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 -- XXX The above flags turn off warnings in the generated code:
35 {-# OPTIONS_GHC -fno-warn-unused-matches #-}
36 {-# OPTIONS_GHC -fno-warn-unused-binds #-}
37 {-# OPTIONS_GHC -fno-warn-unused-imports #-}
38 {-# OPTIONS_GHC -fno-warn-missing-signatures #-}
39 -- But alex still generates some code that causes the "lazy unlifted bindings"
40 -- warning, and old compilers don't know about it so we can't easily turn
41 -- it off, so for now we use the sledge hammer:
42 {-# OPTIONS_GHC -w #-}
44 {-# OPTIONS_GHC -funbox-strict-fields #-}
47 Token(..), lexer, pragState, mkPState, PState(..),
48 P(..), ParseResult(..), getSrcLoc,
49 getPState, getDynFlags, withThisPackage,
50 failLocMsgP, failSpanMsgP, srcParseFail,
52 popContext, pushCurrentContext, setLastToken, setSrcLoc,
53 getLexState, popLexState, pushLexState,
54 extension, bangPatEnabled, datatypeContextsEnabled,
69 import BasicTypes ( InlineSpec(..), RuleMatchInfo(..) )
70 import Util ( readRational )
78 import qualified Data.Map as Map
82 $unispace = \x05 -- Trick Alex into handling Unicode. See alexGetChar.
83 $whitechar = [\ \n\r\f\v $unispace]
84 $white_no_nl = $whitechar # \n
88 $unidigit = \x03 -- Trick Alex into handling Unicode. See alexGetChar.
89 $decdigit = $ascdigit -- for now, should really be $digit (ToDo)
90 $digit = [$ascdigit $unidigit]
92 $special = [\(\)\,\;\[\]\`\{\}]
93 $ascsymbol = [\!\#\$\%\&\*\+\.\/\<\=\>\?\@\\\^\|\-\~]
94 $unisymbol = \x04 -- Trick Alex into handling Unicode. See alexGetChar.
95 $symbol = [$ascsymbol $unisymbol] # [$special \_\:\"\']
97 $unilarge = \x01 -- Trick Alex into handling Unicode. See alexGetChar.
99 $large = [$asclarge $unilarge]
101 $unismall = \x02 -- Trick Alex into handling Unicode. See alexGetChar.
103 $small = [$ascsmall $unismall \_]
105 $unigraphic = \x06 -- Trick Alex into handling Unicode. See alexGetChar.
106 $graphic = [$small $large $symbol $digit $special $unigraphic \:\"\']
109 $hexit = [$decdigit A-F a-f]
110 $symchar = [$symbol \:]
112 $idchar = [$small $large $digit \']
114 $pragmachar = [$small $large $digit]
116 $docsym = [\| \^ \* \$]
118 @varid = $small $idchar*
119 @conid = $large $idchar*
121 @varsym = $symbol $symchar*
122 @consym = \: $symchar*
124 @decimal = $decdigit+
126 @hexadecimal = $hexit+
127 @exponent = [eE] [\-\+]? @decimal
129 -- we support the hierarchical module name extension:
132 @floating_point = @decimal \. @decimal @exponent? | @decimal @exponent
134 -- normal signed numerical literals can only be explicitly negative,
135 -- not explicitly positive (contrast @exponent)
137 @signed = @negative ?
141 -- everywhere: skip whitespace and comments
143 $tab+ { warn Opt_WarnTabs (text "Warning: Tab character") }
145 -- Everywhere: deal with nested comments. We explicitly rule out
146 -- pragmas, "{-#", so that we don't accidentally treat them as comments.
147 -- (this can happen even though pragmas will normally take precedence due to
148 -- longest-match, because pragmas aren't valid in every state, but comments
149 -- are). We also rule out nested Haddock comments, if the -haddock flag is
152 "{-" / { isNormalComment } { nested_comment lexToken }
154 -- Single-line comments are a bit tricky. Haskell 98 says that two or
155 -- more dashes followed by a symbol should be parsed as a varsym, so we
156 -- have to exclude those.
158 -- Since Haddock comments aren't valid in every state, we need to rule them
161 -- The following two rules match comments that begin with two dashes, but
162 -- continue with a different character. The rules test that this character
163 -- is not a symbol (in which case we'd have a varsym), and that it's not a
164 -- space followed by a Haddock comment symbol (docsym) (in which case we'd
165 -- have a Haddock comment). The rules then munch the rest of the line.
167 "-- " ~[$docsym \#] .* { lineCommentToken }
168 "--" [^$symbol : \ ] .* { lineCommentToken }
170 -- Next, match Haddock comments if no -haddock flag
172 "-- " [$docsym \#] .* / { ifExtension (not . haddockEnabled) } { lineCommentToken }
174 -- Now, when we've matched comments that begin with 2 dashes and continue
175 -- with a different character, we need to match comments that begin with three
176 -- or more dashes (which clearly can't be Haddock comments). We only need to
177 -- make sure that the first non-dash character isn't a symbol, and munch the
180 "---"\-* [^$symbol :] .* { lineCommentToken }
182 -- Since the previous rules all match dashes followed by at least one
183 -- character, we also need to match a whole line filled with just dashes.
185 "--"\-* / { atEOL } { lineCommentToken }
187 -- We need this rule since none of the other single line comment rules
188 -- actually match this case.
190 "-- " / { atEOL } { lineCommentToken }
192 -- 'bol' state: beginning of a line. Slurp up all the whitespace (including
193 -- blank lines) until we find a non-whitespace character, then do layout
196 -- One slight wibble here: what if the line begins with {-#? In
197 -- theory, we have to lex the pragma to see if it's one we recognise,
198 -- and if it is, then we backtrack and do_bol, otherwise we treat it
199 -- as a nested comment. We don't bother with this: if the line begins
200 -- with {-#, then we'll assume it's a pragma we know about and go for do_bol.
203 ^\# (line)? { begin line_prag1 }
204 ^\# pragma .* \n ; -- GCC 3.3 CPP generated, apparently
205 ^\# \! .* \n ; -- #!, for scripts
209 -- after a layout keyword (let, where, do, of), we begin a new layout
210 -- context if the curly brace is missing.
211 -- Careful! This stuff is quite delicate.
212 <layout, layout_do> {
213 \{ / { notFollowedBy '-' } { pop_and open_brace }
214 -- we might encounter {-# here, but {- has been handled already
216 ^\# (line)? { begin line_prag1 }
219 -- do is treated in a subtly different way, see new_layout_context
220 <layout> () { new_layout_context True }
221 <layout_do> () { new_layout_context False }
223 -- after a new layout context which was found to be to the left of the
224 -- previous context, we have generated a '{' token, and we now need to
225 -- generate a matching '}' token.
226 <layout_left> () { do_layout_left }
228 <0,option_prags> \n { begin bol }
230 "{-#" $whitechar* $pragmachar+ / { known_pragma linePrags }
231 { dispatch_pragmas linePrags }
233 -- single-line line pragmas, of the form
234 -- # <line> "<file>" <extra-stuff> \n
235 <line_prag1> $decdigit+ { setLine line_prag1a }
236 <line_prag1a> \" [$graphic \ ]* \" { setFile line_prag1b }
237 <line_prag1b> .* { pop }
239 -- Haskell-style line pragmas, of the form
240 -- {-# LINE <line> "<file>" #-}
241 <line_prag2> $decdigit+ { setLine line_prag2a }
242 <line_prag2a> \" [$graphic \ ]* \" { setFile line_prag2b }
243 <line_prag2b> "#-}"|"-}" { pop }
244 -- NOTE: accept -} at the end of a LINE pragma, for compatibility
245 -- with older versions of GHC which generated these.
248 "{-#" $whitechar* $pragmachar+
249 $whitechar+ $pragmachar+ / { known_pragma twoWordPrags }
250 { dispatch_pragmas twoWordPrags }
252 "{-#" $whitechar* $pragmachar+ / { known_pragma oneWordPrags }
253 { dispatch_pragmas oneWordPrags }
255 -- We ignore all these pragmas, but don't generate a warning for them
256 "{-#" $whitechar* $pragmachar+ / { known_pragma ignoredPrags }
257 { dispatch_pragmas ignoredPrags }
259 -- ToDo: should only be valid inside a pragma:
264 "{-#" $whitechar* $pragmachar+ / { known_pragma fileHeaderPrags }
265 { dispatch_pragmas fileHeaderPrags }
267 "-- #" { multiline_doc_comment }
271 -- In the "0" mode we ignore these pragmas
272 "{-#" $whitechar* $pragmachar+ / { known_pragma fileHeaderPrags }
273 { nested_comment lexToken }
277 "-- #" .* { lineCommentToken }
281 "{-#" { warnThen Opt_WarnUnrecognisedPragmas (text "Unrecognised pragma")
282 (nested_comment lexToken) }
285 -- '0' state: ordinary lexemes
290 "-- " $docsym / { ifExtension haddockEnabled } { multiline_doc_comment }
291 "{-" \ ? $docsym / { ifExtension haddockEnabled } { nested_doc_comment }
297 "[:" / { ifExtension parrEnabled } { token ITopabrack }
298 ":]" / { ifExtension parrEnabled } { token ITcpabrack }
302 "[|" / { ifExtension thEnabled } { token ITopenExpQuote }
303 "[e|" / { ifExtension thEnabled } { token ITopenExpQuote }
304 "[p|" / { ifExtension thEnabled } { token ITopenPatQuote }
305 "[d|" / { ifExtension thEnabled } { layout_token ITopenDecQuote }
306 "[t|" / { ifExtension thEnabled } { token ITopenTypQuote }
307 "|]" / { ifExtension thEnabled } { token ITcloseQuote }
308 \$ @varid / { ifExtension thEnabled } { skip_one_varid ITidEscape }
309 "$(" / { ifExtension thEnabled } { token ITparenEscape }
311 -- For backward compatibility, accept the old dollar syntax
312 "[$" @varid "|" / { ifExtension qqEnabled }
313 { lex_quasiquote_tok }
315 "[" @varid "|" / { ifExtension qqEnabled }
316 { lex_quasiquote_tok }
320 "(|" / { ifExtension arrowsEnabled `alexAndPred` notFollowedBySymbol }
321 { special IToparenbar }
322 "|)" / { ifExtension arrowsEnabled } { special ITcparenbar }
326 \? @varid / { ifExtension ipEnabled } { skip_one_varid ITdupipvarid }
330 "(#" / { ifExtension unboxedTuplesEnabled `alexAndPred` notFollowedBySymbol }
331 { token IToubxparen }
332 "#)" / { ifExtension unboxedTuplesEnabled }
333 { token ITcubxparen }
337 "{|" / { ifExtension genericsEnabled } { token ITocurlybar }
338 "|}" / { ifExtension genericsEnabled } { token ITccurlybar }
342 \( { special IToparen }
343 \) { special ITcparen }
344 \[ { special ITobrack }
345 \] { special ITcbrack }
346 \, { special ITcomma }
347 \; { special ITsemi }
348 \` { special ITbackquote }
355 @qual @varid { idtoken qvarid }
356 @qual @conid { idtoken qconid }
358 @conid { idtoken conid }
362 @qual @varid "#"+ / { ifExtension magicHashEnabled } { idtoken qvarid }
363 @qual @conid "#"+ / { ifExtension magicHashEnabled } { idtoken qconid }
364 @varid "#"+ / { ifExtension magicHashEnabled } { varid }
365 @conid "#"+ / { ifExtension magicHashEnabled } { idtoken conid }
368 -- ToDo: - move `var` and (sym) into lexical syntax?
369 -- - remove backquote from $special?
371 @qual @varsym / { ifExtension oldQualOps } { idtoken qvarsym }
372 @qual @consym / { ifExtension oldQualOps } { idtoken qconsym }
373 @qual \( @varsym \) / { ifExtension newQualOps } { idtoken prefixqvarsym }
374 @qual \( @consym \) / { ifExtension newQualOps } { idtoken prefixqconsym }
379 -- For the normal boxed literals we need to be careful
380 -- when trying to be close to Haskell98
382 -- Normal integral literals (:: Num a => a, from Integer)
383 @decimal { tok_num positive 0 0 decimal }
384 0[oO] @octal { tok_num positive 2 2 octal }
385 0[xX] @hexadecimal { tok_num positive 2 2 hexadecimal }
387 -- Normal rational literals (:: Fractional a => a, from Rational)
388 @floating_point { strtoken tok_float }
392 -- Unboxed ints (:: Int#) and words (:: Word#)
393 -- It's simpler (and faster?) to give separate cases to the negatives,
394 -- especially considering octal/hexadecimal prefixes.
395 @decimal \# / { ifExtension magicHashEnabled } { tok_primint positive 0 1 decimal }
396 0[oO] @octal \# / { ifExtension magicHashEnabled } { tok_primint positive 2 3 octal }
397 0[xX] @hexadecimal \# / { ifExtension magicHashEnabled } { tok_primint positive 2 3 hexadecimal }
398 @negative @decimal \# / { ifExtension magicHashEnabled } { tok_primint negative 1 2 decimal }
399 @negative 0[oO] @octal \# / { ifExtension magicHashEnabled } { tok_primint negative 3 4 octal }
400 @negative 0[xX] @hexadecimal \# / { ifExtension magicHashEnabled } { tok_primint negative 3 4 hexadecimal }
402 @decimal \# \# / { ifExtension magicHashEnabled } { tok_primword 0 2 decimal }
403 0[oO] @octal \# \# / { ifExtension magicHashEnabled } { tok_primword 2 4 octal }
404 0[xX] @hexadecimal \# \# / { ifExtension magicHashEnabled } { tok_primword 2 4 hexadecimal }
406 -- Unboxed floats and doubles (:: Float#, :: Double#)
407 -- prim_{float,double} work with signed literals
408 @signed @floating_point \# / { ifExtension magicHashEnabled } { init_strtoken 1 tok_primfloat }
409 @signed @floating_point \# \# / { ifExtension magicHashEnabled } { init_strtoken 2 tok_primdouble }
412 -- Strings and chars are lexed by hand-written code. The reason is
413 -- that even if we recognise the string or char here in the regex
414 -- lexer, we would still have to parse the string afterward in order
415 -- to convert it to a String.
418 \" { lex_string_tok }
422 -- -----------------------------------------------------------------------------
426 = ITas -- Haskell keywords
450 | ITscc -- ToDo: remove (we use {-# SCC "..." #-} now)
452 | ITforall -- GHC extension keywords
471 | ITinline_prag InlineSpec RuleMatchInfo
472 | ITspec_prag -- SPECIALISE
473 | ITspec_inline_prag Bool -- SPECIALISE INLINE (or NOINLINE)
481 | ITcore_prag -- hdaume: core annotations
485 | IToptions_prag String
486 | ITinclude_prag String
489 | ITdotdot -- reserved symbols
505 | ITbiglam -- GHC-extension symbols
507 | ITocurly -- special symbols
509 | ITocurlybar -- {|, for type applications
510 | ITccurlybar -- |}, for type applications
514 | ITopabrack -- [:, for parallel arrays with -XParr
515 | ITcpabrack -- :], for parallel arrays with -XParr
526 | ITvarid FastString -- identifiers
528 | ITvarsym FastString
529 | ITconsym FastString
530 | ITqvarid (FastString,FastString)
531 | ITqconid (FastString,FastString)
532 | ITqvarsym (FastString,FastString)
533 | ITqconsym (FastString,FastString)
534 | ITprefixqvarsym (FastString,FastString)
535 | ITprefixqconsym (FastString,FastString)
537 | ITdupipvarid FastString -- GHC extension: implicit param: ?x
540 | ITstring FastString
542 | ITrational Rational
545 | ITprimstring FastString
548 | ITprimfloat Rational
549 | ITprimdouble Rational
551 -- Template Haskell extension tokens
552 | ITopenExpQuote -- [| or [e|
553 | ITopenPatQuote -- [p|
554 | ITopenDecQuote -- [d|
555 | ITopenTypQuote -- [t|
557 | ITidEscape FastString -- $x
558 | ITparenEscape -- $(
561 | ITquasiQuote (FastString,FastString,SrcSpan) -- [:...|...|]
563 -- Arrow notation extension
570 | ITLarrowtail -- -<<
571 | ITRarrowtail -- >>-
573 | ITunknown String -- Used when the lexer can't make sense of it
574 | ITeof -- end of file token
576 -- Documentation annotations
577 | ITdocCommentNext String -- something beginning '-- |'
578 | ITdocCommentPrev String -- something beginning '-- ^'
579 | ITdocCommentNamed String -- something beginning '-- $'
580 | ITdocSection Int String -- a section heading
581 | ITdocOptions String -- doc options (prune, ignore-exports, etc)
582 | ITdocOptionsOld String -- doc options declared "-- # ..."-style
583 | ITlineComment String -- comment starting by "--"
584 | ITblockComment String -- comment in {- -}
587 deriving Show -- debugging
591 isSpecial :: Token -> Bool
592 -- If we see M.x, where x is a keyword, but
593 -- is special, we treat is as just plain M.x,
595 isSpecial ITas = True
596 isSpecial IThiding = True
597 isSpecial ITqualified = True
598 isSpecial ITforall = True
599 isSpecial ITexport = True
600 isSpecial ITlabel = True
601 isSpecial ITdynamic = True
602 isSpecial ITsafe = True
603 isSpecial ITthreadsafe = True
604 isSpecial ITinterruptible = True
605 isSpecial ITunsafe = True
606 isSpecial ITccallconv = True
607 isSpecial ITstdcallconv = True
608 isSpecial ITprimcallconv = True
609 isSpecial ITmdo = True
610 isSpecial ITfamily = True
611 isSpecial ITgroup = True
612 isSpecial ITby = True
613 isSpecial ITusing = True
617 -- the bitmap provided as the third component indicates whether the
618 -- corresponding extension keyword is valid under the extension options
619 -- provided to the compiler; if the extension corresponding to *any* of the
620 -- bits set in the bitmap is enabled, the keyword is valid (this setup
621 -- facilitates using a keyword in two different extensions that can be
622 -- activated independently)
624 reservedWordsFM :: UniqFM (Token, Int)
625 reservedWordsFM = listToUFM $
626 map (\(x, y, z) -> (mkFastString x, (y, z)))
627 [( "_", ITunderscore, 0 ),
629 ( "case", ITcase, 0 ),
630 ( "class", ITclass, 0 ),
631 ( "data", ITdata, 0 ),
632 ( "default", ITdefault, 0 ),
633 ( "deriving", ITderiving, 0 ),
635 ( "else", ITelse, 0 ),
636 ( "hiding", IThiding, 0 ),
638 ( "import", ITimport, 0 ),
640 ( "infix", ITinfix, 0 ),
641 ( "infixl", ITinfixl, 0 ),
642 ( "infixr", ITinfixr, 0 ),
643 ( "instance", ITinstance, 0 ),
645 ( "module", ITmodule, 0 ),
646 ( "newtype", ITnewtype, 0 ),
648 ( "qualified", ITqualified, 0 ),
649 ( "then", ITthen, 0 ),
650 ( "type", ITtype, 0 ),
651 ( "where", ITwhere, 0 ),
652 ( "_scc_", ITscc, 0 ), -- ToDo: remove
654 ( "forall", ITforall, bit explicitForallBit .|. bit inRulePragBit),
655 ( "mdo", ITmdo, bit recursiveDoBit),
656 ( "family", ITfamily, bit tyFamBit),
657 ( "group", ITgroup, bit transformComprehensionsBit),
658 ( "by", ITby, bit transformComprehensionsBit),
659 ( "using", ITusing, bit transformComprehensionsBit),
661 ( "foreign", ITforeign, bit ffiBit),
662 ( "export", ITexport, bit ffiBit),
663 ( "label", ITlabel, bit ffiBit),
664 ( "dynamic", ITdynamic, bit ffiBit),
665 ( "safe", ITsafe, bit ffiBit),
666 ( "threadsafe", ITthreadsafe, bit ffiBit), -- ToDo: remove
667 ( "interruptible", ITinterruptible, bit ffiBit),
668 ( "unsafe", ITunsafe, bit ffiBit),
669 ( "stdcall", ITstdcallconv, bit ffiBit),
670 ( "ccall", ITccallconv, bit ffiBit),
671 ( "prim", ITprimcallconv, bit ffiBit),
673 ( "rec", ITrec, bit recBit),
674 ( "proc", ITproc, bit arrowsBit)
677 reservedSymsFM :: UniqFM (Token, Int -> Bool)
678 reservedSymsFM = listToUFM $
679 map (\ (x,y,z) -> (mkFastString x,(y,z)))
680 [ ("..", ITdotdot, always)
681 -- (:) is a reserved op, meaning only list cons
682 ,(":", ITcolon, always)
683 ,("::", ITdcolon, always)
684 ,("=", ITequal, always)
685 ,("\\", ITlam, always)
686 ,("|", ITvbar, always)
687 ,("<-", ITlarrow, always)
688 ,("->", ITrarrow, always)
690 ,("~", ITtilde, always)
691 ,("=>", ITdarrow, always)
692 ,("-", ITminus, always)
693 ,("!", ITbang, always)
695 -- For data T (a::*) = MkT
696 ,("*", ITstar, always) -- \i -> kindSigsEnabled i || tyFamEnabled i)
697 -- For 'forall a . t'
698 ,(".", ITdot, always) -- \i -> explicitForallEnabled i || inRulePrag i)
700 ,("-<", ITlarrowtail, arrowsEnabled)
701 ,(">-", ITrarrowtail, arrowsEnabled)
702 ,("-<<", ITLarrowtail, arrowsEnabled)
703 ,(">>-", ITRarrowtail, arrowsEnabled)
705 ,("∷", ITdcolon, unicodeSyntaxEnabled)
706 ,("⇒", ITdarrow, unicodeSyntaxEnabled)
707 ,("∀", ITforall, \i -> unicodeSyntaxEnabled i &&
708 explicitForallEnabled i)
709 ,("→", ITrarrow, unicodeSyntaxEnabled)
710 ,("←", ITlarrow, unicodeSyntaxEnabled)
712 ,("⤙", ITlarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
713 ,("⤚", ITrarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
714 ,("⤛", ITLarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
715 ,("⤜", ITRarrowtail, \i -> unicodeSyntaxEnabled i && arrowsEnabled i)
717 ,("★", ITstar, unicodeSyntaxEnabled)
719 -- ToDo: ideally, → and ∷ should be "specials", so that they cannot
720 -- form part of a large operator. This would let us have a better
721 -- syntax for kinds: ɑ∷*→* would be a legal kind signature. (maybe).
724 -- -----------------------------------------------------------------------------
727 type Action = SrcSpan -> StringBuffer -> Int -> P (Located Token)
729 special :: Token -> Action
730 special tok span _buf _len = return (L span tok)
732 token, layout_token :: Token -> Action
733 token t span _buf _len = return (L span t)
734 layout_token t span _buf _len = pushLexState layout >> return (L span t)
736 idtoken :: (StringBuffer -> Int -> Token) -> Action
737 idtoken f span buf len = return (L span $! (f buf len))
739 skip_one_varid :: (FastString -> Token) -> Action
740 skip_one_varid f span buf len
741 = return (L span $! f (lexemeToFastString (stepOn buf) (len-1)))
743 strtoken :: (String -> Token) -> Action
744 strtoken f span buf len =
745 return (L span $! (f $! lexemeToString buf len))
747 init_strtoken :: Int -> (String -> Token) -> Action
748 -- like strtoken, but drops the last N character(s)
749 init_strtoken drop f span buf len =
750 return (L span $! (f $! lexemeToString buf (len-drop)))
752 begin :: Int -> Action
753 begin code _span _str _len = do pushLexState code; lexToken
756 pop _span _buf _len = do _ <- popLexState
759 pop_and :: Action -> Action
760 pop_and act span buf len = do _ <- popLexState
763 {-# INLINE nextCharIs #-}
764 nextCharIs :: StringBuffer -> (Char -> Bool) -> Bool
765 nextCharIs buf p = not (atEnd buf) && p (currentChar buf)
767 notFollowedBy :: Char -> AlexAccPred Int
768 notFollowedBy char _ _ _ (AI _ buf)
769 = nextCharIs buf (/=char)
771 notFollowedBySymbol :: AlexAccPred Int
772 notFollowedBySymbol _ _ _ (AI _ buf)
773 = nextCharIs buf (`notElem` "!#$%&*+./<=>?@\\^|-~")
775 -- We must reject doc comments as being ordinary comments everywhere.
776 -- In some cases the doc comment will be selected as the lexeme due to
777 -- maximal munch, but not always, because the nested comment rule is
778 -- valid in all states, but the doc-comment rules are only valid in
779 -- the non-layout states.
780 isNormalComment :: AlexAccPred Int
781 isNormalComment bits _ _ (AI _ buf)
782 | haddockEnabled bits = notFollowedByDocOrPragma
783 | otherwise = nextCharIs buf (/='#')
785 notFollowedByDocOrPragma
786 = not $ spaceAndP buf (`nextCharIs` (`elem` "|^*$#"))
788 spaceAndP :: StringBuffer -> (StringBuffer -> Bool) -> Bool
789 spaceAndP buf p = p buf || nextCharIs buf (==' ') && p (snd (nextChar buf))
792 haddockDisabledAnd p bits _ _ (AI _ buf)
793 = if haddockEnabled bits then False else (p buf)
796 atEOL :: AlexAccPred Int
797 atEOL _ _ _ (AI _ buf) = atEnd buf || currentChar buf == '\n'
799 ifExtension :: (Int -> Bool) -> AlexAccPred Int
800 ifExtension pred bits _ _ _ = pred bits
802 multiline_doc_comment :: Action
803 multiline_doc_comment span buf _len = withLexedDocType (worker "")
805 worker commentAcc input docType oneLine = case alexGetChar input of
807 | oneLine -> docCommentEnd input commentAcc docType buf span
808 | otherwise -> case checkIfCommentLine input' of
809 Just input -> worker ('\n':commentAcc) input docType False
810 Nothing -> docCommentEnd input commentAcc docType buf span
811 Just (c, input) -> worker (c:commentAcc) input docType oneLine
812 Nothing -> docCommentEnd input commentAcc docType buf span
814 checkIfCommentLine input = check (dropNonNewlineSpace input)
816 check input = case alexGetChar input of
817 Just ('-', input) -> case alexGetChar input of
818 Just ('-', input) -> case alexGetChar input of
819 Just (c, _) | c /= '-' -> Just input
824 dropNonNewlineSpace input = case alexGetChar input of
826 | isSpace c && c /= '\n' -> dropNonNewlineSpace input'
830 lineCommentToken :: Action
831 lineCommentToken span buf len = do
832 b <- extension rawTokenStreamEnabled
833 if b then strtoken ITlineComment span buf len else lexToken
836 nested comments require traversing by hand, they can't be parsed
837 using regular expressions.
839 nested_comment :: P (Located Token) -> Action
840 nested_comment cont span _str _len = do
844 go commentAcc 0 input = do setInput input
845 b <- extension rawTokenStreamEnabled
847 then docCommentEnd input commentAcc ITblockComment _str span
849 go commentAcc n input = 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) -> go commentAcc (n-1) input
854 Just (_,_) -> go ('-':commentAcc) n input
855 Just ('\123',input) -> case alexGetChar input of
856 Nothing -> errBrace input span
857 Just ('-',input) -> go ('-':'\123':commentAcc) (n+1) input
858 Just (_,_) -> go ('\123':commentAcc) n input
859 Just (c,input) -> go (c:commentAcc) n input
861 nested_doc_comment :: Action
862 nested_doc_comment span buf _len = withLexedDocType (go "")
864 go commentAcc input docType _ = case alexGetChar input of
865 Nothing -> errBrace input span
866 Just ('-',input) -> case alexGetChar input of
867 Nothing -> errBrace input span
868 Just ('\125',input) ->
869 docCommentEnd input commentAcc docType buf span
870 Just (_,_) -> go ('-':commentAcc) input docType False
871 Just ('\123', input) -> case alexGetChar input of
872 Nothing -> errBrace input span
873 Just ('-',input) -> do
875 let cont = do input <- getInput; go commentAcc input docType False
876 nested_comment cont span buf _len
877 Just (_,_) -> go ('\123':commentAcc) input docType False
878 Just (c,input) -> go (c:commentAcc) input docType False
880 withLexedDocType :: (AlexInput -> (String -> Token) -> Bool -> P (Located Token))
882 withLexedDocType lexDocComment = do
883 input@(AI _ buf) <- getInput
884 case prevChar buf ' ' of
885 '|' -> lexDocComment input ITdocCommentNext False
886 '^' -> lexDocComment input ITdocCommentPrev False
887 '$' -> lexDocComment input ITdocCommentNamed False
888 '*' -> lexDocSection 1 input
889 '#' -> lexDocComment input ITdocOptionsOld False
890 _ -> panic "withLexedDocType: Bad doc type"
892 lexDocSection n input = case alexGetChar input of
893 Just ('*', input) -> lexDocSection (n+1) input
894 Just (_, _) -> lexDocComment input (ITdocSection n) True
895 Nothing -> do setInput input; lexToken -- eof reached, lex it normally
897 -- RULES pragmas turn on the forall and '.' keywords, and we turn them
898 -- off again at the end of the pragma.
900 rulePrag span _buf _len = do
901 setExts (.|. bit inRulePragBit)
902 return (L span ITrules_prag)
905 endPrag span _buf _len = do
906 setExts (.&. complement (bit inRulePragBit))
907 return (L span ITclose_prag)
910 -------------------------------------------------------------------------------
911 -- This function is quite tricky. We can't just return a new token, we also
912 -- need to update the state of the parser. Why? Because the token is longer
913 -- than what was lexed by Alex, and the lexToken function doesn't know this, so
914 -- it writes the wrong token length to the parser state. This function is
915 -- called afterwards, so it can just update the state.
917 docCommentEnd :: AlexInput -> String -> (String -> Token) -> StringBuffer ->
918 SrcSpan -> P (Located Token)
919 docCommentEnd input commentAcc docType buf span = do
921 let (AI loc nextBuf) = input
922 comment = reverse commentAcc
923 span' = mkSrcSpan (srcSpanStart span) loc
924 last_len = byteDiff buf nextBuf
926 span `seq` setLastToken span' last_len
927 return (L span' (docType comment))
929 errBrace :: AlexInput -> SrcSpan -> P a
930 errBrace (AI end _) span = failLocMsgP (srcSpanStart span) end "unterminated `{-'"
932 open_brace, close_brace :: Action
933 open_brace span _str _len = do
935 setContext (NoLayout:ctx)
936 return (L span ITocurly)
937 close_brace span _str _len = do
939 return (L span ITccurly)
941 qvarid, qconid :: StringBuffer -> Int -> Token
942 qvarid buf len = ITqvarid $! splitQualName buf len False
943 qconid buf len = ITqconid $! splitQualName buf len False
945 splitQualName :: StringBuffer -> Int -> Bool -> (FastString,FastString)
946 -- takes a StringBuffer and a length, and returns the module name
947 -- and identifier parts of a qualified name. Splits at the *last* dot,
948 -- because of hierarchical module names.
949 splitQualName orig_buf len parens = split orig_buf orig_buf
952 | orig_buf `byteDiff` buf >= len = done dot_buf
953 | c == '.' = found_dot buf'
954 | otherwise = split buf' dot_buf
956 (c,buf') = nextChar buf
958 -- careful, we might get names like M....
959 -- so, if the character after the dot is not upper-case, this is
960 -- the end of the qualifier part.
961 found_dot buf -- buf points after the '.'
962 | isUpper c = split buf' buf
963 | otherwise = done buf
965 (c,buf') = nextChar buf
968 (lexemeToFastString orig_buf (qual_size - 1),
969 if parens -- Prelude.(+)
970 then lexemeToFastString (stepOn dot_buf) (len - qual_size - 2)
971 else lexemeToFastString dot_buf (len - qual_size))
973 qual_size = orig_buf `byteDiff` dot_buf
978 case lookupUFM reservedWordsFM fs of
979 Just (keyword,0) -> do
981 return (L span keyword)
982 Just (keyword,exts) -> do
983 b <- extension (\i -> exts .&. i /= 0)
984 if b then do maybe_layout keyword
985 return (L span keyword)
986 else return (L span (ITvarid fs))
987 _other -> return (L span (ITvarid fs))
989 fs = lexemeToFastString buf len
991 conid :: StringBuffer -> Int -> Token
992 conid buf len = ITconid fs
993 where fs = lexemeToFastString buf len
995 qvarsym, qconsym, prefixqvarsym, prefixqconsym :: StringBuffer -> Int -> Token
996 qvarsym buf len = ITqvarsym $! splitQualName buf len False
997 qconsym buf len = ITqconsym $! splitQualName buf len False
998 prefixqvarsym buf len = ITprefixqvarsym $! splitQualName buf len True
999 prefixqconsym buf len = ITprefixqconsym $! splitQualName buf len True
1001 varsym, consym :: Action
1002 varsym = sym ITvarsym
1003 consym = sym ITconsym
1005 sym :: (FastString -> Token) -> SrcSpan -> StringBuffer -> Int
1006 -> P (Located Token)
1007 sym con span buf len =
1008 case lookupUFM reservedSymsFM fs of
1009 Just (keyword,exts) -> do
1011 if b then return (L span keyword)
1012 else return (L span $! con fs)
1013 _other -> return (L span $! con fs)
1015 fs = lexemeToFastString buf len
1017 -- Variations on the integral numeric literal.
1018 tok_integral :: (Integer -> Token)
1019 -> (Integer -> Integer)
1020 -- -> (StringBuffer -> StringBuffer) -> (Int -> Int)
1022 -> (Integer, (Char->Int)) -> Action
1023 tok_integral itint transint transbuf translen (radix,char_to_int) span buf len =
1024 return $ L span $ itint $! transint $ parseUnsignedInteger
1025 (offsetBytes transbuf buf) (subtract translen len) radix char_to_int
1027 -- some conveniences for use with tok_integral
1028 tok_num :: (Integer -> Integer)
1030 -> (Integer, (Char->Int)) -> Action
1031 tok_num = tok_integral ITinteger
1032 tok_primint :: (Integer -> Integer)
1034 -> (Integer, (Char->Int)) -> Action
1035 tok_primint = tok_integral ITprimint
1036 tok_primword :: Int -> Int
1037 -> (Integer, (Char->Int)) -> Action
1038 tok_primword = tok_integral ITprimword positive
1039 positive, negative :: (Integer -> Integer)
1042 decimal, octal, hexadecimal :: (Integer, Char -> Int)
1043 decimal = (10,octDecDigit)
1044 octal = (8,octDecDigit)
1045 hexadecimal = (16,hexDigit)
1047 -- readRational can understand negative rationals, exponents, everything.
1048 tok_float, tok_primfloat, tok_primdouble :: String -> Token
1049 tok_float str = ITrational $! readRational str
1050 tok_primfloat str = ITprimfloat $! readRational str
1051 tok_primdouble str = ITprimdouble $! readRational str
1053 -- -----------------------------------------------------------------------------
1054 -- Layout processing
1056 -- we're at the first token on a line, insert layout tokens if necessary
1058 do_bol span _str _len = do
1062 --trace "layout: inserting '}'" $ do
1064 -- do NOT pop the lex state, we might have a ';' to insert
1065 return (L span ITvccurly)
1067 --trace "layout: inserting ';'" $ do
1069 return (L span ITsemi)
1074 -- certain keywords put us in the "layout" state, where we might
1075 -- add an opening curly brace.
1076 maybe_layout :: Token -> P ()
1077 maybe_layout t = do -- If the alternative layout rule is enabled then
1078 -- we never create an implicit layout context here.
1079 -- Layout is handled XXX instead.
1080 -- The code for closing implicit contexts, or
1081 -- inserting implicit semi-colons, is therefore
1082 -- irrelevant as it only applies in an implicit
1084 alr <- extension alternativeLayoutRule
1086 where f ITdo = pushLexState layout_do
1087 f ITmdo = pushLexState layout_do
1088 f ITof = pushLexState layout
1089 f ITlet = pushLexState layout
1090 f ITwhere = pushLexState layout
1091 f ITrec = pushLexState layout
1094 -- Pushing a new implicit layout context. If the indentation of the
1095 -- next token is not greater than the previous layout context, then
1096 -- Haskell 98 says that the new layout context should be empty; that is
1097 -- the lexer must generate {}.
1099 -- We are slightly more lenient than this: when the new context is started
1100 -- by a 'do', then we allow the new context to be at the same indentation as
1101 -- the previous context. This is what the 'strict' argument is for.
1103 new_layout_context :: Bool -> Action
1104 new_layout_context strict span _buf _len = do
1106 (AI l _) <- getInput
1107 let offset = srcLocCol l
1110 Layout prev_off : _ |
1111 (strict && prev_off >= offset ||
1112 not strict && prev_off > offset) -> do
1113 -- token is indented to the left of the previous context.
1114 -- we must generate a {} sequence now.
1115 pushLexState layout_left
1116 return (L span ITvocurly)
1118 setContext (Layout offset : ctx)
1119 return (L span ITvocurly)
1121 do_layout_left :: Action
1122 do_layout_left span _buf _len = do
1124 pushLexState bol -- we must be at the start of a line
1125 return (L span ITvccurly)
1127 -- -----------------------------------------------------------------------------
1130 setLine :: Int -> Action
1131 setLine code span buf len = do
1132 let line = parseUnsignedInteger buf len 10 octDecDigit
1133 setSrcLoc (mkSrcLoc (srcSpanFile span) (fromIntegral line - 1) 1)
1134 -- subtract one: the line number refers to the *following* line
1139 setFile :: Int -> Action
1140 setFile code span buf len = do
1141 let file = lexemeToFastString (stepOn buf) (len-2)
1142 setAlrLastLoc noSrcSpan
1143 setSrcLoc (mkSrcLoc file (srcSpanEndLine span) (srcSpanEndCol span))
1149 -- -----------------------------------------------------------------------------
1150 -- Options, includes and language pragmas.
1152 lex_string_prag :: (String -> Token) -> Action
1153 lex_string_prag mkTok span _buf _len
1154 = do input <- getInput
1158 return (L (mkSrcSpan start end) tok)
1160 = if isString input "#-}"
1161 then do setInput input
1162 return (mkTok (reverse acc))
1163 else case alexGetChar input of
1164 Just (c,i) -> go (c:acc) i
1165 Nothing -> err input
1166 isString _ [] = True
1168 = case alexGetChar i of
1169 Just (c,i') | c == x -> isString i' xs
1171 err (AI end _) = failLocMsgP (srcSpanStart span) end "unterminated options pragma"
1174 -- -----------------------------------------------------------------------------
1177 -- This stuff is horrible. I hates it.
1179 lex_string_tok :: Action
1180 lex_string_tok span _buf _len = do
1181 tok <- lex_string ""
1183 return (L (mkSrcSpan (srcSpanStart span) end) tok)
1185 lex_string :: String -> P Token
1188 case alexGetChar' i of
1189 Nothing -> lit_error i
1193 magicHash <- extension magicHashEnabled
1197 case alexGetChar' i of
1201 then failMsgP "primitive string literal must contain only characters <= \'\\xFF\'"
1202 else let s' = mkZFastString (reverse s) in
1203 return (ITprimstring s')
1204 -- mkZFastString is a hack to avoid encoding the
1205 -- string in UTF-8. We just want the exact bytes.
1207 return (ITstring (mkFastString (reverse s)))
1209 return (ITstring (mkFastString (reverse s)))
1212 | Just ('&',i) <- next -> do
1213 setInput i; lex_string s
1214 | Just (c,i) <- next, c <= '\x7f' && is_space c -> do
1215 -- is_space only works for <= '\x7f' (#3751)
1216 setInput i; lex_stringgap s
1217 where next = alexGetChar' i
1221 '\\' -> do setInput i1; c' <- lex_escape; lex_string (c':s)
1222 c | isAny c -> do setInput i1; lex_string (c:s)
1223 _other -> lit_error i
1225 lex_stringgap :: String -> P Token
1226 lex_stringgap s = do
1228 c <- getCharOrFail i
1230 '\\' -> lex_string s
1231 c | is_space c -> lex_stringgap s
1232 _other -> lit_error i
1235 lex_char_tok :: Action
1236 -- Here we are basically parsing character literals, such as 'x' or '\n'
1237 -- but, when Template Haskell is on, we additionally spot
1238 -- 'x and ''T, returning ITvarQuote and ITtyQuote respectively,
1239 -- but WITHOUT CONSUMING the x or T part (the parser does that).
1240 -- So we have to do two characters of lookahead: when we see 'x we need to
1241 -- see if there's a trailing quote
1242 lex_char_tok span _buf _len = do -- We've seen '
1243 i1 <- getInput -- Look ahead to first character
1244 let loc = srcSpanStart span
1245 case alexGetChar' i1 of
1246 Nothing -> lit_error i1
1248 Just ('\'', i2@(AI end2 _)) -> do -- We've seen ''
1249 th_exts <- extension thEnabled
1252 return (L (mkSrcSpan loc end2) ITtyQuote)
1255 Just ('\\', i2@(AI _end2 _)) -> do -- We've seen 'backslash
1257 lit_ch <- lex_escape
1259 mc <- getCharOrFail i3 -- Trailing quote
1260 if mc == '\'' then finish_char_tok loc lit_ch
1263 Just (c, i2@(AI _end2 _))
1264 | not (isAny c) -> lit_error i1
1267 -- We've seen 'x, where x is a valid character
1268 -- (i.e. not newline etc) but not a quote or backslash
1269 case alexGetChar' i2 of -- Look ahead one more character
1270 Just ('\'', i3) -> do -- We've seen 'x'
1272 finish_char_tok loc c
1273 _other -> do -- We've seen 'x not followed by quote
1274 -- (including the possibility of EOF)
1275 -- If TH is on, just parse the quote only
1276 th_exts <- extension thEnabled
1278 if th_exts then return (L (mkSrcSpan loc end) ITvarQuote)
1281 finish_char_tok :: SrcLoc -> Char -> P (Located Token)
1282 finish_char_tok loc ch -- We've already seen the closing quote
1283 -- Just need to check for trailing #
1284 = do magicHash <- extension magicHashEnabled
1285 i@(AI end _) <- getInput
1286 if magicHash then do
1287 case alexGetChar' i of
1288 Just ('#',i@(AI end _)) -> do
1290 return (L (mkSrcSpan loc end) (ITprimchar ch))
1292 return (L (mkSrcSpan loc end) (ITchar ch))
1294 return (L (mkSrcSpan loc end) (ITchar ch))
1296 isAny :: Char -> Bool
1297 isAny c | c > '\x7f' = isPrint c
1298 | otherwise = is_any c
1300 lex_escape :: P Char
1303 c <- getCharOrFail i0
1315 '^' -> do i1 <- getInput
1316 c <- getCharOrFail i1
1317 if c >= '@' && c <= '_'
1318 then return (chr (ord c - ord '@'))
1321 'x' -> readNum is_hexdigit 16 hexDigit
1322 'o' -> readNum is_octdigit 8 octDecDigit
1323 x | is_decdigit x -> readNum2 is_decdigit 10 octDecDigit (octDecDigit x)
1327 case alexGetChar' i of
1328 Nothing -> lit_error i0
1330 case alexGetChar' i2 of
1331 Nothing -> do lit_error i0
1333 let str = [c1,c2,c3] in
1334 case [ (c,rest) | (p,c) <- silly_escape_chars,
1335 Just rest <- [stripPrefix p str] ] of
1336 (escape_char,[]):_ -> do
1339 (escape_char,_:_):_ -> do
1344 readNum :: (Char -> Bool) -> Int -> (Char -> Int) -> P Char
1345 readNum is_digit base conv = do
1347 c <- getCharOrFail i
1349 then readNum2 is_digit base conv (conv c)
1352 readNum2 :: (Char -> Bool) -> Int -> (Char -> Int) -> Int -> P Char
1353 readNum2 is_digit base conv i = do
1356 where read i input = do
1357 case alexGetChar' input of
1358 Just (c,input') | is_digit c -> do
1359 let i' = i*base + conv c
1361 then setInput input >> lexError "numeric escape sequence out of range"
1364 setInput input; return (chr i)
1367 silly_escape_chars :: [(String, Char)]
1368 silly_escape_chars = [
1405 -- before calling lit_error, ensure that the current input is pointing to
1406 -- the position of the error in the buffer. This is so that we can report
1407 -- a correct location to the user, but also so we can detect UTF-8 decoding
1408 -- errors if they occur.
1409 lit_error :: AlexInput -> P a
1410 lit_error i = do setInput i; lexError "lexical error in string/character literal"
1412 getCharOrFail :: AlexInput -> P Char
1413 getCharOrFail i = do
1414 case alexGetChar' i of
1415 Nothing -> lexError "unexpected end-of-file in string/character literal"
1416 Just (c,i) -> do setInput i; return c
1418 -- -----------------------------------------------------------------------------
1421 lex_quasiquote_tok :: Action
1422 lex_quasiquote_tok span buf len = do
1423 let quoter = tail (lexemeToString buf (len - 1))
1424 -- 'tail' drops the initial '[',
1425 -- while the -1 drops the trailing '|'
1426 quoteStart <- getSrcLoc
1427 quote <- lex_quasiquote ""
1429 return (L (mkSrcSpan (srcSpanStart span) end)
1430 (ITquasiQuote (mkFastString quoter,
1431 mkFastString (reverse quote),
1432 mkSrcSpan quoteStart end)))
1434 lex_quasiquote :: String -> P String
1435 lex_quasiquote s = do
1437 case alexGetChar' i of
1438 Nothing -> lit_error i
1441 | Just ('|',i) <- next -> do
1442 setInput i; lex_quasiquote ('|' : s)
1443 | Just (']',i) <- next -> do
1444 setInput i; lex_quasiquote (']' : s)
1445 where next = alexGetChar' i
1448 | Just (']',i) <- next -> do
1449 setInput i; return s
1450 where next = alexGetChar' i
1453 setInput i; lex_quasiquote (c : s)
1455 -- -----------------------------------------------------------------------------
1458 warn :: DynFlag -> SDoc -> Action
1459 warn option warning srcspan _buf _len = do
1460 addWarning option srcspan warning
1463 warnThen :: DynFlag -> SDoc -> Action -> Action
1464 warnThen option warning action srcspan buf len = do
1465 addWarning option srcspan warning
1466 action srcspan buf len
1468 -- -----------------------------------------------------------------------------
1479 SrcSpan -- The start and end of the text span related to
1480 -- the error. Might be used in environments which can
1481 -- show this span, e.g. by highlighting it.
1482 Message -- The error message
1484 data PState = PState {
1485 buffer :: StringBuffer,
1487 messages :: Messages,
1488 last_loc :: SrcSpan, -- pos of previous token
1489 last_len :: !Int, -- len of previous token
1490 loc :: SrcLoc, -- current loc (end of prev token + 1)
1491 extsBitmap :: !Int, -- bitmap that determines permitted extensions
1492 context :: [LayoutContext],
1494 -- Used in the alternative layout rule:
1495 -- These tokens are the next ones to be sent out. They are
1496 -- just blindly emitted, without the rule looking at them again:
1497 alr_pending_implicit_tokens :: [Located Token],
1498 -- This is the next token to be considered or, if it is Nothing,
1499 -- we need to get the next token from the input stream:
1500 alr_next_token :: Maybe (Located Token),
1501 -- This is what we consider to be the locatino of the last token
1503 alr_last_loc :: SrcSpan,
1504 -- The stack of layout contexts:
1505 alr_context :: [ALRContext],
1506 -- Are we expecting a '{'? If it's Just, then the ALRLayout tells
1507 -- us what sort of layout the '{' will open:
1508 alr_expecting_ocurly :: Maybe ALRLayout,
1509 -- Have we just had the '}' for a let block? If so, than an 'in'
1510 -- token doesn't need to close anything:
1511 alr_justClosedExplicitLetBlock :: Bool
1513 -- last_loc and last_len are used when generating error messages,
1514 -- and in pushCurrentContext only. Sigh, if only Happy passed the
1515 -- current token to happyError, we could at least get rid of last_len.
1516 -- Getting rid of last_loc would require finding another way to
1517 -- implement pushCurrentContext (which is only called from one place).
1519 data ALRContext = ALRNoLayout Bool{- does it contain commas? -}
1520 Bool{- is it a 'let' block? -}
1521 | ALRLayout ALRLayout Int
1522 data ALRLayout = ALRLayoutLet
1527 newtype P a = P { unP :: PState -> ParseResult a }
1529 instance Monad P where
1535 returnP a = a `seq` (P $ \s -> POk s a)
1537 thenP :: P a -> (a -> P b) -> P b
1538 (P m) `thenP` k = P $ \ s ->
1540 POk s1 a -> (unP (k a)) s1
1541 PFailed span err -> PFailed span err
1543 failP :: String -> P a
1544 failP msg = P $ \s -> PFailed (last_loc s) (text msg)
1546 failMsgP :: String -> P a
1547 failMsgP msg = P $ \s -> PFailed (last_loc s) (text msg)
1549 failLocMsgP :: SrcLoc -> SrcLoc -> String -> P a
1550 failLocMsgP loc1 loc2 str = P $ \_ -> PFailed (mkSrcSpan loc1 loc2) (text str)
1552 failSpanMsgP :: SrcSpan -> SDoc -> P a
1553 failSpanMsgP span msg = P $ \_ -> PFailed span msg
1555 getPState :: P PState
1556 getPState = P $ \s -> POk s s
1558 getDynFlags :: P DynFlags
1559 getDynFlags = P $ \s -> POk s (dflags s)
1561 withThisPackage :: (PackageId -> a) -> P a
1563 = do pkg <- liftM thisPackage getDynFlags
1566 extension :: (Int -> Bool) -> P Bool
1567 extension p = P $ \s -> POk s (p $! extsBitmap s)
1570 getExts = P $ \s -> POk s (extsBitmap s)
1572 setExts :: (Int -> Int) -> P ()
1573 setExts f = P $ \s -> POk s{ extsBitmap = f (extsBitmap s) } ()
1575 setSrcLoc :: SrcLoc -> P ()
1576 setSrcLoc new_loc = P $ \s -> POk s{loc=new_loc} ()
1578 getSrcLoc :: P SrcLoc
1579 getSrcLoc = P $ \s@(PState{ loc=loc }) -> POk s loc
1581 setLastToken :: SrcSpan -> Int -> P ()
1582 setLastToken loc len = P $ \s -> POk s {
1587 data AlexInput = AI SrcLoc StringBuffer
1589 alexInputPrevChar :: AlexInput -> Char
1590 alexInputPrevChar (AI _ buf) = prevChar buf '\n'
1592 alexGetChar :: AlexInput -> Maybe (Char,AlexInput)
1593 alexGetChar (AI loc s)
1595 | otherwise = adj_c `seq` loc' `seq` s' `seq`
1596 --trace (show (ord c)) $
1597 Just (adj_c, (AI loc' s'))
1598 where (c,s') = nextChar s
1599 loc' = advanceSrcLoc loc c
1607 other_graphic = '\x6'
1610 | c <= '\x06' = non_graphic
1612 -- Alex doesn't handle Unicode, so when Unicode
1613 -- character is encountered we output these values
1614 -- with the actual character value hidden in the state.
1616 case generalCategory c of
1617 UppercaseLetter -> upper
1618 LowercaseLetter -> lower
1619 TitlecaseLetter -> upper
1620 ModifierLetter -> other_graphic
1621 OtherLetter -> lower -- see #1103
1622 NonSpacingMark -> other_graphic
1623 SpacingCombiningMark -> other_graphic
1624 EnclosingMark -> other_graphic
1625 DecimalNumber -> digit
1626 LetterNumber -> other_graphic
1627 OtherNumber -> other_graphic
1628 ConnectorPunctuation -> symbol
1629 DashPunctuation -> symbol
1630 OpenPunctuation -> other_graphic
1631 ClosePunctuation -> other_graphic
1632 InitialQuote -> other_graphic
1633 FinalQuote -> other_graphic
1634 OtherPunctuation -> symbol
1635 MathSymbol -> symbol
1636 CurrencySymbol -> symbol
1637 ModifierSymbol -> symbol
1638 OtherSymbol -> symbol
1640 _other -> non_graphic
1642 -- This version does not squash unicode characters, it is used when
1644 alexGetChar' :: AlexInput -> Maybe (Char,AlexInput)
1645 alexGetChar' (AI loc s)
1647 | otherwise = c `seq` loc' `seq` s' `seq`
1648 --trace (show (ord c)) $
1649 Just (c, (AI loc' s'))
1650 where (c,s') = nextChar s
1651 loc' = advanceSrcLoc loc c
1653 getInput :: P AlexInput
1654 getInput = P $ \s@PState{ loc=l, buffer=b } -> POk s (AI l b)
1656 setInput :: AlexInput -> P ()
1657 setInput (AI l b) = P $ \s -> POk s{ loc=l, buffer=b } ()
1659 pushLexState :: Int -> P ()
1660 pushLexState ls = P $ \s@PState{ lex_state=l } -> POk s{lex_state=ls:l} ()
1662 popLexState :: P Int
1663 popLexState = P $ \s@PState{ lex_state=ls:l } -> POk s{ lex_state=l } ls
1665 getLexState :: P Int
1666 getLexState = P $ \s@PState{ lex_state=ls:_ } -> POk s ls
1668 popNextToken :: P (Maybe (Located Token))
1670 = P $ \s@PState{ alr_next_token = m } ->
1671 POk (s {alr_next_token = Nothing}) m
1673 setAlrLastLoc :: SrcSpan -> P ()
1674 setAlrLastLoc l = P $ \s -> POk (s {alr_last_loc = l}) ()
1676 getAlrLastLoc :: P SrcSpan
1677 getAlrLastLoc = P $ \s@(PState {alr_last_loc = l}) -> POk s l
1679 getALRContext :: P [ALRContext]
1680 getALRContext = P $ \s@(PState {alr_context = cs}) -> POk s cs
1682 setALRContext :: [ALRContext] -> P ()
1683 setALRContext cs = P $ \s -> POk (s {alr_context = cs}) ()
1685 getJustClosedExplicitLetBlock :: P Bool
1686 getJustClosedExplicitLetBlock
1687 = P $ \s@(PState {alr_justClosedExplicitLetBlock = b}) -> POk s b
1689 setJustClosedExplicitLetBlock :: Bool -> P ()
1690 setJustClosedExplicitLetBlock b
1691 = P $ \s -> POk (s {alr_justClosedExplicitLetBlock = b}) ()
1693 setNextToken :: Located Token -> P ()
1694 setNextToken t = P $ \s -> POk (s {alr_next_token = Just t}) ()
1696 popPendingImplicitToken :: P (Maybe (Located Token))
1697 popPendingImplicitToken
1698 = P $ \s@PState{ alr_pending_implicit_tokens = ts } ->
1701 (t : ts') -> POk (s {alr_pending_implicit_tokens = ts'}) (Just t)
1703 setPendingImplicitTokens :: [Located Token] -> P ()
1704 setPendingImplicitTokens ts = P $ \s -> POk (s {alr_pending_implicit_tokens = ts}) ()
1706 getAlrExpectingOCurly :: P (Maybe ALRLayout)
1707 getAlrExpectingOCurly = P $ \s@(PState {alr_expecting_ocurly = b}) -> POk s b
1709 setAlrExpectingOCurly :: Maybe ALRLayout -> P ()
1710 setAlrExpectingOCurly b = P $ \s -> POk (s {alr_expecting_ocurly = b}) ()
1712 -- for reasons of efficiency, flags indicating language extensions (eg,
1713 -- -fglasgow-exts or -XParr) are represented by a bitmap stored in an unboxed
1717 genericsBit = 0 -- {| and |}
1728 explicitForallBit :: Int
1729 explicitForallBit = 7 -- the 'forall' keyword and '.' symbol
1731 bangPatBit = 8 -- Tells the parser to understand bang-patterns
1732 -- (doesn't affect the lexer)
1734 tyFamBit = 9 -- indexed type families: 'family' keyword and kind sigs
1736 haddockBit = 10 -- Lex and parse Haddock comments
1738 magicHashBit = 11 -- "#" in both functions and operators
1740 kindSigsBit = 12 -- Kind signatures on type variables
1741 recursiveDoBit :: Int
1742 recursiveDoBit = 13 -- mdo
1743 unicodeSyntaxBit :: Int
1744 unicodeSyntaxBit = 14 -- the forall symbol, arrow symbols, etc
1745 unboxedTuplesBit :: Int
1746 unboxedTuplesBit = 15 -- (# and #)
1747 datatypeContextsBit :: Int
1748 datatypeContextsBit = 16
1749 transformComprehensionsBit :: Int
1750 transformComprehensionsBit = 17
1752 qqBit = 18 -- enable quasiquoting
1753 inRulePragBit :: Int
1755 rawTokenStreamBit :: Int
1756 rawTokenStreamBit = 20 -- producing a token stream with all comments included
1757 newQualOpsBit :: Int
1758 newQualOpsBit = 21 -- Haskell' qualified operator syntax, e.g. Prelude.(+)
1761 alternativeLayoutRuleBit :: Int
1762 alternativeLayoutRuleBit = 23
1764 always :: Int -> Bool
1766 genericsEnabled :: Int -> Bool
1767 genericsEnabled flags = testBit flags genericsBit
1768 parrEnabled :: Int -> Bool
1769 parrEnabled flags = testBit flags parrBit
1770 arrowsEnabled :: Int -> Bool
1771 arrowsEnabled flags = testBit flags arrowsBit
1772 thEnabled :: Int -> Bool
1773 thEnabled flags = testBit flags thBit
1774 ipEnabled :: Int -> Bool
1775 ipEnabled flags = testBit flags ipBit
1776 explicitForallEnabled :: Int -> Bool
1777 explicitForallEnabled flags = testBit flags explicitForallBit
1778 bangPatEnabled :: Int -> Bool
1779 bangPatEnabled flags = testBit flags bangPatBit
1780 -- tyFamEnabled :: Int -> Bool
1781 -- tyFamEnabled flags = testBit flags tyFamBit
1782 haddockEnabled :: Int -> Bool
1783 haddockEnabled flags = testBit flags haddockBit
1784 magicHashEnabled :: Int -> Bool
1785 magicHashEnabled flags = testBit flags magicHashBit
1786 -- kindSigsEnabled :: Int -> Bool
1787 -- kindSigsEnabled flags = testBit flags kindSigsBit
1788 unicodeSyntaxEnabled :: Int -> Bool
1789 unicodeSyntaxEnabled flags = testBit flags unicodeSyntaxBit
1790 unboxedTuplesEnabled :: Int -> Bool
1791 unboxedTuplesEnabled flags = testBit flags unboxedTuplesBit
1792 datatypeContextsEnabled :: Int -> Bool
1793 datatypeContextsEnabled flags = testBit flags datatypeContextsBit
1794 qqEnabled :: Int -> Bool
1795 qqEnabled flags = testBit flags qqBit
1796 -- inRulePrag :: Int -> Bool
1797 -- inRulePrag flags = testBit flags inRulePragBit
1798 rawTokenStreamEnabled :: Int -> Bool
1799 rawTokenStreamEnabled flags = testBit flags rawTokenStreamBit
1800 newQualOps :: Int -> Bool
1801 newQualOps flags = testBit flags newQualOpsBit
1802 oldQualOps :: Int -> Bool
1803 oldQualOps flags = not (newQualOps flags)
1804 alternativeLayoutRule :: Int -> Bool
1805 alternativeLayoutRule flags = testBit flags alternativeLayoutRuleBit
1807 -- PState for parsing options pragmas
1809 pragState :: DynFlags -> StringBuffer -> SrcLoc -> PState
1810 pragState dynflags buf loc = (mkPState dynflags buf loc) {
1811 lex_state = [bol, option_prags, 0]
1814 -- create a parse state
1816 mkPState :: DynFlags -> StringBuffer -> SrcLoc -> PState
1817 mkPState flags buf loc =
1821 messages = emptyMessages,
1822 last_loc = mkSrcSpan loc loc,
1825 extsBitmap = fromIntegral bitmap,
1827 lex_state = [bol, 0],
1828 alr_pending_implicit_tokens = [],
1829 alr_next_token = Nothing,
1830 alr_last_loc = noSrcSpan,
1832 alr_expecting_ocurly = Nothing,
1833 alr_justClosedExplicitLetBlock = False
1836 bitmap = genericsBit `setBitIf` xopt Opt_Generics flags
1837 .|. ffiBit `setBitIf` xopt Opt_ForeignFunctionInterface flags
1838 .|. parrBit `setBitIf` xopt Opt_PArr flags
1839 .|. arrowsBit `setBitIf` xopt Opt_Arrows flags
1840 .|. thBit `setBitIf` xopt Opt_TemplateHaskell flags
1841 .|. qqBit `setBitIf` xopt Opt_QuasiQuotes flags
1842 .|. ipBit `setBitIf` xopt Opt_ImplicitParams flags
1843 .|. explicitForallBit `setBitIf` xopt Opt_ExplicitForAll flags
1844 .|. bangPatBit `setBitIf` xopt Opt_BangPatterns flags
1845 .|. tyFamBit `setBitIf` xopt Opt_TypeFamilies flags
1846 .|. haddockBit `setBitIf` dopt Opt_Haddock flags
1847 .|. magicHashBit `setBitIf` xopt Opt_MagicHash flags
1848 .|. kindSigsBit `setBitIf` xopt Opt_KindSignatures flags
1849 .|. recursiveDoBit `setBitIf` xopt Opt_RecursiveDo flags
1850 .|. recBit `setBitIf` xopt Opt_DoRec flags
1851 .|. recBit `setBitIf` xopt Opt_Arrows flags
1852 .|. unicodeSyntaxBit `setBitIf` xopt Opt_UnicodeSyntax flags
1853 .|. unboxedTuplesBit `setBitIf` xopt Opt_UnboxedTuples flags
1854 .|. datatypeContextsBit `setBitIf` xopt Opt_DatatypeContexts flags
1855 .|. transformComprehensionsBit `setBitIf` xopt Opt_TransformListComp flags
1856 .|. rawTokenStreamBit `setBitIf` dopt Opt_KeepRawTokenStream flags
1857 .|. newQualOpsBit `setBitIf` xopt Opt_NewQualifiedOperators flags
1858 .|. alternativeLayoutRuleBit `setBitIf` xopt Opt_AlternativeLayoutRule flags
1860 setBitIf :: Int -> Bool -> Int
1861 b `setBitIf` cond | cond = bit b
1864 addWarning :: DynFlag -> SrcSpan -> SDoc -> P ()
1865 addWarning option srcspan warning
1866 = P $ \s@PState{messages=(ws,es), dflags=d} ->
1867 let warning' = mkWarnMsg srcspan alwaysQualify warning
1868 ws' = if dopt option d then ws `snocBag` warning' else ws
1869 in POk s{messages=(ws', es)} ()
1871 getMessages :: PState -> Messages
1872 getMessages PState{messages=ms} = ms
1874 getContext :: P [LayoutContext]
1875 getContext = P $ \s@PState{context=ctx} -> POk s ctx
1877 setContext :: [LayoutContext] -> P ()
1878 setContext ctx = P $ \s -> POk s{context=ctx} ()
1881 popContext = P $ \ s@(PState{ buffer = buf, context = ctx,
1882 last_len = len, last_loc = last_loc }) ->
1884 (_:tl) -> POk s{ context = tl } ()
1885 [] -> PFailed last_loc (srcParseErr buf len)
1887 -- Push a new layout context at the indentation of the last token read.
1888 -- This is only used at the outer level of a module when the 'module'
1889 -- keyword is missing.
1890 pushCurrentContext :: P ()
1891 pushCurrentContext = P $ \ s@PState{ last_loc=loc, context=ctx } ->
1892 POk s{context = Layout (srcSpanStartCol loc) : ctx} ()
1894 getOffside :: P Ordering
1895 getOffside = P $ \s@PState{last_loc=loc, context=stk} ->
1896 let offs = srcSpanStartCol loc in
1897 let ord = case stk of
1898 (Layout n:_) -> --trace ("layout: " ++ show n ++ ", offs: " ++ show offs) $
1903 -- ---------------------------------------------------------------------------
1904 -- Construct a parse error
1907 :: StringBuffer -- current buffer (placed just after the last token)
1908 -> Int -- length of the previous token
1911 = hcat [ if null token
1912 then ptext (sLit "parse error (possibly incorrect indentation)")
1913 else hcat [ptext (sLit "parse error on input "),
1914 char '`', text token, char '\'']
1916 where token = lexemeToString (offsetBytes (-len) buf) len
1918 -- Report a parse failure, giving the span of the previous token as
1919 -- the location of the error. This is the entry point for errors
1920 -- detected during parsing.
1922 srcParseFail = P $ \PState{ buffer = buf, last_len = len,
1923 last_loc = last_loc } ->
1924 PFailed last_loc (srcParseErr buf len)
1926 -- A lexical error is reported at a particular position in the source file,
1927 -- not over a token range.
1928 lexError :: String -> P a
1931 (AI end buf) <- getInput
1932 reportLexError loc end buf str
1934 -- -----------------------------------------------------------------------------
1935 -- This is the top-level function: called from the parser each time a
1936 -- new token is to be read from the input.
1938 lexer :: (Located Token -> P a) -> P a
1940 alr <- extension alternativeLayoutRule
1941 let lexTokenFun = if alr then lexTokenAlr else lexToken
1942 tok@(L _span _tok__) <- lexTokenFun
1943 --trace ("token: " ++ show _tok__) $ do
1946 lexTokenAlr :: P (Located Token)
1947 lexTokenAlr = do mPending <- popPendingImplicitToken
1948 t <- case mPending of
1950 do mNext <- popNextToken
1953 Just next -> return next
1954 alternativeLayoutRuleToken t
1957 setAlrLastLoc (getLoc t)
1959 ITwhere -> setAlrExpectingOCurly (Just ALRLayoutWhere)
1960 ITlet -> setAlrExpectingOCurly (Just ALRLayoutLet)
1961 ITof -> setAlrExpectingOCurly (Just ALRLayoutOf)
1962 ITdo -> setAlrExpectingOCurly (Just ALRLayoutDo)
1963 ITmdo -> setAlrExpectingOCurly (Just ALRLayoutDo)
1964 ITrec -> setAlrExpectingOCurly (Just ALRLayoutDo)
1968 alternativeLayoutRuleToken :: Located Token -> P (Located Token)
1969 alternativeLayoutRuleToken t
1970 = do context <- getALRContext
1971 lastLoc <- getAlrLastLoc
1972 mExpectingOCurly <- getAlrExpectingOCurly
1973 justClosedExplicitLetBlock <- getJustClosedExplicitLetBlock
1974 setJustClosedExplicitLetBlock False
1975 dflags <- getDynFlags
1976 let transitional = xopt Opt_AlternativeLayoutRuleTransitional dflags
1978 thisCol = srcSpanStartCol thisLoc
1979 newLine = (lastLoc == noSrcSpan)
1980 || (srcSpanStartLine thisLoc > srcSpanEndLine lastLoc)
1981 case (unLoc t, context, mExpectingOCurly) of
1982 -- This case handles a GHC extension to the original H98
1984 (ITocurly, _, Just alrLayout) ->
1985 do setAlrExpectingOCurly Nothing
1986 let isLet = case alrLayout of
1987 ALRLayoutLet -> True
1989 setALRContext (ALRNoLayout (containsCommas ITocurly) isLet : context)
1991 -- ...and makes this case unnecessary
1993 -- I think our implicit open-curly handling is slightly
1994 -- different to John's, in how it interacts with newlines
1996 (ITocurly, _, Just _) ->
1997 do setAlrExpectingOCurly Nothing
2001 (_, ALRLayout _ col : ls, Just expectingOCurly)
2002 | (thisCol > col) ||
2004 isNonDecreasingIntentation expectingOCurly) ->
2005 do setAlrExpectingOCurly Nothing
2006 setALRContext (ALRLayout expectingOCurly thisCol : context)
2008 return (L thisLoc ITocurly)
2010 do setAlrExpectingOCurly Nothing
2011 setPendingImplicitTokens [L lastLoc ITccurly]
2013 return (L lastLoc ITocurly)
2014 (_, _, Just expectingOCurly) ->
2015 do setAlrExpectingOCurly Nothing
2016 setALRContext (ALRLayout expectingOCurly thisCol : context)
2018 return (L thisLoc ITocurly)
2019 -- We do the [] cases earlier than in the spec, as we
2020 -- have an actual EOF token
2021 (ITeof, ALRLayout _ _ : ls, _) ->
2024 return (L thisLoc ITccurly)
2027 -- the other ITeof case omitted; general case below covers it
2029 | justClosedExplicitLetBlock ->
2031 (ITin, ALRLayout ALRLayoutLet _ : ls, _)
2033 do setPendingImplicitTokens [t]
2035 return (L thisLoc ITccurly)
2036 -- This next case is to handle a transitional issue:
2037 (ITwhere, ALRLayout _ col : ls, _)
2038 | newLine && thisCol == col && transitional ->
2039 do addWarning Opt_WarnAlternativeLayoutRuleTransitional
2041 (transitionalAlternativeLayoutWarning
2042 "`where' clause at the same depth as implicit layout block")
2045 -- Note that we use lastLoc, as we may need to close
2046 -- more layouts, or give a semicolon
2047 return (L lastLoc ITccurly)
2048 -- This next case is to handle a transitional issue:
2049 (ITvbar, ALRLayout _ col : ls, _)
2050 | newLine && thisCol == col && transitional ->
2051 do addWarning Opt_WarnAlternativeLayoutRuleTransitional
2053 (transitionalAlternativeLayoutWarning
2054 "`|' at the same depth as implicit layout block")
2057 -- Note that we use lastLoc, as we may need to close
2058 -- more layouts, or give a semicolon
2059 return (L lastLoc ITccurly)
2060 (_, ALRLayout _ col : ls, _)
2061 | newLine && thisCol == col ->
2063 return (L thisLoc ITsemi)
2064 | newLine && thisCol < col ->
2067 -- Note that we use lastLoc, as we may need to close
2068 -- more layouts, or give a semicolon
2069 return (L lastLoc ITccurly)
2070 -- We need to handle close before open, as 'then' is both
2071 -- an open and a close
2075 ALRLayout _ _ : ls ->
2078 return (L thisLoc ITccurly)
2079 ALRNoLayout _ isLet : ls ->
2080 do let ls' = if isALRopen u
2081 then ALRNoLayout (containsCommas u) False : ls
2084 when isLet $ setJustClosedExplicitLetBlock True
2087 do let ls = if isALRopen u
2088 then [ALRNoLayout (containsCommas u) False]
2091 -- XXX This is an error in John's code, but
2092 -- it looks reachable to me at first glance
2096 do setALRContext (ALRNoLayout (containsCommas u) False : context)
2098 (ITin, ALRLayout ALRLayoutLet _ : ls, _) ->
2100 setPendingImplicitTokens [t]
2101 return (L thisLoc ITccurly)
2102 (ITin, ALRLayout _ _ : ls, _) ->
2105 return (L thisLoc ITccurly)
2106 -- the other ITin case omitted; general case below covers it
2107 (ITcomma, ALRLayout _ _ : ls, _)
2108 | topNoLayoutContainsCommas ls ->
2111 return (L thisLoc ITccurly)
2112 (ITwhere, ALRLayout ALRLayoutDo _ : ls, _) ->
2114 setPendingImplicitTokens [t]
2115 return (L thisLoc ITccurly)
2116 -- the other ITwhere case omitted; general case below covers it
2117 (_, _, _) -> return t
2119 transitionalAlternativeLayoutWarning :: String -> SDoc
2120 transitionalAlternativeLayoutWarning msg
2121 = text "transitional layout will not be accepted in the future:"
2124 isALRopen :: Token -> Bool
2125 isALRopen ITcase = True
2126 isALRopen ITif = True
2127 isALRopen ITthen = True
2128 isALRopen IToparen = True
2129 isALRopen ITobrack = True
2130 isALRopen ITocurly = True
2132 isALRopen IToubxparen = True
2133 isALRopen ITparenEscape = True
2136 isALRclose :: Token -> Bool
2137 isALRclose ITof = True
2138 isALRclose ITthen = True
2139 isALRclose ITelse = True
2140 isALRclose ITcparen = True
2141 isALRclose ITcbrack = True
2142 isALRclose ITccurly = True
2144 isALRclose ITcubxparen = True
2145 isALRclose _ = False
2147 isNonDecreasingIntentation :: ALRLayout -> Bool
2148 isNonDecreasingIntentation ALRLayoutDo = True
2149 isNonDecreasingIntentation _ = False
2151 containsCommas :: Token -> Bool
2152 containsCommas IToparen = True
2153 containsCommas ITobrack = True
2154 -- John doesn't have {} as containing commas, but records contain them,
2155 -- which caused a problem parsing Cabal's Distribution.Simple.InstallDirs
2156 -- (defaultInstallDirs).
2157 containsCommas ITocurly = True
2159 containsCommas IToubxparen = True
2160 containsCommas _ = False
2162 topNoLayoutContainsCommas :: [ALRContext] -> Bool
2163 topNoLayoutContainsCommas [] = False
2164 topNoLayoutContainsCommas (ALRLayout _ _ : ls) = topNoLayoutContainsCommas ls
2165 topNoLayoutContainsCommas (ALRNoLayout b _ : _) = b
2167 lexToken :: P (Located Token)
2169 inp@(AI loc1 buf) <- getInput
2172 case alexScanUser exts inp sc of
2174 let span = mkSrcSpan loc1 loc1
2176 return (L span ITeof)
2177 AlexError (AI loc2 buf) ->
2178 reportLexError loc1 loc2 buf "lexical error"
2179 AlexSkip inp2 _ -> do
2182 AlexToken inp2@(AI end buf2) _ t -> do
2184 let span = mkSrcSpan loc1 end
2185 let bytes = byteDiff buf buf2
2186 span `seq` setLastToken span bytes
2189 reportLexError :: SrcLoc -> SrcLoc -> StringBuffer -> [Char] -> P a
2190 reportLexError loc1 loc2 buf str
2191 | atEnd buf = failLocMsgP loc1 loc2 (str ++ " at end of input")
2194 c = fst (nextChar buf)
2196 if c == '\0' -- decoding errors are mapped to '\0', see utf8DecodeChar#
2197 then failLocMsgP loc2 loc2 (str ++ " (UTF-8 decoding error)")
2198 else failLocMsgP loc1 loc2 (str ++ " at character " ++ show c)
2200 lexTokenStream :: StringBuffer -> SrcLoc -> DynFlags -> ParseResult [Located Token]
2201 lexTokenStream buf loc dflags = unP go initState
2202 where dflags' = dopt_set (dopt_unset dflags Opt_Haddock) Opt_KeepRawTokenStream
2203 initState = mkPState dflags' buf loc
2205 ltok <- lexer return
2207 L _ ITeof -> return []
2208 _ -> liftM (ltok:) go
2210 linePrags = Map.singleton "line" (begin line_prag2)
2212 fileHeaderPrags = Map.fromList([("options", lex_string_prag IToptions_prag),
2213 ("options_ghc", lex_string_prag IToptions_prag),
2214 ("options_haddock", lex_string_prag ITdocOptions),
2215 ("language", token ITlanguage_prag),
2216 ("include", lex_string_prag ITinclude_prag)])
2218 ignoredPrags = Map.fromList (map ignored pragmas)
2219 where ignored opt = (opt, nested_comment lexToken)
2220 impls = ["hugs", "nhc98", "jhc", "yhc", "catch", "derive"]
2221 options_pragmas = map ("options_" ++) impls
2222 -- CFILES is a hugs-only thing.
2223 pragmas = options_pragmas ++ ["cfiles", "contract"]
2225 oneWordPrags = Map.fromList([("rules", rulePrag),
2226 ("inline", token (ITinline_prag Inline FunLike)),
2227 ("inlinable", token (ITinline_prag Inlinable FunLike)),
2228 ("inlineable", token (ITinline_prag Inlinable FunLike)),
2230 ("notinline", token (ITinline_prag NoInline FunLike)),
2231 ("specialize", token ITspec_prag),
2232 ("source", token ITsource_prag),
2233 ("warning", token ITwarning_prag),
2234 ("deprecated", token ITdeprecated_prag),
2235 ("scc", token ITscc_prag),
2236 ("generated", token ITgenerated_prag),
2237 ("core", token ITcore_prag),
2238 ("unpack", token ITunpack_prag),
2239 ("ann", token ITann_prag)])
2241 twoWordPrags = Map.fromList([("inline conlike", token (ITinline_prag Inline ConLike)),
2242 ("notinline conlike", token (ITinline_prag NoInline ConLike)),
2243 ("specialize inline", token (ITspec_inline_prag True)),
2244 ("specialize notinline", token (ITspec_inline_prag False))])
2247 dispatch_pragmas :: Map String Action -> Action
2248 dispatch_pragmas prags span buf len = case Map.lookup (clean_pragma (lexemeToString buf len)) prags of
2249 Just found -> found span buf len
2250 Nothing -> lexError "unknown pragma"
2252 known_pragma :: Map String Action -> AlexAccPred Int
2253 known_pragma prags _ _ len (AI _ buf) = (isJust $ Map.lookup (clean_pragma (lexemeToString (offsetBytes (- len) buf) len)) prags)
2254 && (nextCharIs buf (\c -> not (isAlphaNum c || c == '_')))
2256 clean_pragma :: String -> String
2257 clean_pragma prag = canon_ws (map toLower (unprefix prag))
2258 where unprefix prag' = case stripPrefix "{-#" prag' of
2261 canonical prag' = case prag' of
2262 "noinline" -> "notinline"
2263 "specialise" -> "specialize"
2264 "constructorlike" -> "conlike"
2266 canon_ws s = unwords (map canonical (words s))