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|
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE FlexibleContexts #-}
module Scanner
( getKey
) where
import Prelude hiding ((/))
import Control.Applicative
import Control.Monad.Error
import Control.Monad.State
import Control.Monad.Writer
import Data.Bits
import Data.Char
import System.IO
-- high level interface
getKey :: IO String
getKey = do
_ <- hLookAhead stdin -- wait for input
((_, raw_s), _) <- runScanner scan
return $ map toChar raw_s
type P = C
type I = C
type F = C
data Token
= CS [P] [I] F
| Chr C
deriving (Show)
type ScanLog = [C]
type ScanError = String
data ScanState = ScanState
{ _result :: Maybe Token -- TODO underscore supresses warning, rename before usage..
, buffer :: [C]
}
emptyScanState :: ScanState
emptyScanState = ScanState Nothing []
newtype Scanner m a = Scanner
(ErrorT ScanError (WriterT ScanLog (StateT ScanState m)) a)
deriving
( Applicative
, Functor
, Monad
, MonadIO
, MonadState ScanState
, MonadError ScanError
, MonadWriter ScanLog
)
runScanner :: Scanner m a -> m ((Either ScanError a, ScanLog), ScanState)
runScanner (Scanner a) =
runStateT (runWriterT (runErrorT a)) emptyScanState
-- TODO max timeout
timeout :: Int
timeout = 1
scan, scanESC, scanCS ::
( Monad m
, MonadIO m
, MonadError ScanError m
, MonadState ScanState m
, MonadWriter ScanLog m
) => m ()
scan = do
c <- liftIO $ hGetC stdin
tell [c]
case () of _
| c == 01/11 -> scanESC
| otherwise -> return ()
scanESC = do
mb_c <- liftIO $ hWaitGetC timeout stdin
whenJust mb_c $ \ c -> do
tell [c]
case () of _
| c == 05/11 ->
-- CSI
scanCS
| c == 01/11 ->
-- XXX M-F1 and other crazy chords may cause
-- \ESC\ESC... on wu, so we just recurse here...
scanESC
| c == 04/15 ->
-- XXX Non-CSI SS3
one $ between (04/00) (07/14)
| otherwise -> return ()
scanCS = do
zeroOrMore $ between (03/00) (03/15) -- parameter bytes
zeroOrMore $ between (02/00) (02/15) -- intermediate bytes
one $ between (04/00) (07/14) -- final byte
between :: C -> C -> (C -> Bool)
between lo hi = \ x -> lo <= x && x <= hi
zeroOrMore, one ::
( Monad m
, MonadIO m
, MonadError ScanError m
, MonadState ScanState m
, MonadWriter ScanLog m
) => (C -> Bool) -> m ()
zeroOrMore p = do
mb_c <- liftIO $ hWaitLookAheadC timeout stdin
whenJust mb_c $ \ c ->
when (p c) $ do
_ <- liftIO $ hGetC stdin -- drop
tell [c]
modify $ \q -> q { buffer = buffer q ++ [c] }
zeroOrMore p
one p = do
mb_c <- liftIO $ hWaitLookAheadC timeout stdin
whenJust mb_c $ \ c -> do
if p c
then do
_ <- liftIO getChar
tell [c]
modify $ \q -> q { buffer = buffer q ++ [c] }
else do
throwError "expected one TODO"
whenJust :: Monad m => Maybe a -> (a -> m ()) -> m ()
whenJust mb f =
case mb of
Just a -> f a
Nothing -> return ()
(/) :: Int -> Int -> C
c / r = C c r
data C = C { column :: Int, row :: Int }
deriving (Eq)
instance Show C where
show C{..} =
(padl 2 '0' $ show column) ++ "/" ++ (padl 2 '0' $ show row)
where
padl n c s
| length s < n = padl n c (c : s)
| otherwise = s
instance Ord C where
compare (C c1 r1) (C c2 r2) =
case compare c1 c2 of
EQ -> compare r1 r2
x -> x
fromChar :: Char -> C
fromChar c = let i = ord c in C ((shift i (-4)) .&. 0xf) (i .&. 0xf)
toChar :: C -> Char
toChar (C col row) = chr $ (shift col 4) .|. row
--
hGetC :: Handle -> IO C
hGetC h = hGetChar h >>= return . fromChar
hWaitGetChar :: Int -> Handle -> IO (Maybe Char)
hWaitGetChar t h = do
ready <- hWaitForInput h t
if ready
then hGetChar h >>= return . Just
else return Nothing
hWaitGetC :: Int -> Handle -> IO (Maybe C)
hWaitGetC t h = do
mb_ch <- hWaitGetChar t h
case mb_ch of
Nothing -> return Nothing
Just ch -> return $ Just $ fromChar $ ch
hWaitLookAheadC :: Int -> Handle -> IO (Maybe C)
hWaitLookAheadC t h = do
ready <- hWaitForInput h t
if ready
then hLookAhead h >>= return . Just . fromChar
else return Nothing
|
