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, ipName,
11 tvName, uvName, nameSpaceString,
14 OccName, -- Abstract, instance of Outputable
17 mkSrcOccFS, mkSysOcc, mkSysOccFS, mkCCallOcc, mkSrcVarOcc, mkKindOccFS,
18 mkSuperDictSelOcc, mkDFunOcc, mkForeignExportOcc,
19 mkDictOcc, mkIPOcc, mkWorkerOcc, mkMethodOcc, mkDefaultMethodOcc,
20 mkDerivedTyConOcc, mkClassTyConOcc, mkClassDataConOcc, mkSpecOcc,
22 isTvOcc, isUvOcc, isDataOcc, isDataSymOcc, isSymOcc, isIPOcc, isValOcc,
24 occNameFS, occNameString, occNameUserString, occNameSpace, occNameFlavour,
28 TidyOccEnv, emptyTidyOccEnv, tidyOccName, initTidyOccEnv,
31 EncodedString, EncodedFS, UserString, UserFS, encode, encodeFS, decode, pprEncodedFS,
33 -- The basic form of names
34 isLexCon, isLexVar, isLexId, isLexSym,
35 isLexConId, isLexConSym, isLexVarId, isLexVarSym,
36 isLowerISO, isUpperISO
40 #include "HsVersions.h"
42 import Char ( isDigit, isAlpha, isUpper, isLower, ISALPHANUM, ord, chr, digitToInt, intToDigit )
43 import Util ( thenCmp )
44 import FiniteMap ( FiniteMap, emptyFM, lookupFM, addToFM, elemFM )
49 We hold both module names and identifier names in a 'Z-encoded' form
50 that makes them acceptable both as a C identifier and as a Haskell
53 They can always be decoded again when printing error messages
54 or anything else for the user, but it does make sense for it
55 to be represented here in encoded form, so that when generating
56 code the encoding operation is not performed on each occurrence.
58 These type synonyms help documentation.
61 type UserFS = FAST_STRING -- As the user typed it
62 type EncodedFS = FAST_STRING -- Encoded form
64 type UserString = String -- As the user typed it
65 type EncodedString = String -- Encoded form
68 pprEncodedFS :: EncodedFS -> SDoc
70 = getPprStyle $ \ sty ->
72 text (decode (_UNPK_ fs))
77 %************************************************************************
79 \subsection{Name space}
81 %************************************************************************
84 data NameSpace = VarName -- Variables
85 | IPName -- Implicit Parameters
86 | DataName -- Data constructors
87 | TvName -- Type variables
88 | UvName -- Usage 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!
106 nameSpaceString :: NameSpace -> String
107 nameSpaceString DataName = "Data constructor"
108 nameSpaceString VarName = "Variable"
109 nameSpaceString IPName = "Implicit Param"
110 nameSpaceString TvName = "Type variable"
111 nameSpaceString UvName = "Usage variable"
112 nameSpaceString TcClsName = "Type constructor or class"
116 %************************************************************************
118 \subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
120 %************************************************************************
123 data OccName = OccName
130 instance Eq OccName where
131 (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2
133 instance Ord OccName where
134 compare (OccName sp1 s1) (OccName sp2 s2) = (s1 `compare` s2) `thenCmp`
139 %************************************************************************
141 \subsection{Printing}
143 %************************************************************************
146 instance Outputable OccName where
149 pprOccName :: OccName -> SDoc
150 pprOccName (OccName sp occ) = pprEncodedFS occ
154 %************************************************************************
156 \subsection{Construction}
158 %************************************************************************
160 *Sys* things do no encoding; the caller should ensure that the thing is
164 mkSysOcc :: NameSpace -> EncodedString -> OccName
165 mkSysOcc occ_sp str = ASSERT2( alreadyEncoded str, text str )
166 OccName occ_sp (_PK_ str)
168 mkSysOccFS :: NameSpace -> EncodedFS -> OccName
169 mkSysOccFS occ_sp fs = ASSERT2( alreadyEncodedFS fs, ppr fs )
172 mkCCallOcc :: EncodedString -> OccName
173 -- This version of mkSysOcc doesn't check that the string is already encoded,
174 -- because it will be something like "{__ccall f dyn Int# -> Int#}"
175 -- This encodes a lot into something that then parses like an Id.
176 -- But then alreadyEncoded complains about the braces!
177 mkCCallOcc str = OccName varName (_PK_ str)
179 -- Kind constructors get a speical function. Uniquely, they are not encoded,
180 -- so that they have names like '*'. This means that *even in interface files*
181 -- we'll get kinds like (* -> (* -> *)). We can't use mkSysOcc because it
182 -- has an ASSERT that doesn't hold.
183 mkKindOccFS :: NameSpace -> EncodedFS -> OccName
184 mkKindOccFS occ_sp fs = OccName occ_sp fs
187 *Source-code* things are encoded.
190 mkSrcOccFS :: NameSpace -> UserFS -> OccName
191 mkSrcOccFS occ_sp fs = mkSysOccFS occ_sp (encodeFS fs)
193 mkSrcVarOcc :: UserFS -> OccName
194 mkSrcVarOcc fs = mkSysOccFS varName (encodeFS fs)
199 %************************************************************************
201 \subsection{Predicates and taking them apart}
203 %************************************************************************
206 occNameFS :: OccName -> EncodedFS
207 occNameFS (OccName _ s) = s
209 occNameString :: OccName -> EncodedString
210 occNameString (OccName _ s) = _UNPK_ s
212 occNameUserString :: OccName -> UserString
213 occNameUserString occ = decode (occNameString occ)
215 occNameSpace :: OccName -> NameSpace
216 occNameSpace (OccName sp _) = sp
218 setOccNameSpace :: OccName -> NameSpace -> OccName
219 setOccNameSpace (OccName _ occ) sp = OccName sp occ
221 -- occNameFlavour is used only to generate good error messages
222 occNameFlavour :: OccName -> String
223 occNameFlavour (OccName sp _) = nameSpaceString sp
227 isTvOcc, isDataSymOcc, isSymOcc, isUvOcc :: OccName -> Bool
229 isTvOcc (OccName TvName _) = True
230 isTvOcc other = False
232 isUvOcc (OccName UvName _) = True
233 isUvOcc other = False
235 isValOcc (OccName VarName _) = True
236 isValOcc (OccName DataName _) = True
237 isValOcc other = False
239 -- Data constructor operator (starts with ':', or '[]')
240 -- Pretty inefficient!
241 isDataSymOcc (OccName DataName s) = isLexConSym (decodeFS s)
242 isDataSymOcc other = False
244 isDataOcc (OccName DataName _) = True
245 isDataOcc other = False
247 -- Any operator (data constructor or variable)
248 -- Pretty inefficient!
249 isSymOcc (OccName DataName s) = isLexConSym (decodeFS s)
250 isSymOcc (OccName VarName s) = isLexSym (decodeFS s)
252 isIPOcc (OccName IPName _) = True
257 %************************************************************************
259 \subsection{Making system names}
261 %************************************************************************
263 Here's our convention for splitting up the interface file name space:
265 d... dictionary identifiers
266 (local variables, so no name-clash worries)
268 $f... dict-fun identifiers (from inst decls)
269 $dm... default methods
270 $p... superclass selectors
272 $T... compiler-generated tycons for dictionaries
273 $D... ...ditto data cons
274 $sf.. specialised version of f
276 in encoded form these appear as Zdfxxx etc
278 :... keywords (export:, letrec: etc.)
280 This knowledge is encoded in the following functions.
283 @mk_deriv@ generates an @OccName@ from the one-char prefix and a string.
284 NB: The string must already be encoded!
287 mk_deriv :: NameSpace
288 -> String -- Distinguishes one sort of derived name from another
289 -> EncodedString -- Must be already encoded!! We don't want to encode it a
290 -- second time because encoding isn't itempotent
293 mk_deriv occ_sp sys_prefix str = mkSysOcc occ_sp (encode sys_prefix ++ str)
297 mkDictOcc, mkIPOcc, mkWorkerOcc, mkDefaultMethodOcc,
298 mkClassTyConOcc, mkClassDataConOcc, mkSpecOcc
299 :: OccName -> OccName
301 -- These derived variables have a prefix that no Haskell value could have
302 mkWorkerOcc = mk_simple_deriv varName "$w"
303 mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
304 mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
305 mkClassTyConOcc = mk_simple_deriv tcName ":T" -- as a tycon/datacon
306 mkClassDataConOcc = mk_simple_deriv dataName ":D" --
307 mkDictOcc = mk_simple_deriv varName "$d"
308 mkIPOcc = mk_simple_deriv varName "$i"
309 mkSpecOcc = mk_simple_deriv varName "$s"
310 mkForeignExportOcc = mk_simple_deriv varName "$f"
312 mk_simple_deriv sp px occ = mk_deriv sp px (occNameString occ)
316 mkSuperDictSelOcc :: Int -- Index of superclass, eg 3
317 -> OccName -- Class, eg "Ord"
318 -> OccName -- eg "p3Ord"
319 mkSuperDictSelOcc index cls_occ
320 = mk_deriv varName "$p" (show index ++ occNameString cls_occ)
325 mkDFunOcc :: EncodedString -- Typically the class and type glommed together e.g. "OrdMaybe"
326 -> Int -- Unique to distinguish dfuns which share the previous two
328 -- The requirement is that the (string,index) pair be unique in this module
330 -> OccName -- "$fOrdMaybe3"
332 mkDFunOcc string index
333 = mk_deriv VarName "$f" (show_index ++ string)
335 show_index | index == 0 = ""
336 | otherwise = show index
339 We used to add a '$m' to indicate a method, but that gives rise to bad
340 error messages from the type checker when we print the function name or pattern
341 of an instance-decl binding. Why? Because the binding is zapped
342 to use the method name in place of the selector name.
343 (See TcClassDcl.tcMethodBind)
345 The way it is now, -ddump-xx output may look confusing, but
346 you can always say -dppr-debug to get the uniques.
348 However, we *do* have to zap the first character to be lower case,
349 because overloaded constructors (blarg) generate methods too.
350 And convert to VarName space
352 e.g. a call to constructor MkFoo where
353 data (Ord a) => Foo a = MkFoo a
355 If this is necessary, we do it by prefixing '$m'. These
356 guys never show up in error messages. What a hack.
359 mkMethodOcc :: OccName -> OccName
360 mkMethodOcc occ@(OccName VarName fs) = occ
361 mkMethodOcc occ = mk_simple_deriv varName "$m" occ
365 %************************************************************************
367 \subsection{Tidying them up}
369 %************************************************************************
371 Before we print chunks of code we like to rename it so that
372 we don't have to print lots of silly uniques in it. But we mustn't
373 accidentally introduce name clashes! So the idea is that we leave the
374 OccName alone unless it accidentally clashes with one that is already
375 in scope; if so, we tack on '1' at the end and try again, then '2', and
376 so on till we find a unique one.
378 There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
379 because that isn't a single lexeme. So we encode it to 'lle' and *then*
380 tack on the '1', if necessary.
383 type TidyOccEnv = FiniteMap FAST_STRING Int -- The in-scope OccNames
384 emptyTidyOccEnv = emptyFM
386 initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid!
387 initTidyOccEnv = foldl (\env (OccName _ fs) -> addToFM env fs 1) emptyTidyOccEnv
389 tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName)
391 tidyOccName in_scope occ@(OccName occ_sp fs)
392 | not (fs `elemFM` in_scope)
393 = (addToFM in_scope fs 1, occ) -- First occurrence
395 | otherwise -- Already occurs
396 = go in_scope (_UNPK_ fs)
399 go in_scope str = case lookupFM in_scope pk_str of
400 Just n -> go (addToFM in_scope pk_str (n+1)) (str ++ show n)
401 -- Need to go round again, just in case "t3" (say)
402 -- clashes with a "t3" that's already in scope
404 Nothing -> (addToFM in_scope pk_str 1, mkSysOccFS occ_sp pk_str)
411 %************************************************************************
413 \subsection{The 'Z' encoding}
415 %************************************************************************
417 This is the main name-encoding and decoding function. It encodes any
418 string into a string that is acceptable as a C name. This is the name
419 by which things are known right through the compiler.
421 The basic encoding scheme is this.
423 * Tuples (,,,) are coded as Z3T
425 * Alphabetic characters (upper and lower), digits, and '_'
426 all translate to themselves;
427 except 'Z', which translates to 'ZZ'
428 and 'z', which translates to 'zz'
429 We need both so that we can preserve the variable/tycon distinction
431 * Most other printable characters translate to 'Zx' for some
432 alphabetic character x
434 * The others translate as 'Zxdd' where 'dd' is exactly two hexadecimal
435 digits for the ord of the character
438 --------------------------
453 -- alreadyEncoded is used in ASSERTs to check for encoded
454 -- strings. It isn't fail-safe, of course, because, say 'zh' might
455 -- be encoded or not.
456 alreadyEncoded :: String -> Bool
457 alreadyEncoded s = all ok s
460 ok ' ' = True -- This is a bit of a lie; if we really wanted spaces
461 -- in names we'd have to encode them. But we do put
462 -- spaces in ccall "occurrences", and we don't want to
464 ok ch = ISALPHANUM ch
466 alreadyEncodedFS :: FAST_STRING -> Bool
467 alreadyEncodedFS fs = alreadyEncoded (_UNPK_ fs)
469 encode :: UserString -> EncodedString
470 encode cs = case maybe_tuple cs of
471 Just n -> 'Z' : show n ++ "T" -- Tuples go to Z2T etc
475 go (c:cs) = encode_ch c ++ go cs
477 -- ToDo: Unboxed tuples too, perhaps?
478 maybe_tuple ('(' : cs) = check_tuple (0::Int) cs
479 maybe_tuple other = Nothing
481 check_tuple :: Int -> String -> Maybe Int
482 check_tuple n (',' : cs) = check_tuple (n+1) cs
483 check_tuple n ")" = Just n
484 check_tuple n other = Nothing
486 encodeFS :: UserFS -> EncodedFS
487 encodeFS fast_str | all unencodedChar str = fast_str
488 | otherwise = _PK_ (encode str)
490 str = _UNPK_ fast_str
492 unencodedChar :: Char -> Bool -- True for chars that don't need encoding
493 unencodedChar '_' = True
494 unencodedChar 'Z' = False
495 unencodedChar 'z' = False
496 unencodedChar c = ISALPHANUM c
498 encode_ch :: Char -> EncodedString
499 encode_ch c | unencodedChar c = [c] -- Common case first
502 encode_ch '(' = "ZL" -- Needed for things like (,), and (->)
503 encode_ch ')' = "ZR" -- For symmetry with (
522 encode_ch '\'' = "zq"
523 encode_ch '\\' = "zr"
528 encode_ch c = ['z', 'x', intToDigit hi, intToDigit lo]
530 (hi,lo) = ord c `quotRem` 16
533 Decode is used for user printing.
536 decodeFS :: FAST_STRING -> FAST_STRING
537 decodeFS fs = _PK_ (decode (_UNPK_ fs))
539 decode :: EncodedString -> UserString
541 decode ('Z' : rest) = decode_escape rest
542 decode ('z' : rest) = decode_escape rest
543 decode (c : rest) = c : decode rest
545 decode_escape :: EncodedString -> UserString
547 decode_escape ('Z' : rest) = 'Z' : decode rest
548 decode_escape ('C' : rest) = ':' : decode rest
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
554 decode_escape ('z' : rest) = 'z' : decode rest
555 decode_escape ('a' : rest) = '&' : decode rest
556 decode_escape ('b' : rest) = '|' : decode rest
557 decode_escape ('d' : rest) = '$' : decode rest
558 decode_escape ('e' : rest) = '=' : decode rest
559 decode_escape ('g' : rest) = '>' : decode rest
560 decode_escape ('h' : rest) = '#' : decode rest
561 decode_escape ('i' : rest) = '.' : decode rest
562 decode_escape ('l' : rest) = '<' : decode rest
563 decode_escape ('m' : rest) = '-' : decode rest
564 decode_escape ('n' : rest) = '!' : decode rest
565 decode_escape ('p' : rest) = '+' : decode rest
566 decode_escape ('q' : rest) = '\'' : decode rest
567 decode_escape ('r' : rest) = '\\' : decode rest
568 decode_escape ('s' : rest) = '/' : decode rest
569 decode_escape ('t' : rest) = '*' : decode rest
570 decode_escape ('u' : rest) = '^' : decode rest
571 decode_escape ('v' : rest) = '%' : decode rest
572 decode_escape ('x' : d1 : d2 : rest) = chr (digitToInt d1 * 16 + digitToInt d2) : decode rest
574 -- Tuples are coded as Z23T
575 decode_escape (c : rest)
576 | isDigit c = go (digitToInt c) rest
578 go n (c : rest) | isDigit c = go (10*n + digitToInt c) rest
579 go n ('T' : rest) = '(' : replicate n ',' ++ ')' : decode rest
580 go n other = pprPanic "decode_escape" (ppr n <+> text (c:rest))
582 decode_escape (c : rest) = pprTrace "decode_escape" (char c) (decode rest)
586 %************************************************************************
588 n\subsection{Lexical categories}
590 %************************************************************************
592 These functions test strings to see if they fit the lexical categories
593 defined in the Haskell report.
596 isLexCon, isLexVar, isLexId, isLexSym :: FAST_STRING -> Bool
597 isLexConId, isLexConSym, isLexVarId, isLexVarSym :: FAST_STRING -> Bool
599 isLexCon cs = isLexConId cs || isLexConSym cs
600 isLexVar cs = isLexVarId cs || isLexVarSym cs
602 isLexId cs = isLexConId cs || isLexVarId cs
603 isLexSym cs = isLexConSym cs || isLexVarSym cs
607 isLexConId cs -- Prefix type or data constructors
608 | _NULL_ cs = False -- e.g. "Foo", "[]", "(,)"
609 | cs == SLIT("[]") = True
610 | c == '(' = True -- (), (,), (,,), ...
611 | otherwise = isUpper c || isUpperISO c
615 isLexVarId cs -- Ordinary prefix identifiers
616 | _NULL_ cs = False -- e.g. "x", "_x"
617 | otherwise = isLower c || isLowerISO c || c == '_'
621 isLexConSym cs -- Infix type or data constructors
622 | _NULL_ cs = False -- e.g. ":-:", ":", "->"
623 | otherwise = c == ':'
628 isLexVarSym cs -- Infix identifiers
629 | _NULL_ cs = False -- e.g. "+"
630 | otherwise = isSymbolASCII c
636 isSymbolASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
637 isSymbolISO c = ord c `elem` (0xd7 : 0xf7 : [0xa1 .. 0xbf])
638 isUpperISO (C# c#) = c# `geChar#` '\xc0'# && c# `leChar#` '\xde'# && c# `neChar#` '\xd7'#
639 --0xc0 <= oc && oc <= 0xde && oc /= 0xd7 where oc = ord c
640 isLowerISO (C# c#) = c# `geChar#` '\xdf'# && c# `leChar#` '\xff'# && c# `neChar#` '\xf7'#
641 --0xdf <= oc && oc <= 0xff && oc /= 0xf7 where oc = ord c