Re: [wxhaskell-users] event objects

[Anatoly Z. <ana...@gm...>]

On 2/20/06, Robert Dockins <rob...@fa...> wrote:
>
> > There don't appear to be constructors for these object types.
> >
> > For example, KeyEvent
> > (http://wxhaskell.sourceforge.net/doc/
> > Graphics.UI.WXCore.WxcClassesAL.html#99)
> > doesn't have the expected 'keyEventCreate' funciton and PaintEvent,
> > which
> > only has a constructor, doesn't appear in the function listings at
> > all.
>

Hi!

It's not very difficult to add them though the entire Haskell part of
wxHaskell should be rebuilt then. But if you need some custom events
you can use the following hack (trick, technique...):

import Control.Concurrent.Chan
import Graphics.UI.WX
import Graphics.UI.WXCore

makeEvent :: EvtHandler a -> IO (IO (), IO () -> IO ())
makeEvent target =3D
  do
    id <- idCreate
    evt <- commandEventCreate wxEVT_COMMAND_MENU_SELECTED id
    let sender =3D evtHandlerAddPendingEvent target evt
        binder =3D evtHandlerOnMenuCommand target id
    return (sender, binder)

gui =3D do
  f <- frame [text :=3D "Some frame"]

  let newFrameEvent =3D makeEvent f
  (oneThreadReport, reactToOneThread) <- newFrameEvent
  (anotherOneReport, reactToAnotherThread) <- newFrameEvent

  reactToOneThread (putStrLn "OneThread sent event")

  dataChan <- newChan
  reactToAnotherThread $ do
    d <- readChan dataChan
    putStrLn ("Data from AnotherThread: " ++ show d)

  createOneThread oneThreadReport
  createAnotherOne anotherOneReport dataChan

Performing those report actions threads can send events.

My program worked properly only with threaded rts, possibly because
addPendingEvent performs mutex locking. I am not sure about the exact
reason, 'cause there was also some network I/O.

--
Best regards,
Tolik