alex-3.5.0.0: data/AlexWrappers.hs
-- -----------------------------------------------------------------------------
-- Alex wrapper code.
--
-- This code is in the PUBLIC DOMAIN; you may copy it freely and use
-- it for any purpose whatsoever.
#if defined(ALEX_MONAD) || defined(ALEX_MONAD_BYTESTRING) || defined(ALEX_MONAD_STRICT_TEXT)
import Control.Applicative as App (Applicative (..))
#endif
#if defined(ALEX_STRICT_TEXT) || defined (ALEX_POSN_STRICT_TEXT) || defined(ALEX_MONAD_STRICT_TEXT)
import qualified Data.Text
#endif
import Data.Word (Word8)
#if defined(ALEX_BASIC_BYTESTRING) || defined(ALEX_POSN_BYTESTRING) || defined(ALEX_MONAD_BYTESTRING)
import Data.Int (Int64)
import qualified Data.Char
import qualified Data.ByteString.Lazy as ByteString
import qualified Data.ByteString.Internal as ByteString (w2c)
#elif defined(ALEX_STRICT_BYTESTRING)
import qualified Data.Char
import qualified Data.ByteString as ByteString
import qualified Data.ByteString.Internal as ByteString hiding (ByteString)
import qualified Data.ByteString.Unsafe as ByteString
#else
import Data.Char (ord)
import qualified Data.Bits
-- | Encode a Haskell String to a list of Word8 values, in UTF8 format.
utf8Encode :: Char -> [Word8]
utf8Encode = uncurry (:) . utf8Encode'
utf8Encode' :: Char -> (Word8, [Word8])
utf8Encode' c = case go (ord c) of
(x, xs) -> (fromIntegral x, map fromIntegral xs)
where
go oc
| oc <= 0x7f = ( oc
, [
])
| oc <= 0x7ff = ( 0xc0 + (oc `Data.Bits.shiftR` 6)
, [0x80 + oc Data.Bits..&. 0x3f
])
| oc <= 0xffff = ( 0xe0 + (oc `Data.Bits.shiftR` 12)
, [0x80 + ((oc `Data.Bits.shiftR` 6) Data.Bits..&. 0x3f)
, 0x80 + oc Data.Bits..&. 0x3f
])
| otherwise = ( 0xf0 + (oc `Data.Bits.shiftR` 18)
, [0x80 + ((oc `Data.Bits.shiftR` 12) Data.Bits..&. 0x3f)
, 0x80 + ((oc `Data.Bits.shiftR` 6) Data.Bits..&. 0x3f)
, 0x80 + oc Data.Bits..&. 0x3f
])
#endif
type Byte = Word8
-- -----------------------------------------------------------------------------
-- The input type
#if defined(ALEX_POSN) || defined(ALEX_MONAD) || defined(ALEX_GSCAN)
type AlexInput = (AlexPosn, -- current position,
Char, -- previous char
[Byte], -- pending bytes on current char
String) -- current input string
ignorePendingBytes :: AlexInput -> AlexInput
ignorePendingBytes (p,c,_ps,s) = (p,c,[],s)
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar (_p,c,_bs,_s) = c
alexGetByte :: AlexInput -> Maybe (Byte,AlexInput)
alexGetByte (p,c,(b:bs),s) = Just (b,(p,c,bs,s))
alexGetByte (_,_,[],[]) = Nothing
alexGetByte (p,_,[],(c:s)) = let p' = alexMove p c
in case utf8Encode' c of
(b, bs) -> p' `seq` Just (b, (p', c, bs, s))
#endif
#if defined (ALEX_STRICT_TEXT)
type AlexInput = (Char, -- previous char
[Byte], -- pending bytes on current char
Data.Text.Text) -- current input string
ignorePendingBytes :: AlexInput -> AlexInput
ignorePendingBytes (c,_ps,s) = (c,[],s)
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar (c,_bs,_s) = c
alexGetByte :: AlexInput -> Maybe (Byte,AlexInput)
alexGetByte (c,(b:bs),s) = Just (b,(c,bs,s))
alexGetByte (_,[],s) = case Data.Text.uncons s of
Just (c, cs) ->
case utf8Encode' c of
(b, bs) -> Just (b, (c, bs, cs))
Nothing ->
Nothing
#endif
#if defined (ALEX_POSN_STRICT_TEXT) || defined(ALEX_MONAD_STRICT_TEXT)
type AlexInput = (AlexPosn, -- current position,
Char, -- previous char
[Byte], -- pending bytes on current char
Data.Text.Text) -- current input string
ignorePendingBytes :: AlexInput -> AlexInput
ignorePendingBytes (p,c,_ps,s) = (p,c,[],s)
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar (_p,c,_bs,_s) = c
alexGetByte :: AlexInput -> Maybe (Byte,AlexInput)
alexGetByte (p,c,(b:bs),s) = Just (b,(p,c,bs,s))
alexGetByte (p,_,[],s) = case Data.Text.uncons s of
Just (c, cs) ->
let p' = alexMove p c
in case utf8Encode' c of
(b, bs) -> p' `seq` Just (b, (p', c, bs, cs))
Nothing ->
Nothing
#endif
#if defined(ALEX_POSN_BYTESTRING) || defined(ALEX_MONAD_BYTESTRING)
type AlexInput = (AlexPosn, -- current position,
Char, -- previous char
ByteString.ByteString, -- current input string
Int64) -- bytes consumed so far
ignorePendingBytes :: AlexInput -> AlexInput
ignorePendingBytes i = i -- no pending bytes when lexing bytestrings
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar (_,c,_,_) = c
alexGetByte :: AlexInput -> Maybe (Byte,AlexInput)
alexGetByte (p,_,cs,n) =
case ByteString.uncons cs of
Nothing -> Nothing
Just (b, cs') ->
let c = ByteString.w2c b
p' = alexMove p c
n' = n+1
in p' `seq` cs' `seq` n' `seq` Just (b, (p', c, cs',n'))
#endif
#ifdef ALEX_BASIC_BYTESTRING
data AlexInput = AlexInput { alexChar :: {-# UNPACK #-} !Char, -- previous char
alexStr :: !ByteString.ByteString, -- current input string
alexBytePos :: {-# UNPACK #-} !Int64} -- bytes consumed so far
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar = alexChar
alexGetByte (AlexInput {alexStr=cs,alexBytePos=n}) =
case ByteString.uncons cs of
Nothing -> Nothing
Just (c, rest) ->
Just (c, AlexInput {
alexChar = ByteString.w2c c,
alexStr = rest,
alexBytePos = n+1})
#endif
#ifdef ALEX_STRICT_BYTESTRING
data AlexInput = AlexInput { alexChar :: {-# UNPACK #-} !Char,
alexStr :: {-# UNPACK #-} !ByteString.ByteString,
alexBytePos :: {-# UNPACK #-} !Int}
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar = alexChar
alexGetByte (AlexInput {alexStr=cs,alexBytePos=n}) =
case ByteString.uncons cs of
Nothing -> Nothing
Just (c, rest) ->
Just (c, AlexInput {
alexChar = ByteString.w2c c,
alexStr = rest,
alexBytePos = n+1})
#endif
-- -----------------------------------------------------------------------------
-- Token positions
-- `Posn' records the location of a token in the input text. It has three
-- fields: the address (number of characters preceding the token), line number
-- and column of a token within the file. `start_pos' gives the position of the
-- start of the file and `eof_pos' a standard encoding for the end of file.
-- `move_pos' calculates the new position after traversing a given character,
-- assuming the usual eight character tab stops.
#if defined(ALEX_POSN) || defined(ALEX_MONAD) || defined(ALEX_POSN_BYTESTRING) || defined(ALEX_MONAD_BYTESTRING) || defined(ALEX_GSCAN) || defined (ALEX_POSN_STRICT_TEXT) || defined(ALEX_MONAD_STRICT_TEXT)
data AlexPosn = AlexPn !Int !Int !Int
deriving (Eq, Show, Ord)
alexStartPos :: AlexPosn
alexStartPos = AlexPn 0 1 1
alexMove :: AlexPosn -> Char -> AlexPosn
alexMove (AlexPn a l c) '\t' = AlexPn (a+1) l (c+alex_tab_size-((c-1) `mod` alex_tab_size))
alexMove (AlexPn a l _) '\n' = AlexPn (a+1) (l+1) 1
alexMove (AlexPn a l c) _ = AlexPn (a+1) l (c+1)
#endif
-- -----------------------------------------------------------------------------
-- Monad (default and with ByteString input)
#if defined(ALEX_MONAD) || defined(ALEX_MONAD_BYTESTRING) || defined(ALEX_MONAD_STRICT_TEXT)
data AlexState = AlexState {
alex_pos :: !AlexPosn, -- position at current input location
#ifdef ALEX_MONAD_STRICT_TEXT
alex_inp :: Data.Text.Text,
alex_chr :: !Char,
alex_bytes :: [Byte],
#endif /* ALEX_MONAD_STRICT_TEXT */
#ifdef ALEX_MONAD
alex_inp :: String, -- the current input
alex_chr :: !Char, -- the character before the input
alex_bytes :: [Byte],
#endif /* ALEX_MONAD */
#ifdef ALEX_MONAD_BYTESTRING
alex_bpos:: !Int64, -- bytes consumed so far
alex_inp :: ByteString.ByteString, -- the current input
alex_chr :: !Char, -- the character before the input
#endif /* ALEX_MONAD_BYTESTRING */
alex_scd :: !Int -- the current startcode
#ifdef ALEX_MONAD_USER_STATE
, alex_ust :: AlexUserState -- AlexUserState will be defined in the user program
#endif
}
-- Compile with -funbox-strict-fields for best results!
#ifdef ALEX_MONAD
runAlex :: String -> Alex a -> Either String a
runAlex input__ (Alex f)
= case f (AlexState {alex_bytes = [],
alex_pos = alexStartPos,
alex_inp = input__,
alex_chr = '\n',
#ifdef ALEX_MONAD_USER_STATE
alex_ust = alexInitUserState,
#endif
alex_scd = 0}) of Left msg -> Left msg
Right ( _, a ) -> Right a
#endif
#ifdef ALEX_MONAD_BYTESTRING
runAlex :: ByteString.ByteString -> Alex a -> Either String a
runAlex input__ (Alex f)
= case f (AlexState {alex_bpos = 0,
alex_pos = alexStartPos,
alex_inp = input__,
alex_chr = '\n',
#ifdef ALEX_MONAD_USER_STATE
alex_ust = alexInitUserState,
#endif
alex_scd = 0}) of Left msg -> Left msg
Right ( _, a ) -> Right a
#endif
#ifdef ALEX_MONAD_STRICT_TEXT
runAlex :: Data.Text.Text -> Alex a -> Either String a
runAlex input__ (Alex f)
= case f (AlexState {alex_bytes = [],
alex_pos = alexStartPos,
alex_inp = input__,
alex_chr = '\n',
#ifdef ALEX_MONAD_USER_STATE
alex_ust = alexInitUserState,
#endif
alex_scd = 0}) of Left msg -> Left msg
Right ( _, a ) -> Right a
#endif
newtype Alex a = Alex { unAlex :: AlexState -> Either String (AlexState, a) }
instance Functor Alex where
fmap f a = Alex $ \s -> case unAlex a s of
Left msg -> Left msg
Right (s', a') -> Right (s', f a')
instance Applicative Alex where
pure a = Alex $ \s -> Right (s, a)
fa <*> a = Alex $ \s -> case unAlex fa s of
Left msg -> Left msg
Right (s', f) -> case unAlex a s' of
Left msg -> Left msg
Right (s'', b) -> Right (s'', f b)
instance Monad Alex where
m >>= k = Alex $ \s -> case unAlex m s of
Left msg -> Left msg
Right (s',a) -> unAlex (k a) s'
return = App.pure
#ifdef ALEX_MONAD
alexGetInput :: Alex AlexInput
alexGetInput
= Alex $ \s@AlexState{alex_pos=pos,alex_chr=c,alex_bytes=bs,alex_inp=inp__} ->
Right (s, (pos,c,bs,inp__))
#endif
#ifdef ALEX_MONAD_BYTESTRING
alexGetInput :: Alex AlexInput
alexGetInput
= Alex $ \s@AlexState{alex_pos=pos,alex_bpos=bpos,alex_chr=c,alex_inp=inp__} ->
Right (s, (pos,c,inp__,bpos))
#endif
#ifdef ALEX_MONAD_STRICT_TEXT
alexGetInput :: Alex AlexInput
alexGetInput
= Alex $ \s@AlexState{alex_pos=pos,alex_chr=c,alex_bytes=bs,alex_inp=inp__} ->
Right (s, (pos,c,bs,inp__))
#endif
#ifdef ALEX_MONAD
alexSetInput :: AlexInput -> Alex ()
alexSetInput (pos,c,bs,inp__)
= Alex $ \s -> case s{alex_pos=pos,alex_chr=c,alex_bytes=bs,alex_inp=inp__} of
state__@(AlexState{}) -> Right (state__, ())
#endif
#ifdef ALEX_MONAD_BYTESTRING
alexSetInput :: AlexInput -> Alex ()
alexSetInput (pos,c,inp__,bpos)
= Alex $ \s -> case s{alex_pos=pos,
alex_bpos=bpos,
alex_chr=c,
alex_inp=inp__} of
state__@(AlexState{}) -> Right (state__, ())
#endif
#ifdef ALEX_MONAD_STRICT_TEXT
alexSetInput :: AlexInput -> Alex ()
alexSetInput (pos,c,bs,inp__)
= Alex $ \s -> case s{alex_pos=pos,alex_chr=c,alex_bytes=bs,alex_inp=inp__} of
state__@(AlexState{}) -> Right (state__, ())
#endif
alexError :: String -> Alex a
alexError message = Alex $ const $ Left message
alexGetStartCode :: Alex Int
alexGetStartCode = Alex $ \s@AlexState{alex_scd=sc} -> Right (s, sc)
alexSetStartCode :: Int -> Alex ()
alexSetStartCode sc = Alex $ \s -> Right (s{alex_scd=sc}, ())
#if defined(ALEX_MONAD_USER_STATE)
alexGetUserState :: Alex AlexUserState
alexGetUserState = Alex $ \s@AlexState{alex_ust=ust} -> Right (s,ust)
alexSetUserState :: AlexUserState -> Alex ()
alexSetUserState ss = Alex $ \s -> Right (s{alex_ust=ss}, ())
#endif /* defined(ALEX_MONAD_USER_STATE) */
#ifdef ALEX_MONAD
alexMonadScan = do
inp__ <- alexGetInput
sc <- alexGetStartCode
case alexScan inp__ sc of
AlexEOF -> alexEOF
AlexError ((AlexPn _ line column),_,_,_) -> alexError $ "lexical error at line " ++ (show line) ++ ", column " ++ (show column)
AlexSkip inp__' _len -> do
alexSetInput inp__'
alexMonadScan
AlexToken inp__' len action -> do
alexSetInput inp__'
action (ignorePendingBytes inp__) len
#endif
#ifdef ALEX_MONAD_BYTESTRING
alexMonadScan = do
inp__@(_,_,_,n) <- alexGetInput
sc <- alexGetStartCode
case alexScan inp__ sc of
AlexEOF -> alexEOF
AlexError ((AlexPn _ line column),_,_,_) -> alexError $ "lexical error at line " ++ (show line) ++ ", column " ++ (show column)
AlexSkip inp__' _len -> do
alexSetInput inp__'
alexMonadScan
AlexToken inp__'@(_,_,_,n') _ action -> let len = n'-n in do
alexSetInput inp__'
action (ignorePendingBytes inp__) len
#endif
#ifdef ALEX_MONAD_STRICT_TEXT
alexMonadScan = do
inp__ <- alexGetInput
sc <- alexGetStartCode
case alexScan inp__ sc of
AlexEOF -> alexEOF
AlexError ((AlexPn _ line column),_,_,_) -> alexError $ "lexical error at line " ++ (show line) ++ ", column " ++ (show column)
AlexSkip inp__' _len -> do
alexSetInput inp__'
alexMonadScan
AlexToken inp__' len action -> do
alexSetInput inp__'
action (ignorePendingBytes inp__) len
#endif
-- -----------------------------------------------------------------------------
-- Useful token actions
#ifdef ALEX_MONAD
type AlexAction result = AlexInput -> Int -> Alex result
#endif
#ifdef ALEX_MONAD_BYTESTRING
type AlexAction result = AlexInput -> Int64 -> Alex result
#endif
#ifdef ALEX_MONAD_STRICT_TEXT
type AlexAction result = AlexInput -> Int -> Alex result
#endif
-- just ignore this token and scan another one
-- skip :: AlexAction result
skip _input _len = alexMonadScan
-- ignore this token, but set the start code to a new value
-- begin :: Int -> AlexAction result
begin code _input _len = do alexSetStartCode code; alexMonadScan
-- perform an action for this token, and set the start code to a new value
andBegin :: AlexAction result -> Int -> AlexAction result
(action `andBegin` code) input__ len = do
alexSetStartCode code
action input__ len
#ifdef ALEX_MONAD
token :: (AlexInput -> Int -> token) -> AlexAction token
token t input__ len = return (t input__ len)
#endif
#ifdef ALEX_MONAD_BYTESTRING
token :: (AlexInput -> Int64 -> token) -> AlexAction token
token t input__ len = return (t input__ len)
#endif
#ifdef ALEX_MONAD_STRICT_TEXT
token :: (AlexInput -> Int -> token) -> AlexAction token
token t input__ len = return (t input__ len)
#endif
#endif /* defined(ALEX_MONAD) || defined(ALEX_MONAD_BYTESTRING) || defined(ALEX_MONAD_STRICT_TEXT) */
-- -----------------------------------------------------------------------------
-- Basic wrapper
#ifdef ALEX_BASIC
type AlexInput = (Char,[Byte],String)
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar (c,_,_) = c
-- alexScanTokens :: String -> [token]
alexScanTokens str = go ('\n',[],str)
where go inp__@(_,_bs,s) =
case alexScan inp__ 0 of
AlexEOF -> []
AlexError _ -> error "lexical error"
AlexSkip inp__' _ln -> go inp__'
AlexToken inp__' len act -> act (take len s) : go inp__'
alexGetByte :: AlexInput -> Maybe (Byte,AlexInput)
alexGetByte (c,(b:bs),s) = Just (b,(c,bs,s))
alexGetByte (_,[],[]) = Nothing
alexGetByte (_,[],(c:s)) = case utf8Encode' c of
(b, bs) -> Just (b, (c, bs, s))
#endif
-- -----------------------------------------------------------------------------
-- Basic wrapper, ByteString version
#ifdef ALEX_BASIC_BYTESTRING
-- alexScanTokens :: ByteString.ByteString -> [token]
alexScanTokens str = go (AlexInput '\n' str 0)
where go inp__ =
case alexScan inp__ 0 of
AlexEOF -> []
AlexError _ -> error "lexical error"
AlexSkip inp__' _len -> go inp__'
AlexToken inp__' _ act ->
let len = alexBytePos inp__' - alexBytePos inp__ in
act (ByteString.take len (alexStr inp__)) : go inp__'
#endif
#ifdef ALEX_STRICT_BYTESTRING
-- alexScanTokens :: ByteString.ByteString -> [token]
alexScanTokens str = go (AlexInput '\n' str 0)
where go inp__ =
case alexScan inp__ 0 of
AlexEOF -> []
AlexError _ -> error "lexical error"
AlexSkip inp__' _len -> go inp__'
AlexToken inp__' _ act ->
let len = alexBytePos inp__' - alexBytePos inp__ in
act (ByteString.take len (alexStr inp__)) : go inp__'
#endif
#ifdef ALEX_STRICT_TEXT
-- alexScanTokens :: Data.Text.Text -> [token]
alexScanTokens str = go ('\n',[],str)
where go inp__@(_,_bs,s) =
case alexScan inp__ 0 of
AlexEOF -> []
AlexError _ -> error "lexical error"
AlexSkip inp__' _len -> go inp__'
AlexToken inp__' len act -> act (Data.Text.take len s) : go inp__'
#endif
#ifdef ALEX_POSN_STRICT_TEXT
-- alexScanTokens :: Data.Text.Text -> [token]
alexScanTokens str = go (alexStartPos,'\n',[],str)
where go inp__@(pos,_,_bs,s) =
case alexScan inp__ 0 of
AlexEOF -> []
AlexError ((AlexPn _ line column),_,_,_) -> error $ "lexical error at line " ++ (show line) ++ ", column " ++ (show column)
AlexSkip inp__' _len -> go inp__'
AlexToken inp__' len act -> act pos (Data.Text.take len s) : go inp__'
#endif
-- -----------------------------------------------------------------------------
-- Posn wrapper
-- Adds text positions to the basic model.
#ifdef ALEX_POSN
--alexScanTokens :: String -> [token]
alexScanTokens str0 = go (alexStartPos,'\n',[],str0)
where go inp__@(pos,_,_,str) =
case alexScan inp__ 0 of
AlexEOF -> []
AlexError ((AlexPn _ line column),_,_,_) -> error $ "lexical error at line " ++ (show line) ++ ", column " ++ (show column)
AlexSkip inp__' _ln -> go inp__'
AlexToken inp__' len act -> act pos (take len str) : go inp__'
#endif
-- -----------------------------------------------------------------------------
-- Posn wrapper, ByteString version
#ifdef ALEX_POSN_BYTESTRING
--alexScanTokens :: ByteString.ByteString -> [token]
alexScanTokens str0 = go (alexStartPos,'\n',str0,0)
where go inp__@(pos,_,str,n) =
case alexScan inp__ 0 of
AlexEOF -> []
AlexError ((AlexPn _ line column),_,_,_) -> error $ "lexical error at line " ++ (show line) ++ ", column " ++ (show column)
AlexSkip inp__' _len -> go inp__'
AlexToken inp__'@(_,_,_,n') _ act ->
act pos (ByteString.take (n'-n) str) : go inp__'
#endif
-- -----------------------------------------------------------------------------
-- GScan wrapper
-- For compatibility with previous versions of Alex, and because we can.
#ifdef ALEX_GSCAN
alexGScan stop__ state__ inp__ =
alex_gscan stop__ alexStartPos '\n' [] inp__ (0,state__)
alex_gscan stop__ p c bs inp__ (sc,state__) =
case alexScan (p,c,bs,inp__) sc of
AlexEOF -> stop__ p c inp__ (sc,state__)
AlexError _ -> stop__ p c inp__ (sc,state__)
AlexSkip (p',c',bs',inp__') _len ->
alex_gscan stop__ p' c' bs' inp__' (sc,state__)
AlexToken (p',c',bs',inp__') len k ->
k p c inp__ len (\scs -> alex_gscan stop__ p' c' bs' inp__' scs) (sc,state__)
#endif