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 )
55 import Char ( chr, ord )
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
672 s' = mkFastStringNarrow (map chr (reverse s))
673 in case currentChar# buf' of
674 '#'# | flag glaexts -> if all (<= 0xFF) s
675 then cont (ITprimstring s') (incLexeme buf')
676 else lexError "primitive string literal must contain only characters <= \'\\xFF\'" buf'
677 _ -> cont (ITstring s') buf'
679 -- ignore \& in a string, deal with string gaps
680 '\\'# | next_ch `eqChar#` '&'#
681 -> lex_string cont glaexts s buf'
683 -> lex_stringgap cont glaexts s (incLexeme buf)
685 where next_ch = lookAhead# buf 1#
686 buf' = setCurrentPos# buf 2#
688 _ -> lex_char (lex_next_string cont s) glaexts buf
690 lex_stringgap cont glaexts s buf
691 = let buf' = incLexeme buf in
692 case currentChar# buf of
693 '\n'# -> \st@PState{loc = loc} -> lex_stringgap cont glaexts s buf'
694 st{loc = incSrcLine loc}
695 '\\'# -> lex_string cont glaexts s buf'
696 c | is_space c -> lex_stringgap cont glaexts s buf'
697 other -> charError buf'
699 lex_next_string cont s glaexts c buf = lex_string cont glaexts (c:s) buf
701 lex_char :: (Int# -> Int -> P a) -> Int# -> P a
702 lex_char cont glaexts buf
703 = case currentChar# buf of
704 '\\'# -> lex_escape (cont glaexts) (incLexeme buf)
705 c | is_any c -> cont glaexts (I# (ord# c)) (incLexeme buf)
706 other -> charError buf
708 char_end cont glaexts c buf
709 = case currentChar# buf of
710 '\''# -> let buf' = incLexeme buf in
711 case currentChar# buf' of
713 -> cont (ITprimchar c) (incLexeme buf')
714 _ -> cont (ITchar c) buf'
718 = let buf' = incLexeme buf in
719 case currentChar# buf of
720 'a'# -> cont (ord '\a') buf'
721 'b'# -> cont (ord '\b') buf'
722 'f'# -> cont (ord '\f') buf'
723 'n'# -> cont (ord '\n') buf'
724 'r'# -> cont (ord '\r') buf'
725 't'# -> cont (ord '\t') buf'
726 'v'# -> cont (ord '\v') buf'
727 '\\'# -> cont (ord '\\') buf'
728 '"'# -> cont (ord '\"') buf'
729 '\''# -> cont (ord '\'') buf'
730 '^'# -> let c = currentChar# buf' in
731 if c `geChar#` '@'# && c `leChar#` '_'#
732 then cont (I# (ord# c -# ord# '@'#)) (incLexeme buf')
735 'x'# -> readNum (after_charnum cont) buf' is_hexdigit 16 hex
736 'o'# -> readNum (after_charnum cont) buf' is_octdigit 8 oct_or_dec
738 -> readNum (after_charnum cont) buf is_digit 10 oct_or_dec
740 _ -> case [ (c,buf2) | (p,c) <- silly_escape_chars,
741 Just buf2 <- [prefixMatch buf p] ] of
742 (c,buf2):_ -> cont (ord c) buf2
745 after_charnum cont i buf
746 = if i >= 0 && i <= 0x10FFFF
747 then cont (fromInteger i) buf
750 readNum cont buf is_digit base conv = read buf 0
752 = case currentChar# buf of { c ->
754 then read (incLexeme buf) (i*base + (toInteger (I# (conv c))))
760 || (c `geChar#` 'a'# && c `leChar#` 'f'#)
761 || (c `geChar#` 'A'# && c `leChar#` 'F'#)
763 hex c | is_digit c = ord# c -# ord# '0'#
764 | otherwise = ord# (to_lower c) -# ord# 'a'# +# 10#
765 oct_or_dec c = ord# c -# ord# '0'#
767 is_octdigit c = c `geChar#` '0'# && c `leChar#` '7'#
770 | c `geChar#` 'A'# && c `leChar#` 'Z'#
771 = chr# (ord# c -# (ord# 'A'# -# ord# 'a'#))
774 charError buf = lexError "error in character literal" buf
776 silly_escape_chars = [
813 -------------------------------------------------------------------------------
815 lex_demand cont buf =
816 case read_em [] buf of { (ls,buf') ->
817 case currentChar# buf' of
818 'B'# -> cont (ITstrict (ls, True )) (incLexeme buf')
819 _ -> cont (ITstrict (ls, False)) buf'
822 -- code snatched from Demand.lhs
824 case currentChar# buf of
825 'L'# -> read_em (WwLazy False : acc) (stepOn buf)
826 'A'# -> read_em (WwLazy True : acc) (stepOn buf)
827 'S'# -> read_em (WwStrict : acc) (stepOn buf)
828 'P'# -> read_em (WwPrim : acc) (stepOn buf)
829 'E'# -> read_em (WwEnum : acc) (stepOn buf)
830 ')'# -> (reverse acc, stepOn buf)
831 'U'# -> do_unpack DataType True acc (stepOnBy# buf 2#)
832 'u'# -> do_unpack DataType False acc (stepOnBy# buf 2#)
833 'N'# -> do_unpack NewType True acc (stepOnBy# buf 2#)
834 'n'# -> do_unpack NewType False acc (stepOnBy# buf 2#)
835 _ -> (reverse acc, buf)
837 do_unpack new_or_data wrapper_unpacks acc buf
838 = case read_em [] buf of
839 (stuff, rest) -> read_em (WwUnpack new_or_data wrapper_unpacks stuff : acc) rest
844 case currentChar# buf of
845 'C'# -> cont ITsccAllCafs (incLexeme buf)
846 other -> cont ITscc buf
848 -----------------------------------------------------------------------------
851 lex_num :: (Token -> P a) -> Int# -> Integer -> P a
852 lex_num cont glaexts acc buf =
853 case scanNumLit acc buf of
855 case currentChar# buf' of
856 '.'# | is_digit (lookAhead# buf' 1#) ->
857 -- this case is not optimised at all, as the
858 -- presence of floating point numbers in interface
859 -- files is not that common. (ToDo)
860 case expandWhile# is_digit (incLexeme buf') of
861 buf2 -> -- points to first non digit char
863 let l = case currentChar# buf2 of
869 = let buf3 = incLexeme buf2 in
870 case currentChar# buf3 of
871 '-'# -> expandWhile# is_digit (incLexeme buf3)
872 '+'# -> expandWhile# is_digit (incLexeme buf3)
873 x | is_digit x -> expandWhile# is_digit buf3
876 v = readRational__ (lexemeToString l)
878 in case currentChar# l of -- glasgow exts only
879 '#'# | flag glaexts -> let l' = incLexeme l in
880 case currentChar# l' of
881 '#'# -> cont (ITprimdouble v) (incLexeme l')
882 _ -> cont (ITprimfloat v) l'
883 _ -> cont (ITrational v) l
885 _ -> after_lexnum cont glaexts acc' buf'
887 after_lexnum cont glaexts i buf
888 = case currentChar# buf of
889 '#'# | flag glaexts -> cont (ITprimint i) (incLexeme buf)
890 _ -> cont (ITinteger i) buf
892 -----------------------------------------------------------------------------
893 -- C "literal literal"s (i.e. things like ``NULL'', ``stdout'' etc.)
895 -- we lexemeToFastString on the bit between the ``''s, but include the
896 -- quotes in the full lexeme.
898 lex_cstring cont buf =
899 case expandUntilMatch (stepOverLexeme buf) "\'\'" of
900 Just buf' -> cont (ITlitlit (lexemeToFastString
901 (setCurrentPos# buf' (negateInt# 2#))))
902 (mergeLexemes buf buf')
903 Nothing -> lexError "unterminated ``" buf
905 -----------------------------------------------------------------------------
906 -- identifiers, symbols etc.
909 case expandWhile# is_ident buf of
910 buf' -> cont (ITipvarid lexeme) buf'
911 where lexeme = lexemeToFastString buf'
913 lex_id cont glaexts buf =
914 let buf1 = expandWhile# is_ident buf in
917 case (if flag glaexts
918 then expandWhile# (eqChar# '#'#) buf1 -- slurp trailing hashes
919 else buf1) of { buf' ->
921 let lexeme = lexemeToFastString buf' in
923 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
924 Just kwd_token -> --trace ("hkeywd: "++_UNPK_(lexeme)) $
928 let var_token = cont (ITvarid lexeme) buf' in
930 if not (flag glaexts)
934 case lookupUFM ghcExtensionKeywordsFM lexeme of {
935 Just kwd_token -> cont kwd_token buf';
942 case expandWhile# is_symbol buf of
943 buf' -> case lookupUFM haskellKeySymsFM lexeme of {
944 Just kwd_token -> --trace ("keysym: "++unpackFS lexeme) $
945 cont kwd_token buf' ;
946 Nothing -> --trace ("sym: "++unpackFS lexeme) $
947 cont (mk_var_token lexeme) buf'
949 where lexeme = lexemeToFastString buf'
952 lex_con cont glaexts buf =
953 -- trace ("con: "{-++unpackFS lexeme-}) $
954 case expandWhile# is_ident buf of { buf1 ->
955 case slurp_trailing_hashes buf1 glaexts of { buf' ->
957 case currentChar# buf' of
962 just_a_conid = cont (ITconid lexeme) buf'
963 lexeme = lexemeToFastString buf'
964 munch = lex_qid cont glaexts lexeme (incLexeme buf') just_a_conid
967 lex_qid cont glaexts mod buf just_a_conid =
968 -- trace ("quid: "{-++unpackFS lexeme-}) $
969 case currentChar# buf of
970 '['# -> -- Special case for []
971 case lookAhead# buf 1# of
972 ']'# -> cont (ITqconid (mod,SLIT("[]"))) (setCurrentPos# buf 2#)
975 '('# -> -- Special case for (,,,)
976 -- This *is* necessary to deal with e.g. "instance C PrelBase.(,,)"
977 case lookAhead# buf 1# of
978 '#'# | flag glaexts -> case lookAhead# buf 2# of
979 ','# -> lex_ubx_tuple cont mod (setCurrentPos# buf 3#)
982 ')'# -> cont (ITqconid (mod,SLIT("()"))) (setCurrentPos# buf 2#)
983 ','# -> lex_tuple cont mod (setCurrentPos# buf 2#) just_a_conid
986 '-'# -> case lookAhead# buf 1# of
987 '>'# -> cont (ITqconid (mod,SLIT("(->)"))) (setCurrentPos# buf 2#)
988 _ -> lex_id3 cont glaexts mod buf just_a_conid
989 _ -> lex_id3 cont glaexts mod buf just_a_conid
991 lex_id3 cont glaexts mod buf just_a_conid
992 | is_symbol (currentChar# buf) =
994 start_new_lexeme = stepOverLexeme buf
996 -- trace ("lex_id31 "{-++unpackFS lexeme-}) $
997 case expandWhile# is_symbol start_new_lexeme of { buf' ->
999 lexeme = lexemeToFastString buf'
1000 -- real lexeme is M.<sym>
1001 new_buf = mergeLexemes buf buf'
1003 cont (mk_qvar_token mod lexeme) new_buf
1004 -- wrong, but arguably morally right: M... is now a qvarsym
1009 start_new_lexeme = stepOverLexeme buf
1011 -- trace ("lex_id32 "{-++unpackFS lexeme-}) $
1012 case expandWhile# is_ident start_new_lexeme of { buf1 ->
1017 case slurp_trailing_hashes buf1 glaexts of { buf' ->
1020 lexeme = lexemeToFastString buf'
1021 new_buf = mergeLexemes buf buf'
1022 is_a_qvarid = cont (mk_qvar_token mod lexeme) new_buf
1024 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
1025 Nothing -> is_a_qvarid ;
1027 Just kwd_token | isSpecial kwd_token -- special ids (as, qualified, hiding) shouldn't be
1028 -> is_a_qvarid -- recognised as keywords here.
1030 -> just_a_conid -- avoid M.where etc.
1033 slurp_trailing_hashes buf glaexts
1034 | flag glaexts = expandWhile# (`eqChar#` '#'#) buf
1039 | is_upper f = ITconid pk_str
1040 | is_ident f = ITvarid pk_str
1041 | f `eqChar#` ':'# = ITconsym pk_str
1042 | otherwise = ITvarsym pk_str
1044 (C# f) = _HEAD_ pk_str
1045 -- tl = _TAIL_ pk_str
1047 mk_qvar_token m token =
1048 -- trace ("mk_qvar ") $
1049 case mk_var_token token of
1050 ITconid n -> ITqconid (m,n)
1051 ITvarid n -> ITqvarid (m,n)
1052 ITconsym n -> ITqconsym (m,n)
1053 ITvarsym n -> ITqvarsym (m,n)
1054 _ -> ITunknown (show token)
1057 ----------------------------------------------------------------------------
1058 Horrible stuff for dealing with M.(,,,)
1061 lex_tuple cont mod buf back_off =
1065 case currentChar# buf of
1066 ','# -> go (n+1) (stepOn buf)
1067 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Boxed n))) (stepOn buf)
1070 lex_ubx_tuple cont mod buf back_off =
1074 case currentChar# buf of
1075 ','# -> go (n+1) (stepOn buf)
1076 '#'# -> case lookAhead# buf 1# of
1077 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Unboxed n)))
1083 -----------------------------------------------------------------------------
1084 doDiscard rips along really fast, looking for a '##-}',
1085 indicating the end of the pragma we're skipping
1088 doDiscard inStr buf =
1089 case currentChar# buf of
1090 '#'# | inStr ==# 0# ->
1091 case lookAhead# buf 1# of { '#'# ->
1092 case lookAhead# buf 2# of { '-'# ->
1093 case lookAhead# buf 3# of { '}'# ->
1094 (lexemeToBuffer buf, stepOverLexeme (setCurrentPos# buf 4#));
1095 _ -> doDiscard inStr (incLexeme buf) };
1096 _ -> doDiscard inStr (incLexeme buf) };
1097 _ -> doDiscard inStr (incLexeme buf) }
1101 odd_slashes buf flg i# =
1102 case lookAhead# buf i# of
1103 '\\'# -> odd_slashes buf (not flg) (i# -# 1#)
1106 not_inStr = if inStr ==# 0# then 1# else 0#
1108 case lookAhead# buf (negateInt# 1#) of --backwards, actually
1109 '\\'# -> -- escaping something..
1110 if odd_slashes buf True (negateInt# 2#)
1111 then -- odd number of slashes, " is escaped.
1112 doDiscard inStr (incLexeme buf)
1113 else -- even number of slashes, \ is escaped.
1114 doDiscard not_inStr (incLexeme buf)
1115 _ -> doDiscard not_inStr (incLexeme buf)
1117 '\''# | inStr ==# 0# ->
1118 case lookAhead# buf 1# of { '"'# ->
1119 case lookAhead# buf 2# of { '\''# ->
1120 doDiscard inStr (setCurrentPos# buf 3#);
1121 _ -> doDiscard inStr (incLexeme buf) };
1122 _ -> doDiscard inStr (incLexeme buf) }
1124 _ -> doDiscard inStr (incLexeme buf)
1128 -----------------------------------------------------------------------------
1139 data PState = PState {
1141 glasgow_exts :: Int#,
1144 context :: [LayoutContext]
1147 type P a = StringBuffer -- Input string
1152 returnP a buf s = POk s a
1154 thenP :: P a -> (a -> P b) -> P b
1155 m `thenP` k = \ buf s ->
1157 POk s1 a -> k a buf s1
1158 PFailed err -> PFailed err
1160 thenP_ :: P a -> P b -> P b
1161 m `thenP_` k = m `thenP` \_ -> k
1163 mapP :: (a -> P b) -> [a] -> P [b]
1164 mapP f [] = returnP []
1167 mapP f as `thenP` \bs ->
1170 failP :: String -> P a
1171 failP msg buf s = PFailed (text msg)
1173 failMsgP :: Message -> P a
1174 failMsgP msg buf s = PFailed msg
1176 lexError :: String -> P a
1177 lexError str buf s@PState{ loc = loc }
1178 = failMsgP (hcat [ppr loc, text ": ", text str]) buf s
1180 getSrcLocP :: P SrcLoc
1181 getSrcLocP buf s@(PState{ loc = loc }) = POk s loc
1183 getSrcFile :: P FAST_STRING
1184 getSrcFile buf s@(PState{ loc = loc }) = POk s (srcLocFile loc)
1186 getContext :: P [LayoutContext]
1187 getContext buf s@(PState{ context = ctx }) = POk s ctx
1189 pushContext :: LayoutContext -> P ()
1190 pushContext ctxt buf s@(PState{ context = ctx }) = POk s{context = ctxt:ctx} ()
1194 This special case in layoutOn is to handle layout contexts with are
1195 indented the same or less than the current context. This is illegal
1196 according to the Haskell spec, so we have to arrange to close the
1197 current context. eg.
1202 after the first 'where', the sequence of events is:
1204 - layout system inserts a ';' (column 0)
1205 - parser begins a new context at column 0
1206 - parser shifts ';' (legal empty declaration)
1207 - parser sees 'class': parse error (we're still in the inner context)
1209 trouble is, by the time we know we need a new context, the lexer has
1210 already generated the ';'. Hacky solution is as follows: since we
1211 know the column of the next token (it's the column number of the new
1212 context), we set the ACTUAL column number of the new context to this
1213 numer plus one. Hence the next time the lexer is called, a '}' will
1214 be generated to close the new context straight away. Furthermore, we
1215 have to set the atbol flag so that the ';' that the parser shifted as
1216 part of the new context is re-generated.
1218 when the new context is *less* indented than the current one:
1220 f = f where g = g where
1223 - current context: column 12.
1224 - on seeing 'h' (column 0), the layout system inserts '}'
1225 - parser starts a new context, column 0
1226 - parser sees '}', uses it to close new context
1227 - we still need to insert another '}' followed by a ';',
1228 hence the atbol trick.
1230 There's also a special hack in here to deal with
1237 i.e. the inner context is at the same indentation level as the outer
1238 context. This is strictly illegal according to Haskell 98, but
1239 there's a lot of existing code using this style and it doesn't make
1240 any sense to disallow it, since empty 'do' lists don't make sense.
1243 layoutOn :: Bool -> P ()
1244 layoutOn strict buf s@(PState{ bol = bol, context = ctx }) =
1245 let offset = lexemeIndex buf -# bol in
1248 | if strict then prev_off >=# offset else prev_off ># offset ->
1249 --trace ("layout on, column: " ++ show (I# offset)) $
1250 POk s{ context = Layout (offset +# 1#) : ctx, atbol = 1# } ()
1252 --trace ("layout on, column: " ++ show (I# offset)) $
1253 POk s{ context = Layout offset : ctx } ()
1256 layoutOff buf s@(PState{ context = ctx }) =
1257 POk s{ context = NoLayout:ctx } ()
1260 popContext = \ buf s@(PState{ context = ctx, loc = loc }) ->
1262 (_:tl) -> POk s{ context = tl } ()
1263 [] -> PFailed (srcParseErr buf loc)
1266 Note that if the name of the file we're processing ends
1267 with `hi-boot', we accept it on faith as having the right
1268 version. This is done so that .hi-boot files that comes
1269 with hsc don't have to be updated before every release,
1270 *and* it allows us to share .hi-boot files with versions
1271 of hsc that don't have .hi version checking (e.g., ghc-2.10's)
1273 If the version number is 0, the checking is also turned off.
1274 (needed to deal with GHC.hi only!)
1276 Once we can assume we're compiling with a version of ghc that
1277 supports interface file checking, we can drop the special
1280 checkVersion :: Maybe Integer -> P ()
1281 checkVersion mb@(Just v) buf s@(PState{loc = loc})
1282 | (v==0) || (v == fromInt opt_HiVersion) || opt_NoHiCheck = POk s ()
1283 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1284 checkVersion mb@Nothing buf s@(PState{loc = loc})
1285 | "hi-boot" `isSuffixOf` (_UNPK_ (srcLocFile loc)) = POk s ()
1286 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1288 -----------------------------------------------------------------
1290 ifaceParseErr :: StringBuffer -> SrcLoc -> Message
1292 = hsep [ppr l, ptext SLIT("Interface file parse error; on input `"),
1293 text (lexemeToString s), char '\'']
1295 ifaceVersionErr hi_vers l toks
1296 = hsep [ppr l, ptext SLIT("Interface file version error;"),
1297 ptext SLIT("Expected"), int opt_HiVersion,
1298 ptext SLIT("found "), pp_version]
1302 Nothing -> ptext SLIT("pre ghc-3.02 version")
1303 Just v -> ptext SLIT("version") <+> integer v
1305 -----------------------------------------------------------------------------
1307 srcParseErr :: StringBuffer -> SrcLoc -> Message
1311 then ptext SLIT(": parse error (possibly incorrect indentation)")
1312 else hcat [ptext SLIT(": parse error on input "),
1313 char '`', text token, char '\'']
1316 token = lexemeToString s