From: matz@... (Yukihiro Matsumoto)
Date: 2002-08-15T23:53:23+09:00
Subject: Re: ruby/tk internals...?

Hi,

In message "Re: ruby/tk internals...?"
    on 02/08/15, Ferenc Engard <engard@all.hu> writes:

|> The argument string is evaluated under the context created for each
|> invocation of "ruby" command.
|
|And what is this context? Is it a plain new Object for every invocation,
|i.e. I can use only global variables and methods defined in main, cannot
|define new methods or classes, etc.?

It is a plain new "scope" for every invocation.  You can define new
methods or classes, but I do recommend you to keep the argument to the
"ruby" command small.

|How does it work with GTK?

The context is saved in the Proc object.  It is same for Ruby/Tk, for
example,

  require "tk"

  TkButton.new(nil, 
               'text' => 'hello',
               'command' => proc{print "hello\n"}).pack('fill'=>'x')
  TkButton.new(nil,
               'text' => 'quit',
               'command' => 'exit').pack('fill'=>'x')

The callback (print "hello\n") is executed under the current context.
"ruby" command is used to trigger the callback.

							matz.