Gtk2Hs/Tutorials/TreeView

I had much trouble with creating a simple selection from a list, lacking examples on the web i could find. Therefore i post here the solution I have working - it is not optimal and I would appreciate comments. I shows a simple list with four names and after clicking on one it says which one you selected. i hope it is useful for others!

module Main where

{- an example how to select from a list

   not satisfactory yet:
       - there should be a simpler way to render a simple list
       - i could not convert the model i got back to a list 
           from which to get the value
       
       - the interface offers a great number of functions 
           and it is very difficult to find which ones are 
           really needed for simple tasks
       

-}

import Graphics.UI.Gtk

import Graphics.UI.Gtk.ModelView as Model

main :: IO ()

main = do

   initGUI       -- is start
   window <- windowNew
   list <- listStoreNew ["Vince", "Jhen", "Chris", "Sharon"]
   treeview <- Model.treeViewNewWithModel list
   Model.treeViewSetHeadersVisible treeview True
           -- there should be a simpler way to render a list!
   col <- Model.treeViewColumnNew
   Model.treeViewColumnSetTitle col "colTitle"
   renderer <- Model.cellRendererTextNew
   Model.cellLayoutPackStart col renderer False
   Model.cellLayoutSetAttributes col renderer list
           $ \ind -> [Model.cellText := ind]
   Model.treeViewAppendColumn treeview col

   tree <- Model.treeViewGetSelection treeview
   Model.treeSelectionSetMode tree  SelectionSingle
   Model.onSelectionChanged tree (oneSelection list tree)

   set window [ windowDefaultWidth := 100
               , windowDefaultHeight := 200
               , containerChild := treeview
              ]
   onDestroy window mainQuit
   widgetShowAll window
   mainGUI
   return ()

oneSelection :: ListStore String -> Model.TreeSelection -> IO ()

oneSelection list tree = do

   sel <- Model.treeSelectionGetSelectedRows tree
   let s = head  (head sel)
   tree <- Model.treeSelectionGetTreeView tree
   v <- Model.listStoreGetValue list s
   putStrLn $ "selected " ++ v