{
module Lexer (
- Token(..), Token__(..), lexer, mkPState, showPFailed,
- P(..), ParseResult(..), setSrcLocFor, getSrcLoc,
- failMsgP, failLocMsgP, srcParseFail,
- popContext, pushCurrentContext,
+ Token(..), lexer, mkPState, PState(..),
+ P(..), ParseResult(..), getSrcLoc,
+ failLocMsgP, failSpanMsgP, srcParseFail,
+ popContext, pushCurrentContext, setLastToken, setSrcLoc,
+ getLexState, popLexState, pushLexState
) where
#include "HsVersions.h"
import UniqFM
import CmdLineOpts
import Ctype
-import Util ( maybePrefixMatch )
+import Util ( maybePrefixMatch, readRational )
import DATA_BITS
import Char
-- have to exclude those.
-- The regex says: "munch all the characters after the dashes, as long as
-- the first one is not a symbol".
-"--"\-* ([^$symbol] .*)? ;
+"--"\-* [^$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
\n ;
^\# (line)? { begin line_prag1 }
^\# pragma .* \n ; -- GCC 3.3 CPP generated, apparently
+ ^\# \! .* \n ; -- #!, for scripts
() { do_bol }
}
-- single-line line pragmas, of the form
-- # <line> "<file>" <extra-stuff> \n
-<line_prag1> $digit+ { set_line line_prag1a }
-<line_prag1a> \" [$graphic \ ]* \" { set_file line_prag1b }
+<line_prag1> $digit+ { setLine line_prag1a }
+<line_prag1a> \" [$graphic \ ]* \" { setFile line_prag1b }
<line_prag1b> .* { pop }
-- Haskell-style line pragmas, of the form
-- {-# LINE <line> "<file>" #-}
-<line_prag2> $digit+ { set_line line_prag2a }
-<line_prag2a> \" [$graphic \ ]* \" { set_file line_prag2b }
-<line_prag2b> "#-}" { pop }
+<line_prag2> $digit+ { setLine line_prag2a }
+<line_prag2a> \" [$graphic \ ]* \" { setFile line_prag2b }
+<line_prag2b> "#-}"|"-}" { pop }
+ -- NOTE: accept -} at the end of a LINE pragma, for compatibility
+ -- with older versions of GHC which generated these.
<0,glaexts> {
"{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e)
{ token ITdeprecated_prag }
"{-#" $whitechar* (SCC|scc) { token ITscc_prag }
"{-#" $whitechar* (CORE|core) { token ITcore_prag }
+ "{-#" $whitechar* (UNPACK|unpack) { token ITunpack_prag }
"{-#" { nested_comment }
-- -----------------------------------------------------------------------------
-- The token type
-data Token = T SrcSpan Token__
-
-data Token__
+data Token
= ITas -- Haskell keywords
| ITcase
| ITclass
| ITline_prag
| ITscc_prag
| ITcore_prag -- hdaume: core annotations
+ | ITunpack_prag
| ITclose_prag
| ITdotdot -- reserved symbols
deriving Show -- debugging
#endif
-isSpecial :: Token__ -> Bool
+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.
-- -----------------------------------------------------------------------------
-- Lexer actions
-type Action = SrcSpan -> StringBuffer -> Int -> P Token
+type Action = SrcSpan -> StringBuffer -> Int -> P (Located Token)
-special :: Token__ -> Action
-special tok span _buf len = return (T span tok)
+special :: Token -> Action
+special tok span _buf len = return (L span tok)
-token, layout_token :: Token__ -> Action
-token t span buf len = return (T span t)
-layout_token t span buf len = pushLexState layout >> return (T span t)
+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 (T span $! (f buf len))
+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 :: (FastString -> Token) -> Action
skip_one_varid f span buf len
- = return (T span $! f (lexemeToFastString (stepOn buf) (len-1)))
+ = return (L span $! f (lexemeToFastString (stepOn buf) (len-1)))
-strtoken :: (String -> Token__) -> Action
+strtoken :: (String -> Token) -> Action
strtoken f span buf len =
- return (T span $! (f $! lexemeToString buf len))
+ return (L span $! (f $! lexemeToString buf len))
-init_strtoken :: Int -> (String -> Token__) -> Action
+init_strtoken :: Int -> (String -> Token) -> Action
-- like strtoken, but drops the last N character(s)
init_strtoken drop f span buf len =
- return (T span $! (f $! lexemeToString buf (len-drop)))
+ return (L span $! (f $! lexemeToString buf (len-drop)))
begin :: Int -> Action
begin code _span _str _len = do pushLexState code; lexToken
notFollowedBySymbol _ _ _ (_,buf)
= atEnd buf || currentChar buf `notElem` "!#$%&*+./<=>?@\\^|-~"
+atEOL _ _ _ (_,buf) = atEnd buf || currentChar buf == '\n'
+
ifExtension pred bits _ _ _ = pred bits
{-
Just (c,input) -> go n input
c -> go n input
- err input = do failLocMsgP (srcSpanStart span) (fst input) "unterminated `{-'"
+ err input = do failLocMsgP (srcSpanStart span) (fst input)
+ "unterminated `{-'"
open_brace, close_brace :: Action
-open_brace span _str _len = do
+open_brace span _str _len = do
ctx <- getContext
setContext (NoLayout:ctx)
- return (T span ITocurly)
+ return (L span ITocurly)
close_brace span _str _len = do
popContext
- return (T span ITccurly)
+ return (L span ITccurly)
-- We have to be careful not to count M.<varid> as a qualified name
-- when <varid> is a keyword. We hack around this by catching
_other -> return token
where
(mod,var) = splitQualName buf len
- token = T span (ITqvarid (mod,var))
+ token = L span (ITqvarid (mod,var))
try_again = do
setInput (srcSpanStart span,buf)
case lookupUFM reservedWordsFM fs of
Just (keyword,0) -> do
maybe_layout keyword
- return (T span keyword)
+ return (L span keyword)
Just (keyword,exts) -> do
b <- extension (\i -> exts .&. i /= 0)
if b then do maybe_layout keyword
- return (T span keyword)
- else return (T span (ITvarid fs))
- _other -> return (T span (ITvarid fs))
+ return (L span keyword)
+ else return (L span (ITvarid fs))
+ _other -> return (L span (ITvarid fs))
where
fs = lexemeToFastString buf len
sym con span buf len =
case lookupUFM reservedSymsFM fs of
- Just (keyword,0) -> return (T span keyword)
+ Just (keyword,0) -> return (L span keyword)
Just (keyword,exts) -> do
b <- extension (\i -> exts .&. i /= 0)
- if b then return (T span keyword)
- else return (T span $! con fs)
- _other -> return (T span $! con fs)
+ 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 (T span (ITinteger $! parseInteger buf len 10 oct_or_dec))
+ = return (L span (ITinteger $! parseInteger buf len 10 octDecDigit))
tok_octal span buf len
- = return (T span (ITinteger $! parseInteger (stepOnBy 2 buf) (len-2) 8 oct_or_dec))
+ = return (L span (ITinteger $! parseInteger (stepOnBy 2 buf) (len-2) 8 octDecDigit))
tok_hexadecimal span buf len
- = return (T span (ITinteger $! parseInteger (stepOnBy 2 buf) (len-2) 16 hex))
+ = return (L span (ITinteger $! parseInteger (stepOnBy 2 buf) (len-2) 16 hexDigit))
prim_decimal span buf len
- = return (T span (ITprimint $! parseInteger buf (len-1) 10 oct_or_dec))
+ = return (L span (ITprimint $! parseInteger buf (len-1) 10 octDecDigit))
prim_octal span buf len
- = return (T span (ITprimint $! parseInteger (stepOnBy 2 buf) (len-3) 8 oct_or_dec))
+ = return (L span (ITprimint $! parseInteger (stepOnBy 2 buf) (len-3) 8 octDecDigit))
prim_hexadecimal span buf len
- = return (T span (ITprimint $! parseInteger (stepOnBy 2 buf) (len-3) 16 hex))
+ = return (L span (ITprimint $! parseInteger (stepOnBy 2 buf) (len-3) 16 hexDigit))
-tok_float str = ITrational $! readRational__ str
-prim_float str = ITprimfloat $! readRational__ str
-prim_double str = ITprimdouble $! readRational__ str
-
-parseInteger :: StringBuffer -> Int -> Integer -> (Char->Int) -> Integer
-parseInteger buf len radix to_int
- = go 0 0
- where go i x | i == len = x
- | otherwise = go (i+1) (x * radix + toInteger (to_int (lookAhead buf i)))
+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 (srcSpanEndCol span)
+ pos <- getOffside (srcSpanEnd span)
case pos of
LT -> do
--trace "layout: inserting '}'" $ do
popContext
-- do NOT pop the lex state, we might have a ';' to insert
- return (T span ITvccurly)
+ return (L span ITvccurly)
EQ -> do
--trace "layout: inserting ';'" $ do
popLexState
- return (T span ITsemi)
+ return (L span ITsemi)
GT -> do
popLexState
lexToken
-- token is indented to the left of the previous context.
-- we must generate a {} sequence now.
pushLexState layout_left
- return (T span ITvocurly)
+ return (L span ITvocurly)
other -> do
setContext (Layout offset : ctx)
- return (T span ITvocurly)
+ return (L span ITvocurly)
do_layout_left span _buf _len = do
popLexState
pushLexState bol -- we must be at the start of a line
- return (T span ITvccurly)
+ return (L span ITvccurly)
-- -----------------------------------------------------------------------------
-- LINE pragmas
-set_line :: Int -> Action
-set_line code span buf len = do
- let line = parseInteger buf len 10 oct_or_dec
+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
-set_file :: Int -> Action
-set_file code span buf len = do
+setFile :: Int -> Action
+setFile code span buf len = do
let file = lexemeToFastString (stepOn buf) (len-2)
setSrcLoc (mkSrcLoc file (srcSpanEndLine span) (srcSpanEndCol span))
popLexState
lex_string_tok span buf len = do
tok <- lex_string ""
end <- getSrcLoc
- return (T (mkSrcSpan (srcSpanStart span) end) tok)
+ return (L (mkSrcSpan (srcSpanStart span) end) tok)
-lex_string :: String -> P Token__
+lex_string :: String -> P Token
lex_string s = do
i <- getInput
case alexGetChar i of
th_exts <- extension thEnabled
if th_exts then do
setInput i2
- return (T (mkSrcSpan loc end2) ITtyQuote)
+ return (L (mkSrcSpan loc end2) ITtyQuote)
else lit_error
Just ('\\', i2@(end2,_)) -> do -- We've seen 'backslash
_other -> do -- We've seen 'x not followed by quote
-- If TH is on, just parse the quote only
th_exts <- extension thEnabled
- if th_exts then return (T (mkSrcSpan loc (fst i1)) ITvarQuote)
+ if th_exts then return (L (mkSrcSpan loc (fst i1)) ITvarQuote)
else lit_error
-finish_char_tok :: SrcLoc -> Char -> P Token
+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@(end,_) <- getInput
if glaexts then do
- i@(end,_) <- getInput
case alexGetChar i of
Just ('#',i@(end,_)) -> do
setInput i
- return (T (mkSrcSpan loc end) (ITprimchar ch))
+ return (L (mkSrcSpan loc end) (ITprimchar ch))
_other ->
- return (T (mkSrcSpan loc end) (ITchar ch))
+ return (L (mkSrcSpan loc end) (ITchar ch))
else do
- end <- getSrcLoc
- return (T (mkSrcSpan loc end) (ITchar ch))
+ return (L (mkSrcSpan loc end) (ITchar ch))
lex_char :: P Char
lex_char = do
then return (chr (ord c - ord '@'))
else lit_error
- 'x' -> readNum is_hexdigit 16 hex
- 'o' -> readNum is_octdigit 8 oct_or_dec
- x | is_digit x -> readNum2 is_digit 10 oct_or_dec (oct_or_dec x)
+ '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
then return (chr i)
else lit_error
-is_hexdigit c
- = is_digit c
- || (c >= 'a' && c <= 'f')
- || (c >= 'A' && c <= 'F')
-
-hex c | is_digit c = ord c - ord '0'
- | otherwise = ord (to_lower c) - ord 'a' + 10
-
-oct_or_dec c = ord c - ord '0'
-
-is_octdigit c = c >= '0' && c <= '7'
-
-to_lower c
- | c >= 'A' && c <= 'Z' = chr (ord c - (ord 'A' - ord 'a'))
- | otherwise = c
-
silly_escape_chars = [
("NUL", '\NUL'),
("SOH", '\SOH'),
Just (c,i) -> do setInput i; return c
-- -----------------------------------------------------------------------------
--- Floats
-
-readRational :: ReadS Rational -- NB: doesn't handle leading "-"
-readRational r = do
- (n,d,s) <- readFix r
- (k,t) <- readExp s
- return ((n%1)*10^^(k-d), t)
- where
- readFix r = do
- (ds,s) <- lexDecDigits r
- (ds',t) <- lexDotDigits s
- return (read (ds++ds'), length ds', t)
-
- readExp (e:s) | e `elem` "eE" = readExp' s
- readExp s = return (0,s)
-
- readExp' ('+':s) = readDec s
- readExp' ('-':s) = do
- (k,t) <- readDec s
- return (-k,t)
- readExp' s = readDec s
-
- readDec s = do
- (ds,r) <- nonnull isDigit s
- return (foldl1 (\n d -> n * 10 + d) [ ord d - ord '0' | d <- ds ],
- r)
-
- lexDecDigits = nonnull isDigit
-
- lexDotDigits ('.':s) = return (span isDigit s)
- lexDotDigits s = return ("",s)
-
- nonnull p s = do (cs@(_:_),t) <- return (span p s)
- return (cs,t)
-
-readRational__ :: String -> Rational -- NB: *does* handle a leading "-"
-readRational__ top_s
- = case top_s of
- '-' : xs -> - (read_me xs)
- xs -> read_me xs
- where
- read_me s
- = case (do { (x,"") <- readRational s ; return x }) of
- [x] -> x
- [] -> error ("readRational__: no parse:" ++ top_s)
- _ -> error ("readRational__: ambiguous parse:" ++ top_s)
-
--- -----------------------------------------------------------------------------
-- The Parse Monad
data LayoutContext
data ParseResult a
= POk PState a
| PFailed
- SrcSpan -- The spam the error. Might be used in environments
- -- which can show this span, e.g. by highlighting it.
+ 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
-showPFailed span err = hcat [ppr span, text ": ", err]
-
data PState = PState {
buffer :: StringBuffer,
- last_span :: SrcSpan, -- span of previous token
- last_len :: !Int,
+ last_loc :: SrcSpan, -- pos of previous token
+ 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_span is used when generating error messages,
- -- and in pushCurrentContext only.
- -- last_len is used when generating error messages, and is
- -- needed because we need to back up the buffer pointer by that
- -- number of characters for outputing the token in the error message.
+ -- 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 }
PFailed span err -> PFailed span err
failP :: String -> P a
-failP msg = P $ \s -> PFailed (last_span s) (text msg)
+failP msg = P $ \s -> PFailed (last_loc s) (text msg)
failMsgP :: String -> P a
-failMsgP msg = P $ \s -> PFailed (last_span s) (text msg)
+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)
setSrcLoc :: SrcLoc -> P ()
setSrcLoc new_loc = P $ \s -> POk s{loc=new_loc} ()
--- tmp, for supporting stuff in RdrHsSyn. The scope better not include
--- any calls to the lexer, because it assumes things about the SrcLoc.
-setSrcLocFor :: SrcLoc -> P a -> P a
-setSrcLocFor new_loc scope = P $ \s@PState{ loc = old_loc } ->
- case unP scope s{loc=new_loc} of
- PFailed span msg -> PFailed span msg
- POk _ r -> POk s r
-
getSrcLoc :: P SrcLoc
getSrcLoc = P $ \s@(PState{ loc=loc }) -> POk s loc
setLastToken :: SrcSpan -> Int -> P ()
-setLastToken span len = P $ \s -> POk s{ last_span=span, last_len=len } ()
+setLastToken loc len = P $ \s -> POk s{ last_loc=loc, last_len=len } ()
type AlexInput = (SrcLoc,StringBuffer)
mkPState buf loc flags =
PState {
buffer = buf,
- last_span = mkSrcSpan loc loc,
+ last_loc = mkSrcSpan loc loc,
last_len = 0,
loc = loc,
extsBitmap = fromIntegral bitmap,
popContext :: P ()
popContext = P $ \ s@(PState{ buffer = buf, context = ctx,
- loc = loc, last_len = len, last_span = last_span }) ->
+ loc = loc, last_len = len, last_loc = last_loc }) ->
case ctx of
(_:tl) -> POk s{ context = tl } ()
- [] -> PFailed last_span (srcParseErr buf len)
+ [] -> 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_span=span, context=ctx } ->
- POk s{ context = Layout (srcSpanStartCol span) : ctx} ()
+pushCurrentContext = P $ \ s@PState{ last_loc=loc, context=ctx } ->
+ POk s{ context = Layout (srcSpanStartCol loc) : ctx} ()
-getOffside :: Int -> P Ordering
-getOffside col = P $ \s@PState{context=stk} ->
+getOffside :: SrcLoc -> P Ordering
+getOffside loc = P $ \s@PState{context=stk} ->
let ord = case stk of
- (Layout n:_) -> compare col n
+ (Layout n:_) -> compare (srcLocCol loc) n
_ -> GT
- in POk s $! ord
+ in POk s ord
-- ---------------------------------------------------------------------------
-- Construct a parse error
-- detected during parsing.
srcParseFail :: P a
srcParseFail = P $ \PState{ buffer = buf, last_len = len,
- last_span = last_span, loc = loc } ->
- PFailed last_span (srcParseErr buf 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. TODO: this is slightly wrong, because we record
lexError :: String -> P a
lexError str = do
loc <- getSrcLoc
- failLocMsgP loc loc str
+ i@(end,_) <- getInput
+ failLocMsgP loc end str
-- -----------------------------------------------------------------------------
-- This is the top-level function: called from the parser each time a
-- new token is to be read from the input.
-lexer :: (Token -> P a) -> P a
+lexer :: (Located Token -> P a) -> P a
lexer cont = do
- tok@(T _ tok__) <- lexToken
+ tok@(L _ tok__) <- lexToken
--trace ("token: " ++ show tok__) $ do
cont tok
-lexToken :: P Token
+lexToken :: P (Located Token)
lexToken = do
inp@(loc1,buf) <- getInput
sc <- getLexState
case alexScanUser exts inp sc of
AlexEOF -> do let span = mkSrcSpan loc1 loc1
setLastToken span 0
- return (T span ITeof)
+ return (L span ITeof)
AlexError (loc2,_) -> do failLocMsgP loc1 loc2 "lexical error"
AlexSkip inp2 _ -> do
setInput inp2
AlexToken inp2@(end,buf2) len t -> do
setInput inp2
let span = mkSrcSpan loc1 end
- (setLastToken $! span) $! len
+ span `seq` setLastToken span len
t span buf len
}
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