[Haskell-cafe] How to use dyre relaunch/restore State of Gtk2hs Object?

[Andy Stewart]

Hi all.

I try to use dyre
(http://hackage.haskell.org/packages/archive/dyre/0.7.2/doc/html/Config-Dyre.html)
to relaunch/restore State of TextView to make TextView's content can't
lost when main program reboot.

Below is source code for example:
------------------------------> source code start <------------------------------
module DyreExample where

import Graphics.UI.Gtk hiding (get)

import qualified Config.Dyre as Dyre

import Config.Dyre.Relaunch
import Config.Dyre.Compile
import System.IO
import Event 
import Test
import Data.Binary
import qualified Graphics.UI.Gtk.Gdk.Events as E

data Config = Config { message :: String, errorMsg :: Maybe String }

defaultConfig :: Config
defaultConfig = Config "Dyre Example v0.1" Nothing

showError :: Config -> String -> Config
showError cfg msg = cfg { errorMsg = Just msg }

realMain Config{message = message, errorMsg = errorMsg } = do
  initGUI

  textView <- textViewNew
  tn <- restoreTextState testName 
  tv <- restoreBinaryState textView
  putStrLn tn

  rootWindow <- windowNew
  rootWindow `onDestroy` mainQuit
  windowFullscreen rootWindow

  -- rootWindow `containerAdd` textView
  rootWindow `containerAdd` tv

  widgetShowAll rootWindow
  
  rootWindow `onKeyPress` (\event -> dyreKeyTest event textView)

  mainGUI

dyreExample = Dyre.wrapMain $ Dyre.defaultParams
    { Dyre.projectName = "Main"
    , Dyre.configDir   = Just (return "/home/andy/Projects/Haskell/dyre/")
    , Dyre.cacheDir    = Just (return "/test/Download/cache/")
    , Dyre.realMain    = realMain
    , Dyre.showError   = showError
    }
    
dyreMainParams = Dyre.defaultParams
                 { Dyre.projectName = "Main"
                 , Dyre.configDir   = Just (return "/home/andy/Projects/Haskell/dyre/")
                 , Dyre.cacheDir    = Just (return "/test/Download/cache/")
                 , Dyre.realMain    = realMain
                 , Dyre.showError   = showError
                 }

dyreTestParams = Dyre.defaultParams 
                 {Dyre.projectName = "Test"
                 ,Dyre.configDir   = Just (return "/home/andy/Projects/Haskell/dyre/")}


dyreKeyTest :: E.Event -> TextView -> IO Bool
dyreKeyTest ev textView = do
  case eventTransform ev of
    Nothing -> return False
    Just e  -> do
      let eventName = eventGetName e
      case eventName of
        "M-m" -> do
                out2 <- customCompile dyreMainParams
                putStrLn $ show out2
                relaunchWithTextState testName Nothing
                relaunchWithBinaryState textView Nothing 
                return True
        _     -> return False

-- instance Binary TextView where
--     put a = put a
--     get = get      
------------------------------> source code end   <------------------------------

On the surface, just add TextView's Binary instance can fix problem.
But TextView is Haskell binding (by gtk2hs) for C struct in GTK+
library, i wonder how to write Binary instance for TextView.

My aim is write GUI program (through gtk2hs) will keep GUI State when
main program recompile/reboot (like XMonad). 

Example, above code, i add TextView widget in Window, and type "I love
Haskell" in it, when this program recompile/reboot itself, the content
"I love Haskell" still display in TextView widget, and not empty.

So any ideas or suggestions?

Thanks!

  -- Andy