From: nagai@...
Date: 2002-03-27T17:57:24+09:00
Subject: Re: Error calling Tk in a loop

Hi, 

From: <james@rubyxml.com>
Subject: Error calling Tk in a loop
Date: Wed, 27 Mar 2002 03:46:02 +0900
Message-ID: <PGEPJIFLPEPOHCKEEEIKIEDGDBAA.james@rubyxml.com>
james> class AlertBox
james>   def initialize( caption, box_text )
james>     root = TkRoot.new { title caption }
james>     TkLabel.new(root) {
james>       text  box_text
james>       pack  { padx 25 ; pady 25; side 'left' }
james>     }
james>     Tk.mainloop
james>   end
james> end

The problem is that Tk.mainloop doesn't return while the root widget 
alives. Therefore, this initialize method does not finish till the 
root widget is destroyed. If the root widget is destroyed, Tk extension 
is finished and cannot generate new widgets. 
Well, Ruby/Tk on Ruby 1.6.7 has Tk.restart method. I don't recommend, 
but it can restart Tk extension and generate new root widget on same 
Tcl/Tk interpreter. 
If your purpose is only to generate AlertBox windows, 
you should use one TkToplevel widget for one AlertBox window. 
-- 
                                  Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)