Láďa má velkou hlavu

C:\JarmileHynkuVilemino\WWW\>ruby lada.rb
#<Lada @hlava=#<Hlava @jako=#<Pytel @od=#<Banan>>, @velikost="Velka">>

Kód

class Pisnicka
  def self.zpivej
    lada = Lada.new
    yield lada
    p lada
  end
end

class Lada
  attr_accessor :hlava
end

class Hlava
  def initialize( config )
    config.each_pair do |name, value|
      self.instance_variable_set "@#{ name }".to_sym, value
    end
  end
end

class Banan
end

class Pytel
  def initialize( config )
    @od = config[:od]
  end
end

Pisnicka.zpivej do |lada|
  lada.hlava = Hlava.new :velikost => 'Velka', :jako => Pytel.new( :od => Banan.new )
end