1 -----------------------------------------------------------------------------
2 -- (c) The University of Glasgow, 2006
6 -- This is a combination of an Alex-generated lexer from a regex
7 -- definition, with some hand-coded bits.
9 -- Completely accurate information about token-spans within the source
10 -- file is maintained. Every token has a start and end SrcLoc attached to it.
12 -----------------------------------------------------------------------------
15 -- - parsing integers is a bit slow
16 -- - readRational is a bit slow
18 -- Known bugs, that were also in the previous version:
19 -- - M... should be 3 tokens, not 1.
20 -- - pragma-end should be only valid in a pragma
22 -- qualified operator NOTES.
24 -- - If M.(+) is a single lexeme, then..
25 -- - Probably (+) should be a single lexeme too, for consistency.
26 -- Otherwise ( + ) would be a prefix operator, but M.( + ) would not be.
27 -- - But we have to rule out reserved operators, otherwise (..) becomes
28 -- a different lexeme.
29 -- - Should we therefore also rule out reserved operators in the qualified
30 -- form? This is quite difficult to achieve. We don't do it for
34 {-# OPTIONS -Wwarn -w #-}
35 -- The above warning supression flag is a temporary kludge.
36 -- While working on this module you are encouraged to remove it and fix
37 -- any warnings in the module. See
38 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
41 -- Note that Alex itself generates code with with some unused bindings and
42 -- without type signatures, so removing the flag might not be possible.
44 {-# OPTIONS_GHC -funbox-strict-fields #-}
47 Token(..), lexer, pragState, mkPState, PState(..),
48 P(..), ParseResult(..), getSrcLoc,
50 failLocMsgP, failSpanMsgP, srcParseFail,
52 popContext, pushCurrentContext, setLastToken, setSrcLoc,
53 getLexState, popLexState, pushLexState,
54 extension, standaloneDerivingEnabled, bangPatEnabled,
68 import Util ( readRational )
76 import qualified Data.Map as Map
80 $unispace = \x05 -- Trick Alex into handling Unicode. See alexGetChar.
81 $whitechar = [\ \n\r\f\v $unispace]
82 $white_no_nl = $whitechar # \n
86 $unidigit = \x03 -- Trick Alex into handling Unicode. See alexGetChar.
87 $decdigit = $ascdigit -- for now, should really be $digit (ToDo)
88 $digit = [$ascdigit $unidigit]
90 $special = [\(\)\,\;\[\]\`\{\}]
91 $ascsymbol = [\!\#\$\%\&\*\+\.\/\<\=\>\?\@\\\^\|\-\~]
92 $unisymbol = \x04 -- Trick Alex into handling Unicode. See alexGetChar.
93 $symbol = [$ascsymbol $unisymbol] # [$special \_\:\"\']
95 $unilarge = \x01 -- Trick Alex into handling Unicode. See alexGetChar.
97 $large = [$asclarge $unilarge]
99 $unismall = \x02 -- Trick Alex into handling Unicode. See alexGetChar.
101 $small = [$ascsmall $unismall \_]
103 $unigraphic = \x06 -- Trick Alex into handling Unicode. See alexGetChar.
104 $graphic = [$small $large $symbol $digit $special $unigraphic \:\"\']
107 $hexit = [$decdigit A-F a-f]
108 $symchar = [$symbol \:]
110 $idchar = [$small $large $digit \']
112 $pragmachar = [$small $large $digit]
114 $docsym = [\| \^ \* \$]
116 @varid = $small $idchar*
117 @conid = $large $idchar*
119 @varsym = $symbol $symchar*
120 @consym = \: $symchar*
122 @decimal = $decdigit+
124 @hexadecimal = $hexit+
125 @exponent = [eE] [\-\+]? @decimal
127 -- we support the hierarchical module name extension:
130 @floating_point = @decimal \. @decimal @exponent? | @decimal @exponent
132 -- normal signed numerical literals can only be explicitly negative,
133 -- not explicitly positive (contrast @exponent)
135 @signed = @negative ?
139 -- everywhere: skip whitespace and comments
141 $tab+ { warn Opt_WarnTabs (text "Tab character") }
143 -- Everywhere: deal with nested comments. We explicitly rule out
144 -- pragmas, "{-#", so that we don't accidentally treat them as comments.
145 -- (this can happen even though pragmas will normally take precedence due to
146 -- longest-match, because pragmas aren't valid in every state, but comments
147 -- are). We also rule out nested Haddock comments, if the -haddock flag is
150 "{-" / { isNormalComment } { nested_comment lexToken }
152 -- Single-line comments are a bit tricky. Haskell 98 says that two or
153 -- more dashes followed by a symbol should be parsed as a varsym, so we
154 -- have to exclude those.
156 -- Since Haddock comments aren't valid in every state, we need to rule them
159 -- The following two rules match comments that begin with two dashes, but
160 -- continue with a different character. The rules test that this character
161 -- is not a symbol (in which case we'd have a varsym), and that it's not a
162 -- space followed by a Haddock comment symbol (docsym) (in which case we'd
163 -- have a Haddock comment). The rules then munch the rest of the line.
165 "-- " ~[$docsym \#] .* { lineCommentToken }
166 "--" [^$symbol : \ ] .* { lineCommentToken }
168 -- Next, match Haddock comments if no -haddock flag
170 "-- " [$docsym \#] .* / { ifExtension (not . haddockEnabled) } { lineCommentToken }
172 -- Now, when we've matched comments that begin with 2 dashes and continue
173 -- with a different character, we need to match comments that begin with three
174 -- or more dashes (which clearly can't be Haddock comments). We only need to
175 -- make sure that the first non-dash character isn't a symbol, and munch the
178 "---"\-* [^$symbol :] .* { lineCommentToken }
180 -- Since the previous rules all match dashes followed by at least one
181 -- character, we also need to match a whole line filled with just dashes.
183 "--"\-* / { atEOL } { lineCommentToken }
185 -- We need this rule since none of the other single line comment rules
186 -- actually match this case.
188 "-- " / { atEOL } { lineCommentToken }
190 -- 'bol' state: beginning of a line. Slurp up all the whitespace (including
191 -- blank lines) until we find a non-whitespace character, then do layout
194 -- One slight wibble here: what if the line begins with {-#? In
195 -- theory, we have to lex the pragma to see if it's one we recognise,
196 -- and if it is, then we backtrack and do_bol, otherwise we treat it
197 -- as a nested comment. We don't bother with this: if the line begins
198 -- with {-#, then we'll assume it's a pragma we know about and go for do_bol.
201 ^\# (line)? { begin line_prag1 }
202 ^\# pragma .* \n ; -- GCC 3.3 CPP generated, apparently
203 ^\# \! .* \n ; -- #!, for scripts
207 -- after a layout keyword (let, where, do, of), we begin a new layout
208 -- context if the curly brace is missing.
209 -- Careful! This stuff is quite delicate.
210 <layout, layout_do> {
211 \{ / { notFollowedBy '-' } { pop_and open_brace }
212 -- we might encounter {-# here, but {- has been handled already
214 ^\# (line)? { begin line_prag1 }
217 -- do is treated in a subtly different way, see new_layout_context
218 <layout> () { new_layout_context True }
219 <layout_do> () { new_layout_context False }
221 -- after a new layout context which was found to be to the left of the
222 -- previous context, we have generated a '{' token, and we now need to
223 -- generate a matching '}' token.
224 <layout_left> () { do_layout_left }
226 <0,option_prags> \n { begin bol }
228 "{-#" $whitechar* $pragmachar+ / { known_pragma linePrags }
229 { dispatch_pragmas linePrags }
231 -- single-line line pragmas, of the form
232 -- # <line> "<file>" <extra-stuff> \n
233 <line_prag1> $decdigit+ { setLine line_prag1a }
234 <line_prag1a> \" [$graphic \ ]* \" { setFile line_prag1b }
235 <line_prag1b> .* { pop }
237 -- Haskell-style line pragmas, of the form
238 -- {-# LINE <line> "<file>" #-}
239 <line_prag2> $decdigit+ { setLine line_prag2a }
240 <line_prag2a> \" [$graphic \ ]* \" { setFile line_prag2b }
241 <line_prag2b> "#-}"|"-}" { pop }
242 -- NOTE: accept -} at the end of a LINE pragma, for compatibility
243 -- with older versions of GHC which generated these.
246 "{-#" $whitechar* $pragmachar+
247 $whitechar+ $pragmachar+ / { known_pragma twoWordPrags }
248 { dispatch_pragmas twoWordPrags }
250 "{-#" $whitechar* $pragmachar+ / { known_pragma oneWordPrags }
251 { dispatch_pragmas oneWordPrags }
253 -- We ignore all these pragmas, but don't generate a warning for them
254 "{-#" $whitechar* $pragmachar+ / { known_pragma ignoredPrags }
255 { dispatch_pragmas ignoredPrags }
257 -- ToDo: should only be valid inside a pragma:
262 "{-#" $whitechar* $pragmachar+ / { known_pragma fileHeaderPrags }
263 { dispatch_pragmas fileHeaderPrags }
265 "-- #" { multiline_doc_comment }
269 -- In the "0" mode we ignore these pragmas
270 "{-#" $whitechar* $pragmachar+ / { known_pragma fileHeaderPrags }
271 { nested_comment lexToken }
275 "-- #" .* { lineCommentToken }
279 "{-#" { warnThen Opt_WarnUnrecognisedPragmas (text "Unrecognised pragma")
280 (nested_comment lexToken) }
283 -- '0' state: ordinary lexemes
288 "-- " $docsym / { ifExtension haddockEnabled } { multiline_doc_comment }
289 "{-" \ ? $docsym / { ifExtension haddockEnabled } { nested_doc_comment }
295 "[:" / { ifExtension parrEnabled } { token ITopabrack }
296 ":]" / { ifExtension parrEnabled } { token ITcpabrack }
300 "[|" / { ifExtension thEnabled } { token ITopenExpQuote }
301 "[e|" / { ifExtension thEnabled } { token ITopenExpQuote }
302 "[p|" / { ifExtension thEnabled } { token ITopenPatQuote }
303 "[d|" / { ifExtension thEnabled } { layout_token ITopenDecQuote }
304 "[t|" / { ifExtension thEnabled } { token ITopenTypQuote }
305 "|]" / { ifExtension thEnabled } { token ITcloseQuote }
306 \$ @varid / { ifExtension thEnabled } { skip_one_varid ITidEscape }
307 "$(" / { ifExtension thEnabled } { token ITparenEscape }
309 "[$" @varid "|" / { ifExtension qqEnabled }
310 { lex_quasiquote_tok }
314 "(|" / { ifExtension arrowsEnabled `alexAndPred` notFollowedBySymbol }
315 { special IToparenbar }
316 "|)" / { ifExtension arrowsEnabled } { special ITcparenbar }
320 \? @varid / { ifExtension ipEnabled } { skip_one_varid ITdupipvarid }
324 "(#" / { ifExtension unboxedTuplesEnabled `alexAndPred` notFollowedBySymbol }
325 { token IToubxparen }
326 "#)" / { ifExtension unboxedTuplesEnabled }
327 { token ITcubxparen }
331 "{|" / { ifExtension genericsEnabled } { token ITocurlybar }
332 "|}" / { ifExtension genericsEnabled } { token ITccurlybar }
336 \( { special IToparen }
337 \) { special ITcparen }
338 \[ { special ITobrack }
339 \] { special ITcbrack }
340 \, { special ITcomma }
341 \; { special ITsemi }
342 \` { special ITbackquote }
349 @qual @varid { idtoken qvarid }
350 @qual @conid { idtoken qconid }
352 @conid { idtoken conid }
356 @qual @varid "#"+ / { ifExtension magicHashEnabled } { idtoken qvarid }
357 @qual @conid "#"+ / { ifExtension magicHashEnabled } { idtoken qconid }
358 @varid "#"+ / { ifExtension magicHashEnabled } { varid }
359 @conid "#"+ / { ifExtension magicHashEnabled } { idtoken conid }
362 -- ToDo: - move `var` and (sym) into lexical syntax?
363 -- - remove backquote from $special?
365 @qual @varsym / { ifExtension oldQualOps } { idtoken qvarsym }
366 @qual @consym / { ifExtension oldQualOps } { idtoken qconsym }
367 @qual \( @varsym \) / { ifExtension newQualOps } { idtoken prefixqvarsym }
368 @qual \( @consym \) / { ifExtension newQualOps } { idtoken prefixqconsym }
373 -- For the normal boxed literals we need to be careful
374 -- when trying to be close to Haskell98
376 -- Normal integral literals (:: Num a => a, from Integer)
377 @decimal { tok_num positive 0 0 decimal }
378 0[oO] @octal { tok_num positive 2 2 octal }
379 0[xX] @hexadecimal { tok_num positive 2 2 hexadecimal }
381 -- Normal rational literals (:: Fractional a => a, from Rational)
382 @floating_point { strtoken tok_float }
386 -- Unboxed ints (:: Int#) and words (:: Word#)
387 -- It's simpler (and faster?) to give separate cases to the negatives,
388 -- especially considering octal/hexadecimal prefixes.
389 @decimal \# / { ifExtension magicHashEnabled } { tok_primint positive 0 1 decimal }
390 0[oO] @octal \# / { ifExtension magicHashEnabled } { tok_primint positive 2 3 octal }
391 0[xX] @hexadecimal \# / { ifExtension magicHashEnabled } { tok_primint positive 2 3 hexadecimal }
392 @negative @decimal \# / { ifExtension magicHashEnabled } { tok_primint negative 1 2 decimal }
393 @negative 0[oO] @octal \# / { ifExtension magicHashEnabled } { tok_primint negative 3 4 octal }
394 @negative 0[xX] @hexadecimal \# / { ifExtension magicHashEnabled } { tok_primint negative 3 4 hexadecimal }
396 @decimal \# \# / { ifExtension magicHashEnabled } { tok_primword 0 2 decimal }
397 0[oO] @octal \# \# / { ifExtension magicHashEnabled } { tok_primword 2 4 octal }
398 0[xX] @hexadecimal \# \# / { ifExtension magicHashEnabled } { tok_primword 2 4 hexadecimal }
400 -- Unboxed floats and doubles (:: Float#, :: Double#)
401 -- prim_{float,double} work with signed literals
402 @signed @floating_point \# / { ifExtension magicHashEnabled } { init_strtoken 1 tok_primfloat }
403 @signed @floating_point \# \# / { ifExtension magicHashEnabled } { init_strtoken 2 tok_primdouble }
406 -- Strings and chars are lexed by hand-written code. The reason is
407 -- that even if we recognise the string or char here in the regex
408 -- lexer, we would still have to parse the string afterward in order
409 -- to convert it to a String.
412 \" { lex_string_tok }
416 -- -----------------------------------------------------------------------------
420 = ITas -- Haskell keywords
444 | ITscc -- ToDo: remove (we use {-# SCC "..." #-} now)
446 | ITforall -- GHC extension keywords
464 | ITinline_prag Bool -- True <=> INLINE, False <=> NOINLINE
465 | ITinline_conlike_prag Bool -- same
466 | ITspec_prag -- SPECIALISE
467 | ITspec_inline_prag Bool -- SPECIALISE INLINE (or NOINLINE)
475 | ITcore_prag -- hdaume: core annotations
479 | IToptions_prag String
480 | ITinclude_prag String
483 | ITdotdot -- reserved symbols
499 | ITbiglam -- GHC-extension symbols
501 | ITocurly -- special symbols
503 | ITocurlybar -- {|, for type applications
504 | ITccurlybar -- |}, for type applications
508 | ITopabrack -- [:, for parallel arrays with -XParr
509 | ITcpabrack -- :], for parallel arrays with -XParr
520 | ITvarid FastString -- identifiers
522 | ITvarsym FastString
523 | ITconsym FastString
524 | ITqvarid (FastString,FastString)
525 | ITqconid (FastString,FastString)
526 | ITqvarsym (FastString,FastString)
527 | ITqconsym (FastString,FastString)
528 | ITprefixqvarsym (FastString,FastString)
529 | ITprefixqconsym (FastString,FastString)
531 | ITdupipvarid FastString -- GHC extension: implicit param: ?x
533 | ITpragma StringBuffer
536 | ITstring FastString
538 | ITrational Rational
541 | ITprimstring FastString
544 | ITprimfloat Rational
545 | ITprimdouble Rational
547 -- MetaHaskell extension tokens
548 | ITopenExpQuote -- [| or [e|
549 | ITopenPatQuote -- [p|
550 | ITopenDecQuote -- [d|
551 | ITopenTypQuote -- [t|
553 | ITidEscape FastString -- $x
554 | ITparenEscape -- $(
557 | ITquasiQuote (FastString,FastString,SrcSpan) -- [:...|...|]
559 -- Arrow notation extension
566 | ITLarrowtail -- -<<
567 | ITRarrowtail -- >>-
569 | ITunknown String -- Used when the lexer can't make sense of it
570 | ITeof -- end of file token
572 -- Documentation annotations
573 | ITdocCommentNext String -- something beginning '-- |'
574 | ITdocCommentPrev String -- something beginning '-- ^'
575 | ITdocCommentNamed String -- something beginning '-- $'
576 | ITdocSection Int String -- a section heading
577 | ITdocOptions String -- doc options (prune, ignore-exports, etc)
578 | ITdocOptionsOld String -- doc options declared "-- # ..."-style
579 | ITlineComment String -- comment starting by "--"
580 | ITblockComment String -- comment in {- -}
583 deriving Show -- debugging
587 isSpecial :: Token -> Bool
588 -- If we see M.x, where x is a keyword, but
589 -- is special, we treat is as just plain M.x,
591 isSpecial ITas = True
592 isSpecial IThiding = True
593 isSpecial ITqualified = True
594 isSpecial ITforall = True
595 isSpecial ITexport = True
596 isSpecial ITlabel = True
597 isSpecial ITdynamic = True
598 isSpecial ITsafe = True
599 isSpecial ITthreadsafe = True
600 isSpecial ITunsafe = True
601 isSpecial ITccallconv = True
602 isSpecial ITstdcallconv = True
603 isSpecial ITprimcallconv = True
604 isSpecial ITmdo = True
605 isSpecial ITfamily = True
606 isSpecial ITgroup = True
607 isSpecial ITby = True
608 isSpecial ITusing = True
612 -- the bitmap provided as the third component indicates whether the
613 -- corresponding extension keyword is valid under the extension options
614 -- provided to the compiler; if the extension corresponding to *any* of the
615 -- bits set in the bitmap is enabled, the keyword is valid (this setup
616 -- facilitates using a keyword in two different extensions that can be
617 -- activated independently)
619 reservedWordsFM :: UniqFM (Token, Int)
620 reservedWordsFM = listToUFM $
621 map (\(x, y, z) -> (mkFastString x, (y, z)))
622 [( "_", ITunderscore, 0 ),
624 ( "case", ITcase, 0 ),
625 ( "class", ITclass, 0 ),
626 ( "data", ITdata, 0 ),
627 ( "default", ITdefault, 0 ),
628 ( "deriving", ITderiving, 0 ),
630 ( "else", ITelse, 0 ),
631 ( "hiding", IThiding, 0 ),
633 ( "import", ITimport, 0 ),
635 ( "infix", ITinfix, 0 ),
636 ( "infixl", ITinfixl, 0 ),
637 ( "infixr", ITinfixr, 0 ),
638 ( "instance", ITinstance, 0 ),
640 ( "module", ITmodule, 0 ),
641 ( "newtype", ITnewtype, 0 ),
643 ( "qualified", ITqualified, 0 ),
644 ( "then", ITthen, 0 ),
645 ( "type", ITtype, 0 ),
646 ( "where", ITwhere, 0 ),
647 ( "_scc_", ITscc, 0 ), -- ToDo: remove
649 ( "forall", ITforall, bit explicitForallBit .|. bit inRulePragBit),
650 ( "mdo", ITmdo, bit recursiveDoBit),
651 ( "family", ITfamily, bit tyFamBit),
652 ( "group", ITgroup, bit transformComprehensionsBit),
653 ( "by", ITby, bit transformComprehensionsBit),
654 ( "using", ITusing, bit transformComprehensionsBit),
656 ( "foreign", ITforeign, bit ffiBit),
657 ( "export", ITexport, bit ffiBit),
658 ( "label", ITlabel, bit ffiBit),
659 ( "dynamic", ITdynamic, bit ffiBit),
660 ( "safe", ITsafe, bit ffiBit),
661 ( "threadsafe", ITthreadsafe, bit ffiBit), -- ToDo: remove
662 ( "unsafe", ITunsafe, bit ffiBit),
663 ( "stdcall", ITstdcallconv, bit ffiBit),
664 ( "ccall", ITccallconv, bit ffiBit),
665 ( "prim", ITprimcallconv, bit ffiBit),
667 ( "rec", ITrec, bit arrowsBit),
668 ( "proc", ITproc, bit arrowsBit)
671 reservedSymsFM :: UniqFM (Token, Int -> Bool)
672 reservedSymsFM = listToUFM $
673 map (\ (x,y,z) -> (mkFastString x,(y,z)))
674 [ ("..", ITdotdot, always)
675 -- (:) is a reserved op, meaning only list cons
676 ,(":", ITcolon, always)
677 ,("::", ITdcolon, always)
678 ,("=", ITequal, always)
679 ,("\\", ITlam, always)
680 ,("|", ITvbar, always)
681 ,("<-", ITlarrow, always)
682 ,("->", ITrarrow, always)
684 ,("~", ITtilde, always)
685 ,("=>", ITdarrow, always)
686 ,("-", ITminus, always)
687 ,("!", ITbang, always)
689 -- For data T (a::*) = MkT
690 ,("*", ITstar, always) -- \i -> kindSigsEnabled i || tyFamEnabled i)
691 -- For 'forall a . t'
692 ,(".", ITdot, always) -- \i -> explicitForallEnabled i || inRulePrag i)
694 ,("-<", ITlarrowtail, arrowsEnabled)
695 ,(">-", ITrarrowtail, arrowsEnabled)
696 ,("-<<", ITLarrowtail, arrowsEnabled)
697 ,(">>-", ITRarrowtail, arrowsEnabled)
699 ,("∷", ITdcolon, unicodeSyntaxEnabled)
700 ,("⇒", ITdarrow, unicodeSyntaxEnabled)
701 ,("∀", ITforall, \i -> unicodeSyntaxEnabled i &&
702 explicitForallEnabled i)
703 ,("→", ITrarrow, unicodeSyntaxEnabled)
704 ,("←", ITlarrow, unicodeSyntaxEnabled)
705 ,("⋯", ITdotdot, unicodeSyntaxEnabled)
706 -- ToDo: ideally, → and ∷ should be "specials", so that they cannot
707 -- form part of a large operator. This would let us have a better
708 -- syntax for kinds: ɑ∷*→* would be a legal kind signature. (maybe).
711 -- -----------------------------------------------------------------------------
714 type Action = SrcSpan -> StringBuffer -> Int -> P (Located Token)
716 special :: Token -> Action
717 special tok span _buf _len = return (L span tok)
719 token, layout_token :: Token -> Action
720 token t span _buf _len = return (L span t)
721 layout_token t span _buf _len = pushLexState layout >> return (L span t)
723 idtoken :: (StringBuffer -> Int -> Token) -> Action
724 idtoken f span buf len = return (L span $! (f buf len))
726 skip_one_varid :: (FastString -> Token) -> Action
727 skip_one_varid f span buf len
728 = return (L span $! f (lexemeToFastString (stepOn buf) (len-1)))
730 strtoken :: (String -> Token) -> Action
731 strtoken f span buf len =
732 return (L span $! (f $! lexemeToString buf len))
734 init_strtoken :: Int -> (String -> Token) -> Action
735 -- like strtoken, but drops the last N character(s)
736 init_strtoken drop f span buf len =
737 return (L span $! (f $! lexemeToString buf (len-drop)))
739 begin :: Int -> Action
740 begin code _span _str _len = do pushLexState code; lexToken
743 pop _span _buf _len = do popLexState; lexToken
745 pop_and :: Action -> Action
746 pop_and act span buf len = do popLexState; act span buf len
748 {-# INLINE nextCharIs #-}
749 nextCharIs :: StringBuffer -> (Char -> Bool) -> Bool
750 nextCharIs buf p = not (atEnd buf) && p (currentChar buf)
752 notFollowedBy :: Char -> AlexAccPred Int
753 notFollowedBy char _ _ _ (AI _ _ buf)
754 = nextCharIs buf (/=char)
756 notFollowedBySymbol :: AlexAccPred Int
757 notFollowedBySymbol _ _ _ (AI _ _ buf)
758 = nextCharIs buf (`notElem` "!#$%&*+./<=>?@\\^|-~")
760 -- We must reject doc comments as being ordinary comments everywhere.
761 -- In some cases the doc comment will be selected as the lexeme due to
762 -- maximal munch, but not always, because the nested comment rule is
763 -- valid in all states, but the doc-comment rules are only valid in
764 -- the non-layout states.
765 isNormalComment :: AlexAccPred Int
766 isNormalComment bits _ _ (AI _ _ buf)
767 | haddockEnabled bits = notFollowedByDocOrPragma
768 | otherwise = nextCharIs buf (/='#')
770 notFollowedByDocOrPragma
771 = not $ spaceAndP buf (`nextCharIs` (`elem` "|^*$#"))
773 spaceAndP :: StringBuffer -> (StringBuffer -> Bool) -> Bool
774 spaceAndP buf p = p buf || nextCharIs buf (==' ') && p (snd (nextChar buf))
777 haddockDisabledAnd p bits _ _ (AI _ _ buf)
778 = if haddockEnabled bits then False else (p buf)
781 atEOL :: AlexAccPred Int
782 atEOL _ _ _ (AI _ _ buf) = atEnd buf || currentChar buf == '\n'
784 ifExtension :: (Int -> Bool) -> AlexAccPred Int
785 ifExtension pred bits _ _ _ = pred bits
787 multiline_doc_comment :: Action
788 multiline_doc_comment span buf _len = withLexedDocType (worker "")
790 worker commentAcc input docType oneLine = case alexGetChar input of
792 | oneLine -> docCommentEnd input commentAcc docType buf span
793 | otherwise -> case checkIfCommentLine input' of
794 Just input -> worker ('\n':commentAcc) input docType False
795 Nothing -> docCommentEnd input commentAcc docType buf span
796 Just (c, input) -> worker (c:commentAcc) input docType oneLine
797 Nothing -> docCommentEnd input commentAcc docType buf span
799 checkIfCommentLine input = check (dropNonNewlineSpace input)
801 check input = case alexGetChar input of
802 Just ('-', input) -> case alexGetChar input of
803 Just ('-', input) -> case alexGetChar input of
804 Just (c, _) | c /= '-' -> Just input
809 dropNonNewlineSpace input = case alexGetChar input of
811 | isSpace c && c /= '\n' -> dropNonNewlineSpace input'
815 lineCommentToken :: Action
816 lineCommentToken span buf len = do
817 b <- extension rawTokenStreamEnabled
818 if b then strtoken ITlineComment span buf len else lexToken
821 nested comments require traversing by hand, they can't be parsed
822 using regular expressions.
824 nested_comment :: P (Located Token) -> Action
825 nested_comment cont span _str _len = do
829 go commentAcc 0 input = do setInput input
830 b <- extension rawTokenStreamEnabled
832 then docCommentEnd input commentAcc ITblockComment _str span
834 go commentAcc n input = case alexGetChar input of
835 Nothing -> errBrace input span
836 Just ('-',input) -> case alexGetChar input of
837 Nothing -> errBrace input span
838 Just ('\125',input) -> go commentAcc (n-1) input
839 Just (_,_) -> go ('-':commentAcc) n input
840 Just ('\123',input) -> case alexGetChar input of
841 Nothing -> errBrace input span
842 Just ('-',input) -> go ('-':'\123':commentAcc) (n+1) input
843 Just (_,_) -> go ('\123':commentAcc) n input
844 Just (c,input) -> go (c:commentAcc) n input
846 nested_doc_comment :: Action
847 nested_doc_comment span buf _len = withLexedDocType (go "")
849 go commentAcc input docType _ = case alexGetChar input of
850 Nothing -> errBrace input span
851 Just ('-',input) -> case alexGetChar input of
852 Nothing -> errBrace input span
853 Just ('\125',input) ->
854 docCommentEnd input commentAcc docType buf span
855 Just (_,_) -> go ('-':commentAcc) input docType False
856 Just ('\123', input) -> case alexGetChar input of
857 Nothing -> errBrace input span
858 Just ('-',input) -> do
860 let cont = do input <- getInput; go commentAcc input docType False
861 nested_comment cont span buf _len
862 Just (_,_) -> go ('\123':commentAcc) input docType False
863 Just (c,input) -> go (c:commentAcc) input docType False
865 withLexedDocType :: (AlexInput -> (String -> Token) -> Bool -> P (Located Token))
867 withLexedDocType lexDocComment = do
868 input@(AI _ _ buf) <- getInput
869 case prevChar buf ' ' of
870 '|' -> lexDocComment input ITdocCommentNext False
871 '^' -> lexDocComment input ITdocCommentPrev False
872 '$' -> lexDocComment input ITdocCommentNamed False
873 '*' -> lexDocSection 1 input
874 '#' -> lexDocComment input ITdocOptionsOld False
875 _ -> panic "withLexedDocType: Bad doc type"
877 lexDocSection n input = case alexGetChar input of
878 Just ('*', input) -> lexDocSection (n+1) input
879 Just (_, _) -> lexDocComment input (ITdocSection n) True
880 Nothing -> do setInput input; lexToken -- eof reached, lex it normally
882 -- RULES pragmas turn on the forall and '.' keywords, and we turn them
883 -- off again at the end of the pragma.
885 rulePrag span _ _ = do
886 setExts (.|. bit inRulePragBit)
887 return (L span ITrules_prag)
890 endPrag span _ _ = do
891 setExts (.&. complement (bit inRulePragBit))
892 return (L span ITclose_prag)
895 -------------------------------------------------------------------------------
896 -- This function is quite tricky. We can't just return a new token, we also
897 -- need to update the state of the parser. Why? Because the token is longer
898 -- than what was lexed by Alex, and the lexToken function doesn't know this, so
899 -- it writes the wrong token length to the parser state. This function is
900 -- called afterwards, so it can just update the state.
902 -- This is complicated by the fact that Haddock tokens can span multiple lines,
903 -- which is something that the original lexer didn't account for.
904 -- I have added last_line_len in the parser state which represents the length
905 -- of the part of the token that is on the last line. It is now used for layout
906 -- calculation in pushCurrentContext instead of last_len. last_len is, like it
907 -- was before, the full length of the token, and it is now only used for error
910 docCommentEnd :: AlexInput -> String -> (String -> Token) -> StringBuffer ->
911 SrcSpan -> P (Located Token)
912 docCommentEnd input commentAcc docType buf span = do
914 let (AI loc last_offs nextBuf) = input
915 comment = reverse commentAcc
916 span' = mkSrcSpan (srcSpanStart span) loc
917 last_len = byteDiff buf nextBuf
919 last_line_len = if (last_offs - last_len < 0)
923 span `seq` setLastToken span' last_len last_line_len
924 return (L span' (docType comment))
926 errBrace :: AlexInput -> SrcSpan -> P a
927 errBrace (AI end _ _) span = failLocMsgP (srcSpanStart span) end "unterminated `{-'"
929 open_brace, close_brace :: Action
930 open_brace span _str _len = do
932 setContext (NoLayout:ctx)
933 return (L span ITocurly)
934 close_brace span _str _len = do
936 return (L span ITccurly)
938 qvarid, qconid :: StringBuffer -> Int -> Token
939 qvarid buf len = ITqvarid $! splitQualName buf len False
940 qconid buf len = ITqconid $! splitQualName buf len False
942 splitQualName :: StringBuffer -> Int -> Bool -> (FastString,FastString)
943 -- takes a StringBuffer and a length, and returns the module name
944 -- and identifier parts of a qualified name. Splits at the *last* dot,
945 -- because of hierarchical module names.
946 splitQualName orig_buf len parens = split orig_buf orig_buf
949 | orig_buf `byteDiff` buf >= len = done dot_buf
950 | c == '.' = found_dot buf'
951 | otherwise = split buf' dot_buf
953 (c,buf') = nextChar buf
955 -- careful, we might get names like M....
956 -- so, if the character after the dot is not upper-case, this is
957 -- the end of the qualifier part.
958 found_dot buf -- buf points after the '.'
959 | isUpper c = split buf' buf
960 | otherwise = done buf
962 (c,buf') = nextChar buf
965 (lexemeToFastString orig_buf (qual_size - 1),
966 if parens -- Prelude.(+)
967 then lexemeToFastString (stepOn dot_buf) (len - qual_size - 2)
968 else lexemeToFastString dot_buf (len - qual_size))
970 qual_size = orig_buf `byteDiff` dot_buf
975 case lookupUFM reservedWordsFM fs of
976 Just (keyword,0) -> do
978 return (L span keyword)
979 Just (keyword,exts) -> do
980 b <- extension (\i -> exts .&. i /= 0)
981 if b then do maybe_layout keyword
982 return (L span keyword)
983 else return (L span (ITvarid fs))
984 _other -> return (L span (ITvarid fs))
986 fs = lexemeToFastString buf len
988 conid :: StringBuffer -> Int -> Token
989 conid buf len = ITconid fs
990 where fs = lexemeToFastString buf len
992 qvarsym, qconsym, prefixqvarsym, prefixqconsym :: StringBuffer -> Int -> Token
993 qvarsym buf len = ITqvarsym $! splitQualName buf len False
994 qconsym buf len = ITqconsym $! splitQualName buf len False
995 prefixqvarsym buf len = ITprefixqvarsym $! splitQualName buf len True
996 prefixqconsym buf len = ITprefixqconsym $! splitQualName buf len True
998 varsym, consym :: Action
999 varsym = sym ITvarsym
1000 consym = sym ITconsym
1002 sym :: (FastString -> Token) -> SrcSpan -> StringBuffer -> Int
1003 -> P (Located Token)
1004 sym con span buf len =
1005 case lookupUFM reservedSymsFM fs of
1006 Just (keyword,exts) -> do
1008 if b then return (L span keyword)
1009 else return (L span $! con fs)
1010 _other -> return (L span $! con fs)
1012 fs = lexemeToFastString buf len
1014 -- Variations on the integral numeric literal.
1015 tok_integral :: (Integer -> Token)
1016 -> (Integer -> Integer)
1017 -- -> (StringBuffer -> StringBuffer) -> (Int -> Int)
1019 -> (Integer, (Char->Int)) -> Action
1020 tok_integral itint transint transbuf translen (radix,char_to_int) span buf len =
1021 return $ L span $ itint $! transint $ parseUnsignedInteger
1022 (offsetBytes transbuf buf) (subtract translen len) radix char_to_int
1024 -- some conveniences for use with tok_integral
1025 tok_num :: (Integer -> Integer)
1027 -> (Integer, (Char->Int)) -> Action
1028 tok_num = tok_integral ITinteger
1029 tok_primint :: (Integer -> Integer)
1031 -> (Integer, (Char->Int)) -> Action
1032 tok_primint = tok_integral ITprimint
1033 tok_primword :: Int -> Int
1034 -> (Integer, (Char->Int)) -> Action
1035 tok_primword = tok_integral ITprimword positive
1036 positive, negative :: (Integer -> Integer)
1039 decimal, octal, hexadecimal :: (Integer, Char -> Int)
1040 decimal = (10,octDecDigit)
1041 octal = (8,octDecDigit)
1042 hexadecimal = (16,hexDigit)
1044 -- readRational can understand negative rationals, exponents, everything.
1045 tok_float, tok_primfloat, tok_primdouble :: String -> Token
1046 tok_float str = ITrational $! readRational str
1047 tok_primfloat str = ITprimfloat $! readRational str
1048 tok_primdouble str = ITprimdouble $! readRational str
1050 -- -----------------------------------------------------------------------------
1051 -- Layout processing
1053 -- we're at the first token on a line, insert layout tokens if necessary
1055 do_bol span _str _len = do
1059 --trace "layout: inserting '}'" $ do
1061 -- do NOT pop the lex state, we might have a ';' to insert
1062 return (L span ITvccurly)
1064 --trace "layout: inserting ';'" $ do
1066 return (L span ITsemi)
1071 -- certain keywords put us in the "layout" state, where we might
1072 -- add an opening curly brace.
1073 maybe_layout :: Token -> P ()
1074 maybe_layout ITdo = pushLexState layout_do
1075 maybe_layout ITmdo = pushLexState layout_do
1076 maybe_layout ITof = pushLexState layout
1077 maybe_layout ITlet = pushLexState layout
1078 maybe_layout ITwhere = pushLexState layout
1079 maybe_layout ITrec = pushLexState layout
1080 maybe_layout _ = return ()
1082 -- Pushing a new implicit layout context. If the indentation of the
1083 -- next token is not greater than the previous layout context, then
1084 -- Haskell 98 says that the new layout context should be empty; that is
1085 -- the lexer must generate {}.
1087 -- We are slightly more lenient than this: when the new context is started
1088 -- by a 'do', then we allow the new context to be at the same indentation as
1089 -- the previous context. This is what the 'strict' argument is for.
1091 new_layout_context :: Bool -> Action
1092 new_layout_context strict span _buf _len = do
1094 (AI _ offset _) <- getInput
1097 Layout prev_off : _ |
1098 (strict && prev_off >= offset ||
1099 not strict && prev_off > offset) -> do
1100 -- token is indented to the left of the previous context.
1101 -- we must generate a {} sequence now.
1102 pushLexState layout_left
1103 return (L span ITvocurly)
1105 setContext (Layout offset : ctx)
1106 return (L span ITvocurly)
1108 do_layout_left :: Action
1109 do_layout_left span _buf _len = do
1111 pushLexState bol -- we must be at the start of a line
1112 return (L span ITvccurly)
1114 -- -----------------------------------------------------------------------------
1117 setLine :: Int -> Action
1118 setLine code span buf len = do
1119 let line = parseUnsignedInteger buf len 10 octDecDigit
1120 setSrcLoc (mkSrcLoc (srcSpanFile span) (fromIntegral line - 1) 0)
1121 -- subtract one: the line number refers to the *following* line
1126 setFile :: Int -> Action
1127 setFile code span buf len = do
1128 let file = lexemeToFastString (stepOn buf) (len-2)
1129 setSrcLoc (mkSrcLoc file (srcSpanEndLine span) (srcSpanEndCol span))
1135 -- -----------------------------------------------------------------------------
1136 -- Options, includes and language pragmas.
1138 lex_string_prag :: (String -> Token) -> Action
1139 lex_string_prag mkTok span _buf _len
1140 = do input <- getInput
1144 return (L (mkSrcSpan start end) tok)
1146 = if isString input "#-}"
1147 then do setInput input
1148 return (mkTok (reverse acc))
1149 else case alexGetChar input of
1150 Just (c,i) -> go (c:acc) i
1151 Nothing -> err input
1152 isString _ [] = True
1154 = case alexGetChar i of
1155 Just (c,i') | c == x -> isString i' xs
1157 err (AI end _ _) = failLocMsgP (srcSpanStart span) end "unterminated options pragma"
1160 -- -----------------------------------------------------------------------------
1163 -- This stuff is horrible. I hates it.
1165 lex_string_tok :: Action
1166 lex_string_tok span _buf _len = do
1167 tok <- lex_string ""
1169 return (L (mkSrcSpan (srcSpanStart span) end) tok)
1171 lex_string :: String -> P Token
1174 case alexGetChar' i of
1175 Nothing -> lit_error
1179 magicHash <- extension magicHashEnabled
1183 case alexGetChar' i of
1187 then failMsgP "primitive string literal must contain only characters <= \'\\xFF\'"
1188 else let s' = mkZFastString (reverse s) in
1189 return (ITprimstring s')
1190 -- mkZFastString is a hack to avoid encoding the
1191 -- string in UTF-8. We just want the exact bytes.
1193 return (ITstring (mkFastString (reverse s)))
1195 return (ITstring (mkFastString (reverse s)))
1198 | Just ('&',i) <- next -> do
1199 setInput i; lex_string s
1200 | Just (c,i) <- next, is_space c -> do
1201 setInput i; lex_stringgap s
1202 where next = alexGetChar' i
1208 lex_stringgap :: String -> P Token
1209 lex_stringgap s = do
1212 '\\' -> lex_string s
1213 c | is_space c -> lex_stringgap s
1217 lex_char_tok :: Action
1218 -- Here we are basically parsing character literals, such as 'x' or '\n'
1219 -- but, when Template Haskell is on, we additionally spot
1220 -- 'x and ''T, returning ITvarQuote and ITtyQuote respectively,
1221 -- but WITHOUT CONSUMING the x or T part (the parser does that).
1222 -- So we have to do two characters of lookahead: when we see 'x we need to
1223 -- see if there's a trailing quote
1224 lex_char_tok span _buf _len = do -- We've seen '
1225 i1 <- getInput -- Look ahead to first character
1226 let loc = srcSpanStart span
1227 case alexGetChar' i1 of
1228 Nothing -> lit_error
1230 Just ('\'', i2@(AI end2 _ _)) -> do -- We've seen ''
1231 th_exts <- extension thEnabled
1234 return (L (mkSrcSpan loc end2) ITtyQuote)
1237 Just ('\\', i2@(AI _end2 _ _)) -> do -- We've seen 'backslash
1239 lit_ch <- lex_escape
1240 mc <- getCharOrFail -- Trailing quote
1241 if mc == '\'' then finish_char_tok loc lit_ch
1242 else do setInput i2; lit_error
1244 Just (c, i2@(AI _end2 _ _))
1245 | not (isAny c) -> lit_error
1248 -- We've seen 'x, where x is a valid character
1249 -- (i.e. not newline etc) but not a quote or backslash
1250 case alexGetChar' i2 of -- Look ahead one more character
1251 Just ('\'', i3) -> do -- We've seen 'x'
1253 finish_char_tok loc c
1254 _other -> do -- We've seen 'x not followed by quote
1255 -- (including the possibility of EOF)
1256 -- If TH is on, just parse the quote only
1257 th_exts <- extension thEnabled
1258 let (AI end _ _) = i1
1259 if th_exts then return (L (mkSrcSpan loc end) ITvarQuote)
1260 else do setInput i2; lit_error
1262 finish_char_tok :: SrcLoc -> Char -> P (Located Token)
1263 finish_char_tok loc ch -- We've already seen the closing quote
1264 -- Just need to check for trailing #
1265 = do magicHash <- extension magicHashEnabled
1266 i@(AI end _ _) <- getInput
1267 if magicHash then do
1268 case alexGetChar' i of
1269 Just ('#',i@(AI end _ _)) -> do
1271 return (L (mkSrcSpan loc end) (ITprimchar ch))
1273 return (L (mkSrcSpan loc end) (ITchar ch))
1275 return (L (mkSrcSpan loc end) (ITchar ch))
1277 lex_char :: Char -> AlexInput -> P Char
1280 '\\' -> do setInput inp; lex_escape
1281 c | isAny c -> do setInput inp; return c
1284 isAny :: Char -> Bool
1285 isAny c | c > '\x7f' = isPrint c
1286 | otherwise = is_any c
1288 lex_escape :: P Char
1302 '^' -> do c <- getCharOrFail
1303 if c >= '@' && c <= '_'
1304 then return (chr (ord c - ord '@'))
1307 'x' -> readNum is_hexdigit 16 hexDigit
1308 'o' -> readNum is_octdigit 8 octDecDigit
1309 x | is_decdigit x -> readNum2 is_decdigit 10 octDecDigit (octDecDigit x)
1313 case alexGetChar' i of
1314 Nothing -> lit_error
1316 case alexGetChar' i2 of
1317 Nothing -> do setInput i2; lit_error
1319 let str = [c1,c2,c3] in
1320 case [ (c,rest) | (p,c) <- silly_escape_chars,
1321 Just rest <- [stripPrefix p str] ] of
1322 (escape_char,[]):_ -> do
1325 (escape_char,_:_):_ -> do
1330 readNum :: (Char -> Bool) -> Int -> (Char -> Int) -> P Char
1331 readNum is_digit base conv = do
1335 then readNum2 is_digit base conv (conv c)
1336 else do setInput i; lit_error
1338 readNum2 :: (Char -> Bool) -> Int -> (Char -> Int) -> Int -> P Char
1339 readNum2 is_digit base conv i = do
1342 where read i input = do
1343 case alexGetChar' input of
1344 Just (c,input') | is_digit c -> do
1345 read (i*base + conv c) input'
1347 if i >= 0 && i <= 0x10FFFF
1348 then do setInput input; return (chr i)
1351 silly_escape_chars :: [(String, Char)]
1352 silly_escape_chars = [
1389 -- before calling lit_error, ensure that the current input is pointing to
1390 -- the position of the error in the buffer. This is so that we can report
1391 -- a correct location to the user, but also so we can detect UTF-8 decoding
1392 -- errors if they occur.
1394 lit_error = lexError "lexical error in string/character literal"
1396 getCharOrFail :: P Char
1399 case alexGetChar' i of
1400 Nothing -> lexError "unexpected end-of-file in string/character literal"
1401 Just (c,i) -> do setInput i; return c
1403 -- -----------------------------------------------------------------------------
1406 lex_quasiquote_tok :: Action
1407 lex_quasiquote_tok span buf len = do
1408 let quoter = reverse $ takeWhile (/= '$')
1409 $ reverse $ lexemeToString buf (len - 1)
1410 quoteStart <- getSrcLoc
1411 quote <- lex_quasiquote ""
1413 return (L (mkSrcSpan (srcSpanStart span) end)
1414 (ITquasiQuote (mkFastString quoter,
1415 mkFastString (reverse quote),
1416 mkSrcSpan quoteStart end)))
1418 lex_quasiquote :: String -> P String
1419 lex_quasiquote s = do
1421 case alexGetChar' i of
1422 Nothing -> lit_error
1425 | Just ('|',i) <- next -> do
1426 setInput i; lex_quasiquote ('|' : s)
1427 | Just (']',i) <- next -> do
1428 setInput i; lex_quasiquote (']' : s)
1429 where next = alexGetChar' i
1432 | Just (']',i) <- next -> do
1433 setInput i; return s
1434 where next = alexGetChar' i
1437 setInput i; lex_quasiquote (c : s)
1439 -- -----------------------------------------------------------------------------
1442 warn :: DynFlag -> SDoc -> Action
1443 warn option warning srcspan _buf _len = do
1444 addWarning option srcspan warning
1447 warnThen :: DynFlag -> SDoc -> Action -> Action
1448 warnThen option warning action srcspan buf len = do
1449 addWarning option srcspan warning
1450 action srcspan buf len
1452 -- -----------------------------------------------------------------------------
1463 SrcSpan -- The start and end of the text span related to
1464 -- the error. Might be used in environments which can
1465 -- show this span, e.g. by highlighting it.
1466 Message -- The error message
1468 data PState = PState {
1469 buffer :: StringBuffer,
1471 messages :: Messages,
1472 last_loc :: SrcSpan, -- pos of previous token
1473 last_offs :: !Int, -- offset of the previous token from the
1474 -- beginning of the current line.
1475 -- \t is equal to 8 spaces.
1476 last_len :: !Int, -- len of previous token
1477 last_line_len :: !Int,
1478 loc :: SrcLoc, -- current loc (end of prev token + 1)
1479 extsBitmap :: !Int, -- bitmap that determines permitted extensions
1480 context :: [LayoutContext],
1483 -- last_loc and last_len are used when generating error messages,
1484 -- and in pushCurrentContext only. Sigh, if only Happy passed the
1485 -- current token to happyError, we could at least get rid of last_len.
1486 -- Getting rid of last_loc would require finding another way to
1487 -- implement pushCurrentContext (which is only called from one place).
1489 newtype P a = P { unP :: PState -> ParseResult a }
1491 instance Monad P where
1497 returnP a = a `seq` (P $ \s -> POk s a)
1499 thenP :: P a -> (a -> P b) -> P b
1500 (P m) `thenP` k = P $ \ s ->
1502 POk s1 a -> (unP (k a)) s1
1503 PFailed span err -> PFailed span err
1505 failP :: String -> P a
1506 failP msg = P $ \s -> PFailed (last_loc s) (text msg)
1508 failMsgP :: String -> P a
1509 failMsgP msg = P $ \s -> PFailed (last_loc s) (text msg)
1511 failLocMsgP :: SrcLoc -> SrcLoc -> String -> P a
1512 failLocMsgP loc1 loc2 str = P $ \_ -> PFailed (mkSrcSpan loc1 loc2) (text str)
1514 failSpanMsgP :: SrcSpan -> SDoc -> P a
1515 failSpanMsgP span msg = P $ \_ -> PFailed span msg
1517 getPState :: P PState
1518 getPState = P $ \s -> POk s s
1520 extension :: (Int -> Bool) -> P Bool
1521 extension p = P $ \s -> POk s (p $! extsBitmap s)
1524 getExts = P $ \s -> POk s (extsBitmap s)
1526 setExts :: (Int -> Int) -> P ()
1527 setExts f = P $ \s -> POk s{ extsBitmap = f (extsBitmap s) } ()
1529 setSrcLoc :: SrcLoc -> P ()
1530 setSrcLoc new_loc = P $ \s -> POk s{loc=new_loc} ()
1532 getSrcLoc :: P SrcLoc
1533 getSrcLoc = P $ \s@(PState{ loc=loc }) -> POk s loc
1535 setLastToken :: SrcSpan -> Int -> Int -> P ()
1536 setLastToken loc len line_len = P $ \s -> POk s {
1539 last_line_len=line_len
1542 data AlexInput = AI SrcLoc {-#UNPACK#-}!Int StringBuffer
1544 alexInputPrevChar :: AlexInput -> Char
1545 alexInputPrevChar (AI _ _ buf) = prevChar buf '\n'
1547 alexGetChar :: AlexInput -> Maybe (Char,AlexInput)
1548 alexGetChar (AI loc ofs s)
1550 | otherwise = adj_c `seq` loc' `seq` ofs' `seq` s' `seq`
1551 --trace (show (ord c)) $
1552 Just (adj_c, (AI loc' ofs' s'))
1553 where (c,s') = nextChar s
1554 loc' = advanceSrcLoc loc c
1555 ofs' = advanceOffs c ofs
1563 other_graphic = '\x6'
1566 | c <= '\x06' = non_graphic
1568 -- Alex doesn't handle Unicode, so when Unicode
1569 -- character is encountered we output these values
1570 -- with the actual character value hidden in the state.
1572 case generalCategory c of
1573 UppercaseLetter -> upper
1574 LowercaseLetter -> lower
1575 TitlecaseLetter -> upper
1576 ModifierLetter -> other_graphic
1577 OtherLetter -> lower -- see #1103
1578 NonSpacingMark -> other_graphic
1579 SpacingCombiningMark -> other_graphic
1580 EnclosingMark -> other_graphic
1581 DecimalNumber -> digit
1582 LetterNumber -> other_graphic
1583 OtherNumber -> other_graphic
1584 ConnectorPunctuation -> symbol
1585 DashPunctuation -> symbol
1586 OpenPunctuation -> other_graphic
1587 ClosePunctuation -> other_graphic
1588 InitialQuote -> other_graphic
1589 FinalQuote -> other_graphic
1590 OtherPunctuation -> symbol
1591 MathSymbol -> symbol
1592 CurrencySymbol -> symbol
1593 ModifierSymbol -> symbol
1594 OtherSymbol -> symbol
1596 _other -> non_graphic
1598 -- This version does not squash unicode characters, it is used when
1600 alexGetChar' :: AlexInput -> Maybe (Char,AlexInput)
1601 alexGetChar' (AI loc ofs s)
1603 | otherwise = c `seq` loc' `seq` ofs' `seq` s' `seq`
1604 --trace (show (ord c)) $
1605 Just (c, (AI loc' ofs' s'))
1606 where (c,s') = nextChar s
1607 loc' = advanceSrcLoc loc c
1608 ofs' = advanceOffs c ofs
1610 advanceOffs :: Char -> Int -> Int
1611 advanceOffs '\n' _ = 0
1612 advanceOffs '\t' offs = (offs `quot` 8 + 1) * 8
1613 advanceOffs _ offs = offs + 1
1615 getInput :: P AlexInput
1616 getInput = P $ \s@PState{ loc=l, last_offs=o, buffer=b } -> POk s (AI l o b)
1618 setInput :: AlexInput -> P ()
1619 setInput (AI l o b) = P $ \s -> POk s{ loc=l, last_offs=o, buffer=b } ()
1621 pushLexState :: Int -> P ()
1622 pushLexState ls = P $ \s@PState{ lex_state=l } -> POk s{lex_state=ls:l} ()
1624 popLexState :: P Int
1625 popLexState = P $ \s@PState{ lex_state=ls:l } -> POk s{ lex_state=l } ls
1627 getLexState :: P Int
1628 getLexState = P $ \s@PState{ lex_state=ls:_ } -> POk s ls
1630 -- for reasons of efficiency, flags indicating language extensions (eg,
1631 -- -fglasgow-exts or -XParr) are represented by a bitmap stored in an unboxed
1635 genericsBit = 0 -- {| and |}
1646 explicitForallBit :: Int
1647 explicitForallBit = 7 -- the 'forall' keyword and '.' symbol
1649 bangPatBit = 8 -- Tells the parser to understand bang-patterns
1650 -- (doesn't affect the lexer)
1652 tyFamBit = 9 -- indexed type families: 'family' keyword and kind sigs
1654 haddockBit = 10 -- Lex and parse Haddock comments
1656 magicHashBit = 11 -- "#" in both functions and operators
1658 kindSigsBit = 12 -- Kind signatures on type variables
1659 recursiveDoBit :: Int
1660 recursiveDoBit = 13 -- mdo
1661 unicodeSyntaxBit :: Int
1662 unicodeSyntaxBit = 14 -- the forall symbol, arrow symbols, etc
1663 unboxedTuplesBit :: Int
1664 unboxedTuplesBit = 15 -- (# and #)
1665 standaloneDerivingBit :: Int
1666 standaloneDerivingBit = 16 -- standalone instance deriving declarations
1667 transformComprehensionsBit :: Int
1668 transformComprehensionsBit = 17
1670 qqBit = 18 -- enable quasiquoting
1671 inRulePragBit :: Int
1673 rawTokenStreamBit :: Int
1674 rawTokenStreamBit = 20 -- producing a token stream with all comments included
1675 newQualOpsBit :: Int
1676 newQualOpsBit = 21 -- Haskell' qualified operator syntax, e.g. Prelude.(+)
1678 always :: Int -> Bool
1680 genericsEnabled :: Int -> Bool
1681 genericsEnabled flags = testBit flags genericsBit
1682 parrEnabled :: Int -> Bool
1683 parrEnabled flags = testBit flags parrBit
1684 arrowsEnabled :: Int -> Bool
1685 arrowsEnabled flags = testBit flags arrowsBit
1686 thEnabled :: Int -> Bool
1687 thEnabled flags = testBit flags thBit
1688 ipEnabled :: Int -> Bool
1689 ipEnabled flags = testBit flags ipBit
1690 explicitForallEnabled :: Int -> Bool
1691 explicitForallEnabled flags = testBit flags explicitForallBit
1692 bangPatEnabled :: Int -> Bool
1693 bangPatEnabled flags = testBit flags bangPatBit
1694 -- tyFamEnabled :: Int -> Bool
1695 -- tyFamEnabled flags = testBit flags tyFamBit
1696 haddockEnabled :: Int -> Bool
1697 haddockEnabled flags = testBit flags haddockBit
1698 magicHashEnabled :: Int -> Bool
1699 magicHashEnabled flags = testBit flags magicHashBit
1700 -- kindSigsEnabled :: Int -> Bool
1701 -- kindSigsEnabled flags = testBit flags kindSigsBit
1702 unicodeSyntaxEnabled :: Int -> Bool
1703 unicodeSyntaxEnabled flags = testBit flags unicodeSyntaxBit
1704 unboxedTuplesEnabled :: Int -> Bool
1705 unboxedTuplesEnabled flags = testBit flags unboxedTuplesBit
1706 standaloneDerivingEnabled :: Int -> Bool
1707 standaloneDerivingEnabled flags = testBit flags standaloneDerivingBit
1708 qqEnabled :: Int -> Bool
1709 qqEnabled flags = testBit flags qqBit
1710 -- inRulePrag :: Int -> Bool
1711 -- inRulePrag flags = testBit flags inRulePragBit
1712 rawTokenStreamEnabled :: Int -> Bool
1713 rawTokenStreamEnabled flags = testBit flags rawTokenStreamBit
1714 newQualOps :: Int -> Bool
1715 newQualOps flags = testBit flags newQualOpsBit
1716 oldQualOps :: Int -> Bool
1717 oldQualOps flags = not (newQualOps flags)
1719 -- PState for parsing options pragmas
1721 pragState :: DynFlags -> StringBuffer -> SrcLoc -> PState
1722 pragState dynflags buf loc =
1725 messages = emptyMessages,
1727 last_loc = mkSrcSpan loc loc,
1734 lex_state = [bol, option_prags, 0]
1738 -- create a parse state
1740 mkPState :: StringBuffer -> SrcLoc -> DynFlags -> PState
1741 mkPState buf loc flags =
1745 messages = emptyMessages,
1746 last_loc = mkSrcSpan loc loc,
1751 extsBitmap = fromIntegral bitmap,
1753 lex_state = [bol, 0]
1754 -- we begin in the layout state if toplev_layout is set
1757 bitmap = genericsBit `setBitIf` dopt Opt_Generics flags
1758 .|. ffiBit `setBitIf` dopt Opt_ForeignFunctionInterface flags
1759 .|. parrBit `setBitIf` dopt Opt_PArr flags
1760 .|. arrowsBit `setBitIf` dopt Opt_Arrows flags
1761 .|. thBit `setBitIf` dopt Opt_TemplateHaskell flags
1762 .|. qqBit `setBitIf` dopt Opt_QuasiQuotes flags
1763 .|. ipBit `setBitIf` dopt Opt_ImplicitParams flags
1764 .|. explicitForallBit `setBitIf` dopt Opt_ScopedTypeVariables flags
1765 .|. explicitForallBit `setBitIf` dopt Opt_LiberalTypeSynonyms flags
1766 .|. explicitForallBit `setBitIf` dopt Opt_PolymorphicComponents flags
1767 .|. explicitForallBit `setBitIf` dopt Opt_ExistentialQuantification flags
1768 .|. explicitForallBit `setBitIf` dopt Opt_Rank2Types flags
1769 .|. explicitForallBit `setBitIf` dopt Opt_RankNTypes flags
1770 .|. bangPatBit `setBitIf` dopt Opt_BangPatterns flags
1771 .|. tyFamBit `setBitIf` dopt Opt_TypeFamilies flags
1772 .|. haddockBit `setBitIf` dopt Opt_Haddock flags
1773 .|. magicHashBit `setBitIf` dopt Opt_MagicHash flags
1774 .|. kindSigsBit `setBitIf` dopt Opt_KindSignatures flags
1775 .|. recursiveDoBit `setBitIf` dopt Opt_RecursiveDo flags
1776 .|. unicodeSyntaxBit `setBitIf` dopt Opt_UnicodeSyntax flags
1777 .|. unboxedTuplesBit `setBitIf` dopt Opt_UnboxedTuples flags
1778 .|. standaloneDerivingBit `setBitIf` dopt Opt_StandaloneDeriving flags
1779 .|. transformComprehensionsBit `setBitIf` dopt Opt_TransformListComp flags
1780 .|. rawTokenStreamBit `setBitIf` dopt Opt_KeepRawTokenStream flags
1781 .|. newQualOpsBit `setBitIf` dopt Opt_NewQualifiedOperators flags
1783 setBitIf :: Int -> Bool -> Int
1784 b `setBitIf` cond | cond = bit b
1787 addWarning :: DynFlag -> SrcSpan -> SDoc -> P ()
1788 addWarning option srcspan warning
1789 = P $ \s@PState{messages=(ws,es), dflags=d} ->
1790 let warning' = mkWarnMsg srcspan alwaysQualify warning
1791 ws' = if dopt option d then ws `snocBag` warning' else ws
1792 in POk s{messages=(ws', es)} ()
1794 getMessages :: PState -> Messages
1795 getMessages PState{messages=ms} = ms
1797 getContext :: P [LayoutContext]
1798 getContext = P $ \s@PState{context=ctx} -> POk s ctx
1800 setContext :: [LayoutContext] -> P ()
1801 setContext ctx = P $ \s -> POk s{context=ctx} ()
1804 popContext = P $ \ s@(PState{ buffer = buf, context = ctx,
1805 last_len = len, last_loc = last_loc }) ->
1807 (_:tl) -> POk s{ context = tl } ()
1808 [] -> PFailed last_loc (srcParseErr buf len)
1810 -- Push a new layout context at the indentation of the last token read.
1811 -- This is only used at the outer level of a module when the 'module'
1812 -- keyword is missing.
1813 pushCurrentContext :: P ()
1814 pushCurrentContext = P $ \ s@PState{ last_offs=offs, last_line_len=len, context=ctx } ->
1815 POk s{context = Layout (offs-len) : ctx} ()
1816 --trace ("off: " ++ show offs ++ ", len: " ++ show len) $ POk s{context = Layout (offs-len) : ctx} ()
1818 getOffside :: P Ordering
1819 getOffside = P $ \s@PState{last_offs=offs, context=stk} ->
1820 let ord = case stk of
1821 (Layout n:_) -> compare offs n
1825 -- ---------------------------------------------------------------------------
1826 -- Construct a parse error
1829 :: StringBuffer -- current buffer (placed just after the last token)
1830 -> Int -- length of the previous token
1833 = hcat [ if null token
1834 then ptext (sLit "parse error (possibly incorrect indentation)")
1835 else hcat [ptext (sLit "parse error on input "),
1836 char '`', text token, char '\'']
1838 where token = lexemeToString (offsetBytes (-len) buf) len
1840 -- Report a parse failure, giving the span of the previous token as
1841 -- the location of the error. This is the entry point for errors
1842 -- detected during parsing.
1844 srcParseFail = P $ \PState{ buffer = buf, last_len = len,
1845 last_loc = last_loc } ->
1846 PFailed last_loc (srcParseErr buf len)
1848 -- A lexical error is reported at a particular position in the source file,
1849 -- not over a token range.
1850 lexError :: String -> P a
1853 (AI end _ buf) <- getInput
1854 reportLexError loc end buf str
1856 -- -----------------------------------------------------------------------------
1857 -- This is the top-level function: called from the parser each time a
1858 -- new token is to be read from the input.
1860 lexer :: (Located Token -> P a) -> P a
1862 tok@(L _span _tok__) <- lexToken
1863 -- trace ("token: " ++ show tok__) $ do
1866 lexToken :: P (Located Token)
1868 inp@(AI loc1 _ buf) <- getInput
1871 case alexScanUser exts inp sc of
1873 let span = mkSrcSpan loc1 loc1
1874 setLastToken span 0 0
1875 return (L span ITeof)
1876 AlexError (AI loc2 _ buf) ->
1877 reportLexError loc1 loc2 buf "lexical error"
1878 AlexSkip inp2 _ -> do
1881 AlexToken inp2@(AI end _ buf2) _ t -> do
1883 let span = mkSrcSpan loc1 end
1884 let bytes = byteDiff buf buf2
1885 span `seq` setLastToken span bytes bytes
1888 reportLexError :: SrcLoc -> SrcLoc -> StringBuffer -> [Char] -> P a
1889 reportLexError loc1 loc2 buf str
1890 | atEnd buf = failLocMsgP loc1 loc2 (str ++ " at end of input")
1893 c = fst (nextChar buf)
1895 if c == '\0' -- decoding errors are mapped to '\0', see utf8DecodeChar#
1896 then failLocMsgP loc2 loc2 (str ++ " (UTF-8 decoding error)")
1897 else failLocMsgP loc1 loc2 (str ++ " at character " ++ show c)
1899 lexTokenStream :: StringBuffer -> SrcLoc -> DynFlags -> ParseResult [Located Token]
1900 lexTokenStream buf loc dflags = unP go initState
1901 where initState = mkPState buf loc (dopt_set (dopt_unset dflags Opt_Haddock) Opt_KeepRawTokenStream)
1903 ltok <- lexer return
1905 L _ ITeof -> return []
1906 _ -> liftM (ltok:) go
1908 linePrags = Map.singleton "line" (begin line_prag2)
1910 fileHeaderPrags = Map.fromList([("options", lex_string_prag IToptions_prag),
1911 ("options_ghc", lex_string_prag IToptions_prag),
1912 ("options_haddock", lex_string_prag ITdocOptions),
1913 ("language", token ITlanguage_prag),
1914 ("include", lex_string_prag ITinclude_prag)])
1916 ignoredPrags = Map.fromList (map ignored pragmas)
1917 where ignored opt = (opt, nested_comment lexToken)
1918 impls = ["hugs", "nhc98", "jhc", "yhc", "catch", "derive"]
1919 options_pragmas = map ("options_" ++) impls
1920 -- CFILES is a hugs-only thing.
1921 pragmas = options_pragmas ++ ["cfiles", "contract"]
1923 oneWordPrags = Map.fromList([("rules", rulePrag),
1924 ("inline", token (ITinline_prag True)),
1925 ("notinline", token (ITinline_prag False)),
1926 ("specialize", token ITspec_prag),
1927 ("source", token ITsource_prag),
1928 ("warning", token ITwarning_prag),
1929 ("deprecated", token ITdeprecated_prag),
1930 ("scc", token ITscc_prag),
1931 ("generated", token ITgenerated_prag),
1932 ("core", token ITcore_prag),
1933 ("unpack", token ITunpack_prag),
1934 ("ann", token ITann_prag)])
1936 twoWordPrags = Map.fromList([("inline conlike", token (ITinline_conlike_prag True)),
1937 ("notinline conlike", token (ITinline_conlike_prag False)),
1938 ("specialize inline", token (ITspec_inline_prag True)),
1939 ("specialize notinline", token (ITspec_inline_prag False))])
1942 dispatch_pragmas :: Map String Action -> Action
1943 dispatch_pragmas prags span buf len = case Map.lookup (clean_pragma (lexemeToString buf len)) prags of
1944 Just found -> found span buf len
1945 Nothing -> lexError "unknown pragma"
1947 known_pragma :: Map String Action -> AlexAccPred Int
1948 known_pragma prags _ _ len (AI _ _ buf) = (isJust $ Map.lookup (clean_pragma (lexemeToString (offsetBytes (- len) buf) len)) prags)
1949 && (nextCharIs buf (\c -> not (isAlphaNum c || c == '_')))
1951 clean_pragma :: String -> String
1952 clean_pragma prag = canon_ws (map toLower (unprefix prag))
1953 where unprefix prag' = case stripPrefix "{-#" prag' of
1956 canonical prag' = case prag' of
1957 "noinline" -> "notinline"
1958 "specialise" -> "specialize"
1959 "constructorlike" -> "conlike"
1961 canon_ws s = unwords (map canonical (words s))