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 -----------------------------------------------------------------------------
16 -- - parsing integers is a bit slow
17 -- - readRational is a bit slow
19 -- Known bugs, that were also in the previous version:
20 -- - M... should be 3 tokens, not 1.
21 -- - pragma-end should be only valid in a pragma
25 -- The above warning supression flag is a temporary kludge.
26 -- While working on this module you are encouraged to remove it and fix
27 -- any warnings in the module. See
28 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
31 -- Note that Alex itself generates code with with some unused bindings and
32 -- without type signatures, so removing the flag might not be possible.
34 {-# OPTIONS_GHC -funbox-strict-fields #-}
37 Token(..), lexer, pragState, mkPState, PState(..),
38 P(..), ParseResult(..), getSrcLoc,
39 failLocMsgP, failSpanMsgP, srcParseFail,
41 popContext, pushCurrentContext, setLastToken, setSrcLoc,
42 getLexState, popLexState, pushLexState,
43 extension, standaloneDerivingEnabled, bangPatEnabled,
57 import Util ( maybePrefixMatch, readRational )
61 import Data.Char ( chr, ord, isSpace )
65 import Unicode ( GeneralCategory(..), generalCategory, isPrint, isUpper )
68 $unispace = \x05 -- Trick Alex into handling Unicode. See alexGetChar.
69 $whitechar = [\ \n\r\f\v $unispace]
70 $white_no_nl = $whitechar # \n
74 $unidigit = \x03 -- Trick Alex into handling Unicode. See alexGetChar.
75 $decdigit = $ascdigit -- for now, should really be $digit (ToDo)
76 $digit = [$ascdigit $unidigit]
78 $special = [\(\)\,\;\[\]\`\{\}]
79 $ascsymbol = [\!\#\$\%\&\*\+\.\/\<\=\>\?\@\\\^\|\-\~]
80 $unisymbol = \x04 -- Trick Alex into handling Unicode. See alexGetChar.
81 $symbol = [$ascsymbol $unisymbol] # [$special \_\:\"\']
83 $unilarge = \x01 -- Trick Alex into handling Unicode. See alexGetChar.
85 $large = [$asclarge $unilarge]
87 $unismall = \x02 -- Trick Alex into handling Unicode. See alexGetChar.
89 $small = [$ascsmall $unismall \_]
91 $unigraphic = \x06 -- Trick Alex into handling Unicode. See alexGetChar.
92 $graphic = [$small $large $symbol $digit $special $unigraphic \:\"\']
95 $hexit = [$decdigit A-F a-f]
96 $symchar = [$symbol \:]
98 $idchar = [$small $large $digit \']
100 $docsym = [\| \^ \* \$]
102 @varid = $small $idchar*
103 @conid = $large $idchar*
105 @varsym = $symbol $symchar*
106 @consym = \: $symchar*
108 @decimal = $decdigit+
110 @hexadecimal = $hexit+
111 @exponent = [eE] [\-\+]? @decimal
113 -- we support the hierarchical module name extension:
116 @floating_point = @decimal \. @decimal @exponent? | @decimal @exponent
118 -- normal signed numerical literals can only be explicitly negative,
119 -- not explicitly positive (contrast @exponent)
121 @signed = @negative ?
125 -- everywhere: skip whitespace and comments
127 $tab+ { warn Opt_WarnTabs (text "Tab character") }
129 -- Everywhere: deal with nested comments. We explicitly rule out
130 -- pragmas, "{-#", so that we don't accidentally treat them as comments.
131 -- (this can happen even though pragmas will normally take precedence due to
132 -- longest-match, because pragmas aren't valid in every state, but comments
133 -- are). We also rule out nested Haddock comments, if the -haddock flag is
136 "{-" / { isNormalComment } { nested_comment lexToken }
138 -- Single-line comments are a bit tricky. Haskell 98 says that two or
139 -- more dashes followed by a symbol should be parsed as a varsym, so we
140 -- have to exclude those.
142 -- Since Haddock comments aren't valid in every state, we need to rule them
145 -- The following two rules match comments that begin with two dashes, but
146 -- continue with a different character. The rules test that this character
147 -- is not a symbol (in which case we'd have a varsym), and that it's not a
148 -- space followed by a Haddock comment symbol (docsym) (in which case we'd
149 -- have a Haddock comment). The rules then munch the rest of the line.
151 "-- " ~[$docsym \#] .* ;
152 "--" [^$symbol : \ ] .* ;
154 -- Next, match Haddock comments if no -haddock flag
156 "-- " [$docsym \#] .* / { ifExtension (not . haddockEnabled) } ;
158 -- Now, when we've matched comments that begin with 2 dashes and continue
159 -- with a different character, we need to match comments that begin with three
160 -- or more dashes (which clearly can't be Haddock comments). We only need to
161 -- make sure that the first non-dash character isn't a symbol, and munch the
164 "---"\-* [^$symbol :] .* ;
166 -- Since the previous rules all match dashes followed by at least one
167 -- character, we also need to match a whole line filled with just dashes.
169 "--"\-* / { atEOL } ;
171 -- We need this rule since none of the other single line comment rules
172 -- actually match this case.
176 -- 'bol' state: beginning of a line. Slurp up all the whitespace (including
177 -- blank lines) until we find a non-whitespace character, then do layout
180 -- One slight wibble here: what if the line begins with {-#? In
181 -- theory, we have to lex the pragma to see if it's one we recognise,
182 -- and if it is, then we backtrack and do_bol, otherwise we treat it
183 -- as a nested comment. We don't bother with this: if the line begins
184 -- with {-#, then we'll assume it's a pragma we know about and go for do_bol.
187 ^\# (line)? { begin line_prag1 }
188 ^\# pragma .* \n ; -- GCC 3.3 CPP generated, apparently
189 ^\# \! .* \n ; -- #!, for scripts
193 -- after a layout keyword (let, where, do, of), we begin a new layout
194 -- context if the curly brace is missing.
195 -- Careful! This stuff is quite delicate.
196 <layout, layout_do> {
197 \{ / { notFollowedBy '-' } { pop_and open_brace }
198 -- we might encounter {-# here, but {- has been handled already
200 ^\# (line)? { begin line_prag1 }
203 -- do is treated in a subtly different way, see new_layout_context
204 <layout> () { new_layout_context True }
205 <layout_do> () { new_layout_context False }
207 -- after a new layout context which was found to be to the left of the
208 -- previous context, we have generated a '{' token, and we now need to
209 -- generate a matching '}' token.
210 <layout_left> () { do_layout_left }
212 <0,option_prags> \n { begin bol }
214 "{-#" $whitechar* (line|LINE) { begin line_prag2 }
216 -- single-line line pragmas, of the form
217 -- # <line> "<file>" <extra-stuff> \n
218 <line_prag1> $decdigit+ { setLine line_prag1a }
219 <line_prag1a> \" [$graphic \ ]* \" { setFile line_prag1b }
220 <line_prag1b> .* { pop }
222 -- Haskell-style line pragmas, of the form
223 -- {-# LINE <line> "<file>" #-}
224 <line_prag2> $decdigit+ { setLine line_prag2a }
225 <line_prag2a> \" [$graphic \ ]* \" { setFile line_prag2b }
226 <line_prag2b> "#-}"|"-}" { pop }
227 -- NOTE: accept -} at the end of a LINE pragma, for compatibility
228 -- with older versions of GHC which generated these.
230 -- We only want RULES pragmas to be picked up when explicit forall
231 -- syntax is enabled is on, because the contents of the pragma always
232 -- uses it. If it's not on then we're sure to get a parse error.
233 -- (ToDo: we should really emit a warning when ignoring pragmas)
234 -- XXX Now that we can enable this without the -fglasgow-exts hammer,
235 -- is it better just to let the parse error happen?
237 "{-#" $whitechar* (RULES|rules) / { ifExtension explicitForallEnabled } { token ITrules_prag }
240 "{-#" $whitechar* (INLINE|inline) { token (ITinline_prag True) }
241 "{-#" $whitechar* (NO(T?)INLINE|no(t?)inline)
242 { token (ITinline_prag False) }
243 "{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e)
244 { token ITspec_prag }
245 "{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e)
246 $whitechar* (INLINE|inline) { token (ITspec_inline_prag True) }
247 "{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e)
248 $whitechar* (NO(T?)INLINE|no(t?)inline)
249 { token (ITspec_inline_prag False) }
250 "{-#" $whitechar* (SOURCE|source) { token ITsource_prag }
251 "{-#" $whitechar* (WARNING|warning)
252 { token ITwarning_prag }
253 "{-#" $whitechar* (DEPRECATED|deprecated)
254 { token ITdeprecated_prag }
255 "{-#" $whitechar* (SCC|scc) { token ITscc_prag }
256 "{-#" $whitechar* (GENERATED|generated)
257 { token ITgenerated_prag }
258 "{-#" $whitechar* (CORE|core) { token ITcore_prag }
259 "{-#" $whitechar* (UNPACK|unpack) { token ITunpack_prag }
261 "{-#" { nested_comment lexToken }
263 -- ToDo: should only be valid inside a pragma:
264 "#-}" { token ITclose_prag}
268 "{-#" $whitechar* (OPTIONS|options) { lex_string_prag IToptions_prag }
269 "{-#" $whitechar* (OPTIONS_GHC|options_ghc)
270 { lex_string_prag IToptions_prag }
271 "{-#" $whitechar* (OPTIONS_HADDOCK|options_haddock)
272 { lex_string_prag ITdocOptions }
273 "-- #" { multiline_doc_comment }
274 "{-#" $whitechar* (LANGUAGE|language) { token ITlanguage_prag }
275 "{-#" $whitechar* (INCLUDE|include) { lex_string_prag ITinclude_prag }
283 -- This is to catch things like {-# OPTIONS OPTIONS_HUGS ...
284 "{-#" $whitechar* $idchar+ { nested_comment lexToken }
287 -- '0' state: ordinary lexemes
292 "-- " $docsym / { ifExtension haddockEnabled } { multiline_doc_comment }
293 "{-" \ ? $docsym / { ifExtension haddockEnabled } { nested_doc_comment }
299 "[:" / { ifExtension parrEnabled } { token ITopabrack }
300 ":]" / { ifExtension parrEnabled } { token ITcpabrack }
304 "[|" / { ifExtension thEnabled } { token ITopenExpQuote }
305 "[e|" / { ifExtension thEnabled } { token ITopenExpQuote }
306 "[p|" / { ifExtension thEnabled } { token ITopenPatQuote }
307 "[d|" / { ifExtension thEnabled } { layout_token ITopenDecQuote }
308 "[t|" / { ifExtension thEnabled } { token ITopenTypQuote }
309 "|]" / { ifExtension thEnabled } { token ITcloseQuote }
310 \$ @varid / { ifExtension thEnabled } { skip_one_varid ITidEscape }
311 "$(" / { ifExtension thEnabled } { token ITparenEscape }
313 "[$" @varid "|" / { ifExtension qqEnabled }
314 { lex_quasiquote_tok }
318 "(|" / { ifExtension arrowsEnabled `alexAndPred` notFollowedBySymbol }
319 { special IToparenbar }
320 "|)" / { ifExtension arrowsEnabled } { special ITcparenbar }
324 \? @varid / { ifExtension ipEnabled } { skip_one_varid ITdupipvarid }
328 "(#" / { ifExtension unboxedTuplesEnabled `alexAndPred` notFollowedBySymbol }
329 { token IToubxparen }
330 "#)" / { ifExtension unboxedTuplesEnabled }
331 { token ITcubxparen }
335 "{|" / { ifExtension genericsEnabled } { token ITocurlybar }
336 "|}" / { ifExtension genericsEnabled } { token ITccurlybar }
340 \( { special IToparen }
341 \) { special ITcparen }
342 \[ { special ITobrack }
343 \] { special ITcbrack }
344 \, { special ITcomma }
345 \; { special ITsemi }
346 \` { special ITbackquote }
353 @qual @varid { idtoken qvarid }
354 @qual @conid { idtoken qconid }
356 @conid { idtoken conid }
360 @qual @varid "#"+ / { ifExtension magicHashEnabled } { idtoken qvarid }
361 @qual @conid "#"+ / { ifExtension magicHashEnabled } { idtoken qconid }
362 @varid "#"+ / { ifExtension magicHashEnabled } { varid }
363 @conid "#"+ / { ifExtension magicHashEnabled } { idtoken conid }
369 @qual @varsym { idtoken qvarsym }
370 @qual @consym { idtoken qconsym }
375 -- For the normal boxed literals we need to be careful
376 -- when trying to be close to Haskell98
378 -- Normal integral literals (:: Num a => a, from Integer)
379 @decimal { tok_num positive 0 0 decimal }
380 0[oO] @octal { tok_num positive 2 2 octal }
381 0[xX] @hexadecimal { tok_num positive 2 2 hexadecimal }
383 -- Normal rational literals (:: Fractional a => a, from Rational)
384 @floating_point { strtoken tok_float }
388 -- Unboxed ints (:: Int#) and words (:: Word#)
389 -- It's simpler (and faster?) to give separate cases to the negatives,
390 -- especially considering octal/hexadecimal prefixes.
391 @decimal \# / { ifExtension magicHashEnabled } { tok_primint positive 0 1 decimal }
392 0[oO] @octal \# / { ifExtension magicHashEnabled } { tok_primint positive 2 3 octal }
393 0[xX] @hexadecimal \# / { ifExtension magicHashEnabled } { tok_primint positive 2 3 hexadecimal }
394 @negative @decimal \# / { ifExtension magicHashEnabled } { tok_primint negative 1 2 decimal }
395 @negative 0[oO] @octal \# / { ifExtension magicHashEnabled } { tok_primint negative 3 4 octal }
396 @negative 0[xX] @hexadecimal \# / { ifExtension magicHashEnabled } { tok_primint negative 3 4 hexadecimal }
398 @decimal \# \# / { ifExtension magicHashEnabled } { tok_primword 0 2 decimal }
399 0[oO] @octal \# \# / { ifExtension magicHashEnabled } { tok_primword 2 4 octal }
400 0[xX] @hexadecimal \# \# / { ifExtension magicHashEnabled } { tok_primword 2 4 hexadecimal }
402 -- Unboxed floats and doubles (:: Float#, :: Double#)
403 -- prim_{float,double} work with signed literals
404 @signed @floating_point \# / { ifExtension magicHashEnabled } { init_strtoken 1 tok_primfloat }
405 @signed @floating_point \# \# / { ifExtension magicHashEnabled } { init_strtoken 2 tok_primdouble }
408 -- Strings and chars are lexed by hand-written code. The reason is
409 -- that even if we recognise the string or char here in the regex
410 -- lexer, we would still have to parse the string afterward in order
411 -- to convert it to a String.
414 \" { lex_string_tok }
418 -- -----------------------------------------------------------------------------
422 = ITas -- Haskell keywords
446 | ITscc -- ToDo: remove (we use {-# SCC "..." #-} now)
448 | ITforall -- GHC extension keywords
466 | ITinline_prag Bool -- True <=> INLINE, False <=> NOINLINE
467 | ITspec_prag -- SPECIALISE
468 | ITspec_inline_prag Bool -- SPECIALISE INLINE (or NOINLINE)
476 | 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)
529 | ITdupipvarid FastString -- GHC extension: implicit param: ?x
531 | ITpragma StringBuffer
534 | ITstring FastString
536 | ITrational Rational
539 | ITprimstring FastString
542 | ITprimfloat Rational
543 | ITprimdouble Rational
545 -- MetaHaskell extension tokens
546 | ITopenExpQuote -- [| or [e|
547 | ITopenPatQuote -- [p|
548 | ITopenDecQuote -- [d|
549 | ITopenTypQuote -- [t|
551 | ITidEscape FastString -- $x
552 | ITparenEscape -- $(
555 | ITquasiQuote (FastString,FastString,SrcSpan) -- [:...|...|]
557 -- Arrow notation extension
564 | ITLarrowtail -- -<<
565 | ITRarrowtail -- >>-
567 | ITunknown String -- Used when the lexer can't make sense of it
568 | ITeof -- end of file token
570 -- Documentation annotations
571 | ITdocCommentNext String -- something beginning '-- |'
572 | ITdocCommentPrev String -- something beginning '-- ^'
573 | ITdocCommentNamed String -- something beginning '-- $'
574 | ITdocSection Int String -- a section heading
575 | ITdocOptions String -- doc options (prune, ignore-exports, etc)
576 | ITdocOptionsOld String -- doc options declared "-- # ..."-style
579 deriving Show -- debugging
583 isSpecial :: Token -> Bool
584 -- If we see M.x, where x is a keyword, but
585 -- is special, we treat is as just plain M.x,
587 isSpecial ITas = True
588 isSpecial IThiding = True
589 isSpecial ITqualified = True
590 isSpecial ITforall = True
591 isSpecial ITexport = True
592 isSpecial ITlabel = True
593 isSpecial ITdynamic = True
594 isSpecial ITsafe = True
595 isSpecial ITthreadsafe = True
596 isSpecial ITunsafe = True
597 isSpecial ITccallconv = True
598 isSpecial ITstdcallconv = True
599 isSpecial ITmdo = True
600 isSpecial ITfamily = True
601 isSpecial ITgroup = True
602 isSpecial ITby = True
603 isSpecial ITusing = True
607 -- the bitmap provided as the third component indicates whether the
608 -- corresponding extension keyword is valid under the extension options
609 -- provided to the compiler; if the extension corresponding to *any* of the
610 -- bits set in the bitmap is enabled, the keyword is valid (this setup
611 -- facilitates using a keyword in two different extensions that can be
612 -- activated independently)
614 reservedWordsFM = listToUFM $
615 map (\(x, y, z) -> (mkFastString x, (y, z)))
616 [( "_", ITunderscore, 0 ),
618 ( "case", ITcase, 0 ),
619 ( "class", ITclass, 0 ),
620 ( "data", ITdata, 0 ),
621 ( "default", ITdefault, 0 ),
622 ( "deriving", ITderiving, 0 ),
624 ( "else", ITelse, 0 ),
625 ( "hiding", IThiding, 0 ),
627 ( "import", ITimport, 0 ),
629 ( "infix", ITinfix, 0 ),
630 ( "infixl", ITinfixl, 0 ),
631 ( "infixr", ITinfixr, 0 ),
632 ( "instance", ITinstance, 0 ),
634 ( "module", ITmodule, 0 ),
635 ( "newtype", ITnewtype, 0 ),
637 ( "qualified", ITqualified, 0 ),
638 ( "then", ITthen, 0 ),
639 ( "type", ITtype, 0 ),
640 ( "where", ITwhere, 0 ),
641 ( "_scc_", ITscc, 0 ), -- ToDo: remove
643 ( "forall", ITforall, bit explicitForallBit),
644 ( "mdo", ITmdo, bit recursiveDoBit),
645 ( "family", ITfamily, bit tyFamBit),
646 ( "group", ITgroup, bit transformComprehensionsBit),
647 ( "by", ITby, bit transformComprehensionsBit),
648 ( "using", ITusing, bit transformComprehensionsBit),
650 ( "foreign", ITforeign, bit ffiBit),
651 ( "export", ITexport, bit ffiBit),
652 ( "label", ITlabel, bit ffiBit),
653 ( "dynamic", ITdynamic, bit ffiBit),
654 ( "safe", ITsafe, bit ffiBit),
655 ( "threadsafe", ITthreadsafe, bit ffiBit),
656 ( "unsafe", ITunsafe, bit ffiBit),
657 ( "stdcall", ITstdcallconv, bit ffiBit),
658 ( "ccall", ITccallconv, bit ffiBit),
659 ( "dotnet", ITdotnet, bit ffiBit),
661 ( "rec", ITrec, bit arrowsBit),
662 ( "proc", ITproc, bit arrowsBit)
665 reservedSymsFM :: UniqFM (Token, Int -> Bool)
666 reservedSymsFM = listToUFM $
667 map (\ (x,y,z) -> (mkFastString x,(y,z)))
668 [ ("..", ITdotdot, always)
669 -- (:) is a reserved op, meaning only list cons
670 ,(":", ITcolon, always)
671 ,("::", ITdcolon, always)
672 ,("=", ITequal, always)
673 ,("\\", ITlam, always)
674 ,("|", ITvbar, always)
675 ,("<-", ITlarrow, always)
676 ,("->", ITrarrow, always)
678 ,("~", ITtilde, always)
679 ,("=>", ITdarrow, always)
680 ,("-", ITminus, always)
681 ,("!", ITbang, always)
683 -- For data T (a::*) = MkT
684 ,("*", ITstar, \i -> kindSigsEnabled i || tyFamEnabled i)
685 -- For 'forall a . t'
686 ,(".", ITdot, explicitForallEnabled)
688 ,("-<", ITlarrowtail, arrowsEnabled)
689 ,(">-", ITrarrowtail, arrowsEnabled)
690 ,("-<<", ITLarrowtail, arrowsEnabled)
691 ,(">>-", ITRarrowtail, arrowsEnabled)
693 #if __GLASGOW_HASKELL__ >= 605
694 ,("∷", ITdcolon, unicodeSyntaxEnabled)
695 ,("⇒", ITdarrow, unicodeSyntaxEnabled)
696 ,("∀", ITforall, \i -> unicodeSyntaxEnabled i &&
697 explicitForallEnabled i)
698 ,("→", ITrarrow, unicodeSyntaxEnabled)
699 ,("←", ITlarrow, unicodeSyntaxEnabled)
700 ,("⋯", ITdotdot, unicodeSyntaxEnabled)
701 -- ToDo: ideally, → and ∷ should be "specials", so that they cannot
702 -- form part of a large operator. This would let us have a better
703 -- syntax for kinds: ɑ∷*→* would be a legal kind signature. (maybe).
707 -- -----------------------------------------------------------------------------
710 type Action = SrcSpan -> StringBuffer -> Int -> P (Located Token)
712 special :: Token -> Action
713 special tok span _buf _len = return (L span tok)
715 token, layout_token :: Token -> Action
716 token t span _buf _len = return (L span t)
717 layout_token t span _buf _len = pushLexState layout >> return (L span t)
719 idtoken :: (StringBuffer -> Int -> Token) -> Action
720 idtoken f span buf len = return (L span $! (f buf len))
722 skip_one_varid :: (FastString -> Token) -> Action
723 skip_one_varid f span buf len
724 = return (L span $! f (lexemeToFastString (stepOn buf) (len-1)))
726 strtoken :: (String -> Token) -> Action
727 strtoken f span buf len =
728 return (L span $! (f $! lexemeToString buf len))
730 init_strtoken :: Int -> (String -> Token) -> Action
731 -- like strtoken, but drops the last N character(s)
732 init_strtoken drop f span buf len =
733 return (L span $! (f $! lexemeToString buf (len-drop)))
735 begin :: Int -> Action
736 begin code _span _str _len = do pushLexState code; lexToken
739 pop _span _buf _len = do popLexState; lexToken
741 pop_and :: Action -> Action
742 pop_and act span buf len = do popLexState; act span buf len
744 {-# INLINE nextCharIs #-}
745 nextCharIs buf p = not (atEnd buf) && p (currentChar buf)
747 notFollowedBy char _ _ _ (AI _ _ buf)
748 = nextCharIs buf (/=char)
750 notFollowedBySymbol _ _ _ (AI _ _ buf)
751 = nextCharIs buf (`notElem` "!#$%&*+./<=>?@\\^|-~")
753 -- We must reject doc comments as being ordinary comments everywhere.
754 -- In some cases the doc comment will be selected as the lexeme due to
755 -- maximal munch, but not always, because the nested comment rule is
756 -- valid in all states, but the doc-comment rules are only valid in
757 -- the non-layout states.
758 isNormalComment bits _ _ (AI _ _ buf)
759 | haddockEnabled bits = notFollowedByDocOrPragma
760 | otherwise = nextCharIs buf (/='#')
762 notFollowedByDocOrPragma
763 = not $ spaceAndP buf (`nextCharIs` (`elem` "|^*$#"))
765 spaceAndP buf p = p buf || nextCharIs buf (==' ') && p (snd (nextChar buf))
768 haddockDisabledAnd p bits _ _ (AI _ _ buf)
769 = if haddockEnabled bits then False else (p buf)
772 atEOL _ _ _ (AI _ _ buf) = atEnd buf || currentChar buf == '\n'
774 ifExtension pred bits _ _ _ = pred bits
776 multiline_doc_comment :: Action
777 multiline_doc_comment span buf _len = withLexedDocType (worker "")
779 worker commentAcc input docType oneLine = case alexGetChar input of
781 | oneLine -> docCommentEnd input commentAcc docType buf span
782 | otherwise -> case checkIfCommentLine input' of
783 Just input -> worker ('\n':commentAcc) input docType False
784 Nothing -> docCommentEnd input commentAcc docType buf span
785 Just (c, input) -> worker (c:commentAcc) input docType oneLine
786 Nothing -> docCommentEnd input commentAcc docType buf span
788 checkIfCommentLine input = check (dropNonNewlineSpace input)
790 check input = case alexGetChar input of
791 Just ('-', input) -> case alexGetChar input of
792 Just ('-', input) -> case alexGetChar input of
793 Just (c, _) | c /= '-' -> Just input
798 dropNonNewlineSpace input = case alexGetChar input of
800 | isSpace c && c /= '\n' -> dropNonNewlineSpace input'
805 nested comments require traversing by hand, they can't be parsed
806 using regular expressions.
808 nested_comment :: P (Located Token) -> Action
809 nested_comment cont span _str _len = do
813 go 0 input = do setInput input; cont
814 go n input = case alexGetChar input of
815 Nothing -> errBrace input span
816 Just ('-',input) -> case alexGetChar input of
817 Nothing -> errBrace input span
818 Just ('\125',input) -> go (n-1) input
819 Just (_,_) -> go n input
820 Just ('\123',input) -> case alexGetChar input of
821 Nothing -> errBrace input span
822 Just ('-',input) -> go (n+1) input
823 Just (_,_) -> go n input
824 Just (_,input) -> go n input
826 nested_doc_comment :: Action
827 nested_doc_comment span buf _len = withLexedDocType (go "")
829 go commentAcc input docType _ = case alexGetChar input of
830 Nothing -> errBrace input span
831 Just ('-',input) -> case alexGetChar input of
832 Nothing -> errBrace input span
833 Just ('\125',input) ->
834 docCommentEnd input commentAcc docType buf span
835 Just (_,_) -> go ('-':commentAcc) input docType False
836 Just ('\123', input) -> case alexGetChar input of
837 Nothing -> errBrace input span
838 Just ('-',input) -> do
840 let cont = do input <- getInput; go commentAcc input docType False
841 nested_comment cont span buf _len
842 Just (_,_) -> go ('\123':commentAcc) input docType False
843 Just (c,input) -> go (c:commentAcc) input docType False
845 withLexedDocType lexDocComment = do
846 input@(AI _ _ buf) <- getInput
847 case prevChar buf ' ' of
848 '|' -> lexDocComment input ITdocCommentNext False
849 '^' -> lexDocComment input ITdocCommentPrev False
850 '$' -> lexDocComment input ITdocCommentNamed False
851 '*' -> lexDocSection 1 input
852 '#' -> lexDocComment input ITdocOptionsOld False
854 lexDocSection n input = case alexGetChar input of
855 Just ('*', input) -> lexDocSection (n+1) input
856 Just (_, _) -> lexDocComment input (ITdocSection n) True
857 Nothing -> do setInput input; lexToken -- eof reached, lex it normally
860 -------------------------------------------------------------------------------
861 -- This function is quite tricky. We can't just return a new token, we also
862 -- need to update the state of the parser. Why? Because the token is longer
863 -- than what was lexed by Alex, and the lexToken function doesn't know this, so
864 -- it writes the wrong token length to the parser state. This function is
865 -- called afterwards, so it can just update the state.
867 -- This is complicated by the fact that Haddock tokens can span multiple lines,
868 -- which is something that the original lexer didn't account for.
869 -- I have added last_line_len in the parser state which represents the length
870 -- of the part of the token that is on the last line. It is now used for layout
871 -- calculation in pushCurrentContext instead of last_len. last_len is, like it
872 -- was before, the full length of the token, and it is now only used for error
875 docCommentEnd :: AlexInput -> String -> (String -> Token) -> StringBuffer ->
876 SrcSpan -> P (Located Token)
877 docCommentEnd input commentAcc docType buf span = do
879 let (AI loc last_offs nextBuf) = input
880 comment = reverse commentAcc
881 span' = mkSrcSpan (srcSpanStart span) loc
882 last_len = byteDiff buf nextBuf
884 last_line_len = if (last_offs - last_len < 0)
888 span `seq` setLastToken span' last_len last_line_len
889 return (L span' (docType comment))
891 errBrace (AI end _ _) span = failLocMsgP (srcSpanStart span) end "unterminated `{-'"
893 open_brace, close_brace :: Action
894 open_brace span _str _len = do
896 setContext (NoLayout:ctx)
897 return (L span ITocurly)
898 close_brace span _str _len = do
900 return (L span ITccurly)
902 qvarid buf len = ITqvarid $! splitQualName buf len
903 qconid buf len = ITqconid $! splitQualName buf len
905 splitQualName :: StringBuffer -> Int -> (FastString,FastString)
906 -- takes a StringBuffer and a length, and returns the module name
907 -- and identifier parts of a qualified name. Splits at the *last* dot,
908 -- because of hierarchical module names.
909 splitQualName orig_buf len = split orig_buf orig_buf
912 | orig_buf `byteDiff` buf >= len = done dot_buf
913 | c == '.' = found_dot buf'
914 | otherwise = split buf' dot_buf
916 (c,buf') = nextChar buf
918 -- careful, we might get names like M....
919 -- so, if the character after the dot is not upper-case, this is
920 -- the end of the qualifier part.
921 found_dot buf -- buf points after the '.'
922 | isUpper c = split buf' buf
923 | otherwise = done buf
925 (c,buf') = nextChar buf
928 (lexemeToFastString orig_buf (qual_size - 1),
929 lexemeToFastString dot_buf (len - qual_size))
931 qual_size = orig_buf `byteDiff` dot_buf
935 case lookupUFM reservedWordsFM fs of
936 Just (keyword,0) -> do
938 return (L span keyword)
939 Just (keyword,exts) -> do
940 b <- extension (\i -> exts .&. i /= 0)
941 if b then do maybe_layout keyword
942 return (L span keyword)
943 else return (L span (ITvarid fs))
944 _other -> return (L span (ITvarid fs))
946 fs = lexemeToFastString buf len
948 conid buf len = ITconid fs
949 where fs = lexemeToFastString buf len
951 qvarsym buf len = ITqvarsym $! splitQualName buf len
952 qconsym buf len = ITqconsym $! splitQualName buf len
954 varsym = sym ITvarsym
955 consym = sym ITconsym
957 sym con span buf len =
958 case lookupUFM reservedSymsFM fs of
959 Just (keyword,exts) -> do
961 if b then return (L span keyword)
962 else return (L span $! con fs)
963 _other -> return (L span $! con fs)
965 fs = lexemeToFastString buf len
967 -- Variations on the integral numeric literal.
968 tok_integral :: (Integer -> Token)
969 -> (Integer -> Integer)
970 -- -> (StringBuffer -> StringBuffer) -> (Int -> Int)
972 -> (Integer, (Char->Int)) -> Action
973 tok_integral itint transint transbuf translen (radix,char_to_int) span buf len =
974 return $ L span $ itint $! transint $ parseUnsignedInteger
975 (offsetBytes transbuf buf) (subtract translen len) radix char_to_int
977 -- some conveniences for use with tok_integral
978 tok_num = tok_integral ITinteger
979 tok_primint = tok_integral ITprimint
980 tok_primword = tok_integral ITprimword positive
983 decimal = (10,octDecDigit)
984 octal = (8,octDecDigit)
985 hexadecimal = (16,hexDigit)
987 -- readRational can understand negative rationals, exponents, everything.
988 tok_float str = ITrational $! readRational str
989 tok_primfloat str = ITprimfloat $! readRational str
990 tok_primdouble str = ITprimdouble $! readRational str
992 -- -----------------------------------------------------------------------------
995 -- we're at the first token on a line, insert layout tokens if necessary
997 do_bol span _str _len = do
1001 --trace "layout: inserting '}'" $ do
1003 -- do NOT pop the lex state, we might have a ';' to insert
1004 return (L span ITvccurly)
1006 --trace "layout: inserting ';'" $ do
1008 return (L span ITsemi)
1013 -- certain keywords put us in the "layout" state, where we might
1014 -- add an opening curly brace.
1015 maybe_layout ITdo = pushLexState layout_do
1016 maybe_layout ITmdo = pushLexState layout_do
1017 maybe_layout ITof = pushLexState layout
1018 maybe_layout ITlet = pushLexState layout
1019 maybe_layout ITwhere = pushLexState layout
1020 maybe_layout ITrec = pushLexState layout
1021 maybe_layout _ = return ()
1023 -- Pushing a new implicit layout context. If the indentation of the
1024 -- next token is not greater than the previous layout context, then
1025 -- Haskell 98 says that the new layout context should be empty; that is
1026 -- the lexer must generate {}.
1028 -- We are slightly more lenient than this: when the new context is started
1029 -- by a 'do', then we allow the new context to be at the same indentation as
1030 -- the previous context. This is what the 'strict' argument is for.
1032 new_layout_context strict span _buf _len = do
1034 (AI _ offset _) <- getInput
1037 Layout prev_off : _ |
1038 (strict && prev_off >= offset ||
1039 not strict && prev_off > offset) -> do
1040 -- token is indented to the left of the previous context.
1041 -- we must generate a {} sequence now.
1042 pushLexState layout_left
1043 return (L span ITvocurly)
1045 setContext (Layout offset : ctx)
1046 return (L span ITvocurly)
1048 do_layout_left span _buf _len = do
1050 pushLexState bol -- we must be at the start of a line
1051 return (L span ITvccurly)
1053 -- -----------------------------------------------------------------------------
1056 setLine :: Int -> Action
1057 setLine code span buf len = do
1058 let line = parseUnsignedInteger buf len 10 octDecDigit
1059 setSrcLoc (mkSrcLoc (srcSpanFile span) (fromIntegral line - 1) 0)
1060 -- subtract one: the line number refers to the *following* line
1065 setFile :: Int -> Action
1066 setFile code span buf len = do
1067 let file = lexemeToFastString (stepOn buf) (len-2)
1068 setSrcLoc (mkSrcLoc file (srcSpanEndLine span) (srcSpanEndCol span))
1074 -- -----------------------------------------------------------------------------
1075 -- Options, includes and language pragmas.
1077 lex_string_prag :: (String -> Token) -> Action
1078 lex_string_prag mkTok span _buf _len
1079 = do input <- getInput
1083 return (L (mkSrcSpan start end) tok)
1085 = if isString input "#-}"
1086 then do setInput input
1087 return (mkTok (reverse acc))
1088 else case alexGetChar input of
1089 Just (c,i) -> go (c:acc) i
1090 Nothing -> err input
1091 isString _ [] = True
1093 = case alexGetChar i of
1094 Just (c,i') | c == x -> isString i' xs
1096 err (AI end _ _) = failLocMsgP (srcSpanStart span) end "unterminated options pragma"
1099 -- -----------------------------------------------------------------------------
1102 -- This stuff is horrible. I hates it.
1104 lex_string_tok :: Action
1105 lex_string_tok span _buf _len = do
1106 tok <- lex_string ""
1108 return (L (mkSrcSpan (srcSpanStart span) end) tok)
1110 lex_string :: String -> P Token
1113 case alexGetChar' i of
1114 Nothing -> lit_error
1118 magicHash <- extension magicHashEnabled
1122 case alexGetChar' i of
1126 then failMsgP "primitive string literal must contain only characters <= \'\\xFF\'"
1127 else let s' = mkZFastString (reverse s) in
1128 return (ITprimstring s')
1129 -- mkZFastString is a hack to avoid encoding the
1130 -- string in UTF-8. We just want the exact bytes.
1132 return (ITstring (mkFastString (reverse s)))
1134 return (ITstring (mkFastString (reverse s)))
1137 | Just ('&',i) <- next -> do
1138 setInput i; lex_string s
1139 | Just (c,i) <- next, is_space c -> do
1140 setInput i; lex_stringgap s
1141 where next = alexGetChar' i
1147 lex_stringgap s = do
1150 '\\' -> lex_string s
1151 c | is_space c -> lex_stringgap s
1155 lex_char_tok :: Action
1156 -- Here we are basically parsing character literals, such as 'x' or '\n'
1157 -- but, when Template Haskell is on, we additionally spot
1158 -- 'x and ''T, returning ITvarQuote and ITtyQuote respectively,
1159 -- but WIHTOUT CONSUMING the x or T part (the parser does that).
1160 -- So we have to do two characters of lookahead: when we see 'x we need to
1161 -- see if there's a trailing quote
1162 lex_char_tok span _buf _len = do -- We've seen '
1163 i1 <- getInput -- Look ahead to first character
1164 let loc = srcSpanStart span
1165 case alexGetChar' i1 of
1166 Nothing -> lit_error
1168 Just ('\'', i2@(AI end2 _ _)) -> do -- We've seen ''
1169 th_exts <- extension thEnabled
1172 return (L (mkSrcSpan loc end2) ITtyQuote)
1175 Just ('\\', i2@(AI _end2 _ _)) -> do -- We've seen 'backslash
1177 lit_ch <- lex_escape
1178 mc <- getCharOrFail -- Trailing quote
1179 if mc == '\'' then finish_char_tok loc lit_ch
1180 else do setInput i2; lit_error
1182 Just (c, i2@(AI _end2 _ _))
1183 | not (isAny c) -> lit_error
1186 -- We've seen 'x, where x is a valid character
1187 -- (i.e. not newline etc) but not a quote or backslash
1188 case alexGetChar' i2 of -- Look ahead one more character
1189 Nothing -> lit_error
1190 Just ('\'', i3) -> do -- We've seen 'x'
1192 finish_char_tok loc c
1193 _other -> do -- We've seen 'x not followed by quote
1194 -- If TH is on, just parse the quote only
1195 th_exts <- extension thEnabled
1196 let (AI end _ _) = i1
1197 if th_exts then return (L (mkSrcSpan loc end) ITvarQuote)
1198 else do setInput i2; lit_error
1200 finish_char_tok :: SrcLoc -> Char -> P (Located Token)
1201 finish_char_tok loc ch -- We've already seen the closing quote
1202 -- Just need to check for trailing #
1203 = do magicHash <- extension magicHashEnabled
1204 i@(AI end _ _) <- getInput
1205 if magicHash then do
1206 case alexGetChar' i of
1207 Just ('#',i@(AI end _ _)) -> do
1209 return (L (mkSrcSpan loc end) (ITprimchar ch))
1211 return (L (mkSrcSpan loc end) (ITchar ch))
1213 return (L (mkSrcSpan loc end) (ITchar ch))
1215 lex_char :: Char -> AlexInput -> P Char
1218 '\\' -> do setInput inp; lex_escape
1219 c | isAny c -> do setInput inp; return c
1222 isAny c | c > '\x7f' = isPrint c
1223 | otherwise = is_any c
1225 lex_escape :: P Char
1239 '^' -> do c <- getCharOrFail
1240 if c >= '@' && c <= '_'
1241 then return (chr (ord c - ord '@'))
1244 'x' -> readNum is_hexdigit 16 hexDigit
1245 'o' -> readNum is_octdigit 8 octDecDigit
1246 x | is_decdigit x -> readNum2 is_decdigit 10 octDecDigit (octDecDigit x)
1250 case alexGetChar' i of
1251 Nothing -> lit_error
1253 case alexGetChar' i2 of
1254 Nothing -> do setInput i2; lit_error
1256 let str = [c1,c2,c3] in
1257 case [ (c,rest) | (p,c) <- silly_escape_chars,
1258 Just rest <- [maybePrefixMatch p str] ] of
1259 (escape_char,[]):_ -> do
1262 (escape_char,_:_):_ -> do
1267 readNum :: (Char -> Bool) -> Int -> (Char -> Int) -> P Char
1268 readNum is_digit base conv = do
1272 then readNum2 is_digit base conv (conv c)
1273 else do setInput i; lit_error
1275 readNum2 is_digit base conv i = do
1278 where read i input = do
1279 case alexGetChar' input of
1280 Just (c,input') | is_digit c -> do
1281 read (i*base + conv c) input'
1283 if i >= 0 && i <= 0x10FFFF
1284 then do setInput input; return (chr i)
1287 silly_escape_chars = [
1324 -- before calling lit_error, ensure that the current input is pointing to
1325 -- the position of the error in the buffer. This is so that we can report
1326 -- a correct location to the user, but also so we can detect UTF-8 decoding
1327 -- errors if they occur.
1328 lit_error = lexError "lexical error in string/character literal"
1330 getCharOrFail :: P Char
1333 case alexGetChar' i of
1334 Nothing -> lexError "unexpected end-of-file in string/character literal"
1335 Just (c,i) -> do setInput i; return c
1337 -- -----------------------------------------------------------------------------
1340 lex_quasiquote_tok :: Action
1341 lex_quasiquote_tok span buf len = do
1342 let quoter = reverse $ takeWhile (/= '$')
1343 $ reverse $ lexemeToString buf (len - 1)
1344 quoteStart <- getSrcLoc
1345 quote <- lex_quasiquote ""
1347 return (L (mkSrcSpan (srcSpanStart span) end)
1348 (ITquasiQuote (mkFastString quoter,
1349 mkFastString (reverse quote),
1350 mkSrcSpan quoteStart end)))
1352 lex_quasiquote :: String -> P String
1353 lex_quasiquote s = do
1355 case alexGetChar' i of
1356 Nothing -> lit_error
1359 | Just ('|',i) <- next -> do
1360 setInput i; lex_quasiquote ('|' : s)
1361 | Just (']',i) <- next -> do
1362 setInput i; lex_quasiquote (']' : s)
1363 where next = alexGetChar' i
1366 | Just (']',i) <- next -> do
1367 setInput i; return s
1368 where next = alexGetChar' i
1371 setInput i; lex_quasiquote (c : s)
1373 -- -----------------------------------------------------------------------------
1376 warn :: DynFlag -> SDoc -> Action
1377 warn option warning srcspan _buf _len = do
1378 addWarning option srcspan warning
1381 -- -----------------------------------------------------------------------------
1392 SrcSpan -- The start and end of the text span related to
1393 -- the error. Might be used in environments which can
1394 -- show this span, e.g. by highlighting it.
1395 Message -- The error message
1397 data PState = PState {
1398 buffer :: StringBuffer,
1400 messages :: Messages,
1401 last_loc :: SrcSpan, -- pos of previous token
1402 last_offs :: !Int, -- offset of the previous token from the
1403 -- beginning of the current line.
1404 -- \t is equal to 8 spaces.
1405 last_len :: !Int, -- len of previous token
1406 last_line_len :: !Int,
1407 loc :: SrcLoc, -- current loc (end of prev token + 1)
1408 extsBitmap :: !Int, -- bitmap that determines permitted extensions
1409 context :: [LayoutContext],
1412 -- last_loc and last_len are used when generating error messages,
1413 -- and in pushCurrentContext only. Sigh, if only Happy passed the
1414 -- current token to happyError, we could at least get rid of last_len.
1415 -- Getting rid of last_loc would require finding another way to
1416 -- implement pushCurrentContext (which is only called from one place).
1418 newtype P a = P { unP :: PState -> ParseResult a }
1420 instance Monad P where
1426 returnP a = a `seq` (P $ \s -> POk s a)
1428 thenP :: P a -> (a -> P b) -> P b
1429 (P m) `thenP` k = P $ \ s ->
1431 POk s1 a -> (unP (k a)) s1
1432 PFailed span err -> PFailed span err
1434 failP :: String -> P a
1435 failP msg = P $ \s -> PFailed (last_loc s) (text msg)
1437 failMsgP :: String -> P a
1438 failMsgP msg = P $ \s -> PFailed (last_loc s) (text msg)
1440 failLocMsgP :: SrcLoc -> SrcLoc -> String -> P a
1441 failLocMsgP loc1 loc2 str = P $ \_ -> PFailed (mkSrcSpan loc1 loc2) (text str)
1443 failSpanMsgP :: SrcSpan -> SDoc -> P a
1444 failSpanMsgP span msg = P $ \_ -> PFailed span msg
1446 extension :: (Int -> Bool) -> P Bool
1447 extension p = P $ \s -> POk s (p $! extsBitmap s)
1450 getExts = P $ \s -> POk s (extsBitmap s)
1452 setSrcLoc :: SrcLoc -> P ()
1453 setSrcLoc new_loc = P $ \s -> POk s{loc=new_loc} ()
1455 getSrcLoc :: P SrcLoc
1456 getSrcLoc = P $ \s@(PState{ loc=loc }) -> POk s loc
1458 setLastToken :: SrcSpan -> Int -> Int -> P ()
1459 setLastToken loc len line_len = P $ \s -> POk s {
1462 last_line_len=line_len
1465 data AlexInput = AI SrcLoc {-#UNPACK#-}!Int StringBuffer
1467 alexInputPrevChar :: AlexInput -> Char
1468 alexInputPrevChar (AI _ _ buf) = prevChar buf '\n'
1470 alexGetChar :: AlexInput -> Maybe (Char,AlexInput)
1471 alexGetChar (AI loc ofs s)
1473 | otherwise = adj_c `seq` loc' `seq` ofs' `seq` s' `seq`
1474 --trace (show (ord c)) $
1475 Just (adj_c, (AI loc' ofs' s'))
1476 where (c,s') = nextChar s
1477 loc' = advanceSrcLoc loc c
1478 ofs' = advanceOffs c ofs
1486 other_graphic = '\x6'
1489 | c <= '\x06' = non_graphic
1491 -- Alex doesn't handle Unicode, so when Unicode
1492 -- character is encoutered we output these values
1493 -- with the actual character value hidden in the state.
1495 case generalCategory c of
1496 UppercaseLetter -> upper
1497 LowercaseLetter -> lower
1498 TitlecaseLetter -> upper
1499 ModifierLetter -> other_graphic
1500 OtherLetter -> lower -- see #1103
1501 NonSpacingMark -> other_graphic
1502 SpacingCombiningMark -> other_graphic
1503 EnclosingMark -> other_graphic
1504 DecimalNumber -> digit
1505 LetterNumber -> other_graphic
1506 OtherNumber -> other_graphic
1507 ConnectorPunctuation -> other_graphic
1508 DashPunctuation -> other_graphic
1509 OpenPunctuation -> other_graphic
1510 ClosePunctuation -> other_graphic
1511 InitialQuote -> other_graphic
1512 FinalQuote -> other_graphic
1513 OtherPunctuation -> other_graphic
1514 MathSymbol -> symbol
1515 CurrencySymbol -> symbol
1516 ModifierSymbol -> symbol
1517 OtherSymbol -> symbol
1519 _other -> non_graphic
1521 -- This version does not squash unicode characters, it is used when
1523 alexGetChar' :: AlexInput -> Maybe (Char,AlexInput)
1524 alexGetChar' (AI loc ofs s)
1526 | otherwise = c `seq` loc' `seq` ofs' `seq` s' `seq`
1527 --trace (show (ord c)) $
1528 Just (c, (AI loc' ofs' s'))
1529 where (c,s') = nextChar s
1530 loc' = advanceSrcLoc loc c
1531 ofs' = advanceOffs c ofs
1533 advanceOffs :: Char -> Int -> Int
1534 advanceOffs '\n' _ = 0
1535 advanceOffs '\t' offs = (offs `quot` 8 + 1) * 8
1536 advanceOffs _ offs = offs + 1
1538 getInput :: P AlexInput
1539 getInput = P $ \s@PState{ loc=l, last_offs=o, buffer=b } -> POk s (AI l o b)
1541 setInput :: AlexInput -> P ()
1542 setInput (AI l o b) = P $ \s -> POk s{ loc=l, last_offs=o, buffer=b } ()
1544 pushLexState :: Int -> P ()
1545 pushLexState ls = P $ \s@PState{ lex_state=l } -> POk s{lex_state=ls:l} ()
1547 popLexState :: P Int
1548 popLexState = P $ \s@PState{ lex_state=ls:l } -> POk s{ lex_state=l } ls
1550 getLexState :: P Int
1551 getLexState = P $ \s@PState{ lex_state=ls:_ } -> POk s ls
1553 -- for reasons of efficiency, flags indicating language extensions (eg,
1554 -- -fglasgow-exts or -XParr) are represented by a bitmap stored in an unboxed
1557 genericsBit, ffiBit, parrBit :: Int
1558 genericsBit = 0 -- {| and |}
1564 explicitForallBit = 7 -- the 'forall' keyword and '.' symbol
1565 bangPatBit = 8 -- Tells the parser to understand bang-patterns
1566 -- (doesn't affect the lexer)
1567 tyFamBit = 9 -- indexed type families: 'family' keyword and kind sigs
1568 haddockBit = 10 -- Lex and parse Haddock comments
1569 magicHashBit = 11 -- "#" in both functions and operators
1570 kindSigsBit = 12 -- Kind signatures on type variables
1571 recursiveDoBit = 13 -- mdo
1572 unicodeSyntaxBit = 14 -- the forall symbol, arrow symbols, etc
1573 unboxedTuplesBit = 15 -- (# and #)
1574 standaloneDerivingBit = 16 -- standalone instance deriving declarations
1575 transformComprehensionsBit = 17
1576 qqBit = 18 -- enable quasiquoting
1578 genericsEnabled, ffiEnabled, parrEnabled :: Int -> Bool
1580 genericsEnabled flags = testBit flags genericsBit
1581 ffiEnabled flags = testBit flags ffiBit
1582 parrEnabled flags = testBit flags parrBit
1583 arrowsEnabled flags = testBit flags arrowsBit
1584 thEnabled flags = testBit flags thBit
1585 ipEnabled flags = testBit flags ipBit
1586 explicitForallEnabled flags = testBit flags explicitForallBit
1587 bangPatEnabled flags = testBit flags bangPatBit
1588 tyFamEnabled flags = testBit flags tyFamBit
1589 haddockEnabled flags = testBit flags haddockBit
1590 magicHashEnabled flags = testBit flags magicHashBit
1591 kindSigsEnabled flags = testBit flags kindSigsBit
1592 recursiveDoEnabled flags = testBit flags recursiveDoBit
1593 unicodeSyntaxEnabled flags = testBit flags unicodeSyntaxBit
1594 unboxedTuplesEnabled flags = testBit flags unboxedTuplesBit
1595 standaloneDerivingEnabled flags = testBit flags standaloneDerivingBit
1596 transformComprehensionsEnabled flags = testBit flags transformComprehensionsBit
1597 qqEnabled flags = testBit flags qqBit
1599 -- PState for parsing options pragmas
1601 pragState :: DynFlags -> StringBuffer -> SrcLoc -> PState
1602 pragState dynflags buf loc =
1605 messages = emptyMessages,
1607 last_loc = mkSrcSpan loc loc,
1614 lex_state = [bol, option_prags, 0]
1618 -- create a parse state
1620 mkPState :: StringBuffer -> SrcLoc -> DynFlags -> PState
1621 mkPState buf loc flags =
1625 messages = emptyMessages,
1626 last_loc = mkSrcSpan loc loc,
1631 extsBitmap = fromIntegral bitmap,
1633 lex_state = [bol, 0]
1634 -- we begin in the layout state if toplev_layout is set
1637 bitmap = genericsBit `setBitIf` dopt Opt_Generics flags
1638 .|. ffiBit `setBitIf` dopt Opt_ForeignFunctionInterface flags
1639 .|. parrBit `setBitIf` dopt Opt_PArr flags
1640 .|. arrowsBit `setBitIf` dopt Opt_Arrows flags
1641 .|. thBit `setBitIf` dopt Opt_TemplateHaskell flags
1642 .|. qqBit `setBitIf` dopt Opt_QuasiQuotes flags
1643 .|. ipBit `setBitIf` dopt Opt_ImplicitParams flags
1644 .|. explicitForallBit `setBitIf` dopt Opt_ScopedTypeVariables flags
1645 .|. explicitForallBit `setBitIf` dopt Opt_PolymorphicComponents flags
1646 .|. explicitForallBit `setBitIf` dopt Opt_ExistentialQuantification flags
1647 .|. explicitForallBit `setBitIf` dopt Opt_Rank2Types flags
1648 .|. explicitForallBit `setBitIf` dopt Opt_RankNTypes flags
1649 .|. bangPatBit `setBitIf` dopt Opt_BangPatterns flags
1650 .|. tyFamBit `setBitIf` dopt Opt_TypeFamilies flags
1651 .|. haddockBit `setBitIf` dopt Opt_Haddock flags
1652 .|. magicHashBit `setBitIf` dopt Opt_MagicHash flags
1653 .|. kindSigsBit `setBitIf` dopt Opt_KindSignatures flags
1654 .|. recursiveDoBit `setBitIf` dopt Opt_RecursiveDo flags
1655 .|. unicodeSyntaxBit `setBitIf` dopt Opt_UnicodeSyntax flags
1656 .|. unboxedTuplesBit `setBitIf` dopt Opt_UnboxedTuples flags
1657 .|. standaloneDerivingBit `setBitIf` dopt Opt_StandaloneDeriving flags
1658 .|. transformComprehensionsBit `setBitIf` dopt Opt_TransformListComp flags
1660 setBitIf :: Int -> Bool -> Int
1661 b `setBitIf` cond | cond = bit b
1664 addWarning :: DynFlag -> SrcSpan -> SDoc -> P ()
1665 addWarning option srcspan warning
1666 = P $ \s@PState{messages=(ws,es), dflags=d} ->
1667 let warning' = mkWarnMsg srcspan alwaysQualify warning
1668 ws' = if dopt option d then ws `snocBag` warning' else ws
1669 in POk s{messages=(ws', es)} ()
1671 getMessages :: PState -> Messages
1672 getMessages PState{messages=ms} = ms
1674 getContext :: P [LayoutContext]
1675 getContext = P $ \s@PState{context=ctx} -> POk s ctx
1677 setContext :: [LayoutContext] -> P ()
1678 setContext ctx = P $ \s -> POk s{context=ctx} ()
1681 popContext = P $ \ s@(PState{ buffer = buf, context = ctx,
1682 last_len = len, last_loc = last_loc }) ->
1684 (_:tl) -> POk s{ context = tl } ()
1685 [] -> PFailed last_loc (srcParseErr buf len)
1687 -- Push a new layout context at the indentation of the last token read.
1688 -- This is only used at the outer level of a module when the 'module'
1689 -- keyword is missing.
1690 pushCurrentContext :: P ()
1691 pushCurrentContext = P $ \ s@PState{ last_offs=offs, last_line_len=len, context=ctx } ->
1692 POk s{context = Layout (offs-len) : ctx} ()
1693 --trace ("off: " ++ show offs ++ ", len: " ++ show len) $ POk s{context = Layout (offs-len) : ctx} ()
1695 getOffside :: P Ordering
1696 getOffside = P $ \s@PState{last_offs=offs, context=stk} ->
1697 let ord = case stk of
1698 (Layout n:_) -> compare offs n
1702 -- ---------------------------------------------------------------------------
1703 -- Construct a parse error
1706 :: StringBuffer -- current buffer (placed just after the last token)
1707 -> Int -- length of the previous token
1710 = hcat [ if null token
1711 then ptext (sLit "parse error (possibly incorrect indentation)")
1712 else hcat [ptext (sLit "parse error on input "),
1713 char '`', text token, char '\'']
1715 where token = lexemeToString (offsetBytes (-len) buf) len
1717 -- Report a parse failure, giving the span of the previous token as
1718 -- the location of the error. This is the entry point for errors
1719 -- detected during parsing.
1721 srcParseFail = P $ \PState{ buffer = buf, last_len = len,
1722 last_loc = last_loc } ->
1723 PFailed last_loc (srcParseErr buf len)
1725 -- A lexical error is reported at a particular position in the source file,
1726 -- not over a token range.
1727 lexError :: String -> P a
1730 (AI end _ buf) <- getInput
1731 reportLexError loc end buf str
1733 -- -----------------------------------------------------------------------------
1734 -- This is the top-level function: called from the parser each time a
1735 -- new token is to be read from the input.
1737 lexer :: (Located Token -> P a) -> P a
1739 tok@(L _span _tok__) <- lexToken
1740 -- trace ("token: " ++ show tok__) $ do
1743 lexToken :: P (Located Token)
1745 inp@(AI loc1 _ buf) <- getInput
1748 case alexScanUser exts inp sc of
1750 let span = mkSrcSpan loc1 loc1
1751 setLastToken span 0 0
1752 return (L span ITeof)
1753 AlexError (AI loc2 _ buf) ->
1754 reportLexError loc1 loc2 buf "lexical error"
1755 AlexSkip inp2 _ -> do
1758 AlexToken inp2@(AI end _ buf2) _ t -> do
1760 let span = mkSrcSpan loc1 end
1761 let bytes = byteDiff buf buf2
1762 span `seq` setLastToken span bytes bytes
1765 reportLexError loc1 loc2 buf str
1766 | atEnd buf = failLocMsgP loc1 loc2 (str ++ " at end of input")
1769 c = fst (nextChar buf)
1771 if c == '\0' -- decoding errors are mapped to '\0', see utf8DecodeChar#
1772 then failLocMsgP loc2 loc2 (str ++ " (UTF-8 decoding error)")
1773 else failLocMsgP loc1 loc2 (str ++ " at character " ++ show c)