From: u235321044@... (Ronald Fischer)
Date: 2006-02-27T21:18:35+09:00
Subject: Ruby/Tk: How to access surrounding class from Tk Callback?

Assume that I'm modelling a visible form, consisting of entry fields,
buttons etc., as a class:

require 'tk'
class Form
  def initialize(...)
    @foo=1234
    ...
    @root=TkRoot.new() { title "My Form" }
    action_button=TkButton.new(@root) { 
      text "Action!" 
      command {
        # Do something with @root and @foo
        puts @root.foo # DOES NOT WORK
      }
    }
    action_button.pack("side" => "right");
  end
end

The problem is with the command routine inside the action_button:
Both @root and @foo are undefined here. Obviously, the class context
is not present anymore inside this callback function.

How would one model this situation in Ruby? In C++ terms: How do
I pass the 'this' pointer of my class into the command callback
of the button?

In my case, I happen to have only one instance of the Form, so
I could use a global variable, $form, to hold a reference to my
Form object and access it via this global, but of course this
solution would be ugly beyond imagination...

Kind regards,

Ronald

 



-- 
Sent by mn-pg-p-e-b-consultant-3.com from  siemens subdomain of  com
This is a spam protected message. Please answer with reference header.
Posted via http://www.usenet-replayer.com