X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fparser%2FLexer.x;fp=ghc%2Fcompiler%2Fparser%2FLexer.x;h=0000000000000000000000000000000000000000;hb=0065d5ab628975892cea1ec7303f968c3338cbe1;hp=4c1b48efc0845f3009dc19f4d8e5e26eadb36103;hpb=28a464a75e14cece5db40f2765a29348273ff2d2;p=ghc-hetmet.git diff --git a/ghc/compiler/parser/Lexer.x b/ghc/compiler/parser/Lexer.x deleted file mode 100644 index 4c1b48e..0000000 --- a/ghc/compiler/parser/Lexer.x +++ /dev/null @@ -1,1457 +0,0 @@ ------------------------------------------------------------------------------ --- (c) The University of Glasgow, 2006 --- --- GHC's lexer. --- --- This is a combination of an Alex-generated lexer from a regex --- definition, with some hand-coded bits. --- --- Completely accurate information about token-spans within the source --- file is maintained. Every token has a start and end SrcLoc attached to it. --- ------------------------------------------------------------------------------ - --- ToDo / known bugs: --- - Unicode --- - parsing integers is a bit slow --- - readRational is a bit slow --- --- Known bugs, that were also in the previous version: --- - M... should be 3 tokens, not 1. --- - pragma-end should be only valid in a pragma - -{ -module Lexer ( - Token(..), lexer, pragState, mkPState, PState(..), - P(..), ParseResult(..), getSrcLoc, - failLocMsgP, failSpanMsgP, srcParseFail, - popContext, pushCurrentContext, setLastToken, setSrcLoc, - getLexState, popLexState, pushLexState, - extension, bangPatEnabled - ) where - -#include "HsVersions.h" - -import ErrUtils ( Message ) -import Outputable -import StringBuffer -import FastString -import FastTypes -import SrcLoc -import UniqFM -import DynFlags -import Ctype -import Util ( maybePrefixMatch, readRational ) - -import DATA_BITS -import Data.Char ( chr ) -import Ratio ---import TRACE - -#if __GLASGOW_HASKELL__ >= 605 -import Data.Char ( GeneralCategory(..), generalCategory, isPrint, isUpper ) -#else -import Compat.Unicode ( GeneralCategory(..), generalCategory, isPrint, isUpper ) -#endif -} - -$unispace = \x05 -$whitechar = [\ \t\n\r\f\v\xa0 $unispace] -$white_no_nl = $whitechar # \n - -$ascdigit = 0-9 -$unidigit = \x03 -$decdigit = $ascdigit -- for now, should really be $digit (ToDo) -$digit = [$ascdigit $unidigit] - -$special = [\(\)\,\;\[\]\`\{\}] -$ascsymbol = [\!\#\$\%\&\*\+\.\/\<\=\>\?\@\\\^\|\-\~] -$unisymbol = \x04 -$symbol = [$ascsymbol $unisymbol] # [$special \_\:\"\'] - -$unilarge = \x01 -$asclarge = [A-Z \xc0-\xd6 \xd8-\xde] -$large = [$asclarge $unilarge] - -$unismall = \x02 -$ascsmall = [a-z \xdf-\xf6 \xf8-\xff] -$small = [$ascsmall $unismall \_] - -$unigraphic = \x06 -$graphic = [$small $large $symbol $digit $special $unigraphic \:\"\'] - -$octit = 0-7 -$hexit = [$decdigit A-F a-f] -$symchar = [$symbol \:] -$nl = [\n\r] -$idchar = [$small $large $digit \'] - -@varid = $small $idchar* -@conid = $large $idchar* - -@varsym = $symbol $symchar* -@consym = \: $symchar* - -@decimal = $decdigit+ -@octal = $octit+ -@hexadecimal = $hexit+ -@exponent = [eE] [\-\+]? @decimal - --- we support the hierarchical module name extension: -@qual = (@conid \.)+ - -@floating_point = @decimal \. @decimal @exponent? | @decimal @exponent - -haskell :- - --- everywhere: skip whitespace and comments -$white_no_nl+ ; - --- Everywhere: deal with nested comments. We explicitly rule out --- pragmas, "{-#", so that we don't accidentally treat them as comments. --- (this can happen even though pragmas will normally take precedence due to --- longest-match, because pragmas aren't valid in every state, but comments --- are). -"{-" / { notFollowedBy '#' } { nested_comment } - --- Single-line comments are a bit tricky. Haskell 98 says that two or --- more dashes followed by a symbol should be parsed as a varsym, so we --- have to exclude those. --- The regex says: "munch all the characters after the dashes, as long as --- the first one is not a symbol". -"--"\-* [^$symbol :] .* ; -"--"\-* / { atEOL } ; - --- 'bol' state: beginning of a line. Slurp up all the whitespace (including --- blank lines) until we find a non-whitespace character, then do layout --- processing. --- --- One slight wibble here: what if the line begins with {-#? In --- theory, we have to lex the pragma to see if it's one we recognise, --- and if it is, then we backtrack and do_bol, otherwise we treat it --- as a nested comment. We don't bother with this: if the line begins --- with {-#, then we'll assume it's a pragma we know about and go for do_bol. - { - \n ; - ^\# (line)? { begin line_prag1 } - ^\# pragma .* \n ; -- GCC 3.3 CPP generated, apparently - ^\# \! .* \n ; -- #!, for scripts - () { do_bol } -} - --- after a layout keyword (let, where, do, of), we begin a new layout --- context if the curly brace is missing. --- Careful! This stuff is quite delicate. - { - \{ / { notFollowedBy '-' } { pop_and open_brace } - -- we might encounter {-# here, but {- has been handled already - \n ; - ^\# (line)? { begin line_prag1 } -} - --- do is treated in a subtly different way, see new_layout_context - () { new_layout_context True } - () { new_layout_context False } - --- after a new layout context which was found to be to the left of the --- previous context, we have generated a '{' token, and we now need to --- generate a matching '}' token. - () { do_layout_left } - -<0,option_prags,glaexts> \n { begin bol } - -"{-#" $whitechar* (line|LINE) { begin line_prag2 } - --- single-line line pragmas, of the form --- # "" \n - $decdigit+ { setLine line_prag1a } - \" [$graphic \ ]* \" { setFile line_prag1b } - .* { pop } - --- Haskell-style line pragmas, of the form --- {-# LINE "" #-} - $decdigit+ { setLine line_prag2a } - \" [$graphic \ ]* \" { setFile line_prag2b } - "#-}"|"-}" { pop } - -- NOTE: accept -} at the end of a LINE pragma, for compatibility - -- with older versions of GHC which generated these. - --- We only want RULES pragmas to be picked up when -fglasgow-exts --- is on, because the contents of the pragma is always written using --- glasgow-exts syntax (using forall etc.), so if glasgow exts are not --- enabled, we're sure to get a parse error. --- (ToDo: we should really emit a warning when ignoring pragmas) - - "{-#" $whitechar* (RULES|rules) { token ITrules_prag } - -<0,option_prags,glaexts> { - "{-#" $whitechar* (INLINE|inline) { token (ITinline_prag True) } - "{-#" $whitechar* (NO(T?)INLINE|no(t?)inline) - { token (ITinline_prag False) } - "{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e) - { token ITspec_prag } - "{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e) - $whitechar* (INLINE|inline) { token (ITspec_inline_prag True) } - "{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e) - $whitechar* (NO(T?)INLINE|no(t?)inline) - { token (ITspec_inline_prag False) } - "{-#" $whitechar* (SOURCE|source) { token ITsource_prag } - "{-#" $whitechar* (DEPRECATED|deprecated) - { token ITdeprecated_prag } - "{-#" $whitechar* (SCC|scc) { token ITscc_prag } - "{-#" $whitechar* (CORE|core) { token ITcore_prag } - "{-#" $whitechar* (UNPACK|unpack) { token ITunpack_prag } - - "{-#" { nested_comment } - - -- ToDo: should only be valid inside a pragma: - "#-}" { token ITclose_prag} -} - - { - "{-#" $whitechar* (OPTIONS|options) { lex_string_prag IToptions_prag } - "{-#" $whitechar* (OPTIONS_GHC|options_ghc) - { lex_string_prag IToptions_prag } - "{-#" $whitechar* (LANGUAGE|language) { token ITlanguage_prag } - "{-#" $whitechar* (INCLUDE|include) { lex_string_prag ITinclude_prag } -} - --- '0' state: ordinary lexemes --- 'glaexts' state: glasgow extensions (postfix '#', etc.) - --- "special" symbols - -<0,glaexts> { - "[:" / { ifExtension parrEnabled } { token ITopabrack } - ":]" / { ifExtension parrEnabled } { token ITcpabrack } -} - -<0,glaexts> { - "[|" / { ifExtension thEnabled } { token ITopenExpQuote } - "[e|" / { ifExtension thEnabled } { token ITopenExpQuote } - "[p|" / { ifExtension thEnabled } { token ITopenPatQuote } - "[d|" / { ifExtension thEnabled } { layout_token ITopenDecQuote } - "[t|" / { ifExtension thEnabled } { token ITopenTypQuote } - "|]" / { ifExtension thEnabled } { token ITcloseQuote } - \$ @varid / { ifExtension thEnabled } { skip_one_varid ITidEscape } - "$(" / { ifExtension thEnabled } { token ITparenEscape } -} - -<0,glaexts> { - "(|" / { ifExtension arrowsEnabled `alexAndPred` notFollowedBySymbol } - { special IToparenbar } - "|)" / { ifExtension arrowsEnabled } { special ITcparenbar } -} - -<0,glaexts> { - \? @varid / { ifExtension ipEnabled } { skip_one_varid ITdupipvarid } - \% @varid / { ifExtension ipEnabled } { skip_one_varid ITsplitipvarid } -} - - { - "(#" / { notFollowedBySymbol } { token IToubxparen } - "#)" { token ITcubxparen } - "{|" { token ITocurlybar } - "|}" { token ITccurlybar } -} - -<0,option_prags,glaexts> { - \( { special IToparen } - \) { special ITcparen } - \[ { special ITobrack } - \] { special ITcbrack } - \, { special ITcomma } - \; { special ITsemi } - \` { special ITbackquote } - - \{ { open_brace } - \} { close_brace } -} - -<0,option_prags,glaexts> { - @qual @varid { check_qvarid } - @qual @conid { idtoken qconid } - @varid { varid } - @conid { idtoken conid } -} - --- after an illegal qvarid, such as 'M.let', --- we back up and try again in the bad_qvarid state: - { - @conid { pop_and (idtoken conid) } - @qual @conid { pop_and (idtoken qconid) } -} - - { - @qual @varid "#"+ { idtoken qvarid } - @qual @conid "#"+ { idtoken qconid } - @varid "#"+ { varid } - @conid "#"+ { idtoken conid } -} - --- ToDo: M.(,,,) - -<0,glaexts> { - @qual @varsym { idtoken qvarsym } - @qual @consym { idtoken qconsym } - @varsym { varsym } - @consym { consym } -} - -<0,glaexts> { - @decimal { tok_decimal } - 0[oO] @octal { tok_octal } - 0[xX] @hexadecimal { tok_hexadecimal } -} - - { - @decimal \# { prim_decimal } - 0[oO] @octal \# { prim_octal } - 0[xX] @hexadecimal \# { prim_hexadecimal } -} - -<0,glaexts> @floating_point { strtoken tok_float } - @floating_point \# { init_strtoken 1 prim_float } - @floating_point \# \# { init_strtoken 2 prim_double } - --- Strings and chars are lexed by hand-written code. The reason is --- that even if we recognise the string or char here in the regex --- lexer, we would still have to parse the string afterward in order --- to convert it to a String. -<0,glaexts> { - \' { lex_char_tok } - \" { lex_string_tok } -} - -{ --- work around bug in Alex 2.0 -#if __GLASGOW_HASKELL__ < 503 -unsafeAt arr i = arr ! i -#endif - --- ----------------------------------------------------------------------------- --- The token type - -data Token - = ITas -- Haskell keywords - | ITcase - | ITclass - | ITdata - | ITdefault - | ITderiving - | ITdo - | ITelse - | IThiding - | ITif - | ITimport - | ITin - | ITinfix - | ITinfixl - | ITinfixr - | ITinstance - | ITlet - | ITmodule - | ITnewtype - | ITof - | ITqualified - | ITthen - | ITtype - | ITwhere - | ITscc -- ToDo: remove (we use {-# SCC "..." #-} now) - - | ITforall -- GHC extension keywords - | ITforeign - | ITexport - | ITlabel - | ITdynamic - | ITsafe - | ITthreadsafe - | ITunsafe - | ITstdcallconv - | ITccallconv - | ITdotnet - | ITmdo - - -- Pragmas - | ITinline_prag Bool -- True <=> INLINE, False <=> NOINLINE - | ITspec_prag -- SPECIALISE - | ITspec_inline_prag Bool -- SPECIALISE INLINE (or NOINLINE) - | ITsource_prag - | ITrules_prag - | ITdeprecated_prag - | ITline_prag - | ITscc_prag - | ITcore_prag -- hdaume: core annotations - | ITunpack_prag - | ITclose_prag - | IToptions_prag String - | ITinclude_prag String - | ITlanguage_prag - - | ITdotdot -- reserved symbols - | ITcolon - | ITdcolon - | ITequal - | ITlam - | ITvbar - | ITlarrow - | ITrarrow - | ITat - | ITtilde - | ITdarrow - | ITminus - | ITbang - | ITstar - | ITdot - - | ITbiglam -- GHC-extension symbols - - | ITocurly -- special symbols - | ITccurly - | ITocurlybar -- {|, for type applications - | ITccurlybar -- |}, for type applications - | ITvocurly - | ITvccurly - | ITobrack - | ITopabrack -- [:, for parallel arrays with -fparr - | ITcpabrack -- :], for parallel arrays with -fparr - | ITcbrack - | IToparen - | ITcparen - | IToubxparen - | ITcubxparen - | ITsemi - | ITcomma - | ITunderscore - | ITbackquote - - | ITvarid FastString -- identifiers - | ITconid FastString - | ITvarsym FastString - | ITconsym FastString - | ITqvarid (FastString,FastString) - | ITqconid (FastString,FastString) - | ITqvarsym (FastString,FastString) - | ITqconsym (FastString,FastString) - - | ITdupipvarid FastString -- GHC extension: implicit param: ?x - | ITsplitipvarid FastString -- GHC extension: implicit param: %x - - | ITpragma StringBuffer - - | ITchar Char - | ITstring FastString - | ITinteger Integer - | ITrational Rational - - | ITprimchar Char - | ITprimstring FastString - | ITprimint Integer - | ITprimfloat Rational - | ITprimdouble Rational - - -- MetaHaskell extension tokens - | ITopenExpQuote -- [| or [e| - | ITopenPatQuote -- [p| - | ITopenDecQuote -- [d| - | ITopenTypQuote -- [t| - | ITcloseQuote -- |] - | ITidEscape FastString -- $x - | ITparenEscape -- $( - | ITvarQuote -- ' - | ITtyQuote -- '' - - -- Arrow notation extension - | ITproc - | ITrec - | IToparenbar -- (| - | ITcparenbar -- |) - | ITlarrowtail -- -< - | ITrarrowtail -- >- - | ITLarrowtail -- -<< - | ITRarrowtail -- >>- - - | ITunknown String -- Used when the lexer can't make sense of it - | ITeof -- end of file token -#ifdef DEBUG - deriving Show -- debugging -#endif - -isSpecial :: Token -> Bool --- If we see M.x, where x is a keyword, but --- is special, we treat is as just plain M.x, --- not as a keyword. -isSpecial ITas = True -isSpecial IThiding = True -isSpecial ITqualified = True -isSpecial ITforall = True -isSpecial ITexport = True -isSpecial ITlabel = True -isSpecial ITdynamic = True -isSpecial ITsafe = True -isSpecial ITthreadsafe = True -isSpecial ITunsafe = True -isSpecial ITccallconv = True -isSpecial ITstdcallconv = True -isSpecial ITmdo = True -isSpecial _ = False - --- the bitmap provided as the third component indicates whether the --- corresponding extension keyword is valid under the extension options --- provided to the compiler; if the extension corresponding to *any* of the --- bits set in the bitmap is enabled, the keyword is valid (this setup --- facilitates using a keyword in two different extensions that can be --- activated independently) --- -reservedWordsFM = listToUFM $ - map (\(x, y, z) -> (mkFastString x, (y, z))) - [( "_", ITunderscore, 0 ), - ( "as", ITas, 0 ), - ( "case", ITcase, 0 ), - ( "class", ITclass, 0 ), - ( "data", ITdata, 0 ), - ( "default", ITdefault, 0 ), - ( "deriving", ITderiving, 0 ), - ( "do", ITdo, 0 ), - ( "else", ITelse, 0 ), - ( "hiding", IThiding, 0 ), - ( "if", ITif, 0 ), - ( "import", ITimport, 0 ), - ( "in", ITin, 0 ), - ( "infix", ITinfix, 0 ), - ( "infixl", ITinfixl, 0 ), - ( "infixr", ITinfixr, 0 ), - ( "instance", ITinstance, 0 ), - ( "let", ITlet, 0 ), - ( "module", ITmodule, 0 ), - ( "newtype", ITnewtype, 0 ), - ( "of", ITof, 0 ), - ( "qualified", ITqualified, 0 ), - ( "then", ITthen, 0 ), - ( "type", ITtype, 0 ), - ( "where", ITwhere, 0 ), - ( "_scc_", ITscc, 0 ), -- ToDo: remove - - ( "forall", ITforall, bit tvBit), - ( "mdo", ITmdo, bit glaExtsBit), - - ( "foreign", ITforeign, bit ffiBit), - ( "export", ITexport, bit ffiBit), - ( "label", ITlabel, bit ffiBit), - ( "dynamic", ITdynamic, bit ffiBit), - ( "safe", ITsafe, bit ffiBit), - ( "threadsafe", ITthreadsafe, bit ffiBit), - ( "unsafe", ITunsafe, bit ffiBit), - ( "stdcall", ITstdcallconv, bit ffiBit), - ( "ccall", ITccallconv, bit ffiBit), - ( "dotnet", ITdotnet, bit ffiBit), - - ( "rec", ITrec, bit arrowsBit), - ( "proc", ITproc, bit arrowsBit) - ] - -reservedSymsFM = listToUFM $ - map (\ (x,y,z) -> (mkFastString x,(y,z))) - [ ("..", ITdotdot, 0) - ,(":", ITcolon, 0) -- (:) is a reserved op, - -- meaning only list cons - ,("::", ITdcolon, 0) - ,("=", ITequal, 0) - ,("\\", ITlam, 0) - ,("|", ITvbar, 0) - ,("<-", ITlarrow, 0) - ,("->", ITrarrow, 0) - ,("@", ITat, 0) - ,("~", ITtilde, 0) - ,("=>", ITdarrow, 0) - ,("-", ITminus, 0) - ,("!", ITbang, 0) - - ,("*", ITstar, bit glaExtsBit) -- For data T (a::*) = MkT - ,(".", ITdot, bit tvBit) -- For 'forall a . t' - - ,("-<", ITlarrowtail, bit arrowsBit) - ,(">-", ITrarrowtail, bit arrowsBit) - ,("-<<", ITLarrowtail, bit arrowsBit) - ,(">>-", ITRarrowtail, bit arrowsBit) - -#if __GLASGOW_HASKELL__ >= 605 - ,("λ", ITlam, bit glaExtsBit) - ,("∷", ITdcolon, bit glaExtsBit) - ,("⇒", ITdarrow, bit glaExtsBit) - ,("∀", ITforall, bit glaExtsBit) - ,("→", ITrarrow, bit glaExtsBit) - ,("←", ITlarrow, bit glaExtsBit) - ,("⋯", ITdotdot, bit glaExtsBit) -#endif - ] - --- ----------------------------------------------------------------------------- --- Lexer actions - -type Action = SrcSpan -> StringBuffer -> Int -> P (Located Token) - -special :: Token -> Action -special tok span _buf len = return (L span tok) - -token, layout_token :: Token -> Action -token t span buf len = return (L span t) -layout_token t span buf len = pushLexState layout >> return (L span t) - -idtoken :: (StringBuffer -> Int -> Token) -> Action -idtoken f span buf len = return (L span $! (f buf len)) - -skip_one_varid :: (FastString -> Token) -> Action -skip_one_varid f span buf len - = return (L span $! f (lexemeToFastString (stepOn buf) (len-1))) - -strtoken :: (String -> Token) -> Action -strtoken f span buf len = - return (L span $! (f $! lexemeToString buf len)) - -init_strtoken :: Int -> (String -> Token) -> Action --- like strtoken, but drops the last N character(s) -init_strtoken drop f span buf len = - return (L span $! (f $! lexemeToString buf (len-drop))) - -begin :: Int -> Action -begin code _span _str _len = do pushLexState code; lexToken - -pop :: Action -pop _span _buf _len = do popLexState; lexToken - -pop_and :: Action -> Action -pop_and act span buf len = do popLexState; act span buf len - -notFollowedBy char _ _ _ (AI _ _ buf) = atEnd buf || currentChar buf /= char - -notFollowedBySymbol _ _ _ (AI _ _ buf) - = atEnd buf || currentChar buf `notElem` "!#$%&*+./<=>?@\\^|-~" - -atEOL _ _ _ (AI _ _ buf) = atEnd buf || currentChar buf == '\n' - -ifExtension pred bits _ _ _ = pred bits - -{- - nested comments require traversing by hand, they can't be parsed - using regular expressions. --} -nested_comment :: Action -nested_comment span _str _len = do - input <- getInput - go 1 input - where go 0 input = do setInput input; lexToken - go n input = do - case alexGetChar input of - Nothing -> err input - Just (c,input) -> do - case c of - '-' -> do - case alexGetChar input of - Nothing -> err input - Just ('\125',input) -> go (n-1) input - Just (c,_) -> go n input - '\123' -> do - case alexGetChar input of - Nothing -> err input - Just ('-',input') -> go (n+1) input' - Just (c,input) -> go n input - c -> go n input - - err (AI end _ _) = failLocMsgP (srcSpanStart span) end "unterminated `{-'" - -open_brace, close_brace :: Action -open_brace span _str _len = do - ctx <- getContext - setContext (NoLayout:ctx) - return (L span ITocurly) -close_brace span _str _len = do - popContext - return (L span ITccurly) - --- We have to be careful not to count M. as a qualified name --- when is a keyword. We hack around this by catching --- the offending tokens afterward, and re-lexing in a different state. -check_qvarid span buf len = do - case lookupUFM reservedWordsFM var of - Just (keyword,exts) - | not (isSpecial keyword) -> - if exts == 0 - then try_again - else do - b <- extension (\i -> exts .&. i /= 0) - if b then try_again - else return token - _other -> return token - where - (mod,var) = splitQualName buf len - token = L span (ITqvarid (mod,var)) - - try_again = do - (AI _ offs _) <- getInput - setInput (AI (srcSpanStart span) (offs-len) buf) - pushLexState bad_qvarid - lexToken - -qvarid buf len = ITqvarid $! splitQualName buf len -qconid buf len = ITqconid $! splitQualName buf len - -splitQualName :: StringBuffer -> Int -> (FastString,FastString) --- takes a StringBuffer and a length, and returns the module name --- and identifier parts of a qualified name. Splits at the *last* dot, --- because of hierarchical module names. -splitQualName orig_buf len = split orig_buf orig_buf - where - split buf dot_buf - | orig_buf `byteDiff` buf >= len = done dot_buf - | c == '.' = found_dot buf' - | otherwise = split buf' dot_buf - where - (c,buf') = nextChar buf - - -- careful, we might get names like M.... - -- so, if the character after the dot is not upper-case, this is - -- the end of the qualifier part. - found_dot buf -- buf points after the '.' - | isUpper c = split buf' buf - | otherwise = done buf - where - (c,buf') = nextChar buf - - done dot_buf = - (lexemeToFastString orig_buf (qual_size - 1), - lexemeToFastString dot_buf (len - qual_size)) - where - qual_size = orig_buf `byteDiff` dot_buf - -varid span buf len = - case lookupUFM reservedWordsFM fs of - Just (keyword,0) -> do - maybe_layout keyword - return (L span keyword) - Just (keyword,exts) -> do - b <- extension (\i -> exts .&. i /= 0) - if b then do maybe_layout keyword - return (L span keyword) - else return (L span (ITvarid fs)) - _other -> return (L span (ITvarid fs)) - where - fs = lexemeToFastString buf len - -conid buf len = ITconid fs - where fs = lexemeToFastString buf len - -qvarsym buf len = ITqvarsym $! splitQualName buf len -qconsym buf len = ITqconsym $! splitQualName buf len - -varsym = sym ITvarsym -consym = sym ITconsym - -sym con span buf len = - case lookupUFM reservedSymsFM fs of - Just (keyword,0) -> return (L span keyword) - Just (keyword,exts) -> do - b <- extension (\i -> exts .&. i /= 0) - if b then return (L span keyword) - else return (L span $! con fs) - _other -> return (L span $! con fs) - where - fs = lexemeToFastString buf len - -tok_decimal span buf len - = return (L span (ITinteger $! parseInteger buf len 10 octDecDigit)) - -tok_octal span buf len - = return (L span (ITinteger $! parseInteger (offsetBytes 2 buf) (len-2) 8 octDecDigit)) - -tok_hexadecimal span buf len - = return (L span (ITinteger $! parseInteger (offsetBytes 2 buf) (len-2) 16 hexDigit)) - -prim_decimal span buf len - = return (L span (ITprimint $! parseInteger buf (len-1) 10 octDecDigit)) - -prim_octal span buf len - = return (L span (ITprimint $! parseInteger (offsetBytes 2 buf) (len-3) 8 octDecDigit)) - -prim_hexadecimal span buf len - = return (L span (ITprimint $! parseInteger (offsetBytes 2 buf) (len-3) 16 hexDigit)) - -tok_float str = ITrational $! readRational str -prim_float str = ITprimfloat $! readRational str -prim_double str = ITprimdouble $! readRational str - --- ----------------------------------------------------------------------------- --- Layout processing - --- we're at the first token on a line, insert layout tokens if necessary -do_bol :: Action -do_bol span _str _len = do - pos <- getOffside - case pos of - LT -> do - --trace "layout: inserting '}'" $ do - popContext - -- do NOT pop the lex state, we might have a ';' to insert - return (L span ITvccurly) - EQ -> do - --trace "layout: inserting ';'" $ do - popLexState - return (L span ITsemi) - GT -> do - popLexState - lexToken - --- certain keywords put us in the "layout" state, where we might --- add an opening curly brace. -maybe_layout ITdo = pushLexState layout_do -maybe_layout ITmdo = pushLexState layout_do -maybe_layout ITof = pushLexState layout -maybe_layout ITlet = pushLexState layout -maybe_layout ITwhere = pushLexState layout -maybe_layout ITrec = pushLexState layout -maybe_layout _ = return () - --- Pushing a new implicit layout context. If the indentation of the --- next token is not greater than the previous layout context, then --- Haskell 98 says that the new layout context should be empty; that is --- the lexer must generate {}. --- --- We are slightly more lenient than this: when the new context is started --- by a 'do', then we allow the new context to be at the same indentation as --- the previous context. This is what the 'strict' argument is for. --- -new_layout_context strict span _buf _len = do - popLexState - (AI _ offset _) <- getInput - ctx <- getContext - case ctx of - Layout prev_off : _ | - (strict && prev_off >= offset || - not strict && prev_off > offset) -> do - -- token is indented to the left of the previous context. - -- we must generate a {} sequence now. - pushLexState layout_left - return (L span ITvocurly) - other -> do - setContext (Layout offset : ctx) - return (L span ITvocurly) - -do_layout_left span _buf _len = do - popLexState - pushLexState bol -- we must be at the start of a line - return (L span ITvccurly) - --- ----------------------------------------------------------------------------- --- LINE pragmas - -setLine :: Int -> Action -setLine code span buf len = do - let line = parseInteger buf len 10 octDecDigit - setSrcLoc (mkSrcLoc (srcSpanFile span) (fromIntegral line - 1) 0) - -- subtract one: the line number refers to the *following* line - popLexState - pushLexState code - lexToken - -setFile :: Int -> Action -setFile code span buf len = do - let file = lexemeToFastString (stepOn buf) (len-2) - setSrcLoc (mkSrcLoc file (srcSpanEndLine span) (srcSpanEndCol span)) - popLexState - pushLexState code - lexToken - - --- ----------------------------------------------------------------------------- --- Options, includes and language pragmas. - -lex_string_prag :: (String -> Token) -> Action -lex_string_prag mkTok span buf len - = do input <- getInput - start <- getSrcLoc - tok <- go [] input - end <- getSrcLoc - return (L (mkSrcSpan start end) tok) - where go acc input - = if isString input "#-}" - then do setInput input - return (mkTok (reverse acc)) - else case alexGetChar input of - Just (c,i) -> go (c:acc) i - Nothing -> err input - isString i [] = True - isString i (x:xs) - = case alexGetChar i of - Just (c,i') | c == x -> isString i' xs - _other -> False - err (AI end _ _) = failLocMsgP (srcSpanStart span) end "unterminated options pragma" - - --- ----------------------------------------------------------------------------- --- Strings & Chars - --- This stuff is horrible. I hates it. - -lex_string_tok :: Action -lex_string_tok span buf len = do - tok <- lex_string "" - end <- getSrcLoc - return (L (mkSrcSpan (srcSpanStart span) end) tok) - -lex_string :: String -> P Token -lex_string s = do - i <- getInput - case alexGetChar' i of - Nothing -> lit_error - - Just ('"',i) -> do - setInput i - glaexts <- extension glaExtsEnabled - if glaexts - then do - i <- getInput - case alexGetChar' i of - Just ('#',i) -> do - setInput i - if any (> '\xFF') s - then failMsgP "primitive string literal must contain only characters <= \'\\xFF\'" - else let s' = mkZFastString (reverse s) in - return (ITprimstring s') - -- mkZFastString is a hack to avoid encoding the - -- string in UTF-8. We just want the exact bytes. - _other -> - return (ITstring (mkFastString (reverse s))) - else - return (ITstring (mkFastString (reverse s))) - - Just ('\\',i) - | Just ('&',i) <- next -> do - setInput i; lex_string s - | Just (c,i) <- next, is_space c -> do - setInput i; lex_stringgap s - where next = alexGetChar' i - - Just (c, i) -> do - c' <- lex_char c i - lex_string (c':s) - -lex_stringgap s = do - c <- getCharOrFail - case c of - '\\' -> lex_string s - c | is_space c -> lex_stringgap s - _other -> lit_error - - -lex_char_tok :: Action --- Here we are basically parsing character literals, such as 'x' or '\n' --- but, when Template Haskell is on, we additionally spot --- 'x and ''T, returning ITvarQuote and ITtyQuote respectively, --- but WIHTOUT CONSUMING the x or T part (the parser does that). --- So we have to do two characters of lookahead: when we see 'x we need to --- see if there's a trailing quote -lex_char_tok span buf len = do -- We've seen ' - i1 <- getInput -- Look ahead to first character - let loc = srcSpanStart span - case alexGetChar' i1 of - Nothing -> lit_error - - Just ('\'', i2@(AI end2 _ _)) -> do -- We've seen '' - th_exts <- extension thEnabled - if th_exts then do - setInput i2 - return (L (mkSrcSpan loc end2) ITtyQuote) - else lit_error - - Just ('\\', i2@(AI end2 _ _)) -> do -- We've seen 'backslash - setInput i2 - lit_ch <- lex_escape - mc <- getCharOrFail -- Trailing quote - if mc == '\'' then finish_char_tok loc lit_ch - else do setInput i2; lit_error - - Just (c, i2@(AI end2 _ _)) - | not (isAny c) -> lit_error - | otherwise -> - - -- We've seen 'x, where x is a valid character - -- (i.e. not newline etc) but not a quote or backslash - case alexGetChar' i2 of -- Look ahead one more character - Nothing -> lit_error - Just ('\'', i3) -> do -- We've seen 'x' - setInput i3 - finish_char_tok loc c - _other -> do -- We've seen 'x not followed by quote - -- If TH is on, just parse the quote only - th_exts <- extension thEnabled - let (AI end _ _) = i1 - if th_exts then return (L (mkSrcSpan loc end) ITvarQuote) - else do setInput i2; lit_error - -finish_char_tok :: SrcLoc -> Char -> P (Located Token) -finish_char_tok loc ch -- We've already seen the closing quote - -- Just need to check for trailing # - = do glaexts <- extension glaExtsEnabled - i@(AI end _ _) <- getInput - if glaexts then do - case alexGetChar' i of - Just ('#',i@(AI end _ _)) -> do - setInput i - return (L (mkSrcSpan loc end) (ITprimchar ch)) - _other -> - return (L (mkSrcSpan loc end) (ITchar ch)) - else do - return (L (mkSrcSpan loc end) (ITchar ch)) - -lex_char :: Char -> AlexInput -> P Char -lex_char c inp = do - case c of - '\\' -> do setInput inp; lex_escape - c | isAny c -> do setInput inp; return c - _other -> lit_error - -isAny c | c > '\xff' = isPrint c - | otherwise = is_any c - -lex_escape :: P Char -lex_escape = do - c <- getCharOrFail - case c of - 'a' -> return '\a' - 'b' -> return '\b' - 'f' -> return '\f' - 'n' -> return '\n' - 'r' -> return '\r' - 't' -> return '\t' - 'v' -> return '\v' - '\\' -> return '\\' - '"' -> return '\"' - '\'' -> return '\'' - '^' -> do c <- getCharOrFail - if c >= '@' && c <= '_' - then return (chr (ord c - ord '@')) - else lit_error - - 'x' -> readNum is_hexdigit 16 hexDigit - 'o' -> readNum is_octdigit 8 octDecDigit - x | is_digit x -> readNum2 is_digit 10 octDecDigit (octDecDigit x) - - c1 -> do - i <- getInput - case alexGetChar' i of - Nothing -> lit_error - Just (c2,i2) -> - case alexGetChar' i2 of - Nothing -> do setInput i2; lit_error - Just (c3,i3) -> - let str = [c1,c2,c3] in - case [ (c,rest) | (p,c) <- silly_escape_chars, - Just rest <- [maybePrefixMatch p str] ] of - (escape_char,[]):_ -> do - setInput i3 - return escape_char - (escape_char,_:_):_ -> do - setInput i2 - return escape_char - [] -> lit_error - -readNum :: (Char -> Bool) -> Int -> (Char -> Int) -> P Char -readNum is_digit base conv = do - i <- getInput - c <- getCharOrFail - if is_digit c - then readNum2 is_digit base conv (conv c) - else do setInput i; lit_error - -readNum2 is_digit base conv i = do - input <- getInput - read i input - where read i input = do - case alexGetChar' input of - Just (c,input') | is_digit c -> do - read (i*base + conv c) input' - _other -> do - if i >= 0 && i <= 0x10FFFF - then do setInput input; return (chr i) - else lit_error - -silly_escape_chars = [ - ("NUL", '\NUL'), - ("SOH", '\SOH'), - ("STX", '\STX'), - ("ETX", '\ETX'), - ("EOT", '\EOT'), - ("ENQ", '\ENQ'), - ("ACK", '\ACK'), - ("BEL", '\BEL'), - ("BS", '\BS'), - ("HT", '\HT'), - ("LF", '\LF'), - ("VT", '\VT'), - ("FF", '\FF'), - ("CR", '\CR'), - ("SO", '\SO'), - ("SI", '\SI'), - ("DLE", '\DLE'), - ("DC1", '\DC1'), - ("DC2", '\DC2'), - ("DC3", '\DC3'), - ("DC4", '\DC4'), - ("NAK", '\NAK'), - ("SYN", '\SYN'), - ("ETB", '\ETB'), - ("CAN", '\CAN'), - ("EM", '\EM'), - ("SUB", '\SUB'), - ("ESC", '\ESC'), - ("FS", '\FS'), - ("GS", '\GS'), - ("RS", '\RS'), - ("US", '\US'), - ("SP", '\SP'), - ("DEL", '\DEL') - ] - --- before calling lit_error, ensure that the current input is pointing to --- the position of the error in the buffer. This is so that we can report --- a correct location to the user, but also so we can detect UTF-8 decoding --- errors if they occur. -lit_error = lexError "lexical error in string/character literal" - -getCharOrFail :: P Char -getCharOrFail = do - i <- getInput - case alexGetChar' i of - Nothing -> lexError "unexpected end-of-file in string/character literal" - Just (c,i) -> do setInput i; return c - --- ----------------------------------------------------------------------------- --- The Parse Monad - -data LayoutContext - = NoLayout - | Layout !Int - -data ParseResult a - = POk PState a - | PFailed - SrcSpan -- The start and end of the text span related to - -- the error. Might be used in environments which can - -- show this span, e.g. by highlighting it. - Message -- The error message - -data PState = PState { - buffer :: StringBuffer, - last_loc :: SrcSpan, -- pos of previous token - last_offs :: !Int, -- offset of the previous token from the - -- beginning of the current line. - -- \t is equal to 8 spaces. - last_len :: !Int, -- len of previous token - loc :: SrcLoc, -- current loc (end of prev token + 1) - extsBitmap :: !Int, -- bitmap that determines permitted extensions - context :: [LayoutContext], - lex_state :: [Int] - } - -- last_loc and last_len are used when generating error messages, - -- and in pushCurrentContext only. Sigh, if only Happy passed the - -- current token to happyError, we could at least get rid of last_len. - -- Getting rid of last_loc would require finding another way to - -- implement pushCurrentContext (which is only called from one place). - -newtype P a = P { unP :: PState -> ParseResult a } - -instance Monad P where - return = returnP - (>>=) = thenP - fail = failP - -returnP :: a -> P a -returnP a = P $ \s -> POk s a - -thenP :: P a -> (a -> P b) -> P b -(P m) `thenP` k = P $ \ s -> - case m s of - POk s1 a -> (unP (k a)) s1 - PFailed span err -> PFailed span err - -failP :: String -> P a -failP msg = P $ \s -> PFailed (last_loc s) (text msg) - -failMsgP :: String -> P a -failMsgP msg = P $ \s -> PFailed (last_loc s) (text msg) - -failLocMsgP :: SrcLoc -> SrcLoc -> String -> P a -failLocMsgP loc1 loc2 str = P $ \s -> PFailed (mkSrcSpan loc1 loc2) (text str) - -failSpanMsgP :: SrcSpan -> String -> P a -failSpanMsgP span msg = P $ \s -> PFailed span (text msg) - -extension :: (Int -> Bool) -> P Bool -extension p = P $ \s -> POk s (p $! extsBitmap s) - -getExts :: P Int -getExts = P $ \s -> POk s (extsBitmap s) - -setSrcLoc :: SrcLoc -> P () -setSrcLoc new_loc = P $ \s -> POk s{loc=new_loc} () - -getSrcLoc :: P SrcLoc -getSrcLoc = P $ \s@(PState{ loc=loc }) -> POk s loc - -setLastToken :: SrcSpan -> Int -> P () -setLastToken loc len = P $ \s -> POk s{ last_loc=loc, last_len=len } () - -data AlexInput = AI SrcLoc {-#UNPACK#-}!Int StringBuffer - -alexInputPrevChar :: AlexInput -> Char -alexInputPrevChar (AI _ _ buf) = prevChar buf '\n' - -alexGetChar :: AlexInput -> Maybe (Char,AlexInput) -alexGetChar (AI loc ofs s) - | atEnd s = Nothing - | otherwise = adj_c `seq` loc' `seq` ofs' `seq` s' `seq` - Just (adj_c, (AI loc' ofs' s')) - where (c,s') = nextChar s - loc' = advanceSrcLoc loc c - ofs' = advanceOffs c ofs - - non_graphic = '\x0' - upper = '\x1' - lower = '\x2' - digit = '\x3' - symbol = '\x4' - space = '\x5' - other_graphic = '\x6' - - adj_c - | c <= '\x06' = non_graphic - | c <= '\xff' = c - | otherwise = - case generalCategory c of - UppercaseLetter -> upper - LowercaseLetter -> lower - TitlecaseLetter -> upper - ModifierLetter -> other_graphic - OtherLetter -> other_graphic - NonSpacingMark -> other_graphic - SpacingCombiningMark -> other_graphic - EnclosingMark -> other_graphic - DecimalNumber -> digit - LetterNumber -> other_graphic - OtherNumber -> other_graphic - ConnectorPunctuation -> other_graphic - DashPunctuation -> other_graphic - OpenPunctuation -> other_graphic - ClosePunctuation -> other_graphic - InitialQuote -> other_graphic - FinalQuote -> other_graphic - OtherPunctuation -> other_graphic - MathSymbol -> symbol - CurrencySymbol -> symbol - ModifierSymbol -> symbol - OtherSymbol -> symbol - Space -> space - _other -> non_graphic - --- This version does not squash unicode characters, it is used when --- lexing strings. -alexGetChar' :: AlexInput -> Maybe (Char,AlexInput) -alexGetChar' (AI loc ofs s) - | atEnd s = Nothing - | otherwise = c `seq` loc' `seq` ofs' `seq` s' `seq` - Just (c, (AI loc' ofs' s')) - where (c,s') = nextChar s - loc' = advanceSrcLoc loc c - ofs' = advanceOffs c ofs - -advanceOffs :: Char -> Int -> Int -advanceOffs '\n' offs = 0 -advanceOffs '\t' offs = (offs `quot` 8 + 1) * 8 -advanceOffs _ offs = offs + 1 - -getInput :: P AlexInput -getInput = P $ \s@PState{ loc=l, last_offs=o, buffer=b } -> POk s (AI l o b) - -setInput :: AlexInput -> P () -setInput (AI l o b) = P $ \s -> POk s{ loc=l, last_offs=o, buffer=b } () - -pushLexState :: Int -> P () -pushLexState ls = P $ \s@PState{ lex_state=l } -> POk s{lex_state=ls:l} () - -popLexState :: P Int -popLexState = P $ \s@PState{ lex_state=ls:l } -> POk s{ lex_state=l } ls - -getLexState :: P Int -getLexState = P $ \s@PState{ lex_state=ls:l } -> POk s ls - --- for reasons of efficiency, flags indicating language extensions (eg, --- -fglasgow-exts or -fparr) are represented by a bitmap stored in an unboxed --- integer - -glaExtsBit, ffiBit, parrBit :: Int -glaExtsBit = 0 -ffiBit = 1 -parrBit = 2 -arrowsBit = 4 -thBit = 5 -ipBit = 6 -tvBit = 7 -- Scoped type variables enables 'forall' keyword -bangPatBit = 8 -- Tells the parser to understand bang-patterns - -- (doesn't affect the lexer) - -glaExtsEnabled, ffiEnabled, parrEnabled :: Int -> Bool -glaExtsEnabled flags = testBit flags glaExtsBit -ffiEnabled flags = testBit flags ffiBit -parrEnabled flags = testBit flags parrBit -arrowsEnabled flags = testBit flags arrowsBit -thEnabled flags = testBit flags thBit -ipEnabled flags = testBit flags ipBit -tvEnabled flags = testBit flags tvBit -bangPatEnabled flags = testBit flags bangPatBit - --- PState for parsing options pragmas --- -pragState :: StringBuffer -> SrcLoc -> PState -pragState buf loc = - PState { - buffer = buf, - last_loc = mkSrcSpan loc loc, - last_offs = 0, - last_len = 0, - loc = loc, - extsBitmap = 0, - context = [], - lex_state = [bol, option_prags, 0] - } - - --- create a parse state --- -mkPState :: StringBuffer -> SrcLoc -> DynFlags -> PState -mkPState buf loc flags = - PState { - buffer = buf, - last_loc = mkSrcSpan loc loc, - last_offs = 0, - last_len = 0, - loc = loc, - extsBitmap = fromIntegral bitmap, - context = [], - lex_state = [bol, if glaExtsEnabled bitmap then glaexts else 0] - -- we begin in the layout state if toplev_layout is set - } - where - bitmap = glaExtsBit `setBitIf` dopt Opt_GlasgowExts flags - .|. ffiBit `setBitIf` dopt Opt_FFI flags - .|. parrBit `setBitIf` dopt Opt_PArr flags - .|. arrowsBit `setBitIf` dopt Opt_Arrows flags - .|. thBit `setBitIf` dopt Opt_TH flags - .|. ipBit `setBitIf` dopt Opt_ImplicitParams flags - .|. tvBit `setBitIf` dopt Opt_ScopedTypeVariables flags - .|. bangPatBit `setBitIf` dopt Opt_BangPatterns flags - -- - setBitIf :: Int -> Bool -> Int - b `setBitIf` cond | cond = bit b - | otherwise = 0 - -getContext :: P [LayoutContext] -getContext = P $ \s@PState{context=ctx} -> POk s ctx - -setContext :: [LayoutContext] -> P () -setContext ctx = P $ \s -> POk s{context=ctx} () - -popContext :: P () -popContext = P $ \ s@(PState{ buffer = buf, context = ctx, - loc = loc, last_len = len, last_loc = last_loc }) -> - case ctx of - (_:tl) -> POk s{ context = tl } () - [] -> PFailed last_loc (srcParseErr buf len) - --- Push a new layout context at the indentation of the last token read. --- This is only used at the outer level of a module when the 'module' --- keyword is missing. -pushCurrentContext :: P () -pushCurrentContext = P $ \ s@PState{ last_offs=offs, last_len=len, context=ctx } -> - POk s{context = Layout (offs-len) : ctx} () - -getOffside :: P Ordering -getOffside = P $ \s@PState{last_offs=offs, context=stk} -> - let ord = case stk of - (Layout n:_) -> compare offs n - _ -> GT - in POk s ord - --- --------------------------------------------------------------------------- --- Construct a parse error - -srcParseErr - :: StringBuffer -- current buffer (placed just after the last token) - -> Int -- length of the previous token - -> Message -srcParseErr buf len - = hcat [ if null token - then ptext SLIT("parse error (possibly incorrect indentation)") - else hcat [ptext SLIT("parse error on input "), - char '`', text token, char '\''] - ] - where token = lexemeToString (offsetBytes (-len) buf) len - --- Report a parse failure, giving the span of the previous token as --- the location of the error. This is the entry point for errors --- detected during parsing. -srcParseFail :: P a -srcParseFail = P $ \PState{ buffer = buf, last_len = len, - last_loc = last_loc } -> - PFailed last_loc (srcParseErr buf len) - --- A lexical error is reported at a particular position in the source file, --- not over a token range. -lexError :: String -> P a -lexError str = do - loc <- getSrcLoc - i@(AI end _ buf) <- getInput - reportLexError loc end buf str - --- ----------------------------------------------------------------------------- --- This is the top-level function: called from the parser each time a --- new token is to be read from the input. - -lexer :: (Located Token -> P a) -> P a -lexer cont = do - tok@(L _ tok__) <- lexToken - --trace ("token: " ++ show tok__) $ do - cont tok - -lexToken :: P (Located Token) -lexToken = do - inp@(AI loc1 _ buf) <- getInput - sc <- getLexState - exts <- getExts - case alexScanUser exts inp sc of - AlexEOF -> do let span = mkSrcSpan loc1 loc1 - setLastToken span 0 - return (L span ITeof) - AlexError (AI loc2 _ buf) -> do - reportLexError loc1 loc2 buf "lexical error" - AlexSkip inp2 _ -> do - setInput inp2 - lexToken - AlexToken inp2@(AI end _ buf2) len t -> do - setInput inp2 - let span = mkSrcSpan loc1 end - let bytes = byteDiff buf buf2 - span `seq` setLastToken span bytes - t span buf bytes - --- ToDo: Alex reports the buffer at the start of the erroneous lexeme, --- but it would be more informative to report the location where the --- error was actually discovered, especially if this is a decoding --- error. -reportLexError loc1 loc2 buf str = - let - c = fst (nextChar buf) - in - if c == '\0' -- decoding errors are mapped to '\0', see utf8DecodeChar# - then failLocMsgP loc2 loc2 "UTF-8 decoding error" - else failLocMsgP loc1 loc2 (str ++ " at character " ++ show c) -}