Implement a native readLine module

Z-IO.cabal

@@ -107,6 +107,7 @@ library
     Z.IO.Resource
     Z.IO.StdStream
     Z.IO.StdStream.Ansi
+    Z.IO.StdStream.ReadLine
     Z.IO.Time
     Z.IO.UV.Errno
     Z.IO.UV.FFI
@@ -124,7 +125,7 @@ library
     , time                  >=1.9   && <2.0
     , unix-time             >=0.4.7 && <0.5
     , unordered-containers  ^>=0.2
-    , Z-Data                >=0.8.1 && <0.9
+    , Z-Data                
 
   default-language:   Haskell2010
   default-extensions:

Z/IO/StdStream.hs

@@ -252,13 +252,13 @@ withRawStdin = bracket_ (setStdinTTYMode TTY_MODE_RAW) (setStdinTTYMode TTY_MODE
 
 -- | Get terminal's output window size in (width, height) format,
 -- return (-1, -1) if stdout is not connected to TTY.
-getStdoutWinSize :: HasCallStack => IO (CInt, CInt)
+getStdoutWinSize :: HasCallStack => IO (Int, Int)
 getStdoutWinSize = case stdout of
     StdStream True hdl _ uvm ->
         withUVManager' uvm $ do
-            (w, (h, ())) <- allocPrimUnsafe $ \ w ->
-                allocPrimUnsafe $ \ h -> throwUVIfMinus_ $ uv_tty_get_winsize hdl w h
-            return (w, h)
+            (w, (h, ())) <- allocPrimUnsafe @CInt $ \ w ->
+                allocPrimUnsafe @CInt $ \ h -> throwUVIfMinus_ $ uv_tty_get_winsize hdl w h
+            return (fromIntegral w, fromIntegral h)
     _ -> return (-1, -1)
 
 --------------------------------------------------------------------------------

Z/IO/StdStream/Ansi.hs

@@ -46,6 +46,7 @@ module Z.IO.StdStream.Ansi
     csi, sgr, colorToCode
   ) where
 
+import Control.Monad
 import qualified Z.Data.Builder as B
 import qualified Z.Data.Parser as P
 import qualified Z.Data.Text    as T
@@ -69,26 +70,25 @@ cursorUp, cursorDown, cursorForward, cursorBackward
   -> B.Builder ()
 cursorDownLine, cursorUpLine :: Int -- ^ Number of lines to move
                                      -> B.Builder ()
-cursorUp n       = csi [n] (B.char8 'A')
-cursorDown n     = csi [n] (B.char8 'B')
-cursorForward n  = csi [n] (B.char8 'C')
-cursorBackward n = csi [n] (B.char8 'D')
-cursorDownLine n = csi [n] (B.char8 'E')
-cursorUpLine n   = csi [n] (B.char8 'F')
-
-getCursorPosition :: IO (Int, Int)
-getCursorPosition = do
-    withRawStdin . withMVar stdinBuf $ \ i -> do
-        clearInputBuffer i
-        putStd (csi [] "6n")
-        readParser (do
-            P.word8 ESC
-            P.word8 BRACKET_LEFT
-            !n <- P.int
-            P.word8 SEMICOLON
-            !m <- P.int
-            P.word8 LETTER_R
-            return (m, n)) i
+cursorUp n       = when (n > 0) $ csi [n] (B.char8 'A')
+cursorDown n     = when (n > 0) $ csi [n] (B.char8 'B')
+cursorForward n  = when (n > 0) $ csi [n] (B.char8 'C')
+cursorBackward n = when (n > 0) $ csi [n] (B.char8 'D')
+cursorDownLine n = when (n > 0) $ csi [n] (B.char8 'E')
+cursorUpLine n   = when (n > 0) $ csi [n] (B.char8 'F')
+
+getCursorPosition :: BufferedInput -> IO (Int, Int)
+getCursorPosition i = do
+    clearInputBuffer i
+    putStd (csi [] "6n")
+    readParser (do
+        P.word8 ESC
+        P.word8 BRACKET_LEFT
+        !n <- P.int
+        P.word8 SEMICOLON
+        !m <- P.int
+        P.word8 LETTER_R
+        return (m, n)) i
 
 -- | Code to move the cursor to the specified column. The column numbering is
 -- 1-based (that is, the left-most column is numbered 1).
@@ -119,8 +119,8 @@ clearLine                        = csi [2] (B.char8 'K')
 
 scrollPageUp, scrollPageDown :: Int -- ^ Number of lines to scroll by
                              -> B.Builder()
-scrollPageUp n   = csi [n] (B.char8 'S')
-scrollPageDown n = csi [n] (B.char8 'T')
+scrollPageUp n   = when (n > 0) $ csi [n] (B.char8 'S')
+scrollPageDown n = when (n > 0) $ csi [n] (B.char8 'T')
 
 hideCursor, showCursor :: B.Builder ()
 hideCursor = csi [] "?25l"