c == '(' -- Ordinary type constructors and data constructors
641 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
642 isSymbolISO c = ord c `elem` (0xd7 : 0xf7 : [0xa1 .. 0xbf])
643 isUpperISO (C# c#) = c# `geChar#` '\xc0'# && c# `leChar#` '\xde'# && c# `neChar#` '\xd7'#
644 --0xc0 <= oc && oc <= 0xde && oc /= 0xd7 where oc = ord c
645 isLowerISO (C# c#) = c# `geChar#` '\xdf'# && c# `leChar#` '\xff'# && c# `neChar#` '\xf7'#
646 --0xdf <= oc && oc <= 0xff && oc /= 0xf7 where oc = ord c