From: Ilya Lopatkin <uriel@...>
Date: 2010-02-04T19:33:18+09:00
Subject: Where is the magic?

I'm learning Ruby and have found some interesting behaviour which I
cann't understand myself yet.
Here's some code and the output:
class Foo
  def self.new(*args)
    obj = super
    yield
    obj
  end
end

Foo.new do
  p self
end

Struct.new("Foo", :foo, :bar) do
  p self
end

=> main
=> Struct::Foo

The first output is quite understandable because self is bounded to the
top-level class of the file and is sent to the closure.
But in the second line it seems that scope of self has been changed
somehow.
I've had a fast look on the source file struct.c and haven't found
something special in the new method.
The same thing can also be found in the QtRuby bindings:
require 'Qt4'

Qt::Application.new(ARGV) do
    Qt::Widget.new do

        self.window_title = 'Hello QtRuby v1.0'
        resize(200, 100)

        button = Qt::PushButton.new('Quit') do
            connect(SIGNAL :clicked) { Qt::Application.instance.quit }
        end

        label = Qt::Label.new('<big>Hello Qt in the Ruby way!</big>')

        self.layout = Qt::VBoxLayout.new do
            add_widget(label, 0, Qt::AlignCenter)
            add_widget(button, 0, Qt::AlignRight)
        end

        show
    end

    exec
end

Please, could anybody explain me how does this work. Links will do too.
:)
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