2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[Lexical analysis]{Lexical analysis}
6 --------------------------------------------------------
8 There's a known bug in here:
10 If an interface file ends prematurely, Lex tries to
11 do headFS of an empty FastString.
13 An example that provokes the error is
15 f _:_ _forall_ [a] <<<END OF FILE>>>
16 --------------------------------------------------------
22 ifaceParseErr, srcParseErr,
25 Token(..), lexer, ParseResult(..), PState(..),
29 P, thenP, thenP_, returnP, mapP, failP, failMsgP,
30 getSrcLocP, getSrcFile,
31 layoutOn, layoutOff, pushContext, popContext
34 #include "HsVersions.h"
36 import Char ( isSpace, toUpper )
37 import List ( isSuffixOf )
39 import IdInfo ( InlinePragInfo(..) )
40 import PrelNames ( mkTupNameStr )
41 import CmdLineOpts ( opt_HiVersion, opt_NoHiCheck )
42 import Demand ( Demand(..) {- instance Read -} )
43 import UniqFM ( listToUFM, lookupUFM )
44 import BasicTypes ( NewOrData(..), Boxity(..) )
45 import SrcLoc ( SrcLoc, incSrcLine, srcLocFile, srcLocLine,
46 replaceSrcLine, mkSrcLoc )
48 import ErrUtils ( Message )
56 import PrelRead ( readRational__ ) -- Glasgow non-std
59 %************************************************************************
61 \subsection{Data types}
63 %************************************************************************
65 The token data type, fairly un-interesting except from one
66 constructor, @ITidinfo@, which is used to lazily lex id info (arity,
67 strictness, unfolding etc).
69 The Idea/Observation here is that the renamer needs to scan through
70 all of an interface file before it can continue. But only a fraction
71 of the information contained in the file turns out to be useful, so
72 delaying as much as possible of the scanning and parsing of an
73 interface file Makes Sense (Heap profiles of the compiler
74 show a reduction in heap usage by at least a factor of two,
77 Hence, the interface file lexer spots when value declarations are
78 being scanned and return the @ITidinfo@ and @ITtype@ constructors
79 for the type and any other id info for that binding (unfolding, strictness
80 etc). These constructors are applied to the result of lexing these sub-chunks.
82 The lexing of the type and id info is all done lazily, of course, so
83 the scanning (and subsequent parsing) will be done *only* on the ids the
84 renamer finds out that it is interested in. The rest will just be junked.
85 Laziness, you know it makes sense :-)
89 = ITas -- Haskell keywords
115 | ITforall -- GHC extension keywords
125 | ITinterface -- interface keywords
133 | ITccall (Bool,Bool,Bool) -- (is_dyn, is_casm, may_gc)
152 | ITunfold InlinePragInfo
153 | ITstrict ([Demand], Bool)
160 | ITspecialise_prag -- Pragmas
169 | ITdotdot -- reserved symbols
183 | ITbiglam -- GHC-extension symbols
185 | ITocurly -- special symbols
199 | ITvarid FAST_STRING -- identifiers
200 | ITconid FAST_STRING
201 | ITvarsym FAST_STRING
202 | ITconsym FAST_STRING
203 | ITqvarid (FAST_STRING,FAST_STRING)
204 | ITqconid (FAST_STRING,FAST_STRING)
205 | ITqvarsym (FAST_STRING,FAST_STRING)
206 | ITqconsym (FAST_STRING,FAST_STRING)
208 | ITipvarid FAST_STRING -- GHC extension: implicit param: ?x
210 | ITpragma StringBuffer
213 | ITstring FAST_STRING
215 | ITrational Rational
218 | ITprimstring FAST_STRING
220 | ITprimfloat Rational
221 | ITprimdouble Rational
222 | ITlitlit FAST_STRING
224 | ITunknown String -- Used when the lexer can't make sense of it
225 | ITeof -- end of file token
226 deriving Show -- debugging
229 -----------------------------------------------------------------------------
233 pragmaKeywordsFM = listToUFM $
234 map (\ (x,y) -> (_PK_ x,y))
235 [( "SPECIALISE", ITspecialise_prag ),
236 ( "SPECIALIZE", ITspecialise_prag ),
237 ( "SOURCE", ITsource_prag ),
238 ( "INLINE", ITinline_prag ),
239 ( "NOINLINE", ITnoinline_prag ),
240 ( "NOTINLINE", ITnoinline_prag ),
241 ( "LINE", ITline_prag ),
242 ( "RULES", ITrules_prag ),
243 ( "RULEZ", ITrules_prag ), -- american spelling :-)
244 ( "DEPRECATED", ITdeprecated_prag )
247 haskellKeywordsFM = listToUFM $
248 map (\ (x,y) -> (_PK_ x,y))
249 [( "_", ITunderscore ),
252 ( "class", ITclass ),
254 ( "default", ITdefault ),
255 ( "deriving", ITderiving ),
258 ( "hiding", IThiding ),
260 ( "import", ITimport ),
262 ( "infix", ITinfix ),
263 ( "infixl", ITinfixl ),
264 ( "infixr", ITinfixr ),
265 ( "instance", ITinstance ),
267 ( "module", ITmodule ),
268 ( "newtype", ITnewtype ),
270 ( "qualified", ITqualified ),
273 ( "where", ITwhere ),
277 -- IMPORTANT: Keep this in synch with ParseIface.y's var_fs production! (SUP)
278 ghcExtensionKeywordsFM = listToUFM $
279 map (\ (x,y) -> (_PK_ x,y))
280 [ ( "forall", ITforall ),
281 ( "foreign", ITforeign ),
282 ( "export", ITexport ),
283 ( "label", ITlabel ),
284 ( "dynamic", ITdynamic ),
285 ( "unsafe", ITunsafe ),
287 ( "stdcall", ITstdcallconv),
288 ( "ccall", ITccallconv),
289 ("_ccall_", ITccall (False, False, False)),
290 ("_ccall_GC_", ITccall (False, False, True)),
291 ("_casm_", ITccall (False, True, False)),
292 ("_casm_GC_", ITccall (False, True, True)),
294 -- interface keywords
295 ("__interface", ITinterface),
296 ("__export", IT__export),
297 ("__depends", ITdepends),
298 ("__forall", IT__forall),
299 ("__letrec", ITletrec),
300 ("__coerce", ITcoerce),
301 ("__inline_me", ITinlineMe),
302 ("__inline_call", ITinlineCall),
303 ("__depends", ITdepends),
304 ("__DEFAULT", ITdefaultbranch),
306 ("__integer", ITinteger_lit),
307 ("__float", ITfloat_lit),
308 ("__int64", ITint64_lit),
309 ("__word", ITword_lit),
310 ("__word64", ITword64_lit),
311 ("__rational", ITrational_lit),
312 ("__addr", ITaddr_lit),
313 ("__label", ITlabel_lit),
314 ("__litlit", ITlit_lit),
315 ("__string", ITstring_lit),
318 ("__fuall", ITfuall),
320 ("__P", ITspecialise),
323 ("__D", ITdeprecated),
324 ("__U", ITunfold NoInlinePragInfo),
326 ("__ccall", ITccall (False, False, False)),
327 ("__ccall_GC", ITccall (False, False, True)),
328 ("__dyn_ccall", ITccall (True, False, False)),
329 ("__dyn_ccall_GC", ITccall (True, False, True)),
330 ("__casm", ITccall (False, True, False)),
331 ("__dyn_casm", ITccall (True, True, False)),
332 ("__casm_GC", ITccall (False, True, True)),
333 ("__dyn_casm_GC", ITccall (True, True, True)),
339 haskellKeySymsFM = listToUFM $
340 map (\ (x,y) -> (_PK_ x,y))
353 ,(".", ITdot) -- sadly, for 'forall a . t'
357 -----------------------------------------------------------------------------
362 - (glaexts) lexing an interface file or -fglasgow-exts
363 - (bol) pointer to beginning of line (for column calculations)
364 - (buf) pointer to beginning of token
365 - (buf) pointer to current char
366 - (atbol) flag indicating whether we're at the beginning of a line
369 lexer :: (Token -> P a) -> P a
370 lexer cont buf s@(PState{
372 glasgow_exts = glaexts,
378 -- first, start a new lexeme and lose all the whitespace
380 tab line bol atbol (stepOverLexeme buf)
382 line = srcLocLine loc
384 tab y bol atbol buf = --trace ("tab: " ++ show (I# y) ++ " : " ++ show (currentChar buf)) $
385 case currentChar# buf of
388 if bufferExhausted (stepOn buf)
389 then cont ITeof buf s'
390 else trace "lexer: misplaced NUL?" $
391 tab y bol atbol (stepOn buf)
393 '\n'# -> let buf' = stepOn buf
394 in tab (y +# 1#) (currentIndex# buf') 1# buf'
396 -- find comments. This got harder in Haskell 98.
397 '-'# -> let trundle n =
398 let next = lookAhead# buf n in
399 if next `eqChar#` '-'# then trundle (n +# 1#)
400 else if is_symbol next || n <# 2#
403 (stepOnUntilChar# (stepOnBy# buf n) '\n'#)
406 -- comments and pragmas. We deal with LINE pragmas here,
407 -- and throw out any unrecognised pragmas as comments. Any
408 -- pragmas we know about are dealt with later (after any layout
409 -- processing if necessary).
411 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
412 if lookAhead# buf 2# `eqChar#` '#'# then
413 if lookAhead# buf 3# `eqChar#` '#'# then is_a_token else
414 case expandWhile# is_space (setCurrentPos# buf 3#) of { buf1->
415 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2->
416 let lexeme = mkFastString -- ToDo: too slow
417 (map toUpper (lexemeToString buf2)) in
418 case lookupUFM pragmaKeywordsFM lexeme of
420 line_prag skip_to_end buf2 s'
421 Just other -> is_a_token
422 Nothing -> skip_to_end (stepOnBy# buf 2#) s'
425 else skip_to_end (stepOnBy# buf 2#) s'
427 skip_to_end = nested_comment (lexer cont)
429 -- special GHC extension: we grok cpp-style #line pragmas
430 '#'# | lexemeIndex buf ==# bol -> -- the '#' must be in column 0
431 line_prag next_line (stepOn buf) s'
433 next_line buf = lexer cont (stepOnUntilChar# buf '\n'#)
435 -- tabs have been expanded beforehand
436 c | is_space c -> tab y bol atbol (stepOn buf)
437 | otherwise -> is_a_token
439 where s' = s{loc = replaceSrcLine loc y,
443 is_a_token | atbol /=# 0# = lexBOL cont buf s'
444 | otherwise = lexToken cont glaexts buf s'
446 -- {-# LINE .. #-} pragmas. yeuch.
447 line_prag cont buf s@PState{loc=loc} =
448 case expandWhile# is_space buf of { buf1 ->
449 case scanNumLit 0 (stepOverLexeme buf1) of { (line,buf2) ->
450 -- subtract one: the line number refers to the *following* line.
451 let real_line = line - 1 in
452 case fromInteger real_line of { i@(I# l) ->
453 -- ToDo, if no filename then we skip the newline.... d'oh
454 case expandWhile# is_space buf2 of { buf3 ->
455 case currentChar# buf3 of
457 case untilEndOfString# (stepOn (stepOverLexeme buf3)) of { buf4 ->
459 file = lexemeToFastString buf4
460 new_buf = stepOn (stepOverLexeme buf4)
462 if nullFastString file
463 then cont new_buf s{loc = replaceSrcLine loc l}
464 else cont new_buf s{loc = mkSrcLoc file i}
466 _other -> cont (stepOverLexeme buf3) s{loc = replaceSrcLine loc l}
469 nested_comment :: P a -> P a
470 nested_comment cont buf = loop buf
473 case currentChar# buf of
474 '\NUL'# | bufferExhausted (stepOn buf) ->
475 lexError "unterminated `{-'" buf
477 '-'# | lookAhead# buf 1# `eqChar#` '}'# ->
478 cont (stepOnBy# buf 2#)
480 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
481 nested_comment (nested_comment cont) (stepOnBy# buf 2#)
483 '\n'# -> \ s@PState{loc=loc} ->
484 let buf' = stepOn buf in
485 nested_comment cont buf'
486 s{loc = incSrcLine loc, bol = currentIndex# buf',
489 _ -> nested_comment cont (stepOn buf)
491 -- When we are lexing the first token of a line, check whether we need to
492 -- insert virtual semicolons or close braces due to layout.
494 lexBOL :: (Token -> P a) -> P a
495 lexBOL cont buf s@(PState{
497 glasgow_exts = glaexts,
502 if need_close_curly then
503 --trace ("col = " ++ show (I# col) ++ ", layout: inserting '}'") $
504 cont ITvccurly buf s{atbol = 1#, context = tail ctx}
505 else if need_semi_colon then
506 --trace ("col = " ++ show (I# col) ++ ", layout: inserting ';'") $
507 cont ITsemi buf s{atbol = 0#}
509 lexToken cont glaexts buf s{atbol = 0#}
511 col = currentIndex# buf -# bol
524 Layout n -> col ==# n
527 lexToken :: (Token -> P a) -> Int# -> P a
528 lexToken cont glaexts buf =
530 case currentChar# buf of
532 -- special symbols ----------------------------------------------------
533 '('# | flag glaexts && lookAhead# buf 1# `eqChar#` '#'#
534 -> cont IToubxparen (setCurrentPos# buf 2#)
536 -> cont IToparen (incLexeme buf)
538 ')'# -> cont ITcparen (incLexeme buf)
539 '['# -> cont ITobrack (incLexeme buf)
540 ']'# -> cont ITcbrack (incLexeme buf)
541 ','# -> cont ITcomma (incLexeme buf)
542 ';'# -> cont ITsemi (incLexeme buf)
544 '}'# -> \ s@PState{context = ctx} ->
546 (_:ctx') -> cont ITccurly (incLexeme buf) s{context=ctx'}
547 _ -> lexError "too many '}'s" buf s
549 '#'# -> case lookAhead# buf 1# of
550 ')'# | flag glaexts -> cont ITcubxparen (setCurrentPos# buf 2#)
551 '-'# -> case lookAhead# buf 2# of
552 '}'# -> cont ITclose_prag (setCurrentPos# buf 3#)
553 _ -> lex_sym cont (incLexeme buf)
554 _ -> lex_sym cont (incLexeme buf)
556 '`'# | flag glaexts && lookAhead# buf 1# `eqChar#` '`'#
557 -> lex_cstring cont (setCurrentPos# buf 2#)
559 -> cont ITbackquote (incLexeme buf)
561 '{'# -> -- look for "{-##" special iface pragma
562 case lookAhead# buf 1# of
563 '-'# -> case lookAhead# buf 2# of
564 '#'# -> case lookAhead# buf 3# of
567 = doDiscard False (stepOnBy# (stepOverLexeme buf) 4#) in
568 cont (ITpragma lexeme) buf'
569 _ -> lex_prag cont (setCurrentPos# buf 3#)
570 _ -> cont ITocurly (incLexeme buf)
571 _ -> (layoutOff `thenP_` cont ITocurly) (incLexeme buf)
573 -- strings/characters -------------------------------------------------
574 '\"'#{-"-} -> lex_string cont glaexts "" (incLexeme buf)
575 '\''# -> lex_char (char_end cont) glaexts (incLexeme buf)
577 -- strictness and cpr pragmas and __scc treated specially.
578 '_'# | flag glaexts ->
579 case lookAhead# buf 1# of
580 '_'# -> case lookAhead# buf 2# of
582 lex_demand cont (stepOnUntil (not . isSpace)
583 (stepOnBy# buf 3#)) -- past __S
585 cont ITcprinfo (stepOnBy# buf 3#) -- past __M
588 case prefixMatch (stepOnBy# buf 3#) "cc" of
589 Just buf' -> lex_scc cont (stepOverLexeme buf')
590 Nothing -> lex_id cont glaexts buf
591 _ -> lex_id cont glaexts buf
592 _ -> lex_id cont glaexts buf
594 -- Hexadecimal and octal constants
595 '0'# | (ch `eqChar#` 'x'# || ch `eqChar#` 'X'#) && is_hexdigit ch2
596 -> readNum (after_lexnum cont glaexts) buf' is_hexdigit 16 hex
597 | (ch `eqChar#` 'o'# || ch `eqChar#` 'O'#) && is_octdigit ch2
598 -> readNum (after_lexnum cont glaexts) buf' is_octdigit 8 oct_or_dec
599 where ch = lookAhead# buf 1#
600 ch2 = lookAhead# buf 2#
601 buf' = setCurrentPos# buf 2#
604 if bufferExhausted (stepOn buf) then
607 trace "lexIface: misplaced NUL?" $
608 cont (ITunknown "\NUL") (stepOn buf)
610 '?'# | flag glaexts && is_lower (lookAhead# buf 1#) ->
611 lex_ip cont (incLexeme buf)
612 c | is_digit c -> lex_num cont glaexts 0 buf
613 | is_symbol c -> lex_sym cont buf
614 | is_upper c -> lex_con cont glaexts buf
615 | is_ident c -> lex_id cont glaexts buf
616 | otherwise -> lexError "illegal character" buf
618 -- Int# is unlifted, and therefore faster than Bool for flags.
624 -------------------------------------------------------------------------------
628 = case expandWhile# is_space buf of { buf1 ->
629 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2 ->
630 let lexeme = mkFastString (map toUpper (lexemeToString buf2)) in
631 case lookupUFM pragmaKeywordsFM lexeme of
632 Just kw -> cont kw (mergeLexemes buf buf2)
633 Nothing -> panic "lex_prag"
636 -------------------------------------------------------------------------------
639 lex_string cont glaexts s buf
640 = case currentChar# buf of
642 let buf' = incLexeme buf; s' = mkFastString (reverse s) in
643 case currentChar# buf' of
644 '#'# | flag glaexts -> cont (ITprimstring s') (incLexeme buf')
645 _ -> cont (ITstring s') buf'
647 -- ignore \& in a string, deal with string gaps
648 '\\'# | next_ch `eqChar#` '&'#
649 -> lex_string cont glaexts s buf'
651 -> lex_stringgap cont glaexts s (incLexeme buf)
653 where next_ch = lookAhead# buf 1#
654 buf' = setCurrentPos# buf 2#
656 _ -> lex_char (lex_next_string cont s) glaexts buf
658 lex_stringgap cont glaexts s buf
659 = let buf' = incLexeme buf in
660 case currentChar# buf of
661 '\n'# -> \st@PState{loc = loc} -> lex_stringgap cont glaexts s buf'
662 st{loc = incSrcLine loc}
663 '\\'# -> lex_string cont glaexts s buf'
664 c | is_space c -> lex_stringgap cont glaexts s buf'
665 other -> charError buf'
667 lex_next_string cont s glaexts c buf = lex_string cont glaexts (c:s) buf
669 lex_char :: (Int# -> Char -> P a) -> Int# -> P a
670 lex_char cont glaexts buf
671 = case currentChar# buf of
672 '\\'# -> lex_escape (cont glaexts) (incLexeme buf)
673 c | is_any c -> cont glaexts (C# c) (incLexeme buf)
674 other -> charError buf
676 char_end cont glaexts c buf
677 = case currentChar# buf of
678 '\''# -> let buf' = incLexeme buf in
679 case currentChar# buf' of
681 -> cont (ITprimchar c) (incLexeme buf')
682 _ -> cont (ITchar c) buf'
686 = let buf' = incLexeme buf in
687 case currentChar# buf of
688 'a'# -> cont '\a' buf'
689 'b'# -> cont '\b' buf'
690 'f'# -> cont '\f' buf'
691 'n'# -> cont '\n' buf'
692 'r'# -> cont '\r' buf'
693 't'# -> cont '\t' buf'
694 'v'# -> cont '\v' buf'
695 '\\'# -> cont '\\' buf'
696 '"'# -> cont '\"' buf'
697 '\''# -> cont '\'' buf'
698 '^'# -> let c = currentChar# buf' in
699 if c `geChar#` '@'# && c `leChar#` '_'#
700 then cont (C# (chr# (ord# c -# ord# '@'#))) (incLexeme buf')
703 'x'# -> readNum (after_charnum cont) buf' is_hexdigit 16 hex
704 'o'# -> readNum (after_charnum cont) buf' is_octdigit 8 oct_or_dec
706 -> readNum (after_charnum cont) buf is_digit 10 oct_or_dec
708 _ -> case [ (c,buf2) | (p,c) <- silly_escape_chars,
709 Just buf2 <- [prefixMatch buf p] ] of
710 (c,buf2):_ -> cont c buf2
713 after_charnum cont i buf
714 = let int = fromInteger i in
715 if i >= 0 && i <= 255
716 then cont (chr int) buf
719 readNum cont buf is_digit base conv = read buf 0
721 = case currentChar# buf of { c ->
723 then read (incLexeme buf) (i*base + (toInteger (I# (conv c))))
729 || (c `geChar#` 'a'# && c `leChar#` 'f'#)
730 || (c `geChar#` 'A'# && c `leChar#` 'F'#)
732 hex c | is_digit c = ord# c -# ord# '0'#
733 | otherwise = ord# (to_lower c) -# ord# 'a'# +# 10#
734 oct_or_dec c = ord# c -# ord# '0'#
736 is_octdigit c = c `geChar#` '0'# && c `leChar#` '7'#
739 | c `geChar#` 'A'# && c `leChar#` 'Z'#
740 = chr# (ord# c -# (ord# 'A'# -# ord# 'a'#))
743 charError buf = lexError "error in character literal" buf
745 silly_escape_chars = [
782 -------------------------------------------------------------------------------
784 lex_demand cont buf =
785 case read_em [] buf of { (ls,buf') ->
786 case currentChar# buf' of
787 'B'# -> cont (ITstrict (ls, True )) (incLexeme buf')
788 _ -> cont (ITstrict (ls, False)) buf'
791 -- code snatched from Demand.lhs
793 case currentChar# buf of
794 'L'# -> read_em (WwLazy False : acc) (stepOn buf)
795 'A'# -> read_em (WwLazy True : acc) (stepOn buf)
796 'S'# -> read_em (WwStrict : acc) (stepOn buf)
797 'P'# -> read_em (WwPrim : acc) (stepOn buf)
798 'E'# -> read_em (WwEnum : acc) (stepOn buf)
799 ')'# -> (reverse acc, stepOn buf)
800 'U'# -> do_unpack DataType True acc (stepOnBy# buf 2#)
801 'u'# -> do_unpack DataType False acc (stepOnBy# buf 2#)
802 'N'# -> do_unpack NewType True acc (stepOnBy# buf 2#)
803 'n'# -> do_unpack NewType False acc (stepOnBy# buf 2#)
804 _ -> (reverse acc, buf)
806 do_unpack new_or_data wrapper_unpacks acc buf
807 = case read_em [] buf of
808 (stuff, rest) -> read_em (WwUnpack new_or_data wrapper_unpacks stuff : acc) rest
813 case currentChar# buf of
814 'C'# -> cont ITsccAllCafs (incLexeme buf)
815 other -> cont ITscc buf
817 -----------------------------------------------------------------------------
820 lex_num :: (Token -> P a) -> Int# -> Integer -> P a
821 lex_num cont glaexts acc buf =
822 case scanNumLit acc buf of
824 case currentChar# buf' of
825 '.'# | is_digit (lookAhead# buf' 1#) ->
826 -- this case is not optimised at all, as the
827 -- presence of floating point numbers in interface
828 -- files is not that common. (ToDo)
829 case expandWhile# is_digit (incLexeme buf') of
830 buf2 -> -- points to first non digit char
832 let l = case currentChar# buf2 of
838 = let buf3 = incLexeme buf2 in
839 case currentChar# buf3 of
840 '-'# -> expandWhile# is_digit (incLexeme buf3)
841 '+'# -> expandWhile# is_digit (incLexeme buf3)
842 x | is_digit x -> expandWhile# is_digit buf3
845 v = readRational__ (lexemeToString l)
847 in case currentChar# l of -- glasgow exts only
848 '#'# | flag glaexts -> let l' = incLexeme l in
849 case currentChar# l' of
850 '#'# -> cont (ITprimdouble v) (incLexeme l')
851 _ -> cont (ITprimfloat v) l'
852 _ -> cont (ITrational v) l
854 _ -> after_lexnum cont glaexts acc' buf'
856 after_lexnum cont glaexts i buf
857 = case currentChar# buf of
858 '#'# | flag glaexts -> cont (ITprimint i) (incLexeme buf)
859 _ -> cont (ITinteger i) buf
861 -----------------------------------------------------------------------------
862 -- C "literal literal"s (i.e. things like ``NULL'', ``stdout'' etc.)
864 -- we lexemeToFastString on the bit between the ``''s, but include the
865 -- quotes in the full lexeme.
867 lex_cstring cont buf =
868 case expandUntilMatch (stepOverLexeme buf) "\'\'" of
869 Just buf' -> cont (ITlitlit (lexemeToFastString
870 (setCurrentPos# buf' (negateInt# 2#))))
871 (mergeLexemes buf buf')
872 Nothing -> lexError "unterminated ``" buf
874 -----------------------------------------------------------------------------
875 -- identifiers, symbols etc.
878 case expandWhile# is_ident buf of
879 buf' -> cont (ITipvarid lexeme) buf'
880 where lexeme = lexemeToFastString buf'
882 lex_id cont glaexts buf =
883 let buf1 = expandWhile# is_ident buf in
886 case (if flag glaexts
887 then expandWhile# (eqChar# '#'#) buf1 -- slurp trailing hashes
888 else buf1) of { buf' ->
890 let lexeme = lexemeToFastString buf' in
892 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
893 Just kwd_token -> --trace ("hkeywd: "++_UNPK_(lexeme)) $
897 let var_token = cont (ITvarid lexeme) buf' in
899 if not (flag glaexts)
903 case lookupUFM ghcExtensionKeywordsFM lexeme of {
904 Just kwd_token -> cont kwd_token buf';
910 case expandWhile# is_symbol buf of
911 buf' -> case lookupUFM haskellKeySymsFM lexeme of {
912 Just kwd_token -> --trace ("keysym: "++unpackFS lexeme) $
913 cont kwd_token buf' ;
914 Nothing -> --trace ("sym: "++unpackFS lexeme) $
915 cont (mk_var_token lexeme) buf'
917 where lexeme = lexemeToFastString buf'
920 lex_con cont glaexts buf =
921 case expandWhile# is_ident buf of { buf1 ->
922 case slurp_trailing_hashes buf1 glaexts of { buf' ->
924 case currentChar# buf' of
929 just_a_conid = --trace ("con: "++unpackFS lexeme) $
930 cont (ITconid lexeme) buf'
931 lexeme = lexemeToFastString buf'
932 munch = lex_qid cont glaexts lexeme (incLexeme buf') just_a_conid
935 lex_qid cont glaexts mod buf just_a_conid =
936 case currentChar# buf of
937 '['# -> -- Special case for []
938 case lookAhead# buf 1# of
939 ']'# -> cont (ITqconid (mod,SLIT("[]"))) (setCurrentPos# buf 2#)
942 '('# -> -- Special case for (,,,)
943 -- This *is* necessary to deal with e.g. "instance C PrelBase.(,,)"
944 case lookAhead# buf 1# of
945 '#'# | flag glaexts -> case lookAhead# buf 2# of
946 ','# -> lex_ubx_tuple cont mod (setCurrentPos# buf 3#)
949 ')'# -> cont (ITqconid (mod,SLIT("()"))) (setCurrentPos# buf 2#)
950 ','# -> lex_tuple cont mod (setCurrentPos# buf 2#) just_a_conid
953 '-'# -> case lookAhead# buf 1# of
954 '>'# -> cont (ITqconid (mod,SLIT("->"))) (setCurrentPos# buf 2#)
955 _ -> lex_id3 cont glaexts mod buf just_a_conid
956 _ -> lex_id3 cont glaexts mod buf just_a_conid
958 lex_id3 cont glaexts mod buf just_a_conid
959 | is_symbol (currentChar# buf) =
961 start_new_lexeme = stepOverLexeme buf
963 case expandWhile# is_symbol start_new_lexeme of { buf' ->
965 lexeme = lexemeToFastString buf'
966 -- real lexeme is M.<sym>
967 new_buf = mergeLexemes buf buf'
969 cont (mk_qvar_token mod lexeme) new_buf
970 -- wrong, but arguably morally right: M... is now a qvarsym
975 start_new_lexeme = stepOverLexeme buf
977 case expandWhile# is_ident start_new_lexeme of { buf1 ->
982 case slurp_trailing_hashes buf1 glaexts of { buf' ->
985 lexeme = lexemeToFastString buf'
986 new_buf = mergeLexemes buf buf'
987 is_a_qvarid = cont (mk_qvar_token mod lexeme) new_buf
989 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
990 Just kwd_token -> just_a_conid; -- avoid M.where etc.
991 Nothing -> is_a_qvarid
992 -- TODO: special ids (as, qualified, hiding) shouldn't be
993 -- recognised as keywords here. ie. M.as is a qualified varid.
997 slurp_trailing_hashes buf glaexts
998 | flag glaexts = expandWhile# (`eqChar#` '#'#) buf
1003 | is_upper f = ITconid pk_str
1004 | is_ident f = ITvarid pk_str
1005 | f `eqChar#` ':'# = ITconsym pk_str
1006 | otherwise = ITvarsym pk_str
1008 (C# f) = _HEAD_ pk_str
1011 mk_qvar_token m token =
1012 case mk_var_token token of
1013 ITconid n -> ITqconid (m,n)
1014 ITvarid n -> ITqvarid (m,n)
1015 ITconsym n -> ITqconsym (m,n)
1016 ITvarsym n -> ITqvarsym (m,n)
1017 _ -> ITunknown (show token)
1020 ----------------------------------------------------------------------------
1021 Horrible stuff for dealing with M.(,,,)
1024 lex_tuple cont mod buf back_off =
1028 case currentChar# buf of
1029 ','# -> go (n+1) (stepOn buf)
1030 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Boxed n))) (stepOn buf)
1033 lex_ubx_tuple cont mod buf back_off =
1037 case currentChar# buf of
1038 ','# -> go (n+1) (stepOn buf)
1039 '#'# -> case lookAhead# buf 1# of
1040 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Unboxed n)))
1046 -----------------------------------------------------------------------------
1047 doDiscard rips along really fast, looking for a '#-}',
1048 indicating the end of the pragma we're skipping
1051 doDiscard inStr buf =
1052 case currentChar# buf of
1054 case lookAhead# buf 1# of { '#'# ->
1055 case lookAhead# buf 2# of { '-'# ->
1056 case lookAhead# buf 3# of { '}'# ->
1057 (lexemeToBuffer buf, stepOverLexeme (setCurrentPos# buf 4#));
1058 _ -> doDiscard inStr (incLexeme buf) };
1059 _ -> doDiscard inStr (incLexeme buf) };
1060 _ -> doDiscard inStr (incLexeme buf) }
1063 odd_slashes buf flg i# =
1064 case lookAhead# buf i# of
1065 '\\'# -> odd_slashes buf (not flg) (i# -# 1#)
1068 case lookAhead# buf (negateInt# 1#) of --backwards, actually
1069 '\\'# -> -- escaping something..
1070 if odd_slashes buf True (negateInt# 2#) then
1071 -- odd number of slashes, " is escaped.
1072 doDiscard inStr (incLexeme buf)
1074 -- even number of slashes, \ is escaped.
1075 doDiscard (not inStr) (incLexeme buf)
1076 _ -> case inStr of -- forced to avoid build-up
1077 True -> doDiscard False (incLexeme buf)
1078 False -> doDiscard True (incLexeme buf)
1079 _ -> doDiscard inStr (incLexeme buf)
1083 -----------------------------------------------------------------------------
1094 data PState = PState {
1096 glasgow_exts :: Int#,
1099 context :: [LayoutContext]
1102 type P a = StringBuffer -- Input string
1107 returnP a buf s = POk s a
1109 thenP :: P a -> (a -> P b) -> P b
1110 m `thenP` k = \ buf s ->
1112 POk s1 a -> k a buf s1
1113 PFailed err -> PFailed err
1115 thenP_ :: P a -> P b -> P b
1116 m `thenP_` k = m `thenP` \_ -> k
1118 mapP :: (a -> P b) -> [a] -> P [b]
1119 mapP f [] = returnP []
1122 mapP f as `thenP` \bs ->
1125 failP :: String -> P a
1126 failP msg buf s = PFailed (text msg)
1128 failMsgP :: Message -> P a
1129 failMsgP msg buf s = PFailed msg
1131 lexError :: String -> P a
1132 lexError str buf s@PState{ loc = loc }
1133 = failMsgP (hcat [ppr loc, text ": ", text str]) buf s
1135 getSrcLocP :: P SrcLoc
1136 getSrcLocP buf s@(PState{ loc = loc }) = POk s loc
1138 getSrcFile :: P FAST_STRING
1139 getSrcFile buf s@(PState{ loc = loc }) = POk s (srcLocFile loc)
1141 getContext :: P [LayoutContext]
1142 getContext buf s@(PState{ context = ctx }) = POk s ctx
1144 pushContext :: LayoutContext -> P ()
1145 pushContext ctxt buf s@(PState{ context = ctx }) = POk s{context = ctxt:ctx} ()
1149 This special case in layoutOn is to handle layout contexts with are
1150 indented the same or less than the current context. This is illegal
1151 according to the Haskell spec, so we have to arrange to close the
1152 current context. eg.
1157 after the first 'where', the sequence of events is:
1159 - layout system inserts a ';' (column 0)
1160 - parser begins a new context at column 0
1161 - parser shifts ';' (legal empty declaration)
1162 - parser sees 'class': parse error (we're still in the inner context)
1164 trouble is, by the time we know we need a new context, the lexer has
1165 already generated the ';'. Hacky solution is as follows: since we
1166 know the column of the next token (it's the column number of the new
1167 context), we set the ACTUAL column number of the new context to this
1168 numer plus one. Hence the next time the lexer is called, a '}' will
1169 be generated to close the new context straight away. Furthermore, we
1170 have to set the atbol flag so that the ';' that the parser shifted as
1171 part of the new context is re-generated.
1173 when the new context is *less* indented than the current one:
1175 f = f where g = g where
1178 - current context: column 12.
1179 - on seeing 'h' (column 0), the layout system inserts '}'
1180 - parser starts a new context, column 0
1181 - parser sees '}', uses it to close new context
1182 - we still need to insert another '}' followed by a ';',
1183 hence the atbol trick.
1185 There's also a special hack in here to deal with
1192 i.e. the inner context is at the same indentation level as the outer
1193 context. This is strictly illegal according to Haskell 98, but
1194 there's a lot of existing code using this style and it doesn't make
1195 any sense to disallow it, since empty 'do' lists don't make sense.
1198 layoutOn :: Bool -> P ()
1199 layoutOn strict buf s@(PState{ bol = bol, context = ctx }) =
1200 let offset = lexemeIndex buf -# bol in
1203 | if strict then prev_off >=# offset else prev_off ># offset ->
1204 --trace ("layout on, column: " ++ show (I# offset)) $
1205 POk s{ context = Layout (offset +# 1#) : ctx, atbol = 1# } ()
1207 --trace ("layout on, column: " ++ show (I# offset)) $
1208 POk s{ context = Layout offset : ctx } ()
1211 layoutOff buf s@(PState{ context = ctx }) =
1212 POk s{ context = NoLayout:ctx } ()
1215 popContext = \ buf s@(PState{ context = ctx, loc = loc }) ->
1217 (_:tl) -> POk s{ context = tl } ()
1218 [] -> PFailed (srcParseErr buf loc)
1221 Note that if the name of the file we're processing ends
1222 with `hi-boot', we accept it on faith as having the right
1223 version. This is done so that .hi-boot files that comes
1224 with hsc don't have to be updated before every release,
1225 *and* it allows us to share .hi-boot files with versions
1226 of hsc that don't have .hi version checking (e.g., ghc-2.10's)
1228 If the version number is 0, the checking is also turned off.
1229 (needed to deal with GHC.hi only!)
1231 Once we can assume we're compiling with a version of ghc that
1232 supports interface file checking, we can drop the special
1235 checkVersion :: Maybe Integer -> P ()
1236 checkVersion mb@(Just v) buf s@(PState{loc = loc})
1237 | (v==0) || (v == fromInt opt_HiVersion) || opt_NoHiCheck = POk s ()
1238 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1239 checkVersion mb@Nothing buf s@(PState{loc = loc})
1240 | "hi-boot" `isSuffixOf` (_UNPK_ (srcLocFile loc)) = POk s ()
1241 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1243 -----------------------------------------------------------------
1245 ifaceParseErr :: StringBuffer -> SrcLoc -> Message
1247 = hsep [ppr l, ptext SLIT("Interface file parse error; on input `"),
1248 text (lexemeToString s), char '\'']
1250 ifaceVersionErr hi_vers l toks
1251 = hsep [ppr l, ptext SLIT("Interface file version error;"),
1252 ptext SLIT("Expected"), int opt_HiVersion,
1253 ptext SLIT("found "), pp_version]
1257 Nothing -> ptext SLIT("pre ghc-3.02 version")
1258 Just v -> ptext SLIT("version") <+> integer v
1260 -----------------------------------------------------------------------------
1262 srcParseErr :: StringBuffer -> SrcLoc -> Message
1266 then ptext SLIT(": parse error (possibly incorrect indentation)")
1267 else hcat [ptext SLIT(": parse error on input "),
1268 char '`', text token, char '\'']
1271 token = lexemeToString s