From c25deb591e8d271c35ade5ac80f8f4b766e839b8 Mon Sep 17 00:00:00 2001
From: tv <tv@shackspace.de>
Date: Mon, 28 Jul 2014 22:08:13 +0200
Subject: Scanner: initial commit (not activated)

---
 src/Scanner.hs | 258 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 258 insertions(+)
 create mode 100644 src/Scanner.hs

diff --git a/src/Scanner.hs b/src/Scanner.hs
new file mode 100644
index 0000000..ba81abb
--- /dev/null
+++ b/src/Scanner.hs
@@ -0,0 +1,258 @@
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE FlexibleContexts #-}
+module Scanner where
+
+import Control.Monad (forever)
+import System.IO
+
+import Data.Ord
+import Data.Bits
+import Data.Char
+
+import Prelude hiding ((/))
+
+import Control.Applicative
+import Control.Monad.Error
+import Control.Monad.State
+import Control.Monad.Writer
+
+import Data.Time.Clock
+
+
+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
+    , buffer :: [C]
+    }
+
+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 = 1
+
+
+main :: IO ()
+main = do
+    hSetEcho stdin False
+    hSetBuffering stdin NoBuffering
+    forever $ do
+
+        _ <- hLookAhead stdin -- wait for input
+
+        t0 <- getCurrentTime
+        ((res, s), _) <- runScanner scan
+        t1 <- getCurrentTime
+
+        putStrLn $ "====> \ESC[32;1m" ++ show s ++ "\ESC[m in " ++
+                    (show $ diffUTCTime t1 t0)
+                    ++ ": \"\ESC[35m" ++ (concat $ map (colorize . toChar) s)
+                    ++ "\ESC[m\""
+        case res of
+            Left msg -> putStrLn $ "  error: " ++ msg
+            Right _ -> return ()
+
+
+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 ()
+
+
+
+
+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
+
+
+
+
+
+colorize :: Char -> String
+colorize c
+  | isPrint c = [c]
+  | otherwise = "\ESC[1m" ++ (showLitChar c "") ++ "\ESC[22m"
+
+
+
+
+
+--
+hWaitGetChar t h = do
+    ready <- hWaitForInput h t
+    if ready
+        then hGetChar h >>= return . Just
+        else return Nothing
+
+hGetC h = hGetChar h >>= return . fromChar
+hWaitGetC t h = do
+    mb_ch <- hWaitGetChar t h
+    case mb_ch of
+        Nothing -> return Nothing
+        Just ch -> return $ Just $ fromChar $ ch
+
+hWaitLookAheadC t h = do
+    ready <- hWaitForInput h t
+    if ready
+        then hLookAhead h >>= return . Just . fromChar
+        else return Nothing
+
+
+-- CRUFT
+--expect cx ca =
+--    when (cx /= ca) $ 
+--        throwError $ "expected: " ++ (show cx) ++ ", got: " ++ (show ca)
+--
+--
+--
+--    expect (01/11) c
+--
+--    c <- (liftIO getChar) >>= return . fromChar
+--
+--    tell [c]
+--
+--    expect (05/11) c
+
+    --liftIO $ putStrLn $ (show c) ++ " -> " ++ (show s)
+
+
-- 
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