gtk2hs simplest drag and drop test

dnd.hs

-- 
-- drag and drop test gist
-- 
-- created by D.Wagner
-- 

import Control.Monad.IO.Class
import Graphics.UI.Gtk 

main = do 
  initGUI
  w <- windowNew
  l <- labelNew $ Just "drag here lol" 
  onDestroy w mainQuit 
  containerAdd w l 
  dragDestSet w [DestDefaultMotion, DestDefaultDrop] [ActionCopy]
  dragDestAddTextTargets w 
  w `on` dragDataReceived $ \dc pos id ts -> do 
    s <- selectionDataGetText
    liftIO . putStrLn $ case s of 
      Nothing -> "didn't understand the drop" 
      Just s -> "understood. here it is : <" ++ s ++ ">"
  widgetShowAll w 
  mainGUI

Copied from http://stackoverflow.com/questions/10966397/could-someone-explain-gtk2hs-drag-and-drop-to-me-the-listdnd-hs-demo-just-isnt