From: "Albert L. Wagner" <alwagner@...>
Date: 2001-08-22T01:32:04+09:00
Subject: [ruby-talk:20063] Re: Ruby/Tk: procs and callbacks

You're right that widget.bind('Key-Up') {|e| aCallback(e)} is the
standard way of doing a callback in Ruby/Tk.  However, how would
you do it if you needed to reference the callback in some place
other than the widget.bind?
In the Perl/Tk book the DoWhenIdle is defined as:

$widget->DoWhenIdle(callback);

	Queues callback in the low priority idle event queue.

Then:
$widget->idleTasks;

	Flushes the low priority idle event queue.

This seemed worth a try as a means of discarding the flood of
callbacks generated by a repeating key.  However, it is probably
moot in that Ruby/Tk apparently does not have a DoWhenIdle nor a
idleTasks method.  With such poor documentation, one is left with
just poking at a black box to see what happens.  Slow going.  

The main reason for all of this is that Tk is so slow.  But, it
is also so easy to use.
Catch-22.

Kero van Gelder wrote:
> 
> > How might I name a block and then use it the widget.bind and
> > widget.DoWhenIdle, i.e.
> >
> > aProc = proc{|e| aCallback(e)}
> > <more>
> > widget.bind('Key-Up') &aProc
> > <more>
> > widget.DoWhenIdle(&aProc)
> > <more>
> > widget.idleTasks
> >
> > I have tried several variations, but can't get past the
> > widget.bind.  I must have a really wrong model of this in my
> > head.
> 
>   widget.bind('Key-Up') { |e|
>     aCallback(e)
>   }
> 
> doing it with aProc is a bit cumbersome:
> 
>   aProc = proc {
>     aCallback(e)
>   }
>   widget.bind('Key-Up') { |e|
>     aProc.call(e)
>   }
> 
> PS: what's with idle? idle means doing nothing, yet you seem to let
> the widget do something...
> 
> +--- Kero ------------------------------ kero@chello.nl ---+
> |  Don't split your mentality without thinking twice       |
> |                          Proud like a God -- Guano Apes  |
> +--- M38c ------- http://members.chello.nl/~k.vangelder ---+

-- 
"It requires wisdom to understand wisdom:
 the music is nothing if the audience is deaf."
 - Walter Lippman