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(..),
26 checkVersion, ExtFlags(..), mkPState,
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
58 import PrelBits ( Bits(..) ) -- non-std
61 %************************************************************************
63 \subsection{Data types}
65 %************************************************************************
67 The token data type, fairly un-interesting except from one
68 constructor, @ITidinfo@, which is used to lazily lex id info (arity,
69 strictness, unfolding etc).
71 The Idea/Observation here is that the renamer needs to scan through
72 all of an interface file before it can continue. But only a fraction
73 of the information contained in the file turns out to be useful, so
74 delaying as much as possible of the scanning and parsing of an
75 interface file Makes Sense (Heap profiles of the compiler
76 show a reduction in heap usage by at least a factor of two,
79 Hence, the interface file lexer spots when value declarations are
80 being scanned and return the @ITidinfo@ and @ITtype@ constructors
81 for the type and any other id info for that binding (unfolding, strictness
82 etc). These constructors are applied to the result of lexing these sub-chunks.
84 The lexing of the type and id info is all done lazily, of course, so
85 the scanning (and subsequent parsing) will be done *only* on the ids the
86 renamer finds out that it is interested in. The rest will just be junked.
87 Laziness, you know it makes sense :-)
91 = ITas -- Haskell keywords
115 | ITscc -- ToDo: remove (we use {-# SCC "..." #-} now)
117 | ITforall -- GHC extension keywords
129 | ITinterface -- interface keywords
137 | ITccall (Bool,Bool,Safety) -- (is_dyn, is_casm, may_gc)
164 | ITspecialise_prag -- Pragmas
174 | ITdotdot -- reserved symbols
189 | ITbiglam -- GHC-extension symbols
191 | ITocurly -- special symbols
193 | ITocurlybar -- {|, for type applications
194 | ITccurlybar -- |}, for type applications
197 | ITopabrack -- [:, for parallel arrays with -fparr
198 | ITcpabrack -- :], for parallel arrays with -fparr
209 | ITvarid FAST_STRING -- identifiers
210 | ITconid FAST_STRING
211 | ITvarsym FAST_STRING
212 | ITconsym FAST_STRING
213 | ITqvarid (FAST_STRING,FAST_STRING)
214 | ITqconid (FAST_STRING,FAST_STRING)
215 | ITqvarsym (FAST_STRING,FAST_STRING)
216 | ITqconsym (FAST_STRING,FAST_STRING)
218 | ITdupipvarid FAST_STRING -- GHC extension: implicit param: ?x
219 | ITsplitipvarid FAST_STRING -- GHC extension: implicit param: %x
221 | ITpragma StringBuffer
224 | ITstring FAST_STRING
226 | ITrational Rational
229 | ITprimstring FAST_STRING
231 | ITprimfloat Rational
232 | ITprimdouble Rational
233 | ITlitlit FAST_STRING
235 | ITunknown String -- Used when the lexer can't make sense of it
236 | ITeof -- end of file token
237 deriving Show -- debugging
240 -----------------------------------------------------------------------------
244 pragmaKeywordsFM = listToUFM $
245 map (\ (x,y) -> (_PK_ x,y))
246 [( "SPECIALISE", ITspecialise_prag ),
247 ( "SPECIALIZE", ITspecialise_prag ),
248 ( "SOURCE", ITsource_prag ),
249 ( "INLINE", ITinline_prag ),
250 ( "NOINLINE", ITnoinline_prag ),
251 ( "NOTINLINE", ITnoinline_prag ),
252 ( "LINE", ITline_prag ),
253 ( "RULES", ITrules_prag ),
254 ( "RULEZ", ITrules_prag ), -- american spelling :-)
255 ( "SCC", ITscc_prag ),
256 ( "DEPRECATED", ITdeprecated_prag )
259 haskellKeywordsFM = listToUFM $
260 map (\ (x,y) -> (_PK_ x,y))
261 [( "_", ITunderscore ),
264 ( "class", ITclass ),
266 ( "default", ITdefault ),
267 ( "deriving", ITderiving ),
270 ( "hiding", IThiding ),
272 ( "import", ITimport ),
274 ( "infix", ITinfix ),
275 ( "infixl", ITinfixl ),
276 ( "infixr", ITinfixr ),
277 ( "instance", ITinstance ),
279 ( "module", ITmodule ),
280 ( "newtype", ITnewtype ),
282 ( "qualified", ITqualified ),
285 ( "where", ITwhere ),
286 ( "_scc_", ITscc ) -- ToDo: remove
289 isSpecial :: Token -> Bool
290 -- If we see M.x, where x is a keyword, but
291 -- is special, we treat is as just plain M.x,
293 isSpecial ITas = True
294 isSpecial IThiding = True
295 isSpecial ITqualified = True
296 isSpecial ITforall = True
297 isSpecial ITexport = True
298 isSpecial ITlabel = True
299 isSpecial ITdynamic = True
300 isSpecial ITsafe = True
301 isSpecial ITunsafe = True
302 isSpecial ITwith = True
303 isSpecial ITccallconv = True
304 isSpecial ITstdcallconv = True
307 -- IMPORTANT: Keep this in synch with ParseIface.y's var_fs production! (SUP)
308 ghcExtensionKeywordsFM = listToUFM $
309 map (\ (x,y) -> (_PK_ x,y))
310 [ ( "forall", ITforall ),
311 ( "foreign", ITforeign ),
312 ( "export", ITexport ),
313 ( "label", ITlabel ),
314 ( "dynamic", ITdynamic ),
315 ( "safe", ITunsafe ),
316 ( "unsafe", ITunsafe ),
318 ( "stdcall", ITstdcallconv),
319 ( "ccall", ITccallconv),
320 ( "dotnet", ITdotnet),
321 ("_ccall_", ITccall (False, False, PlayRisky)),
322 ("_ccall_GC_", ITccall (False, False, PlaySafe)),
323 ("_casm_", ITccall (False, True, PlayRisky)),
324 ("_casm_GC_", ITccall (False, True, PlaySafe)),
326 -- interface keywords
327 ("__interface", ITinterface),
328 ("__export", IT__export),
329 ("__depends", ITdepends),
330 ("__forall", IT__forall),
331 ("__letrec", ITletrec),
332 ("__coerce", ITcoerce),
333 ("__inline_me", ITinlineMe),
334 ("__inline_call", ITinlineCall),
335 ("__depends", ITdepends),
336 ("__DEFAULT", ITdefaultbranch),
338 ("__integer", ITinteger_lit),
339 ("__float", ITfloat_lit),
340 ("__int64", ITint64_lit),
341 ("__word", ITword_lit),
342 ("__word64", ITword64_lit),
343 ("__rational", ITrational_lit),
344 ("__addr", ITaddr_lit),
345 ("__label", ITlabel_lit),
346 ("__litlit", ITlit_lit),
347 ("__string", ITstring_lit),
350 ("__fuall", ITfuall),
352 ("__P", ITspecialise),
355 ("__D", ITdeprecated),
358 ("__ccall", ITccall (False, False, PlayRisky)),
359 ("__ccall_GC", ITccall (False, False, PlaySafe)),
360 ("__dyn_ccall", ITccall (True, False, PlayRisky)),
361 ("__dyn_ccall_GC", ITccall (True, False, PlaySafe)),
362 ("__casm", ITccall (False, True, PlayRisky)),
363 ("__dyn_casm", ITccall (True, True, PlayRisky)),
364 ("__casm_GC", ITccall (False, True, PlaySafe)),
365 ("__dyn_casm_GC", ITccall (True, True, PlaySafe)),
371 haskellKeySymsFM = listToUFM $
372 map (\ (x,y) -> (_PK_ x,y))
386 ,(".", ITdot) -- sadly, for 'forall a . t'
390 -----------------------------------------------------------------------------
395 - (exts) lexing a source with extensions, eg, an interface file or
397 - (bol) pointer to beginning of line (for column calculations)
398 - (buf) pointer to beginning of token
399 - (buf) pointer to current char
400 - (atbol) flag indicating whether we're at the beginning of a line
403 lexer :: (Token -> P a) -> P a
404 lexer cont buf s@(PState{
412 -- first, start a new lexeme and lose all the whitespace
414 tab line bol atbol (stepOverLexeme buf)
416 line = srcLocLine loc
418 tab y bol atbol buf = --trace ("tab: " ++ show (I# y) ++ " : " ++ show (currentChar buf)) $
419 case currentChar# buf of
422 if bufferExhausted (stepOn buf)
423 then cont ITeof buf s'
424 else trace "lexer: misplaced NUL?" $
425 tab y bol atbol (stepOn buf)
427 '\n'# -> let buf' = stepOn buf
428 in tab (y +# 1#) (currentIndex# buf') 1# buf'
430 -- find comments. This got harder in Haskell 98.
431 '-'# -> let trundle n =
432 let next = lookAhead# buf n in
433 if next `eqChar#` '-'# then trundle (n +# 1#)
434 else if is_symbol next || n <# 2#
437 (stepOnUntilChar# (stepOnBy# buf n) '\n'#)
440 -- comments and pragmas. We deal with LINE pragmas here,
441 -- and throw out any unrecognised pragmas as comments. Any
442 -- pragmas we know about are dealt with later (after any layout
443 -- processing if necessary).
444 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
445 if lookAhead# buf 2# `eqChar#` '#'# then
446 if lookAhead# buf 3# `eqChar#` '#'# then is_a_token else
447 case expandWhile# is_space (setCurrentPos# buf 3#) of { buf1->
448 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2->
449 let lexeme = mkFastString -- ToDo: too slow
450 (map toUpper (lexemeToString buf2)) in
451 case lookupUFM pragmaKeywordsFM lexeme of
452 -- ignore RULES pragmas when -fglasgow-exts is off
453 Just ITrules_prag | not (glaExtsEnabled exts) ->
454 skip_to_end (stepOnBy# buf 2#) s'
456 line_prag skip_to_end buf2 s'
457 Just other -> is_a_token
458 Nothing -> skip_to_end (stepOnBy# buf 2#) s'
461 else skip_to_end (stepOnBy# buf 2#) s'
463 skip_to_end = skipNestedComment (lexer cont)
465 -- special GHC extension: we grok cpp-style #line pragmas
466 '#'# | lexemeIndex buf ==# bol -> -- the '#' must be in column 0
467 let buf1 | lookAhead# buf 1# `eqChar#` 'l'# &&
468 lookAhead# buf 2# `eqChar#` 'i'# &&
469 lookAhead# buf 3# `eqChar#` 'n'# &&
470 lookAhead# buf 4# `eqChar#` 'e'# = stepOnBy# buf 5#
471 | otherwise = stepOn buf
473 case expandWhile# is_space buf1 of { buf2 ->
474 if is_digit (currentChar# buf2)
475 then line_prag next_line buf2 s'
479 next_line buf = lexer cont (stepOnUntilChar# buf '\n'#)
481 -- tabs have been expanded beforehand
482 c | is_space c -> tab y bol atbol (stepOn buf)
483 | otherwise -> is_a_token
485 where s' = s{loc = replaceSrcLine loc y,
489 is_a_token | atbol /=# 0# = lexBOL cont buf s'
490 | otherwise = lexToken cont exts buf s'
492 -- {-# LINE .. #-} pragmas. yeuch.
493 line_prag cont buf s@PState{loc=loc} =
494 case expandWhile# is_space buf of { buf1 ->
495 case scanNumLit 0 (stepOverLexeme buf1) of { (line,buf2) ->
496 -- subtract one: the line number refers to the *following* line.
497 let real_line = line - 1 in
498 case fromInteger real_line of { i@(I# l) ->
499 -- ToDo, if no filename then we skip the newline.... d'oh
500 case expandWhile# is_space buf2 of { buf3 ->
501 case currentChar# buf3 of
503 case untilEndOfString# (stepOn (stepOverLexeme buf3)) of { buf4 ->
505 file = lexemeToFastString buf4
506 new_buf = stepOn (stepOverLexeme buf4)
508 if nullFastString file
509 then cont new_buf s{loc = replaceSrcLine loc l}
510 else cont new_buf s{loc = mkSrcLoc file i}
512 _other -> cont (stepOverLexeme buf3) s{loc = replaceSrcLine loc l}
515 skipNestedComment :: P a -> P a
516 skipNestedComment cont buf state = skipNestedComment' (loc state) cont buf state
518 skipNestedComment' :: SrcLoc -> P a -> P a
519 skipNestedComment' orig_loc cont buf = loop buf
522 case currentChar# buf of
523 '-'# | lookAhead# buf 1# `eqChar#` '}'# -> cont (stepOnBy# buf 2#)
525 '{'# | lookAhead# buf 1# `eqChar#` '-'# ->
527 (skipNestedComment' orig_loc cont)
530 '\n'# -> \ s@PState{loc=loc} ->
531 let buf' = stepOn buf in
532 loop buf' s{loc = incSrcLine loc,
533 bol = currentIndex# buf',
536 -- pass the original SrcLoc to lexError so that the error is
537 -- reported at the line it was originally on, not the line at
538 -- the end of the file.
539 '\NUL'# | bufferExhausted (stepOn buf) ->
540 \s -> lexError "unterminated `{-'" buf s{loc=orig_loc} -- -}
542 _ -> loop (stepOn buf)
544 -- When we are lexing the first token of a line, check whether we need to
545 -- insert virtual semicolons or close braces due to layout.
547 lexBOL :: (Token -> P a) -> P a
548 lexBOL cont buf s@(PState{
555 if need_close_curly then
556 --trace ("col = " ++ show (I# col) ++ ", layout: inserting '}'") $
557 cont ITvccurly buf s{atbol = 1#, context = tail ctx}
558 else if need_semi_colon then
559 --trace ("col = " ++ show (I# col) ++ ", layout: inserting ';'") $
560 cont ITsemi buf s{atbol = 0#}
562 lexToken cont exts buf s{atbol = 0#}
564 col = currentIndex# buf -# bol
577 Layout n -> col ==# n
580 lexToken :: (Token -> P a) -> Int# -> P a
581 lexToken cont exts buf =
582 -- trace "lexToken" $
583 case currentChar# buf of
585 -- special symbols ----------------------------------------------------
586 '('# | glaExtsEnabled exts && lookAhead# buf 1# `eqChar#` '#'#
587 -> cont IToubxparen (setCurrentPos# buf 2#)
589 -> cont IToparen (incLexeme buf)
591 ')'# -> cont ITcparen (incLexeme buf)
592 '['# | parrEnabled exts && lookAhead# buf 1# `eqChar#` ':'# ->
593 cont ITopabrack (setCurrentPos# buf 2#)
595 cont ITobrack (incLexeme buf)
596 ']'# -> cont ITcbrack (incLexeme buf)
597 ','# -> cont ITcomma (incLexeme buf)
598 ';'# -> cont ITsemi (incLexeme buf)
599 '}'# -> \ s@PState{context = ctx} ->
601 (_:ctx') -> cont ITccurly (incLexeme buf) s{context=ctx'}
602 _ -> lexError "too many '}'s" buf s
603 '|'# -> case lookAhead# buf 1# of
604 '}'# | glaExtsEnabled exts -> cont ITccurlybar
605 (setCurrentPos# buf 2#)
606 _ -> lex_sym cont (incLexeme buf)
607 ':'# -> case lookAhead# buf 1# of
608 ']'# | parrEnabled exts -> cont ITcpabrack
609 (setCurrentPos# buf 2#)
610 _ -> lex_sym cont (incLexeme buf)
613 '#'# -> case lookAhead# buf 1# of
614 ')'# | glaExtsEnabled exts
615 -> cont ITcubxparen (setCurrentPos# buf 2#)
616 '-'# -> case lookAhead# buf 2# of
617 '}'# -> cont ITclose_prag (setCurrentPos# buf 3#)
618 _ -> lex_sym cont (incLexeme buf)
619 _ -> lex_sym cont (incLexeme buf)
621 '`'# | glaExtsEnabled exts && lookAhead# buf 1# `eqChar#` '`'#
622 -> lex_cstring cont (setCurrentPos# buf 2#)
624 -> cont ITbackquote (incLexeme buf)
626 '{'# -> -- look for "{-##" special iface pragma -- for Emacs: -}
627 case lookAhead# buf 1# of
628 '|'# | glaExtsEnabled exts
629 -> cont ITocurlybar (setCurrentPos# buf 2#)
630 '-'# -> case lookAhead# buf 2# of
631 '#'# -> case lookAhead# buf 3# of
635 (\ cont lexeme buf' -> cont (ITpragma lexeme) buf')
637 (stepOnBy# (stepOverLexeme buf) 4#)
638 _ -> lex_prag cont (setCurrentPos# buf 3#)
639 _ -> cont ITocurly (incLexeme buf)
640 _ -> (layoutOff `thenP_` cont ITocurly) (incLexeme buf)
642 -- strings/characters -------------------------------------------------
643 '\"'#{-"-} -> lex_string cont exts [] (incLexeme buf)
644 '\''# -> lex_char (char_end cont) exts (incLexeme buf)
646 -- strictness and cpr pragmas and __scc treated specially.
647 '_'# | glaExtsEnabled exts ->
648 case lookAhead# buf 1# of
649 '_'# -> case lookAhead# buf 2# of
651 lex_demand cont (stepOnUntil (not . isSpace)
652 (stepOnBy# buf 3#)) -- past __S
654 cont ITcprinfo (stepOnBy# buf 3#) -- past __M
657 case prefixMatch (stepOnBy# buf 3#) "cc" of
658 Just buf' -> lex_scc cont (stepOverLexeme buf')
659 Nothing -> lex_id cont exts buf
660 _ -> lex_id cont exts buf
661 _ -> lex_id cont exts buf
663 -- Hexadecimal and octal constants
664 '0'# | (ch `eqChar#` 'x'# || ch `eqChar#` 'X'#) && is_hexdigit ch2
665 -> readNum (after_lexnum cont exts) buf' is_hexdigit 16 hex
666 | (ch `eqChar#` 'o'# || ch `eqChar#` 'O'#) && is_octdigit ch2
667 -> readNum (after_lexnum cont exts) buf' is_octdigit 8 oct_or_dec
668 where ch = lookAhead# buf 1#
669 ch2 = lookAhead# buf 2#
670 buf' = setCurrentPos# buf 2#
673 if bufferExhausted (stepOn buf) then
676 trace "lexIface: misplaced NUL?" $
677 cont (ITunknown "\NUL") (stepOn buf)
679 '?'# | glaExtsEnabled exts && is_lower (lookAhead# buf 1#) ->
680 lex_ip ITdupipvarid cont (incLexeme buf)
681 '%'# | glaExtsEnabled exts && is_lower (lookAhead# buf 1#) ->
682 lex_ip ITsplitipvarid cont (incLexeme buf)
683 c | is_digit c -> lex_num cont exts 0 buf
684 | is_symbol c -> lex_sym cont buf
685 | is_upper c -> lex_con cont exts buf
686 | is_ident c -> lex_id cont exts buf
687 | otherwise -> lexError "illegal character" buf
689 -- Int# is unlifted, and therefore faster than Bool for flags.
695 -------------------------------------------------------------------------------
699 = case expandWhile# is_space buf of { buf1 ->
700 case expandWhile# is_ident (stepOverLexeme buf1) of { buf2 ->
701 let lexeme = mkFastString (map toUpper (lexemeToString buf2)) in
702 case lookupUFM pragmaKeywordsFM lexeme of
703 Just kw -> cont kw (mergeLexemes buf buf2)
704 Nothing -> panic "lex_prag"
707 -------------------------------------------------------------------------------
710 lex_string cont exts s buf
711 = case currentChar# buf of
713 let buf' = incLexeme buf
714 s' = mkFastStringNarrow (map chr (reverse s))
715 in case currentChar# buf' of
716 '#'# | glaExtsEnabled exts -> if all (<= 0xFF) s
717 then cont (ITprimstring s') (incLexeme buf')
718 else lexError "primitive string literal must contain only characters <= \'\\xFF\'" buf'
719 _ -> cont (ITstring s') buf'
721 -- ignore \& in a string, deal with string gaps
722 '\\'# | next_ch `eqChar#` '&'#
723 -> lex_string cont exts s buf'
725 -> lex_stringgap cont exts s (incLexeme buf)
727 where next_ch = lookAhead# buf 1#
728 buf' = setCurrentPos# buf 2#
730 _ -> lex_char (lex_next_string cont s) exts buf
732 lex_stringgap cont exts s buf
733 = let buf' = incLexeme buf in
734 case currentChar# buf of
735 '\n'# -> \st@PState{loc = loc} -> lex_stringgap cont exts s buf'
736 st{loc = incSrcLine loc}
737 '\\'# -> lex_string cont exts s buf'
738 c | is_space c -> lex_stringgap cont exts s buf'
739 other -> charError buf'
741 lex_next_string cont s exts c buf = lex_string cont exts (c:s) buf
743 lex_char :: (Int# -> Int -> P a) -> Int# -> P a
744 lex_char cont exts buf
745 = case currentChar# buf of
746 '\\'# -> lex_escape (cont exts) (incLexeme buf)
747 c | is_any c -> cont exts (I# (ord# c)) (incLexeme buf)
748 other -> charError buf
750 char_end cont exts c buf
751 = case currentChar# buf of
752 '\''# -> let buf' = incLexeme buf in
753 case currentChar# buf' of
754 '#'# | glaExtsEnabled exts
755 -> cont (ITprimchar c) (incLexeme buf')
756 _ -> cont (ITchar c) buf'
760 = let buf' = incLexeme buf in
761 case currentChar# buf of
762 'a'# -> cont (ord '\a') buf'
763 'b'# -> cont (ord '\b') buf'
764 'f'# -> cont (ord '\f') buf'
765 'n'# -> cont (ord '\n') buf'
766 'r'# -> cont (ord '\r') buf'
767 't'# -> cont (ord '\t') buf'
768 'v'# -> cont (ord '\v') buf'
769 '\\'# -> cont (ord '\\') buf'
770 '"'# -> cont (ord '\"') buf'
771 '\''# -> cont (ord '\'') buf'
772 '^'# -> let c = currentChar# buf' in
773 if c `geChar#` '@'# && c `leChar#` '_'#
774 then cont (I# (ord# c -# ord# '@'#)) (incLexeme buf')
777 'x'# -> readNum (after_charnum cont) buf' is_hexdigit 16 hex
778 'o'# -> readNum (after_charnum cont) buf' is_octdigit 8 oct_or_dec
780 -> readNum (after_charnum cont) buf is_digit 10 oct_or_dec
782 _ -> case [ (c,buf2) | (p,c) <- silly_escape_chars,
783 Just buf2 <- [prefixMatch buf p] ] of
784 (c,buf2):_ -> cont (ord c) buf2
787 after_charnum cont i buf
788 = if i >= 0 && i <= 0x10FFFF
789 then cont (fromInteger i) buf
792 readNum cont buf is_digit base conv = read buf 0
794 = case currentChar# buf of { c ->
796 then read (incLexeme buf) (i*base + (toInteger (I# (conv c))))
802 || (c `geChar#` 'a'# && c `leChar#` 'f'#)
803 || (c `geChar#` 'A'# && c `leChar#` 'F'#)
805 hex c | is_digit c = ord# c -# ord# '0'#
806 | otherwise = ord# (to_lower c) -# ord# 'a'# +# 10#
807 oct_or_dec c = ord# c -# ord# '0'#
809 is_octdigit c = c `geChar#` '0'# && c `leChar#` '7'#
812 | c `geChar#` 'A'# && c `leChar#` 'Z'#
813 = chr# (ord# c -# (ord# 'A'# -# ord# 'a'#))
816 charError buf = lexError "error in character literal" buf
818 silly_escape_chars = [
855 -------------------------------------------------------------------------------
857 lex_demand cont buf =
858 case read_em [] buf of { (ls,buf') ->
859 case currentChar# buf' of
860 'b'# -> cont (ITstrict (StrictSig (mkTopDmdType ls BotRes))) (incLexeme buf')
861 'm'# -> cont (ITstrict (StrictSig (mkTopDmdType ls RetCPR))) (incLexeme buf')
862 _ -> cont (ITstrict (StrictSig (mkTopDmdType ls TopRes))) buf'
866 case currentChar# buf of
867 'T'# -> read_em (Top : acc) (stepOn buf)
868 'L'# -> read_em (lazyDmd : acc) (stepOn buf)
869 'A'# -> read_em (Abs : acc) (stepOn buf)
870 'V'# -> read_em (evalDmd : acc) (stepOn buf) -- Temporary, until
871 -- we've recompiled prelude etc
872 'C'# -> do_unary Call acc (stepOnBy# buf 2#) -- Skip 'C('
874 'U'# -> do_seq1 Eval acc (stepOnBy# buf 1#)
875 'D'# -> do_seq1 Defer acc (stepOnBy# buf 1#)
876 'S'# -> do_seq1 (Box . Eval) acc (stepOnBy# buf 1#)
878 _ -> (reverse acc, buf)
881 = case currentChar# buf of
882 '('# -> do_seq2 fn acc (stepOnBy# buf 1#)
883 _ -> read_em (fn (Poly Abs) : acc) buf
886 = case read_em [] buf of { (dmds, buf) ->
887 case currentChar# buf of
888 ')'# -> read_em (fn (Prod dmds) : acc)
890 '*'# -> ASSERT( length dmds == 1 )
891 read_em (fn (Poly (head dmds)) : acc)
892 (stepOnBy# buf 2#) -- Skip '*)'
896 = case read_em [] buf of
897 ([dmd], rest) -> read_em (fn dmd : acc) (stepOn rest) -- Skip ')'
901 case currentChar# buf of
902 'C'# -> cont ITsccAllCafs (incLexeme buf)
903 other -> cont ITscc buf
905 -----------------------------------------------------------------------------
908 lex_num :: (Token -> P a) -> Int# -> Integer -> P a
909 lex_num cont exts acc buf =
910 case scanNumLit acc buf of
912 case currentChar# buf' of
913 '.'# | is_digit (lookAhead# buf' 1#) ->
914 -- this case is not optimised at all, as the
915 -- presence of floating point numbers in interface
916 -- files is not that common. (ToDo)
917 case expandWhile# is_digit (incLexeme buf') of
918 buf2 -> -- points to first non digit char
920 let l = case currentChar# buf2 of
926 = let buf3 = incLexeme buf2 in
927 case currentChar# buf3 of
928 '-'# -> expandWhile# is_digit (incLexeme buf3)
929 '+'# -> expandWhile# is_digit (incLexeme buf3)
930 x | is_digit x -> expandWhile# is_digit buf3
933 v = readRational__ (lexemeToString l)
935 in case currentChar# l of -- glasgow exts only
936 '#'# | glaExtsEnabled exts -> let l' = incLexeme l in
937 case currentChar# l' of
938 '#'# -> cont (ITprimdouble v) (incLexeme l')
939 _ -> cont (ITprimfloat v) l'
940 _ -> cont (ITrational v) l
942 _ -> after_lexnum cont exts acc' buf'
944 after_lexnum cont exts i buf
945 = case currentChar# buf of
946 '#'# | glaExtsEnabled exts -> cont (ITprimint i) (incLexeme buf)
947 _ -> cont (ITinteger i) buf
949 -----------------------------------------------------------------------------
950 -- C "literal literal"s (i.e. things like ``NULL'', ``stdout'' etc.)
952 -- we lexemeToFastString on the bit between the ``''s, but include the
953 -- quotes in the full lexeme.
955 lex_cstring cont buf =
956 case expandUntilMatch (stepOverLexeme buf) "\'\'" of
957 Just buf' -> cont (ITlitlit (lexemeToFastString
958 (setCurrentPos# buf' (negateInt# 2#))))
959 (mergeLexemes buf buf')
960 Nothing -> lexError "unterminated ``" buf
962 -----------------------------------------------------------------------------
963 -- identifiers, symbols etc.
965 lex_ip ip_constr cont buf =
966 case expandWhile# is_ident buf of
967 buf' -> cont (ip_constr (tailFS lexeme)) buf'
968 where lexeme = lexemeToFastString buf'
970 lex_id cont exts buf =
971 let buf1 = expandWhile# is_ident buf in
974 case (if glaExtsEnabled exts
975 then expandWhile# (eqChar# '#'#) buf1 -- slurp trailing hashes
976 else buf1) of { buf' ->
978 let lexeme = lexemeToFastString buf' in
980 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
981 Just kwd_token -> --trace ("hkeywd: "++_UNPK_(lexeme)) $
985 let var_token = cont (ITvarid lexeme) buf' in
987 if not (glaExtsEnabled exts)
991 case lookupUFM ghcExtensionKeywordsFM lexeme of {
992 Just kwd_token -> cont kwd_token buf';
999 case expandWhile# is_symbol buf of
1000 buf' -> case lookupUFM haskellKeySymsFM lexeme of {
1001 Just kwd_token -> --trace ("keysym: "++unpackFS lexeme) $
1002 cont kwd_token buf' ;
1003 Nothing -> --trace ("sym: "++unpackFS lexeme) $
1004 cont (mk_var_token lexeme) buf'
1006 where lexeme = lexemeToFastString buf'
1009 -- lex_con recursively collects components of a qualified identifer.
1010 -- The argument buf is the StringBuffer representing the lexeme
1011 -- identified so far, where the next character is upper-case.
1013 lex_con cont exts buf =
1014 -- trace ("con: "{-++unpackFS lexeme-}) $
1015 let empty_buf = stepOverLexeme buf in
1016 case expandWhile# is_ident empty_buf of { buf1 ->
1017 case slurp_trailing_hashes buf1 exts of { con_buf ->
1019 let all_buf = mergeLexemes buf con_buf
1021 con_lexeme = lexemeToFastString con_buf
1022 mod_lexeme = lexemeToFastString (decLexeme buf)
1023 all_lexeme = lexemeToFastString all_buf
1026 | emptyLexeme buf = cont (ITconid con_lexeme) all_buf
1027 | otherwise = cont (ITqconid (mod_lexeme,con_lexeme)) all_buf
1030 case currentChar# all_buf of
1031 '.'# -> maybe_qualified cont exts all_lexeme
1032 (incLexeme all_buf) just_a_conid
1037 maybe_qualified cont exts mod buf just_a_conid =
1038 -- trace ("qid: "{-++unpackFS lexeme-}) $
1039 case currentChar# buf of
1040 '['# -> -- Special case for []
1041 case lookAhead# buf 1# of
1042 ']'# -> cont (ITqconid (mod,SLIT("[]"))) (setCurrentPos# buf 2#)
1045 '('# -> -- Special case for (,,,)
1046 -- This *is* necessary to deal with e.g. "instance C PrelBase.(,,)"
1047 case lookAhead# buf 1# of
1048 '#'# | glaExtsEnabled exts -> case lookAhead# buf 2# of
1049 ','# -> lex_ubx_tuple cont mod (setCurrentPos# buf 3#)
1052 ')'# -> cont (ITqconid (mod,SLIT("()"))) (setCurrentPos# buf 2#)
1053 ','# -> lex_tuple cont mod (setCurrentPos# buf 2#) just_a_conid
1056 '-'# -> case lookAhead# buf 1# of
1057 '>'# -> cont (ITqconid (mod,SLIT("(->)"))) (setCurrentPos# buf 2#)
1058 _ -> lex_id3 cont exts mod buf just_a_conid
1060 _ -> lex_id3 cont exts mod buf just_a_conid
1063 lex_id3 cont exts mod buf just_a_conid
1064 | is_upper (currentChar# buf) =
1065 lex_con cont exts buf
1067 | is_symbol (currentChar# buf) =
1069 start_new_lexeme = stepOverLexeme buf
1071 -- trace ("lex_id31 "{-++unpackFS lexeme-}) $
1072 case expandWhile# is_symbol start_new_lexeme of { buf' ->
1074 lexeme = lexemeToFastString buf'
1075 -- real lexeme is M.<sym>
1076 new_buf = mergeLexemes buf buf'
1078 cont (mk_qvar_token mod lexeme) new_buf
1079 -- wrong, but arguably morally right: M... is now a qvarsym
1084 start_new_lexeme = stepOverLexeme buf
1086 -- trace ("lex_id32 "{-++unpackFS lexeme-}) $
1087 case expandWhile# is_ident start_new_lexeme of { buf1 ->
1092 case slurp_trailing_hashes buf1 exts of { buf' ->
1095 lexeme = lexemeToFastString buf'
1096 new_buf = mergeLexemes buf buf'
1097 is_a_qvarid = cont (mk_qvar_token mod lexeme) new_buf
1099 case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
1100 Nothing -> is_a_qvarid ;
1102 Just kwd_token | isSpecial kwd_token -- special ids (as, qualified, hiding) shouldn't be
1103 -> is_a_qvarid -- recognised as keywords here.
1105 -> just_a_conid -- avoid M.where etc.
1108 slurp_trailing_hashes buf exts
1109 | glaExtsEnabled exts = expandWhile# (`eqChar#` '#'#) buf
1114 | is_upper f = ITconid pk_str
1115 | is_ident f = ITvarid pk_str
1116 | f `eqChar#` ':'# = ITconsym pk_str
1117 | otherwise = ITvarsym pk_str
1119 (C# f) = _HEAD_ pk_str
1120 -- tl = _TAIL_ pk_str
1122 mk_qvar_token m token =
1123 -- trace ("mk_qvar ") $
1124 case mk_var_token token of
1125 ITconid n -> ITqconid (m,n)
1126 ITvarid n -> ITqvarid (m,n)
1127 ITconsym n -> ITqconsym (m,n)
1128 ITvarsym n -> ITqvarsym (m,n)
1129 _ -> ITunknown (show token)
1132 ----------------------------------------------------------------------------
1133 Horrible stuff for dealing with M.(,,,)
1136 lex_tuple cont mod buf back_off =
1140 case currentChar# buf of
1141 ','# -> go (n+1) (stepOn buf)
1142 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Boxed n))) (stepOn buf)
1145 lex_ubx_tuple cont mod buf back_off =
1149 case currentChar# buf of
1150 ','# -> go (n+1) (stepOn buf)
1151 '#'# -> case lookAhead# buf 1# of
1152 ')'# -> cont (ITqconid (mod, snd (mkTupNameStr Unboxed n)))
1158 -----------------------------------------------------------------------------
1159 'lexPragma' rips along really fast, looking for a '##-}',
1160 indicating the end of the pragma we're skipping
1163 lexPragma cont contf inStr buf =
1164 case currentChar# buf of
1165 '#'# | inStr ==# 0# ->
1166 case lookAhead# buf 1# of { '#'# ->
1167 case lookAhead# buf 2# of { '-'# ->
1168 case lookAhead# buf 3# of { '}'# ->
1169 contf cont (lexemeToBuffer buf)
1170 (stepOverLexeme (setCurrentPos# buf 4#));
1171 _ -> lexPragma cont contf inStr (incLexeme buf) };
1172 _ -> lexPragma cont contf inStr (incLexeme buf) };
1173 _ -> lexPragma cont contf inStr (incLexeme buf) }
1177 odd_slashes buf flg i# =
1178 case lookAhead# buf i# of
1179 '\\'# -> odd_slashes buf (not flg) (i# -# 1#)
1182 not_inStr = if inStr ==# 0# then 1# else 0#
1184 case lookAhead# buf (negateInt# 1#) of --backwards, actually
1185 '\\'# -> -- escaping something..
1186 if odd_slashes buf True (negateInt# 2#)
1187 then -- odd number of slashes, " is escaped.
1188 lexPragma cont contf inStr (incLexeme buf)
1189 else -- even number of slashes, \ is escaped.
1190 lexPragma cont contf not_inStr (incLexeme buf)
1191 _ -> lexPragma cont contf not_inStr (incLexeme buf)
1193 '\''# | inStr ==# 0# ->
1194 case lookAhead# buf 1# of { '"'# ->
1195 case lookAhead# buf 2# of { '\''# ->
1196 lexPragma cont contf inStr (setCurrentPos# buf 3#);
1197 _ -> lexPragma cont contf inStr (incLexeme buf) };
1198 _ -> lexPragma cont contf inStr (incLexeme buf) }
1200 -- a sign that the input is ill-formed, since pragmas are
1201 -- assumed to always be properly closed (in .hi files).
1202 '\NUL'# -> trace "lexPragma: unexpected end-of-file" $
1203 cont (ITunknown "\NUL") buf
1205 _ -> lexPragma cont contf inStr (incLexeme buf)
1209 -----------------------------------------------------------------------------
1220 data PState = PState {
1222 extsBitmap :: Int#, -- bitmap that determines permitted extensions
1225 context :: [LayoutContext]
1228 type P a = StringBuffer -- Input string
1233 returnP a buf s = POk s a
1235 thenP :: P a -> (a -> P b) -> P b
1236 m `thenP` k = \ buf s ->
1238 POk s1 a -> k a buf s1
1239 PFailed err -> PFailed err
1241 thenP_ :: P a -> P b -> P b
1242 m `thenP_` k = m `thenP` \_ -> k
1244 mapP :: (a -> P b) -> [a] -> P [b]
1245 mapP f [] = returnP []
1248 mapP f as `thenP` \bs ->
1251 failP :: String -> P a
1252 failP msg buf s = PFailed (text msg)
1254 failMsgP :: Message -> P a
1255 failMsgP msg buf s = PFailed msg
1257 lexError :: String -> P a
1258 lexError str buf s@PState{ loc = loc }
1259 = failMsgP (hcat [ppr loc, text ": ", text str]) buf s
1261 getSrcLocP :: P SrcLoc
1262 getSrcLocP buf s@(PState{ loc = loc }) = POk s loc
1264 -- use a temporary SrcLoc for the duration of the argument
1265 setSrcLocP :: SrcLoc -> P a -> P a
1266 setSrcLocP new_loc p buf s =
1267 case p buf s{ loc=new_loc } of
1269 PFailed e -> PFailed e
1271 getSrcFile :: P FAST_STRING
1272 getSrcFile buf s@(PState{ loc = loc }) = POk s (srcLocFile loc)
1274 pushContext :: LayoutContext -> P ()
1275 pushContext ctxt buf s@(PState{ context = ctx }) = POk s{context = ctxt:ctx} ()
1279 This special case in layoutOn is to handle layout contexts with are
1280 indented the same or less than the current context. This is illegal
1281 according to the Haskell spec, so we have to arrange to close the
1282 current context. eg.
1287 after the first 'where', the sequence of events is:
1289 - layout system inserts a ';' (column 0)
1290 - parser begins a new context at column 0
1291 - parser shifts ';' (legal empty declaration)
1292 - parser sees 'class': parse error (we're still in the inner context)
1294 trouble is, by the time we know we need a new context, the lexer has
1295 already generated the ';'. Hacky solution is as follows: since we
1296 know the column of the next token (it's the column number of the new
1297 context), we set the ACTUAL column number of the new context to this
1298 numer plus one. Hence the next time the lexer is called, a '}' will
1299 be generated to close the new context straight away. Furthermore, we
1300 have to set the atbol flag so that the ';' that the parser shifted as
1301 part of the new context is re-generated.
1303 when the new context is *less* indented than the current one:
1305 f = f where g = g where
1308 - current context: column 12.
1309 - on seeing 'h' (column 0), the layout system inserts '}'
1310 - parser starts a new context, column 0
1311 - parser sees '}', uses it to close new context
1312 - we still need to insert another '}' followed by a ';',
1313 hence the atbol trick.
1315 There's also a special hack in here to deal with
1322 i.e. the inner context is at the same indentation level as the outer
1323 context. This is strictly illegal according to Haskell 98, but
1324 there's a lot of existing code using this style and it doesn't make
1325 any sense to disallow it, since empty 'do' lists don't make sense.
1328 layoutOn :: Bool -> P ()
1329 layoutOn strict buf s@(PState{ bol = bol, context = ctx }) =
1330 let offset = lexemeIndex buf -# bol in
1333 | if strict then prev_off >=# offset else prev_off ># offset ->
1334 --trace ("layout on, column: " ++ show (I# offset)) $
1335 POk s{ context = Layout (offset +# 1#) : ctx, atbol = 1# } ()
1337 --trace ("layout on, column: " ++ show (I# offset)) $
1338 POk s{ context = Layout offset : ctx } ()
1341 layoutOff buf s@(PState{ context = ctx }) =
1342 POk s{ context = NoLayout:ctx } ()
1345 popContext = \ buf s@(PState{ context = ctx, loc = loc }) ->
1347 (_:tl) -> POk s{ context = tl } ()
1348 [] -> PFailed (srcParseErr buf loc)
1351 Note that if the name of the file we're processing ends
1352 with `hi-boot', we accept it on faith as having the right
1353 version. This is done so that .hi-boot files that comes
1354 with hsc don't have to be updated before every release,
1355 *and* it allows us to share .hi-boot files with versions
1356 of hsc that don't have .hi version checking (e.g., ghc-2.10's)
1358 If the version number is 0, the checking is also turned off.
1359 (needed to deal with GHC.hi only!)
1361 Once we can assume we're compiling with a version of ghc that
1362 supports interface file checking, we can drop the special
1365 checkVersion :: Maybe Integer -> P ()
1366 checkVersion mb@(Just v) buf s@(PState{loc = loc})
1367 | (v==0) || (v == fromInt opt_HiVersion) || opt_NoHiCheck = POk s ()
1368 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1369 checkVersion mb@Nothing buf s@(PState{loc = loc})
1370 | "hi-boot" `isSuffixOf` (_UNPK_ (srcLocFile loc)) = POk s ()
1371 | otherwise = PFailed (ifaceVersionErr mb loc ([]::[Token]){-Todo-})
1374 -- for reasons of efficiency, flags indicating language extensions (eg,
1375 -- -fglasgow-exts or -fparr) are represented by a bitmap stored in an unboxed
1378 glaExtsBit, ffiBit, parrBit :: Int
1380 ffiBit = 1 -- FIXME: not used yet; still part of `glaExtsBit'
1383 glaExtsEnabled, ffiEnabled, parrEnabled :: Int# -> Bool
1384 glaExtsEnabled flags = testBit (I# flags) glaExtsBit
1385 ffiEnabled flags = testBit (I# flags) ffiBit
1386 parrEnabled flags = testBit (I# flags) parrBit
1388 -- convenient record-based bitmap for the interface to the rest of the world
1390 data ExtFlags = ExtFlags {
1391 glasgowExtsEF :: Bool,
1392 -- ffiEF :: Bool, -- commented out to avoid warnings
1393 parrEF :: Bool -- while not used yet
1396 -- create a parse state
1398 mkPState :: SrcLoc -> ExtFlags -> PState
1399 mkPState loc exts = PState {
1401 extsBitmap = case bitmap of {I# bits -> bits},
1407 bitmap = glaExtsBit `setBitIf` glasgowExtsEF exts
1408 -- .|. ffiBit `setBitIf` ffiEF exts
1409 .|. parrBit `setBitIf` parrEF exts
1411 b `setBitIf` cond | cond = bit b
1415 -----------------------------------------------------------------
1417 ifaceParseErr :: StringBuffer -> SrcLoc -> Message
1419 = hsep [ppr l, ptext SLIT("Interface file parse error; on input `"),
1420 text (lexemeToString s), char '\'']
1422 ifaceVersionErr hi_vers l toks
1423 = hsep [ppr l, ptext SLIT("Interface file version error;"),
1424 ptext SLIT("Expected"), int opt_HiVersion,
1425 ptext SLIT("found "), pp_version]
1429 Nothing -> ptext SLIT("pre ghc-3.02 version")
1430 Just v -> ptext SLIT("version") <+> integer v
1432 -----------------------------------------------------------------------------
1434 srcParseErr :: StringBuffer -> SrcLoc -> Message
1438 then ptext SLIT(": parse error (possibly incorrect indentation)")
1439 else hcat [ptext SLIT(": parse error on input "),
1440 char '`', text token, char '\'']
1443 token = lexemeToString s