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, setSrcLocP, getSrcFile,
31 layoutOn, layoutOff, pushContext, popContext
34 #include "HsVersions.h"
36 import Char ( isSpace, toUpper )
37 import List ( isSuffixOf )
39 import PrelNames ( mkTupNameStr )
40 import CmdLineOpts ( opt_HiVersion, opt_NoHiCheck )
41 import ForeignCall ( Safety(..) )
42 import NewDemand ( StrictSig(..), Demand(..), Demands(..),
43 DmdResult(..), mkTopDmdType, evalDmd, lazyDmd )
44 import UniqFM ( listToUFM, lookupUFM )
45 import BasicTypes ( Boxity(..) )
46 import SrcLoc ( SrcLoc, incSrcLine, srcLocFile, srcLocLine,
47 replaceSrcLine, mkSrcLoc )
49 import ErrUtils ( Message )
56 import Char ( chr, ord )
57 import PrelRead ( readRational__ ) -- Glasgow non-std
60 %************************************************************************
62 \subsection{Data types}
64 %************************************************************************
66 The token data type, fairly un-interesting except from one
67 constructor, @ITidinfo@, which is used to lazily lex id info (arity,
68 strictness, unfolding etc).
70 The Idea/Observation here is that the renamer needs to scan through
71 all of an interface file before it can continue. But only a fraction
72 of the information contained in the file turns out to be useful, so
73 delaying as much as possible of the scanning and parsing of an
74 interface file Makes Sense (Heap profiles of the compiler
75 show a reduction in heap usage by at least a factor of two,
78 Hence, the interface file lexer spots when value declarations are
79 being scanned and return the @ITidinfo@ and @ITtype@ constructors
80 for the type and any other id info for that binding (unfolding, strictness
81 etc). These constructors are applied to the result of lexing these sub-chunks.
83 The lexing of the type and id info is all done lazily, of course, so
84 the scanning (and subsequent parsing) will be done *only* on the ids the
85 renamer finds out that it is interested in. The rest will just be junked.
86 Laziness, you know it makes sense :-)
90 = ITas -- Haskell keywords
114 | ITscc -- ToDo: remove (we use {-# SCC "..." #-} now)
116 | ITforall -- GHC extension keywords
127 | ITinterface -- interface keywords
135 | ITccall (Bool,Bool,Safety) -- (is_dyn, is_casm, may_gc)
162 | ITspecialise_prag -- Pragmas
172 | ITdotdot -- reserved symbols
186 | ITbiglam -- GHC-extension symbols
188 | ITocurly -- special symbols
190 | ITocurlybar -- {|, for type applications
191 | ITccurlybar -- |}, for type applications
204 | ITvarid FAST_STRING -- identifiers
205 | ITconid FAST_STRING
206 | ITvarsym FAST_STRING
207 | ITconsym FAST_STRING
208 | ITqvarid (FAST_STRING,FAST_STRING)
209 | ITqconid (FAST_STRING,FAST_STRING)
210 | ITqvarsym (FAST_STRING,FAST_STRING)
211 | ITqconsym (FAST_STRING,FAST_STRING)
213 | ITipvarid FAST_STRING -- GHC extension: implicit param: ?x
215 | ITpragma StringBuffer
218 | ITstring FAST_STRING
220 | ITrational Rational
223 | ITprimstring FAST_STRING
225 | ITprimfloat Rational
226 | ITprimdouble Rational
227 | ITlitlit FAST_STRING
229 | ITunknown String -- Used when the lexer can't make sense of it
230 | ITeof -- end of file token
231 deriving Show -- debugging
234 -----------------------------------------------------------------------------
238 pragmaKeywordsFM = listToUFM $
239 map (\ (x,y) -> (_PK_ x,y))
240 [( "SPECIALISE", ITspecialise_prag ),
241 ( "SPECIALIZE", ITspecialise_prag ),
242 ( "SOURCE", ITsource_prag ),
243 ( "INLINE", ITinline_prag ),
244 ( "NOINLINE", ITnoinline_prag ),
245 ( "NOTINLINE", ITnoinline_prag ),
246 ( "LINE", ITline_prag ),
247 ( "RULES", ITrules_prag ),
248 ( "RULEZ", ITrules_prag ), -- american spelling :-)
249 ( "SCC", ITscc_prag ),
250 ( "DEPRECATED", ITdeprecated_prag )
253 haskellKeywordsFM = listToUFM $
254 map (\ (x,y) -> (_PK_ x,y))
255 [( "_", ITunderscore ),
258 ( "class", ITclass ),
260 ( "default", ITdefault ),
261 ( "deriving", ITderiving ),
264 ( "hiding", IThiding ),
266 ( "import", ITimport ),
268 ( "infix", ITinfix ),
269 ( "infixl", ITinfixl ),
270 ( "infixr", ITinfixr ),
271 ( "instance", ITinstance ),
273 ( "module", ITmodule ),
274 ( "newtype", ITnewtype ),
276 ( "qualified", ITqualified ),
279 ( "where", ITwhere ),
280 ( "_scc_", ITscc ) -- ToDo: remove
283 isSpecial :: Token -> Bool
284 -- If we see M.x, where x is a keyword, but
285 -- is special, we treat is as just plain M.x,
287 isSpecial ITas = True
288 isSpecial IThiding = True
289 isSpecial ITqualified = True
290 isSpecial ITforall = True
291 isSpecial ITexport = True
292 isSpecial ITlabel = True
293 isSpecial ITdynamic = True
294 isSpecial ITunsafe = True
295 isSpecial ITwith = True
296 isSpecial ITccallconv = True
297 isSpecial ITstdcallconv = True
300 -- IMPORTANT: Keep this in synch with ParseIface.y's var_fs production! (SUP)
301 ghcExtensionKeywordsFM = listToUFM $
302 map (\ (x,y) -> (_PK_ x,y))
303 [ ( "forall", ITforall ),
304 ( "foreign", ITforeign ),
305 ( "export", ITexport ),
306 ( "label", ITlabel ),
307 ( "dynamic", ITdynamic ),
308 ( "unsafe", ITunsafe ),
310 ( "stdcall", ITstdcallconv),
311 ( "ccall", ITccallconv),
312 ( "dotnet", ITdotnet),
313 ("_ccall_", ITccall (False, False, PlayRisky)),
314 ("_ccall_GC_", ITccall (False, False, PlaySafe)),
315 ("_casm_", ITccall (False, True, PlayRisky)),
316 ("_casm_GC_", ITccall (False, True, PlaySafe)),
318 -- interface keywords
319 ("__interface", ITinterface),
320 ("__export", IT__export),
321 ("__depends", ITdepends),
322 ("__forall", IT__forall),
323 ("__letrec", ITletrec),
324 ("__coerce", ITcoerce),
325 ("__inline_me", ITinlineMe),
326 ("__inline_call", ITinlineCall),
327 ("__depends", ITdepends),
328 ("__DEFAULT", ITdefaultbranch),
330 ("__integer", ITinteger_lit),
331 ("__float", ITfloat_lit),
332 ("__int64", ITint64_lit),
333 ("__word", ITword_lit),
334 ("__word64", ITword64_lit),
335 ("__rational", ITrational_lit),
336 ("__addr", ITaddr_lit),
337 ("__label", ITlabel_lit),
338 ("__litlit", ITlit_lit),
339 ("__string", ITstring_lit),
342 ("__fuall", ITfuall),
344 ("__P", ITspecialise),
347 ("__D", ITdeprecated),
350 ("__ccall", ITccall (False, False, PlayRisky)),
351 ("__ccall_GC", ITccall (False, False, PlaySafe)),
352 ("__dyn_ccall", ITccall (True, False, PlayRisky)),
353 ("__dyn_ccall_GC", ITccall (True, False, PlaySafe)),
354 ("__casm", ITccall (False, True, PlayRisky)),
355 ("__dyn_casm", ITccall (True, True, PlayRisky)),
356 ("__casm_GC", ITccall (False, True, PlaySafe)),
357 ("__dyn_casm_GC", ITccall (True, True, PlaySafe)),
363 haskellKeySymsFM = listToUFM $
364 map (\ (x,y) -> (_PK_ x,y))
377 ,(".", ITdot) -- sadly, for 'forall a . t'
381 -----------------------------------------------------------------------------
386 - (glaexts) lexing an interface file or -fglasgow-exts
387 - (bol) pointer to beginning of line (for column calculations)
388 - (buf) pointer to beginning of token
389 - (buf) pointer to current char
390 - (atbol) flag indicating whether we're at the beginning of a line
393 lexer :: (Token -> P a) -> P a
394 lexer cont buf s@(PState{
396 glasgow_exts = glaexts,
402 -- first, start a new lexeme and lose all the whitespace
404 tab line bol atbol (stepOverLexeme buf)
406 line = srcLocLine loc
408 tab y bol atbol buf = --trace ("tab: " ++ show (I# y) ++ " : " ++ show (currentChar buf)) $
409 case currentChar# buf of
412 if bufferExhausted (stepOn buf)
413 then cont ITeof buf s'
414 else trace "lexer: misplaced NUL?" $
415 tab y bol atbol (stepOn buf)
417 '\n'# -> let buf' = stepOn buf
418 in tab (y +# 1#) (currentIndex# buf') 1# buf'
420 -- find comments. This got harder in Haskell 98.
421 '-'# -> let trundle n =
422 let next = lookAhead# buf n in
423 if next `eqChar#` '-'# then trundle (n +# 1#)
424 else if is_symbol next || n <# 2#
427 (stepOnUntilChar# (stepOnBy# buf n) '\n'#)
430 -- comments and pragmas. We deal with LINE pragmas here,
431 -- and throw out any unrecognised pragmas as comments. Any
432 -- pragmas we know about are dealt with later (after any layout
433 -- processing if necessary).
434 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
435 if lookAhead# buf 2# `eqChar#` '#'# then
436 if lookAhead# buf 3# `eqChar#` '#'# then is_a_token else
437 case expandWhile# is_space (setCurrentPos# buf 3#) of { buf1->
438 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2->
439 let lexeme = mkFastString -- ToDo: too slow
440 (map toUpper (lexemeToString buf2)) in
441 case lookupUFM pragmaKeywordsFM lexeme of
442 -- ignore RULES pragmas when -fglasgow-exts is off
443 Just ITrules_prag | not (flag glaexts) ->
444 skip_to_end (stepOnBy# buf 2#) s'
446 line_prag skip_to_end buf2 s'
447 Just other -> is_a_token
448 Nothing -> skip_to_end (stepOnBy# buf 2#) s'
451 else skip_to_end (stepOnBy# buf 2#) s'
453 skip_to_end = skipNestedComment (lexer cont)
455 -- special GHC extension: we grok cpp-style #line pragmas
456 '#'# | lexemeIndex buf ==# bol -> -- the '#' must be in column 0
457 case expandWhile# is_space (stepOn buf) of { buf1 ->
458 if is_digit (currentChar# buf1)
459 then line_prag next_line buf1 s'
463 next_line buf = lexer cont (stepOnUntilChar# buf '\n'#)
465 -- tabs have been expanded beforehand
466 c | is_space c -> tab y bol atbol (stepOn buf)
467 | otherwise -> is_a_token
469 where s' = s{loc = replaceSrcLine loc y,
473 is_a_token | atbol /=# 0# = lexBOL cont buf s'
474 | otherwise = lexToken cont glaexts buf s'
476 -- {-# LINE .. #-} pragmas. yeuch.
477 line_prag cont buf s@PState{loc=loc} =
478 case expandWhile# is_space buf of { buf1 ->
479 case scanNumLit 0 (stepOverLexeme buf1) of { (line,buf2) ->
480 -- subtract one: the line number refers to the *following* line.
481 let real_line = line - 1 in
482 case fromInteger real_line of { i@(I# l) ->
483 -- ToDo, if no filename then we skip the newline.... d'oh
484 case expandWhile# is_space buf2 of { buf3 ->
485 case currentChar# buf3 of
487 case untilEndOfString# (stepOn (stepOverLexeme buf3)) of { buf4 ->
489 file = lexemeToFastString buf4
490 new_buf = stepOn (stepOverLexeme buf4)
492 if nullFastString file
493 then cont new_buf s{loc = replaceSrcLine loc l}
494 else cont new_buf s{loc = mkSrcLoc file i}
496 _other -> cont (stepOverLexeme buf3) s{loc = replaceSrcLine loc l}
499 skipNestedComment :: P a -> P a
500 skipNestedComment cont buf state = skipNestedComment' (loc state) cont buf state
502 skipNestedComment' :: SrcLoc -> P a -> P a
503 skipNestedComment' orig_loc cont buf = loop buf
506 case currentChar# buf of
507 '-'# | lookAhead# buf 1# `eqChar#` '}'# -> cont (stepOnBy# buf 2#)
509 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
511 (skipNestedComment' orig_loc cont)
514 '\n'# -> \ s@PState{loc=loc} ->
515 let buf' = stepOn buf in
516 loop buf' s{loc = incSrcLine loc,
517 bol = currentIndex# buf',
520 -- pass the original SrcLoc to lexError so that the error is
521 -- reported at the line it was originally on, not the line at
522 -- the end of the file.
523 '\NUL'# | bufferExhausted (stepOn buf) ->
524 \s -> lexError "unterminated `{-'" buf s{loc=orig_loc} -- -}
526 _ -> loop (stepOn buf)
528 -- When we are lexing the first token of a line, check whether we need to
529 -- insert virtual semicolons or close braces due to layout.
531 lexBOL :: (Token -> P a) -> P a
532 lexBOL cont buf s@(PState{
534 glasgow_exts = glaexts,
539 if need_close_curly then
540 --trace ("col = " ++ show (I# col) ++ ", layout: inserting '}'") $
541 cont ITvccurly buf s{atbol = 1#, context = tail ctx}
542 else if need_semi_colon then
543 --trace ("col = " ++ show (I# col) ++ ", layout: inserting ';'") $
544 cont ITsemi buf s{atbol = 0#}
546 lexToken cont glaexts buf s{atbol = 0#}
548 col = currentIndex# buf -# bol
561 Layout n -> col ==# n
564 lexToken :: (Token -> P a) -> Int# -> P a
565 lexToken cont glaexts buf =
566 -- trace "lexToken" $
567 case currentChar# buf of
569 -- special symbols ----------------------------------------------------
570 '('# | flag glaexts && lookAhead# buf 1# `eqChar#` '#'#
571 -> cont IToubxparen (setCurrentPos# buf 2#)
573 -> cont IToparen (incLexeme buf)
575 ')'# -> cont ITcparen (incLexeme buf)
576 '['# -> cont ITobrack (incLexeme buf)
577 ']'# -> cont ITcbrack (incLexeme buf)
578 ','# -> cont ITcomma (incLexeme buf)
579 ';'# -> cont ITsemi (incLexeme buf)
580 '}'# -> \ s@PState{context = ctx} ->
582 (_:ctx') -> cont ITccurly (incLexeme buf) s{context=ctx'}
583 _ -> lexError "too many '}'s" buf s
584 '|'# -> case lookAhead# buf 1# of
585 '}'# | flag glaexts -> cont ITccurlybar
586 (setCurrentPos# buf 2#)
587 _ -> lex_sym cont (incLexeme buf)
590 '#'# -> case lookAhead# buf 1# of
591 ')'# | flag glaexts -> cont ITcubxparen (setCurrentPos# buf 2#)
592 '-'# -> case lookAhead# buf 2# of
593 '}'# -> cont ITclose_prag (setCurrentPos# buf 3#)
594 _ -> lex_sym cont (incLexeme buf)
595 _ -> lex_sym cont (incLexeme buf)
597 '`'# | flag glaexts && lookAhead# buf 1# `eqChar#` '`'#
598 -> lex_cstring cont (setCurrentPos# buf 2#)
600 -> cont ITbackquote (incLexeme buf)
602 '{'# -> -- look for "{-##" special iface pragma
603 case lookAhead# buf 1# of
605 -> cont ITocurlybar (setCurrentPos# buf 2#)
606 '-'# -> case lookAhead# buf 2# of
607 '#'# -> case lookAhead# buf 3# of
611 (\ cont lexeme buf' -> cont (ITpragma lexeme) buf')
613 (stepOnBy# (stepOverLexeme buf) 4#)
614 _ -> lex_prag cont (setCurrentPos# buf 3#)
615 _ -> cont ITocurly (incLexeme buf)
616 _ -> (layoutOff `thenP_` cont ITocurly) (incLexeme buf)
618 -- strings/characters -------------------------------------------------
619 '\"'#{-"-} -> lex_string cont glaexts [] (incLexeme buf)
620 '\''# -> lex_char (char_end cont) glaexts (incLexeme buf)
622 -- strictness and cpr pragmas and __scc treated specially.
623 '_'# | flag glaexts ->
624 case lookAhead# buf 1# of
625 '_'# -> case lookAhead# buf 2# of
627 lex_demand cont (stepOnUntil (not . isSpace)
628 (stepOnBy# buf 3#)) -- past __S
630 cont ITcprinfo (stepOnBy# buf 3#) -- past __M
633 case prefixMatch (stepOnBy# buf 3#) "cc" of
634 Just buf' -> lex_scc cont (stepOverLexeme buf')
635 Nothing -> lex_id cont glaexts buf
636 _ -> lex_id cont glaexts buf
637 _ -> lex_id cont glaexts buf
639 -- Hexadecimal and octal constants
640 '0'# | (ch `eqChar#` 'x'# || ch `eqChar#` 'X'#) && is_hexdigit ch2
641 -> readNum (after_lexnum cont glaexts) buf' is_hexdigit 16 hex
642 | (ch `eqChar#` 'o'# || ch `eqChar#` 'O'#) && is_octdigit ch2
643 -> readNum (after_lexnum cont glaexts) buf' is_octdigit 8 oct_or_dec
644 where ch = lookAhead# buf 1#
645 ch2 = lookAhead# buf 2#
646 buf' = setCurrentPos# buf 2#
649 if bufferExhausted (stepOn buf) then
652 trace "lexIface: misplaced NUL?" $
653 cont (ITunknown "\NUL") (stepOn buf)
655 '?'# | flag glaexts && is_lower (lookAhead# buf 1#) ->
656 lex_ip cont (incLexeme buf)
657 c | is_digit c -> lex_num cont glaexts 0 buf
658 | is_symbol c -> lex_sym cont buf
659 | is_upper c -> lex_con cont glaexts buf
660 | is_ident c -> lex_id cont glaexts buf
661 | otherwise -> lexError "illegal character" buf
663 -- Int# is unlifted, and therefore faster than Bool for flags.
669 -------------------------------------------------------------------------------
673 = case expandWhile# is_space buf of { buf1 ->
674 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2 ->
675 let lexeme = mkFastString (map toUpper (lexemeToString buf2)) in
676 case lookupUFM pragmaKeywordsFM lexeme of
677 Just kw -> cont kw (mergeLexemes buf buf2)
678 Nothing -> panic "lex_prag"
681 -------------------------------------------------------------------------------
684 lex_string cont glaexts s buf
685 = case currentChar# buf of
687 let buf' = incLexeme buf
688 s' = mkFastStringNarrow (map chr (reverse s))
689 in case currentChar# buf' of
690 '#'# | flag glaexts -> if all (<= 0xFF) s
691 then cont (ITprimstring s') (incLexeme buf')
692 else lexError "primitive string literal must contain only characters <= \'\\xFF\'" buf'
693 _ -> cont (ITstring s') buf'
695 -- ignore \& in a string, deal with string gaps
696 '\\'# | next_ch `eqChar#` '&'#
697 -> lex_string cont glaexts s buf'
699 -> lex_stringgap cont glaexts s (incLexeme buf)
701 where next_ch = lookAhead# buf 1#
702 buf' = setCurrentPos# buf 2#
704 _ -> lex_char (lex_next_string cont s) glaexts buf
706 lex_stringgap cont glaexts s buf
707 = let buf' = incLexeme buf in
708 case currentChar# buf of
709 '\n'# -> \st@PState{loc = loc} -> lex_stringgap cont glaexts s buf'
710 st{loc = incSrcLine loc}
711 '\\'# -> lex_string cont glaexts s buf'
712 c | is_space c -> lex_stringgap cont glaexts s buf'
713 other -> charError buf'
715 lex_next_string cont s glaexts c buf = lex_string cont glaexts (c:s) buf
717 lex_char :: (Int# -> Int -> P a) -> Int# -> P a
718 lex_char cont glaexts buf
719 = case currentChar# buf of
720 '\\'# -> lex_escape (cont glaexts) (incLexeme buf)
721 c | is_any c -> cont glaexts (I# (ord# c)) (incLexeme buf)
722 other -> charError buf
724 char_end cont glaexts c buf
725 = case currentChar# buf of
726 '\''# -> let buf' = incLexeme buf in
727 case currentChar# buf' of
729 -> cont (ITprimchar c) (incLexeme buf')
730 _ -> cont (ITchar c) buf'
734 = let buf' = incLexeme buf in
735 case currentChar# buf of
736 'a'# -> cont (ord '\a') buf'
737 'b'# -> cont (ord '\b') buf'
738 'f'# -> cont (ord '\f') buf'
739 'n'# -> cont (ord '\n') buf'
740 'r'# -> cont (ord '\r') buf'
741 't'# -> cont (ord '\t') buf'
742 'v'# -> cont (ord '\v') buf'
743 '\\'# -> cont (ord '\\') buf'
744 '"'# -> cont (ord '\"') buf'
745 '\''# -> cont (ord '\'') buf'
746 '^'# -> let c = currentChar# buf' in
747 if c `geChar#` '@'# && c `leChar#` '_'#
748 then cont (I# (ord# c -# ord# '@'#)) (incLexeme buf')
751 'x'# -> readNum (after_charnum cont) buf' is_hexdigit 16 hex
752 'o'# -> readNum (after_charnum cont) buf' is_octdigit 8 oct_or_dec
754 -> readNum (after_charnum cont) buf is_digit 10 oct_or_dec
756 _ -> case [ (c,buf2) | (p,c) <- silly_escape_chars,
757 Just buf2 <- [prefixMatch buf p] ] of
758 (c,buf2):_ -> cont (ord c) buf2
761 after_charnum cont i buf
762 = if i >= 0 && i <= 0x10FFFF
763 then cont (fromInteger i) buf
766 readNum cont buf is_digit base conv = read buf 0
768 = case currentChar# buf of { c ->
770 then read (incLexeme buf) (i*base + (toInteger (I# (conv c))))
776 || (c `geChar#` 'a'# && c `leChar#` 'f'#)
777 || (c `geChar#` 'A'# && c `leChar#` 'F'#)
779 hex c | is_digit c = ord# c -# ord# '0'#
780 | otherwise = ord# (to_lower c) -# ord# 'a'# +# 10#
781 oct_or_dec c = ord# c -# ord# '0'#
783 is_octdigit c = c `geChar#` '0'# && c `leChar#` '7'#
786 | c `geChar#` 'A'# && c `leChar#` 'Z'#
787 = chr# (ord# c -# (ord# 'A'# -# ord# 'a'#))
790 charError buf = lexError "error in character literal" buf
792 silly_escape_chars = [
829 -------------------------------------------------------------------------------
831 lex_demand cont buf =
832 case read_em [] buf of { (ls,buf') ->
833 case currentChar# buf' of
834 'b'# -> cont (ITstrict (StrictSig (mkTopDmdType ls BotRes))) (incLexeme buf')
835 'm'# -> cont (ITstrict (StrictSig (mkTopDmdType ls RetCPR))) (incLexeme buf')
836 _ -> cont (ITstrict (StrictSig (mkTopDmdType ls TopRes))) buf'
840 case currentChar# buf of
841 'T'# -> read_em (Top : acc) (stepOn buf)
842 'L'# -> read_em (lazyDmd : acc) (stepOn buf)
843 'A'# -> read_em (Abs : acc) (stepOn buf)
844 'V'# -> read_em (evalDmd : acc) (stepOn buf) -- Temporary, until
845 -- we've recompiled prelude etc
846 'C'# -> do_unary Call acc (stepOnBy# buf 2#) -- Skip 'C('
848 'U'# -> do_seq1 Eval acc (stepOnBy# buf 1#)
849 'D'# -> do_seq1 Defer acc (stepOnBy# buf 1#)
850 'S'# -> do_seq1 (Box . Eval) acc (stepOnBy# buf 1#)
852 _ -> (reverse acc, buf)
855 = case currentChar# buf of
856 '('# -> do_seq2 fn acc (stepOnBy# buf 1#)
857 _ -> read_em (fn (Poly Abs) : acc) buf
860 = case read_em [] buf of { (dmds, buf) ->
861 case currentChar# buf of
862 ')'# -> read_em (fn (Prod dmds) : acc)
864 '*'# -> ASSERT( length dmds == 1 )
865 read_em (fn (Poly (head dmds)) : acc)
866 (stepOnBy# buf 2#) -- Skip '*)'
870 = case read_em [] buf of
871 ([dmd], rest) -> read_em (fn dmd : acc) (stepOn rest) -- Skip ')'
875 case currentChar# buf of
876 'C'# -> cont ITsccAllCafs (incLexeme buf)
877 other -> cont ITscc buf
879 -----------------------------------------------------------------------------
882 lex_num :: (Token -> P a) -> Int# -> Integer -> P a
883 lex_num cont glaexts acc buf =
884 case scanNumLit acc buf of
886 case currentChar# buf' of
887 '.'# | is_digit (lookAhead# buf' 1#) ->
888 -- this case is not optimised at all, as the
889 -- presence of floating point numbers in interface
890 -- files is not that common. (ToDo)
891 case expandWhile# is_digit (incLexeme buf') of
892 buf2 -> -- points to first non digit char
894 let l = case currentChar# buf2 of
900 = let buf3 = incLexeme buf2 in
901 case currentChar# buf3 of
902 '-'# -> expandWhile# is_digit (incLexeme buf3)
903 '+'# -> expandWhile# is_digit (incLexeme buf3)
904 x | is_digit x -> expandWhile# is_digit buf3
907 v = readRational__ (lexemeToString l)
909 in case currentChar# l of -- glasgow exts only
910 '#'# | flag glaexts -> let l' = incLexeme l in
911 case currentChar# l' of
912 '#'# -> cont (ITprimdouble v) (incLexeme l')
913 _ -> cont (ITprimfloat v) l'
914 _ -> cont (ITrational v) l
916 _ -> after_lexnum cont glaexts acc' buf'
918 after_lexnum cont glaexts i buf
919 = case currentChar# buf of
920 '#'# | flag glaexts -> cont (ITprimint i) (incLexeme buf)
921 _ -> cont (ITinteger i) buf
923 -----------------------------------------------------------------------------
924 -- C "literal literal"s (i.e. things like ``NULL'', ``stdout'' etc.)
926 -- we lexemeToFastString on the bit between the ``''s, but include the
927 -- quotes in the full lexeme.
929 lex_cstring cont buf =
930 case expandUntilMatch (stepOverLexeme buf) "\'\'" of
931 Just buf' -> cont (ITlitlit (lexemeToFastString
932 (setCurrentPos# buf' (negateInt# 2#))))
933 (mergeLexemes buf buf')
934 Nothing -> lexError "unterminated ``" buf
936 -----------------------------------------------------------------------------
937 -- identifiers, symbols etc.
940 case expandWhile# is_ident buf of
941 buf' -> cont (ITipvarid lexeme) buf'
942 where lexeme = lexemeToFastString buf'
944 lex_id cont glaexts buf =
945 let buf1 = expandWhile# is_ident buf in
948 case (if flag glaexts
949 then expandWhile# (eqChar# '#'#) buf1 -- slurp trailing hashes
950 else buf1) of { buf' ->
952 let lexeme = lexemeToFastString buf' in
954 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
955 Just kwd_token -> --trace ("hkeywd: "++_UNPK_(lexeme)) $
959 let var_token = cont (ITvarid lexeme) buf' in
961 if not (flag glaexts)
965 case lookupUFM ghcExtensionKeywordsFM lexeme of {
966 Just kwd_token -> cont kwd_token buf';
973 case expandWhile# is_symbol buf of
974 buf' -> case lookupUFM haskellKeySymsFM lexeme of {
975 Just kwd_token -> --trace ("keysym: "++unpackFS lexeme) $
976 cont kwd_token buf' ;
977 Nothing -> --trace ("sym: "++unpackFS lexeme) $
978 cont (mk_var_token lexeme) buf'
980 where lexeme = lexemeToFastString buf'
983 -- lex_con recursively collects components of a qualified identifer.
984 -- The argument buf is the StringBuffer representing the lexeme
985 -- identified so far, where the next character is upper-case.
987 lex_con cont glaexts buf =
988 -- trace ("con: "{-++unpackFS lexeme-}) $
989 let empty_buf = stepOverLexeme buf in
990 case expandWhile# is_ident empty_buf of { buf1 ->
991 case slurp_trailing_hashes buf1 glaexts of { con_buf ->
993 let all_buf = mergeLexemes buf con_buf
995 con_lexeme = lexemeToFastString con_buf
996 mod_lexeme = lexemeToFastString (decLexeme buf)
997 all_lexeme = lexemeToFastString all_buf
1000 | emptyLexeme buf = cont (ITconid con_lexeme) all_buf
1001 | otherwise = cont (ITqconid (mod_lexeme,con_lexeme)) all_buf
1004 case currentChar# all_buf of
1005 '.'# -> maybe_qualified cont glaexts all_lexeme
1006 (incLexeme all_buf) just_a_conid
1011 maybe_qualified cont glaexts mod buf just_a_conid =
1012 -- trace ("qid: "{-++unpackFS lexeme-}) $
1013 case currentChar# buf of
1014 '['# -> -- Special case for []
1015 case lookAhead# buf 1# of
1016 ']'# -> cont (ITqconid (mod,SLIT("[]"))) (setCurrentPos# buf 2#)
1019 '('# -> -- Special case for (,,,)
1020 -- This *is* necessary to deal with e.g. "instance C PrelBase.(,,)"
1021 case lookAhead# buf 1# of
1022 '#'# | flag glaexts -> case lookAhead# buf 2# of
1023 ','# -> lex_ubx_tuple cont mod (setCurrentPos# buf 3#)
1026 ')'# -> cont (ITqconid (mod,SLIT("()"))) (setCurrentPos# buf 2#)
1027 ','# -> lex_tuple cont mod (setCurrentPos# buf 2#) just_a_conid
1030 '-'# -> case lookAhead# buf 1# of
1031 '>'# -> cont (ITqconid (mod,SLIT("(->)"))) (setCurrentPos# buf 2#)
1032 _ -> lex_id3 cont glaexts mod buf just_a_conid
1034 _ -> lex_id3 cont glaexts mod buf just_a_conid
1037 lex_id3 cont glaexts mod buf just_a_conid
1038 | is_upper (currentChar# buf) =
1039 lex_con cont glaexts buf
1041 | is_symbol (currentChar# buf) =
1043 start_new_lexeme = stepOverLexeme buf
1045 -- trace ("lex_id31 "{-++unpackFS lexeme-}) $
1046 case expandWhile# is_symbol start_new_lexeme of { buf' ->
1048 lexeme = lexemeToFastString buf'
1049 -- real lexeme is M.<sym>
1050 new_buf = mergeLexemes buf buf'
1052 cont (mk_qvar_token mod lexeme) new_buf
1053 -- wrong, but arguably morally right: M... is now a qvarsym
1058 start_new_lexeme = stepOverLexeme buf
1060 -- trace ("lex_id32 "{-++unpackFS lexeme-}) $
1061 case expandWhile# is_ident start_new_lexeme of { buf1 ->
1066 case slurp_trailing_hashes buf1 glaexts of { buf' ->
1069 lexeme = lexemeToFastString buf'
1070 new_buf = mergeLexemes buf buf'
1071 is_a_qvarid = cont (mk_qvar_token mod lexeme) new_buf
1073 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
1074 Nothing -> is_a_qvarid ;
1076 Just kwd_token | isSpecial kwd_token -- special ids (as, qualified, hiding) shouldn't be
1077 -> is_a_qvarid -- recognised as keywords here.
1079 -> just_a_conid -- avoid M.where etc.
1082 slurp_trailing_hashes buf glaexts
1083 | flag glaexts = expandWhile# (`eqChar#` '#'#) buf
1088 | is_upper f = ITconid pk_str
1089 | is_ident f = ITvarid pk_str
1090 | f `eqChar#` ':'# = ITconsym pk_str
1091 | otherwise = ITvarsym pk_str
1093 (C# f) = _HEAD_ pk_str
1094 -- tl = _TAIL_ pk_str
1096 mk_qvar_token m token =
1097 -- trace ("mk_qvar ") $
1098 case mk_var_token token of
1099 ITconid n -> ITqconid (m,n)
1100 ITvarid n -> ITqvarid (m,n)
1101 ITconsym n -> ITqconsym (m,n)
1102 ITvarsym n -> ITqvarsym (m,n)
1103 _ -> ITunknown (show token)
1106 ----------------------------------------------------------------------------
1107 Horrible stuff for dealing with M.(,,,)
1110 lex_tuple cont mod buf back_off =
1114 case currentChar# buf of
1115 ','# -> go (n+1) (stepOn buf)
1116 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Boxed n))) (stepOn buf)
1119 lex_ubx_tuple cont mod buf back_off =
1123 case currentChar# buf of
1124 ','# -> go (n+1) (stepOn buf)
1125 '#'# -> case lookAhead# buf 1# of
1126 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Unboxed n)))
1132 -----------------------------------------------------------------------------
1133 'lexPragma' rips along really fast, looking for a '##-}',
1134 indicating the end of the pragma we're skipping
1137 lexPragma cont contf inStr buf =
1138 case currentChar# buf of
1139 '#'# | inStr ==# 0# ->
1140 case lookAhead# buf 1# of { '#'# ->
1141 case lookAhead# buf 2# of { '-'# ->
1142 case lookAhead# buf 3# of { '}'# ->
1143 contf cont (lexemeToBuffer buf)
1144 (stepOverLexeme (setCurrentPos# buf 4#));
1145 _ -> lexPragma cont contf inStr (incLexeme buf) };
1146 _ -> lexPragma cont contf inStr (incLexeme buf) };
1147 _ -> lexPragma cont contf inStr (incLexeme buf) }
1151 odd_slashes buf flg i# =
1152 case lookAhead# buf i# of
1153 '\\'# -> odd_slashes buf (not flg) (i# -# 1#)
1156 not_inStr = if inStr ==# 0# then 1# else 0#
1158 case lookAhead# buf (negateInt# 1#) of --backwards, actually
1159 '\\'# -> -- escaping something..
1160 if odd_slashes buf True (negateInt# 2#)
1161 then -- odd number of slashes, " is escaped.
1162 lexPragma cont contf inStr (incLexeme buf)
1163 else -- even number of slashes, \ is escaped.
1164 lexPragma cont contf not_inStr (incLexeme buf)
1165 _ -> lexPragma cont contf not_inStr (incLexeme buf)
1167 '\''# | inStr ==# 0# ->
1168 case lookAhead# buf 1# of { '"'# ->
1169 case lookAhead# buf 2# of { '\''# ->
1170 lexPragma cont contf inStr (setCurrentPos# buf 3#);
1171 _ -> lexPragma cont contf inStr (incLexeme buf) };
1172 _ -> lexPragma cont contf inStr (incLexeme buf) }
1174 -- a sign that the input is ill-formed, since pragmas are
1175 -- assumed to always be properly closed (in .hi files).
1176 '\NUL'# -> trace "lexPragma: unexpected end-of-file" $
1177 cont (ITunknown "\NUL") buf
1179 _ -> lexPragma cont contf inStr (incLexeme buf)
1183 -----------------------------------------------------------------------------
1194 data PState = PState {
1196 glasgow_exts :: Int#,
1199 context :: [LayoutContext]
1202 type P a = StringBuffer -- Input string
1207 returnP a buf s = POk s a
1209 thenP :: P a -> (a -> P b) -> P b
1210 m `thenP` k = \ buf s ->
1212 POk s1 a -> k a buf s1
1213 PFailed err -> PFailed err
1215 thenP_ :: P a -> P b -> P b
1216 m `thenP_` k = m `thenP` \_ -> k
1218 mapP :: (a -> P b) -> [a] -> P [b]
1219 mapP f [] = returnP []
1222 mapP f as `thenP` \bs ->
1225 failP :: String -> P a
1226 failP msg buf s = PFailed (text msg)
1228 failMsgP :: Message -> P a
1229 failMsgP msg buf s = PFailed msg
1231 lexError :: String -> P a
1232 lexError str buf s@PState{ loc = loc }
1233 = failMsgP (hcat [ppr loc, text ": ", text str]) buf s
1235 getSrcLocP :: P SrcLoc
1236 getSrcLocP buf s@(PState{ loc = loc }) = POk s loc
1238 -- use a temporary SrcLoc for the duration of the argument
1239 setSrcLocP :: SrcLoc -> P a -> P a
1240 setSrcLocP new_loc p buf s =
1241 case p buf s{ loc=new_loc } of
1243 PFailed e -> PFailed e
1245 getSrcFile :: P FAST_STRING
1246 getSrcFile buf s@(PState{ loc = loc }) = POk s (srcLocFile loc)
1248 pushContext :: LayoutContext -> P ()
1249 pushContext ctxt buf s@(PState{ context = ctx }) = POk s{context = ctxt:ctx} ()
1253 This special case in layoutOn is to handle layout contexts with are
1254 indented the same or less than the current context. This is illegal
1255 according to the Haskell spec, so we have to arrange to close the
1256 current context. eg.
1261 after the first 'where', the sequence of events is:
1263 - layout system inserts a ';' (column 0)
1264 - parser begins a new context at column 0
1265 - parser shifts ';' (legal empty declaration)
1266 - parser sees 'class': parse error (we're still in the inner context)
1268 trouble is, by the time we know we need a new context, the lexer has
1269 already generated the ';'. Hacky solution is as follows: since we
1270 know the column of the next token (it's the column number of the new
1271 context), we set the ACTUAL column number of the new context to this
1272 numer plus one. Hence the next time the lexer is called, a '}' will
1273 be generated to close the new context straight away. Furthermore, we
1274 have to set the atbol flag so that the ';' that the parser shifted as
1275 part of the new context is re-generated.
1277 when the new context is *less* indented than the current one:
1279 f = f where g = g where
1282 - current context: column 12.
1283 - on seeing 'h' (column 0), the layout system inserts '}'
1284 - parser starts a new context, column 0
1285 - parser sees '}', uses it to close new context
1286 - we still need to insert another '}' followed by a ';',
1287 hence the atbol trick.
1289 There's also a special hack in here to deal with
1296 i.e. the inner context is at the same indentation level as the outer
1297 context. This is strictly illegal according to Haskell 98, but
1298 there's a lot of existing code using this style and it doesn't make
1299 any sense to disallow it, since empty 'do' lists don't make sense.
1302 layoutOn :: Bool -> P ()
1303 layoutOn strict buf s@(PState{ bol = bol, context = ctx }) =
1304 let offset = lexemeIndex buf -# bol in
1307 | if strict then prev_off >=# offset else prev_off ># offset ->
1308 --trace ("layout on, column: " ++ show (I# offset)) $
1309 POk s{ context = Layout (offset +# 1#) : ctx, atbol = 1# } ()
1311 --trace ("layout on, column: " ++ show (I# offset)) $
1312 POk s{ context = Layout offset : ctx } ()
1315 layoutOff buf s@(PState{ context = ctx }) =
1316 POk s{ context = NoLayout:ctx } ()
1319 popContext = \ buf s@(PState{ context = ctx, loc = loc }) ->
1321 (_:tl) -> POk s{ context = tl } ()
1322 [] -> PFailed (srcParseErr buf loc)
1325 Note that if the name of the file we're processing ends
1326 with `hi-boot', we accept it on faith as having the right
1327 version. This is done so that .hi-boot files that comes
1328 with hsc don't have to be updated before every release,
1329 *and* it allows us to share .hi-boot files with versions
1330 of hsc that don't have .hi version checking (e.g., ghc-2.10's)
1332 If the version number is 0, the checking is also turned off.
1333 (needed to deal with GHC.hi only!)
1335 Once we can assume we're compiling with a version of ghc that
1336 supports interface file checking, we can drop the special
1339 checkVersion :: Maybe Integer -> P ()
1340 checkVersion mb@(Just v) buf s@(PState{loc = loc})
1341 | (v==0) || (v == fromInt opt_HiVersion) || opt_NoHiCheck = POk s ()
1342 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1343 checkVersion mb@Nothing buf s@(PState{loc = loc})
1344 | "hi-boot" `isSuffixOf` (_UNPK_ (srcLocFile loc)) = POk s ()
1345 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1347 -----------------------------------------------------------------
1349 ifaceParseErr :: StringBuffer -> SrcLoc -> Message
1351 = hsep [ppr l, ptext SLIT("Interface file parse error; on input `"),
1352 text (lexemeToString s), char '\'']
1354 ifaceVersionErr hi_vers l toks
1355 = hsep [ppr l, ptext SLIT("Interface file version error;"),
1356 ptext SLIT("Expected"), int opt_HiVersion,
1357 ptext SLIT("found "), pp_version]
1361 Nothing -> ptext SLIT("pre ghc-3.02 version")
1362 Just v -> ptext SLIT("version") <+> integer v
1364 -----------------------------------------------------------------------------
1366 srcParseErr :: StringBuffer -> SrcLoc -> Message
1370 then ptext SLIT(": parse error (possibly incorrect indentation)")
1371 else hcat [ptext SLIT(": parse error on input "),
1372 char '`', text token, char '\'']
1375 token = lexemeToString s