Date: Sat, 22 Apr 2006 21:19:55 +0900 (JST)
Message-Id: <20060422.211955.71882695.garrigue at math.nagoya-u.ac.jp>
To: ocaml-erikd at mega-nerd.com
Cc: lablgtk at math.nagoya-u.ac.jp
Subject: Re: Setting the cursor in a text_view object
From: Jacques Garrigue <garrigue at math.nagoya-u.ac.jp>
In-Reply-To: <20060422191222.64fba4d7.ocaml-erikd at mega-nerd.com>
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	<20060422191222.64fba4d7.ocaml-erikd@mega-nerd.com>
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From: Erik de Castro Lopo <ocaml-erikd at mega-nerd.com>

> > Gdk.Window.set_cursor tview#misc#window (Gdk.Cursor.create `LEFT_PTR) ;
> 
> I suspect that the above line should actually be something like:
> 
>     Gdk.Window.set_cursor (tview#get_window `TEXT) (Gdk.Cursor.create `LEFT_PTR) ;
> 
> but this does compile due to the following error:
> 
>     This expression has type Gdk.window option but is here used with type
>       Gdk.window = [ `drawable | `gdkwindow ] Gobject.obj
> 
> and I'm not sure how to fix this. The OO aspects of Ocaml are still
> a little unclear to me.

Classical encoding of potentially null pointer.
So you just have to do

let tw =
  match tview#get_window `TEXT with Some w -> w |None -> assert false
in
Gdk.Window.set_cursor tw (Gdk.Cursor.create `LEFT_PTR)

Jacques