{
module Lexer (
- Token(..), lexer, mkPState,
+ Token(..), lexer, mkPState, PState(..),
P(..), ParseResult(..), getSrcLoc,
- failMsgP, failLocMsgP, failSpanMsgP, srcParseFail,
- popContext, pushCurrentContext,
+ failLocMsgP, failSpanMsgP, srcParseFail,
+ popContext, pushCurrentContext, setLastToken, setSrcLoc,
+ getLexState, popLexState, pushLexState
) where
#include "HsVersions.h"
import FastTypes
import SrcLoc
import UniqFM
-import CmdLineOpts
+import DynFlags
import Ctype
-import Util ( maybePrefixMatch )
+import Util ( maybePrefixMatch, readRational )
import DATA_BITS
import Char
-- 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_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.
+-- 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)
+<glaexts>
+ "{-#" $whitechar* (RULES|rules) { token ITrules_prag }
+
<0,glaexts> {
"{-#" $whitechar* (SPECIALI[SZ]E|speciali[sz]e)
{ token ITspecialise_prag }
"{-#" $whitechar* (INLINE|inline) { token ITinline_prag }
"{-#" $whitechar* (NO(T?)INLINE|no(t?)inline)
{ token ITnoinline_prag }
- "{-#" $whitechar* (RULES|rules) { token ITrules_prag }
"{-#" $whitechar* (DEPRECATED|deprecated)
{ token ITdeprecated_prag }
"{-#" $whitechar* (SCC|scc) { token ITscc_prag }
| ITprimdouble Rational
-- MetaHaskell extension tokens
- | ITopenExpQuote -- [| or [e|
- | ITopenPatQuote -- [p|
- | ITopenDecQuote -- [d|
- | ITopenTypQuote -- [t|
- | ITcloseQuote -- |]
- | ITidEscape FastString -- $x
- | ITparenEscape -- $(
- | ITvarQuote -- '
- | ITtyQuote -- ''
+ | ITopenExpQuote -- [| or [e|
+ | ITopenPatQuote -- [p|
+ | ITopenDecQuote -- [d|
+ | ITopenTypQuote -- [t|
+ | ITcloseQuote -- |]
+ | ITidEscape FastString -- $x
+ | ITparenEscape -- $(
+ | ITvarQuote -- '
+ | ITtyQuote -- ''
-- Arrow notation extension
| ITproc
| ITrec
- | IToparenbar -- (|
- | ITcparenbar -- |)
- | ITlarrowtail -- -<
- | ITrarrowtail -- >-
- | ITLarrowtail -- -<<
- | ITRarrowtail -- >>-
+ | IToparenbar -- (|
+ | ITcparenbar -- |)
+ | ITlarrowtail -- -<
+ | ITrarrowtail -- >-
+ | ITLarrowtail -- -<<
+ | ITRarrowtail -- >>-
| ITunknown String -- Used when the lexer can't make sense of it
| ITeof -- end of file token
( "where", ITwhere, 0 ),
( "_scc_", ITscc, 0 ), -- ToDo: remove
- ( "forall", ITforall, bit glaExtsBit),
+ ( "forall", ITforall, bit tvBit),
( "mdo", ITmdo, bit glaExtsBit),
( "foreign", ITforeign, bit ffiBit),
,("!", ITbang, 0)
,("*", ITstar, bit glaExtsBit) -- For data T (a::*) = MkT
- ,(".", ITdot, bit glaExtsBit) -- For 'forall a . t'
+ ,(".", ITdot, bit tvBit) -- For 'forall a . t'
,("-<", ITlarrowtail, bit arrowsBit)
,(">-", ITrarrowtail, bit arrowsBit)
pop_and :: Action -> Action
pop_and act span buf len = do popLexState; act span buf len
-notFollowedBy char _ _ _ (_,buf) = atEnd buf || currentChar buf /= char
+notFollowedBy char _ _ _ (AI _ _ buf) = atEnd buf || currentChar buf /= char
-notFollowedBySymbol _ _ _ (_,buf)
+notFollowedBySymbol _ _ _ (AI _ _ buf)
= atEnd buf || currentChar buf `notElem` "!#$%&*+./<=>?@\\^|-~"
-atEOL _ _ _ (_,buf) = atEnd buf || currentChar buf == '\n'
+atEOL _ _ _ (AI _ _ 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 (AI end _ _) = failLocMsgP (srcSpanStart span) end "unterminated `{-'"
open_brace, close_brace :: Action
open_brace span _str _len = do
token = L span (ITqvarid (mod,var))
try_again = do
- setInput (srcSpanStart span,buf)
+ (AI _ offs _) <- getInput
+ setInput (AI (srcSpanStart span) (offs-len) buf)
pushLexState bad_qvarid
lexToken
fs = lexemeToFastString buf len
tok_decimal span buf len
- = return (L span (ITinteger $! parseInteger buf len 10 oct_or_dec))
+ = return (L span (ITinteger $! parseInteger buf len 10 octDecDigit))
tok_octal span buf len
- = return (L 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 (L 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 (L 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 (L 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 (L span (ITprimint $! parseInteger (stepOnBy 2 buf) (len-3) 16 hex))
-
-tok_float str = ITrational $! readRational__ str
-prim_float str = ITprimfloat $! readRational__ str
-prim_double str = ITprimdouble $! readRational__ str
+ = return (L span (ITprimint $! parseInteger (stepOnBy 2 buf) (len-3) 16 hexDigit))
-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 (srcSpanEnd span)
+ pos <- getOffside
case pos of
LT -> do
--trace "layout: inserting '}'" $ do
--
new_layout_context strict span _buf _len = do
popLexState
- let offset = srcSpanStartCol span
+ (AI _ offset _) <- getInput
ctx <- getContext
case ctx of
Layout prev_off : _ |
-- -----------------------------------------------------------------------------
-- 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
case alexGetChar i1 of
Nothing -> lit_error
- Just ('\'', i2@(end2,_)) -> do -- We've seen ''
+ 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@(end2,_)) -> do -- We've seen 'backslash
+ 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 lit_error
- Just (c, i2@(end2,_)) | not (is_any c) -> lit_error
+ Just (c, i2@(AI end2 _ _)) | not (is_any c) -> lit_error
| otherwise ->
-- We've seen 'x, where x is a valid character
_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 (L (mkSrcSpan loc (fst i1)) ITvarQuote)
+ let (AI end _ _) = i1
+ if th_exts then return (L (mkSrcSpan loc end) ITvarQuote)
else 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@(end,_) <- getInput
+ i@(AI end _ _) <- getInput
if glaexts then do
case alexGetChar i of
- Just ('#',i@(end,_)) -> do
+ Just ('#',i@(AI end _ _)) -> do
setInput i
return (L (mkSrcSpan loc end) (ITprimchar ch))
_other ->
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 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
lex_state :: [Int]
}
-- last_loc and last_len are used when generating error messages,
- -- and in pushCurrentContext only.
+ -- 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 }
setLastToken :: SrcSpan -> Int -> P ()
setLastToken loc len = P $ \s -> POk s{ last_loc=loc, last_len=len } ()
-type AlexInput = (SrcLoc,StringBuffer)
+data AlexInput = AI SrcLoc {-#UNPACK#-}!Int StringBuffer
alexInputPrevChar :: AlexInput -> Char
-alexInputPrevChar (_,s) = prevChar s '\n'
+alexInputPrevChar (AI _ _ s) = prevChar s '\n'
alexGetChar :: AlexInput -> Maybe (Char,AlexInput)
-alexGetChar (loc,s)
+alexGetChar (AI loc ofs s)
| atEnd s = Nothing
- | otherwise = c `seq` loc' `seq` s' `seq` Just (c, (loc', s'))
- where c = currentChar s
+ | otherwise = c `seq` loc' `seq` ofs' `seq` s' `seq` Just (c, (AI loc' ofs' s'))
+ where c = currentChar s
loc' = advanceSrcLoc loc c
+ ofs' = advanceOffs c ofs
s' = stepOn s
+ 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, buffer=b } -> POk s (l,b)
+getInput = P $ \s@PState{ loc=l, last_offs=o, buffer=b } -> POk s (AI l o b)
setInput :: AlexInput -> P ()
-setInput (l,b) = P $ \s -> POk s{ loc=l, buffer=b } ()
+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} ()
arrowsBit = 4
thBit = 5
ipBit = 6
+tvBit = 7 -- Scoped type variables enables 'forall' keyword
glaExtsEnabled, ffiEnabled, parrEnabled :: Int -> Bool
glaExtsEnabled flags = testBit flags glaExtsBit
arrowsEnabled flags = testBit flags arrowsBit
thEnabled flags = testBit flags thBit
ipEnabled flags = testBit flags ipBit
+tvEnabled flags = testBit flags tvBit
-- create a parse state
--
PState {
buffer = buf,
last_loc = mkSrcSpan loc loc,
+ last_offs = 0,
last_len = 0,
loc = loc,
extsBitmap = fromIntegral bitmap,
.|. arrowsBit `setBitIf` dopt Opt_Arrows flags
.|. thBit `setBitIf` dopt Opt_TH flags
.|. ipBit `setBitIf` dopt Opt_ImplicitParams flags
+ .|. tvBit `setBitIf` dopt Opt_ScopedTypeVariables flags
--
setBitIf :: Int -> Bool -> Int
b `setBitIf` cond | cond = bit b
-- This is only used at the outer level of a module when the 'module'
-- keyword is missing.
pushCurrentContext :: P ()
-pushCurrentContext = P $ \ s@PState{ last_loc=loc, context=ctx } ->
- POk s{ context = Layout (srcSpanStartCol loc) : ctx} ()
+pushCurrentContext = P $ \ s@PState{ last_offs=offs, last_len=len, context=ctx } ->
+ POk s{context = Layout (offs-len) : ctx} ()
-getOffside :: SrcLoc -> P Ordering
-getOffside loc = P $ \s@PState{context=stk} ->
+getOffside :: P Ordering
+getOffside = P $ \s@PState{last_offs=offs, context=stk} ->
let ord = case stk of
- (Layout n:_) -> compare (srcLocCol loc) n
+ (Layout n:_) -> compare offs n
_ -> GT
in POk s ord
-- detected during parsing.
srcParseFail :: P a
srcParseFail = P $ \PState{ buffer = buf, last_len = len,
- last_loc = last_loc, loc = loc } ->
+ last_loc = last_loc } ->
PFailed last_loc (srcParseErr buf len)
-- A lexical error is reported at a particular position in the source file,
lexError :: String -> P a
lexError str = do
loc <- getSrcLoc
- i@(end,_) <- getInput
+ i@(AI end _ _) <- getInput
failLocMsgP loc end str
-- -----------------------------------------------------------------------------
lexer :: (Located Token -> P a) -> P a
lexer cont = do
tok@(L _ tok__) <- lexToken
- --trace ("token: " ++ show tok__) $ do
+ -- trace ("token: " ++ show tok__) $ do
cont tok
lexToken :: P (Located Token)
lexToken = do
- inp@(loc1,buf) <- getInput
+ 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 (loc2,_) -> do failLocMsgP loc1 loc2 "lexical error"
+ AlexError (AI loc2 _ _) -> do failLocMsgP loc1 loc2 "lexical error"
AlexSkip inp2 _ -> do
setInput inp2
lexToken
- AlexToken inp2@(end,buf2) len t -> do
+ AlexToken inp2@(AI end _ buf2) len t -> do
setInput inp2
let span = mkSrcSpan loc1 end
span `seq` setLastToken span len
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