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
113 | ITscc -- ToDo: remove (we use {-# SCC "..." #-} now)
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
170 | ITdotdot -- reserved symbols
184 | ITbiglam -- GHC-extension symbols
186 | ITocurly -- special symbols
188 | ITocurlybar -- {|, for type applications
189 | ITccurlybar -- |}, for type applications
202 | ITvarid FAST_STRING -- identifiers
203 | ITconid FAST_STRING
204 | ITvarsym FAST_STRING
205 | ITconsym FAST_STRING
206 | ITqvarid (FAST_STRING,FAST_STRING)
207 | ITqconid (FAST_STRING,FAST_STRING)
208 | ITqvarsym (FAST_STRING,FAST_STRING)
209 | ITqconsym (FAST_STRING,FAST_STRING)
211 | ITipvarid FAST_STRING -- GHC extension: implicit param: ?x
213 | ITpragma StringBuffer
216 | ITstring FAST_STRING
218 | ITrational Rational
221 | ITprimstring FAST_STRING
223 | ITprimfloat Rational
224 | ITprimdouble Rational
225 | ITlitlit FAST_STRING
227 | ITunknown String -- Used when the lexer can't make sense of it
228 | ITeof -- end of file token
229 deriving Show -- debugging
232 -----------------------------------------------------------------------------
236 pragmaKeywordsFM = listToUFM $
237 map (\ (x,y) -> (_PK_ x,y))
238 [( "SPECIALISE", ITspecialise_prag ),
239 ( "SPECIALIZE", ITspecialise_prag ),
240 ( "SOURCE", ITsource_prag ),
241 ( "INLINE", ITinline_prag ),
242 ( "NOINLINE", ITnoinline_prag ),
243 ( "NOTINLINE", ITnoinline_prag ),
244 ( "LINE", ITline_prag ),
245 ( "RULES", ITrules_prag ),
246 ( "RULEZ", ITrules_prag ), -- american spelling :-)
247 ( "SCC", ITscc_prag ),
248 ( "DEPRECATED", ITdeprecated_prag )
251 haskellKeywordsFM = listToUFM $
252 map (\ (x,y) -> (_PK_ x,y))
253 [( "_", ITunderscore ),
256 ( "class", ITclass ),
258 ( "default", ITdefault ),
259 ( "deriving", ITderiving ),
262 ( "hiding", IThiding ),
264 ( "import", ITimport ),
266 ( "infix", ITinfix ),
267 ( "infixl", ITinfixl ),
268 ( "infixr", ITinfixr ),
269 ( "instance", ITinstance ),
271 ( "module", ITmodule ),
272 ( "newtype", ITnewtype ),
274 ( "qualified", ITqualified ),
277 ( "where", ITwhere ),
278 ( "_scc_", ITscc ) -- ToDo: remove
281 isSpecial :: Token -> Bool
282 -- If we see M.x, where x is a keyword, but
283 -- is special, we treat is as just plain M.x,
285 isSpecial ITas = True
286 isSpecial IThiding = True
287 isSpecial ITqualified = True
288 isSpecial ITforall = True
289 isSpecial ITexport = True
290 isSpecial ITlabel = True
291 isSpecial ITdynamic = True
292 isSpecial ITunsafe = True
293 isSpecial ITwith = True
294 isSpecial ITccallconv = True
295 isSpecial ITstdcallconv = True
298 -- IMPORTANT: Keep this in synch with ParseIface.y's var_fs production! (SUP)
299 ghcExtensionKeywordsFM = listToUFM $
300 map (\ (x,y) -> (_PK_ x,y))
301 [ ( "forall", ITforall ),
302 ( "foreign", ITforeign ),
303 ( "export", ITexport ),
304 ( "label", ITlabel ),
305 ( "dynamic", ITdynamic ),
306 ( "unsafe", ITunsafe ),
308 ( "stdcall", ITstdcallconv),
309 ( "ccall", ITccallconv),
310 ("_ccall_", ITccall (False, False, False)),
311 ("_ccall_GC_", ITccall (False, False, True)),
312 ("_casm_", ITccall (False, True, False)),
313 ("_casm_GC_", ITccall (False, True, True)),
315 -- interface keywords
316 ("__interface", ITinterface),
317 ("__export", IT__export),
318 ("__depends", ITdepends),
319 ("__forall", IT__forall),
320 ("__letrec", ITletrec),
321 ("__coerce", ITcoerce),
322 ("__inline_me", ITinlineMe),
323 ("__inline_call", ITinlineCall),
324 ("__depends", ITdepends),
325 ("__DEFAULT", ITdefaultbranch),
327 ("__integer", ITinteger_lit),
328 ("__float", ITfloat_lit),
329 ("__int64", ITint64_lit),
330 ("__word", ITword_lit),
331 ("__word64", ITword64_lit),
332 ("__rational", ITrational_lit),
333 ("__addr", ITaddr_lit),
334 ("__label", ITlabel_lit),
335 ("__litlit", ITlit_lit),
336 ("__string", ITstring_lit),
339 ("__fuall", ITfuall),
341 ("__P", ITspecialise),
344 ("__D", ITdeprecated),
345 ("__U", ITunfold NoInlinePragInfo),
347 ("__ccall", ITccall (False, False, False)),
348 ("__ccall_GC", ITccall (False, False, True)),
349 ("__dyn_ccall", ITccall (True, False, False)),
350 ("__dyn_ccall_GC", ITccall (True, False, True)),
351 ("__casm", ITccall (False, True, False)),
352 ("__dyn_casm", ITccall (True, True, False)),
353 ("__casm_GC", ITccall (False, True, True)),
354 ("__dyn_casm_GC", ITccall (True, True, True)),
360 haskellKeySymsFM = listToUFM $
361 map (\ (x,y) -> (_PK_ x,y))
374 ,(".", ITdot) -- sadly, for 'forall a . t'
378 -----------------------------------------------------------------------------
383 - (glaexts) lexing an interface file or -fglasgow-exts
384 - (bol) pointer to beginning of line (for column calculations)
385 - (buf) pointer to beginning of token
386 - (buf) pointer to current char
387 - (atbol) flag indicating whether we're at the beginning of a line
390 lexer :: (Token -> P a) -> P a
391 lexer cont buf s@(PState{
393 glasgow_exts = glaexts,
399 -- first, start a new lexeme and lose all the whitespace
401 tab line bol atbol (stepOverLexeme buf)
403 line = srcLocLine loc
405 tab y bol atbol buf = -- trace ("tab: " ++ show (I# y) ++ " : " ++ show (currentChar buf)) $
406 case currentChar# buf of
409 if bufferExhausted (stepOn buf)
410 then cont ITeof buf s'
411 else trace "lexer: misplaced NUL?" $
412 tab y bol atbol (stepOn buf)
414 '\n'# -> let buf' = stepOn buf
415 in tab (y +# 1#) (currentIndex# buf') 1# buf'
417 -- find comments. This got harder in Haskell 98.
418 '-'# -> let trundle n =
419 let next = lookAhead# buf n in
420 if next `eqChar#` '-'# then trundle (n +# 1#)
421 else if is_symbol next || n <# 2#
424 (stepOnUntilChar# (stepOnBy# buf n) '\n'#)
427 -- comments and pragmas. We deal with LINE pragmas here,
428 -- and throw out any unrecognised pragmas as comments. Any
429 -- pragmas we know about are dealt with later (after any layout
430 -- processing if necessary).
431 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
432 if lookAhead# buf 2# `eqChar#` '#'# then
433 if lookAhead# buf 3# `eqChar#` '#'# then is_a_token else
434 case expandWhile# is_space (setCurrentPos# buf 3#) of { buf1->
435 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2->
436 let lexeme = mkFastString -- ToDo: too slow
437 (map toUpper (lexemeToString buf2)) in
438 case lookupUFM pragmaKeywordsFM lexeme of
440 line_prag skip_to_end buf2 s'
441 Just other -> is_a_token
442 Nothing -> skip_to_end (stepOnBy# buf 2#) s'
445 else skip_to_end (stepOnBy# buf 2#) s'
447 skip_to_end = nested_comment (lexer cont)
449 -- special GHC extension: we grok cpp-style #line pragmas
450 '#'# | lexemeIndex buf ==# bol -> -- the '#' must be in column 0
451 case expandWhile# is_space (stepOn buf) of { buf1 ->
452 if is_digit (currentChar# buf1)
453 then line_prag next_line buf1 s'
457 next_line buf = lexer cont (stepOnUntilChar# buf '\n'#)
459 -- tabs have been expanded beforehand
460 c | is_space c -> tab y bol atbol (stepOn buf)
461 | otherwise -> is_a_token
463 where s' = s{loc = replaceSrcLine loc y,
467 is_a_token | atbol /=# 0# = lexBOL cont buf s'
468 | otherwise = lexToken cont glaexts buf s'
470 -- {-# LINE .. #-} pragmas. yeuch.
471 line_prag cont buf s@PState{loc=loc} =
472 case expandWhile# is_space buf of { buf1 ->
473 case scanNumLit 0 (stepOverLexeme buf1) of { (line,buf2) ->
474 -- subtract one: the line number refers to the *following* line.
475 let real_line = line - 1 in
476 case fromInteger real_line of { i@(I# l) ->
477 -- ToDo, if no filename then we skip the newline.... d'oh
478 case expandWhile# is_space buf2 of { buf3 ->
479 case currentChar# buf3 of
481 case untilEndOfString# (stepOn (stepOverLexeme buf3)) of { buf4 ->
483 file = lexemeToFastString buf4
484 new_buf = stepOn (stepOverLexeme buf4)
486 if nullFastString file
487 then cont new_buf s{loc = replaceSrcLine loc l}
488 else cont new_buf s{loc = mkSrcLoc file i}
490 _other -> cont (stepOverLexeme buf3) s{loc = replaceSrcLine loc l}
493 nested_comment :: P a -> P a
494 nested_comment cont buf = loop buf
497 case currentChar# buf of
498 '\NUL'# | bufferExhausted (stepOn buf) ->
499 lexError "unterminated `{-'" buf -- -}
500 '-'# | lookAhead# buf 1# `eqChar#` '}'# ->
501 cont (stepOnBy# buf 2#)
503 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
504 nested_comment (nested_comment cont) (stepOnBy# buf 2#)
506 '\n'# -> \ s@PState{loc=loc} ->
507 let buf' = stepOn buf in
508 nested_comment cont buf'
509 s{loc = incSrcLine loc, bol = currentIndex# buf',
512 _ -> nested_comment cont (stepOn buf)
514 -- When we are lexing the first token of a line, check whether we need to
515 -- insert virtual semicolons or close braces due to layout.
517 lexBOL :: (Token -> P a) -> P a
518 lexBOL cont buf s@(PState{
520 glasgow_exts = glaexts,
525 if need_close_curly then
526 --trace ("col = " ++ show (I# col) ++ ", layout: inserting '}'") $
527 cont ITvccurly buf s{atbol = 1#, context = tail ctx}
528 else if need_semi_colon then
529 --trace ("col = " ++ show (I# col) ++ ", layout: inserting ';'") $
530 cont ITsemi buf s{atbol = 0#}
532 lexToken cont glaexts buf s{atbol = 0#}
534 col = currentIndex# buf -# bol
547 Layout n -> col ==# n
550 lexToken :: (Token -> P a) -> Int# -> P a
551 lexToken cont glaexts buf =
552 -- trace "lexToken" $
553 case currentChar# buf of
555 -- special symbols ----------------------------------------------------
556 '('# | flag glaexts && lookAhead# buf 1# `eqChar#` '#'#
557 -> cont IToubxparen (setCurrentPos# buf 2#)
559 -> cont IToparen (incLexeme buf)
561 ')'# -> cont ITcparen (incLexeme buf)
562 '['# -> cont ITobrack (incLexeme buf)
563 ']'# -> cont ITcbrack (incLexeme buf)
564 ','# -> cont ITcomma (incLexeme buf)
565 ';'# -> cont ITsemi (incLexeme buf)
566 '}'# -> \ s@PState{context = ctx} ->
568 (_:ctx') -> cont ITccurly (incLexeme buf) s{context=ctx'}
569 _ -> lexError "too many '}'s" buf s
570 '|'# -> case lookAhead# buf 1# of
571 '}'# | flag glaexts -> cont ITccurlybar
572 (setCurrentPos# buf 2#)
573 _ -> lex_sym cont (incLexeme buf)
576 '#'# -> case lookAhead# buf 1# of
577 ')'# | flag glaexts -> cont ITcubxparen (setCurrentPos# buf 2#)
578 '-'# -> case lookAhead# buf 2# of
579 '}'# -> cont ITclose_prag (setCurrentPos# buf 3#)
580 _ -> lex_sym cont (incLexeme buf)
581 _ -> lex_sym cont (incLexeme buf)
583 '`'# | flag glaexts && lookAhead# buf 1# `eqChar#` '`'#
584 -> lex_cstring cont (setCurrentPos# buf 2#)
586 -> cont ITbackquote (incLexeme buf)
588 '{'# -> -- look for "{-##" special iface pragma
589 case lookAhead# buf 1# of
591 -> cont ITocurlybar (setCurrentPos# buf 2#)
592 '-'# -> case lookAhead# buf 2# of
593 '#'# -> case lookAhead# buf 3# of
596 = doDiscard 0# (stepOnBy# (stepOverLexeme buf) 4#) in
597 cont (ITpragma lexeme) buf'
598 _ -> lex_prag cont (setCurrentPos# buf 3#)
599 _ -> cont ITocurly (incLexeme buf)
600 _ -> (layoutOff `thenP_` cont ITocurly) (incLexeme buf)
602 -- strings/characters -------------------------------------------------
603 '\"'#{-"-} -> lex_string cont glaexts [] (incLexeme buf)
604 '\''# -> lex_char (char_end cont) glaexts (incLexeme buf)
606 -- strictness and cpr pragmas and __scc treated specially.
607 '_'# | flag glaexts ->
608 case lookAhead# buf 1# of
609 '_'# -> case lookAhead# buf 2# of
611 lex_demand cont (stepOnUntil (not . isSpace)
612 (stepOnBy# buf 3#)) -- past __S
614 cont ITcprinfo (stepOnBy# buf 3#) -- past __M
617 case prefixMatch (stepOnBy# buf 3#) "cc" of
618 Just buf' -> lex_scc cont (stepOverLexeme buf')
619 Nothing -> lex_id cont glaexts buf
620 _ -> lex_id cont glaexts buf
621 _ -> lex_id cont glaexts buf
623 -- Hexadecimal and octal constants
624 '0'# | (ch `eqChar#` 'x'# || ch `eqChar#` 'X'#) && is_hexdigit ch2
625 -> readNum (after_lexnum cont glaexts) buf' is_hexdigit 16 hex
626 | (ch `eqChar#` 'o'# || ch `eqChar#` 'O'#) && is_octdigit ch2
627 -> readNum (after_lexnum cont glaexts) buf' is_octdigit 8 oct_or_dec
628 where ch = lookAhead# buf 1#
629 ch2 = lookAhead# buf 2#
630 buf' = setCurrentPos# buf 2#
633 if bufferExhausted (stepOn buf) then
636 trace "lexIface: misplaced NUL?" $
637 cont (ITunknown "\NUL") (stepOn buf)
639 '?'# | flag glaexts && is_lower (lookAhead# buf 1#) ->
640 lex_ip cont (incLexeme buf)
641 c | is_digit c -> lex_num cont glaexts 0 buf
642 | is_symbol c -> lex_sym cont buf
643 | is_upper c -> lex_con cont glaexts buf
644 | is_ident c -> lex_id cont glaexts buf
645 | otherwise -> lexError "illegal character" buf
647 -- Int# is unlifted, and therefore faster than Bool for flags.
653 -------------------------------------------------------------------------------
657 = case expandWhile# is_space buf of { buf1 ->
658 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2 ->
659 let lexeme = mkFastString (map toUpper (lexemeToString buf2)) in
660 case lookupUFM pragmaKeywordsFM lexeme of
661 Just kw -> cont kw (mergeLexemes buf buf2)
662 Nothing -> panic "lex_prag"
665 -------------------------------------------------------------------------------
668 lex_string cont glaexts s buf
669 = case currentChar# buf of
671 let buf' = incLexeme buf; s' = mkFastStringInt (reverse s) in
672 case currentChar# buf' of
673 '#'# | flag glaexts -> if all (<= 0xFF) s
674 then cont (ITprimstring s') (incLexeme buf')
675 else lexError "primitive string literal must contain only characters <= '\xFF'" buf'
676 _ -> cont (ITstring s') buf'
678 -- ignore \& in a string, deal with string gaps
679 '\\'# | next_ch `eqChar#` '&'#
680 -> lex_string cont glaexts s buf'
682 -> lex_stringgap cont glaexts s (incLexeme buf)
684 where next_ch = lookAhead# buf 1#
685 buf' = setCurrentPos# buf 2#
687 _ -> lex_char (lex_next_string cont s) glaexts buf
689 lex_stringgap cont glaexts s buf
690 = let buf' = incLexeme buf in
691 case currentChar# buf of
692 '\n'# -> \st@PState{loc = loc} -> lex_stringgap cont glaexts s buf'
693 st{loc = incSrcLine loc}
694 '\\'# -> lex_string cont glaexts s buf'
695 c | is_space c -> lex_stringgap cont glaexts s buf'
696 other -> charError buf'
698 lex_next_string cont s glaexts c buf = lex_string cont glaexts (c:s) buf
700 lex_char :: (Int# -> Int -> P a) -> Int# -> P a
701 lex_char cont glaexts buf
702 = case currentChar# buf of
703 '\\'# -> lex_escape (cont glaexts) (incLexeme buf)
704 c | is_any c -> cont glaexts (I# (ord# c)) (incLexeme buf)
705 other -> charError buf
707 char_end cont glaexts c buf
708 = case currentChar# buf of
709 '\''# -> let buf' = incLexeme buf in
710 case currentChar# buf' of
712 -> cont (ITprimchar c) (incLexeme buf')
713 _ -> cont (ITchar c) buf'
717 = let buf' = incLexeme buf in
718 case currentChar# buf of
719 'a'# -> cont (ord '\a') buf'
720 'b'# -> cont (ord '\b') buf'
721 'f'# -> cont (ord '\f') buf'
722 'n'# -> cont (ord '\n') buf'
723 'r'# -> cont (ord '\r') buf'
724 't'# -> cont (ord '\t') buf'
725 'v'# -> cont (ord '\v') buf'
726 '\\'# -> cont (ord '\\') buf'
727 '"'# -> cont (ord '\"') buf'
728 '\''# -> cont (ord '\'') buf'
729 '^'# -> let c = currentChar# buf' in
730 if c `geChar#` '@'# && c `leChar#` '_'#
731 then cont (I# (ord# c -# ord# '@'#)) (incLexeme buf')
734 'x'# -> readNum (after_charnum cont) buf' is_hexdigit 16 hex
735 'o'# -> readNum (after_charnum cont) buf' is_octdigit 8 oct_or_dec
737 -> readNum (after_charnum cont) buf is_digit 10 oct_or_dec
739 _ -> case [ (c,buf2) | (p,c) <- silly_escape_chars,
740 Just buf2 <- [prefixMatch buf p] ] of
741 (c,buf2):_ -> cont (ord c) buf2
744 after_charnum cont i buf
745 = if i >= 0 && i <= 0x10FFFF
746 then cont (fromInteger i) buf
749 readNum cont buf is_digit base conv = read buf 0
751 = case currentChar# buf of { c ->
753 then read (incLexeme buf) (i*base + (toInteger (I# (conv c))))
759 || (c `geChar#` 'a'# && c `leChar#` 'f'#)
760 || (c `geChar#` 'A'# && c `leChar#` 'F'#)
762 hex c | is_digit c = ord# c -# ord# '0'#
763 | otherwise = ord# (to_lower c) -# ord# 'a'# +# 10#
764 oct_or_dec c = ord# c -# ord# '0'#
766 is_octdigit c = c `geChar#` '0'# && c `leChar#` '7'#
769 | c `geChar#` 'A'# && c `leChar#` 'Z'#
770 = chr# (ord# c -# (ord# 'A'# -# ord# 'a'#))
773 charError buf = lexError "error in character literal" buf
775 silly_escape_chars = [
812 -------------------------------------------------------------------------------
814 lex_demand cont buf =
815 case read_em [] buf of { (ls,buf') ->
816 case currentChar# buf' of
817 'B'# -> cont (ITstrict (ls, True )) (incLexeme buf')
818 _ -> cont (ITstrict (ls, False)) buf'
821 -- code snatched from Demand.lhs
823 case currentChar# buf of
824 'L'# -> read_em (WwLazy False : acc) (stepOn buf)
825 'A'# -> read_em (WwLazy True : acc) (stepOn buf)
826 'S'# -> read_em (WwStrict : acc) (stepOn buf)
827 'P'# -> read_em (WwPrim : acc) (stepOn buf)
828 'E'# -> read_em (WwEnum : acc) (stepOn buf)
829 ')'# -> (reverse acc, stepOn buf)
830 'U'# -> do_unpack DataType True acc (stepOnBy# buf 2#)
831 'u'# -> do_unpack DataType False acc (stepOnBy# buf 2#)
832 'N'# -> do_unpack NewType True acc (stepOnBy# buf 2#)
833 'n'# -> do_unpack NewType False acc (stepOnBy# buf 2#)
834 _ -> (reverse acc, buf)
836 do_unpack new_or_data wrapper_unpacks acc buf
837 = case read_em [] buf of
838 (stuff, rest) -> read_em (WwUnpack new_or_data wrapper_unpacks stuff : acc) rest
843 case currentChar# buf of
844 'C'# -> cont ITsccAllCafs (incLexeme buf)
845 other -> cont ITscc buf
847 -----------------------------------------------------------------------------
850 lex_num :: (Token -> P a) -> Int# -> Integer -> P a
851 lex_num cont glaexts acc buf =
852 case scanNumLit acc buf of
854 case currentChar# buf' of
855 '.'# | is_digit (lookAhead# buf' 1#) ->
856 -- this case is not optimised at all, as the
857 -- presence of floating point numbers in interface
858 -- files is not that common. (ToDo)
859 case expandWhile# is_digit (incLexeme buf') of
860 buf2 -> -- points to first non digit char
862 let l = case currentChar# buf2 of
868 = let buf3 = incLexeme buf2 in
869 case currentChar# buf3 of
870 '-'# -> expandWhile# is_digit (incLexeme buf3)
871 '+'# -> expandWhile# is_digit (incLexeme buf3)
872 x | is_digit x -> expandWhile# is_digit buf3
875 v = readRational__ (lexemeToString l)
877 in case currentChar# l of -- glasgow exts only
878 '#'# | flag glaexts -> let l' = incLexeme l in
879 case currentChar# l' of
880 '#'# -> cont (ITprimdouble v) (incLexeme l')
881 _ -> cont (ITprimfloat v) l'
882 _ -> cont (ITrational v) l
884 _ -> after_lexnum cont glaexts acc' buf'
886 after_lexnum cont glaexts i buf
887 = case currentChar# buf of
888 '#'# | flag glaexts -> cont (ITprimint i) (incLexeme buf)
889 _ -> cont (ITinteger i) buf
891 -----------------------------------------------------------------------------
892 -- C "literal literal"s (i.e. things like ``NULL'', ``stdout'' etc.)
894 -- we lexemeToFastString on the bit between the ``''s, but include the
895 -- quotes in the full lexeme.
897 lex_cstring cont buf =
898 case expandUntilMatch (stepOverLexeme buf) "\'\'" of
899 Just buf' -> cont (ITlitlit (lexemeToFastString
900 (setCurrentPos# buf' (negateInt# 2#))))
901 (mergeLexemes buf buf')
902 Nothing -> lexError "unterminated ``" buf
904 -----------------------------------------------------------------------------
905 -- identifiers, symbols etc.
908 case expandWhile# is_ident buf of
909 buf' -> cont (ITipvarid lexeme) buf'
910 where lexeme = lexemeToFastString buf'
912 lex_id cont glaexts buf =
913 let buf1 = expandWhile# is_ident buf in
916 case (if flag glaexts
917 then expandWhile# (eqChar# '#'#) buf1 -- slurp trailing hashes
918 else buf1) of { buf' ->
920 let lexeme = lexemeToFastString buf' in
922 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
923 Just kwd_token -> --trace ("hkeywd: "++_UNPK_(lexeme)) $
927 let var_token = cont (ITvarid lexeme) buf' in
929 if not (flag glaexts)
933 case lookupUFM ghcExtensionKeywordsFM lexeme of {
934 Just kwd_token -> cont kwd_token buf';
941 case expandWhile# is_symbol buf of
942 buf' -> case lookupUFM haskellKeySymsFM lexeme of {
943 Just kwd_token -> --trace ("keysym: "++unpackFS lexeme) $
944 cont kwd_token buf' ;
945 Nothing -> --trace ("sym: "++unpackFS lexeme) $
946 cont (mk_var_token lexeme) buf'
948 where lexeme = lexemeToFastString buf'
951 lex_con cont glaexts buf =
952 -- trace ("con: "{-++unpackFS lexeme-}) $
953 case expandWhile# is_ident buf of { buf1 ->
954 case slurp_trailing_hashes buf1 glaexts of { buf' ->
956 case currentChar# buf' of
961 just_a_conid = cont (ITconid lexeme) buf'
962 lexeme = lexemeToFastString buf'
963 munch = lex_qid cont glaexts lexeme (incLexeme buf') just_a_conid
966 lex_qid cont glaexts mod buf just_a_conid =
967 -- trace ("quid: "{-++unpackFS lexeme-}) $
968 case currentChar# buf of
969 '['# -> -- Special case for []
970 case lookAhead# buf 1# of
971 ']'# -> cont (ITqconid (mod,SLIT("[]"))) (setCurrentPos# buf 2#)
974 '('# -> -- Special case for (,,,)
975 -- This *is* necessary to deal with e.g. "instance C PrelBase.(,,)"
976 case lookAhead# buf 1# of
977 '#'# | flag glaexts -> case lookAhead# buf 2# of
978 ','# -> lex_ubx_tuple cont mod (setCurrentPos# buf 3#)
981 ')'# -> cont (ITqconid (mod,SLIT("()"))) (setCurrentPos# buf 2#)
982 ','# -> lex_tuple cont mod (setCurrentPos# buf 2#) just_a_conid
985 '-'# -> case lookAhead# buf 1# of
986 '>'# -> cont (ITqconid (mod,SLIT("(->)"))) (setCurrentPos# buf 2#)
987 _ -> lex_id3 cont glaexts mod buf just_a_conid
988 _ -> lex_id3 cont glaexts mod buf just_a_conid
990 lex_id3 cont glaexts mod buf just_a_conid
991 | is_symbol (currentChar# buf) =
993 start_new_lexeme = stepOverLexeme buf
995 -- trace ("lex_id31 "{-++unpackFS lexeme-}) $
996 case expandWhile# is_symbol start_new_lexeme of { buf' ->
998 lexeme = lexemeToFastString buf'
999 -- real lexeme is M.<sym>
1000 new_buf = mergeLexemes buf buf'
1002 cont (mk_qvar_token mod lexeme) new_buf
1003 -- wrong, but arguably morally right: M... is now a qvarsym
1008 start_new_lexeme = stepOverLexeme buf
1010 -- trace ("lex_id32 "{-++unpackFS lexeme-}) $
1011 case expandWhile# is_ident start_new_lexeme of { buf1 ->
1016 case slurp_trailing_hashes buf1 glaexts of { buf' ->
1019 lexeme = lexemeToFastString buf'
1020 new_buf = mergeLexemes buf buf'
1021 is_a_qvarid = cont (mk_qvar_token mod lexeme) new_buf
1023 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
1024 Nothing -> is_a_qvarid ;
1026 Just kwd_token | isSpecial kwd_token -- special ids (as, qualified, hiding) shouldn't be
1027 -> is_a_qvarid -- recognised as keywords here.
1029 -> just_a_conid -- avoid M.where etc.
1032 slurp_trailing_hashes buf glaexts
1033 | flag glaexts = expandWhile# (`eqChar#` '#'#) buf
1038 | is_upper f = ITconid pk_str
1039 | is_ident f = ITvarid pk_str
1040 | f `eqChar#` ':'# = ITconsym pk_str
1041 | otherwise = ITvarsym pk_str
1043 (C# f) = _HEAD_ pk_str
1044 -- tl = _TAIL_ pk_str
1046 mk_qvar_token m token =
1047 -- trace ("mk_qvar ") $
1048 case mk_var_token token of
1049 ITconid n -> ITqconid (m,n)
1050 ITvarid n -> ITqvarid (m,n)
1051 ITconsym n -> ITqconsym (m,n)
1052 ITvarsym n -> ITqvarsym (m,n)
1053 _ -> ITunknown (show token)
1056 ----------------------------------------------------------------------------
1057 Horrible stuff for dealing with M.(,,,)
1060 lex_tuple cont mod buf back_off =
1064 case currentChar# buf of
1065 ','# -> go (n+1) (stepOn buf)
1066 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Boxed n))) (stepOn buf)
1069 lex_ubx_tuple cont mod buf back_off =
1073 case currentChar# buf of
1074 ','# -> go (n+1) (stepOn buf)
1075 '#'# -> case lookAhead# buf 1# of
1076 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Unboxed n)))
1082 -----------------------------------------------------------------------------
1083 doDiscard rips along really fast, looking for a '##-}',
1084 indicating the end of the pragma we're skipping
1087 doDiscard inStr buf =
1088 case currentChar# buf of
1089 '#'# | inStr ==# 0# ->
1090 case lookAhead# buf 1# of { '#'# ->
1091 case lookAhead# buf 2# of { '-'# ->
1092 case lookAhead# buf 3# of { '}'# ->
1093 (lexemeToBuffer buf, stepOverLexeme (setCurrentPos# buf 4#));
1094 _ -> doDiscard inStr (incLexeme buf) };
1095 _ -> doDiscard inStr (incLexeme buf) };
1096 _ -> doDiscard inStr (incLexeme buf) }
1100 odd_slashes buf flg i# =
1101 case lookAhead# buf i# of
1102 '\\'# -> odd_slashes buf (not flg) (i# -# 1#)
1105 not_inStr = if inStr ==# 0# then 1# else 0#
1107 case lookAhead# buf (negateInt# 1#) of --backwards, actually
1108 '\\'# -> -- escaping something..
1109 if odd_slashes buf True (negateInt# 2#)
1110 then -- odd number of slashes, " is escaped.
1111 doDiscard inStr (incLexeme buf)
1112 else -- even number of slashes, \ is escaped.
1113 doDiscard not_inStr (incLexeme buf)
1114 _ -> doDiscard not_inStr (incLexeme buf)
1116 '\''# | inStr ==# 0# ->
1117 case lookAhead# buf 1# of { '"'# ->
1118 case lookAhead# buf 2# of { '\''# ->
1119 doDiscard inStr (setCurrentPos# buf 3#);
1120 _ -> doDiscard inStr (incLexeme buf) };
1121 _ -> doDiscard inStr (incLexeme buf) }
1123 _ -> doDiscard inStr (incLexeme buf)
1127 -----------------------------------------------------------------------------
1138 data PState = PState {
1140 glasgow_exts :: Int#,
1143 context :: [LayoutContext]
1146 type P a = StringBuffer -- Input string
1151 returnP a buf s = POk s a
1153 thenP :: P a -> (a -> P b) -> P b
1154 m `thenP` k = \ buf s ->
1156 POk s1 a -> k a buf s1
1157 PFailed err -> PFailed err
1159 thenP_ :: P a -> P b -> P b
1160 m `thenP_` k = m `thenP` \_ -> k
1162 mapP :: (a -> P b) -> [a] -> P [b]
1163 mapP f [] = returnP []
1166 mapP f as `thenP` \bs ->
1169 failP :: String -> P a
1170 failP msg buf s = PFailed (text msg)
1172 failMsgP :: Message -> P a
1173 failMsgP msg buf s = PFailed msg
1175 lexError :: String -> P a
1176 lexError str buf s@PState{ loc = loc }
1177 = failMsgP (hcat [ppr loc, text ": ", text str]) buf s
1179 getSrcLocP :: P SrcLoc
1180 getSrcLocP buf s@(PState{ loc = loc }) = POk s loc
1182 getSrcFile :: P FAST_STRING
1183 getSrcFile buf s@(PState{ loc = loc }) = POk s (srcLocFile loc)
1185 getContext :: P [LayoutContext]
1186 getContext buf s@(PState{ context = ctx }) = POk s ctx
1188 pushContext :: LayoutContext -> P ()
1189 pushContext ctxt buf s@(PState{ context = ctx }) = POk s{context = ctxt:ctx} ()
1193 This special case in layoutOn is to handle layout contexts with are
1194 indented the same or less than the current context. This is illegal
1195 according to the Haskell spec, so we have to arrange to close the
1196 current context. eg.
1201 after the first 'where', the sequence of events is:
1203 - layout system inserts a ';' (column 0)
1204 - parser begins a new context at column 0
1205 - parser shifts ';' (legal empty declaration)
1206 - parser sees 'class': parse error (we're still in the inner context)
1208 trouble is, by the time we know we need a new context, the lexer has
1209 already generated the ';'. Hacky solution is as follows: since we
1210 know the column of the next token (it's the column number of the new
1211 context), we set the ACTUAL column number of the new context to this
1212 numer plus one. Hence the next time the lexer is called, a '}' will
1213 be generated to close the new context straight away. Furthermore, we
1214 have to set the atbol flag so that the ';' that the parser shifted as
1215 part of the new context is re-generated.
1217 when the new context is *less* indented than the current one:
1219 f = f where g = g where
1222 - current context: column 12.
1223 - on seeing 'h' (column 0), the layout system inserts '}'
1224 - parser starts a new context, column 0
1225 - parser sees '}', uses it to close new context
1226 - we still need to insert another '}' followed by a ';',
1227 hence the atbol trick.
1229 There's also a special hack in here to deal with
1236 i.e. the inner context is at the same indentation level as the outer
1237 context. This is strictly illegal according to Haskell 98, but
1238 there's a lot of existing code using this style and it doesn't make
1239 any sense to disallow it, since empty 'do' lists don't make sense.
1242 layoutOn :: Bool -> P ()
1243 layoutOn strict buf s@(PState{ bol = bol, context = ctx }) =
1244 let offset = lexemeIndex buf -# bol in
1247 | if strict then prev_off >=# offset else prev_off ># offset ->
1248 --trace ("layout on, column: " ++ show (I# offset)) $
1249 POk s{ context = Layout (offset +# 1#) : ctx, atbol = 1# } ()
1251 --trace ("layout on, column: " ++ show (I# offset)) $
1252 POk s{ context = Layout offset : ctx } ()
1255 layoutOff buf s@(PState{ context = ctx }) =
1256 POk s{ context = NoLayout:ctx } ()
1259 popContext = \ buf s@(PState{ context = ctx, loc = loc }) ->
1261 (_:tl) -> POk s{ context = tl } ()
1262 [] -> PFailed (srcParseErr buf loc)
1265 Note that if the name of the file we're processing ends
1266 with `hi-boot', we accept it on faith as having the right
1267 version. This is done so that .hi-boot files that comes
1268 with hsc don't have to be updated before every release,
1269 *and* it allows us to share .hi-boot files with versions
1270 of hsc that don't have .hi version checking (e.g., ghc-2.10's)
1272 If the version number is 0, the checking is also turned off.
1273 (needed to deal with GHC.hi only!)
1275 Once we can assume we're compiling with a version of ghc that
1276 supports interface file checking, we can drop the special
1279 checkVersion :: Maybe Integer -> P ()
1280 checkVersion mb@(Just v) buf s@(PState{loc = loc})
1281 | (v==0) || (v == fromInt opt_HiVersion) || opt_NoHiCheck = POk s ()
1282 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1283 checkVersion mb@Nothing buf s@(PState{loc = loc})
1284 | "hi-boot" `isSuffixOf` (_UNPK_ (srcLocFile loc)) = POk s ()
1285 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1287 -----------------------------------------------------------------
1289 ifaceParseErr :: StringBuffer -> SrcLoc -> Message
1291 = hsep [ppr l, ptext SLIT("Interface file parse error; on input `"),
1292 text (lexemeToString s), char '\'']
1294 ifaceVersionErr hi_vers l toks
1295 = hsep [ppr l, ptext SLIT("Interface file version error;"),
1296 ptext SLIT("Expected"), int opt_HiVersion,
1297 ptext SLIT("found "), pp_version]
1301 Nothing -> ptext SLIT("pre ghc-3.02 version")
1302 Just v -> ptext SLIT("version") <+> integer v
1304 -----------------------------------------------------------------------------
1306 srcParseErr :: StringBuffer -> SrcLoc -> Message
1310 then ptext SLIT(": parse error (possibly incorrect indentation)")
1311 else hcat [ptext SLIT(": parse error on input "),
1312 char '`', text token, char '\'']
1315 token = lexemeToString s