alex-3.2.4: data/AlexWrapper-gscan

{-# LINE 1 "templates/wrappers.hs" #-}
-- -----------------------------------------------------------------------------
-- Alex wrapper code.
--
-- This code is in the PUBLIC DOMAIN; you may copy it freely and use
-- it for any purpose whatsoever.






import Data.Word (Word8)
















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 = map fromIntegral . go . ord
 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
                        ]



type Byte = Word8

-- -----------------------------------------------------------------------------
-- The input type


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
                                  (b:bs) = utf8Encode c
                              in p' `seq`  Just (b, (p', c, bs, s))





























































-- -----------------------------------------------------------------------------
-- Token positions

-- `Posn' records the location of a token in the input text.  It has three
-- fields: the address (number of chacaters 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.


data AlexPosn = AlexPn !Int !Int !Int
        deriving (Eq,Show)

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-1) `div` alex_tab_size)*alex_tab_size+1)
alexMove (AlexPn a l _) '\n' = AlexPn (a+1) (l+1)   1
alexMove (AlexPn a l c) _    = AlexPn (a+1)  l     (c+1)


-- -----------------------------------------------------------------------------
-- Default monad
















































































































-- -----------------------------------------------------------------------------
-- Monad (with ByteString input)







































































































-- -----------------------------------------------------------------------------
-- Basic wrapper

























-- -----------------------------------------------------------------------------
-- Basic wrapper, ByteString version
































-- -----------------------------------------------------------------------------
-- Posn wrapper

-- Adds text positions to the basic model.













-- -----------------------------------------------------------------------------
-- Posn wrapper, ByteString version














-- -----------------------------------------------------------------------------
-- GScan wrapper

-- For compatibility with previous versions of Alex, and because we can.


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__)