prepend_magic.rb

class Foo
  def self.method_added(method_name)
    super
    create_wrapper_for(method_name)
  end

  def self.create_wrapper_for(method)
    wrap_module.class_eval <<-RUBY
      def #{method}(*)
        p '#{method} called!'
        super
      end
    RUBY
  end

  def self.wrap_module
    @wrap_module ||= begin
      mod = Module.new
      prepend mod
      mod
    end
  end
end

class Bar < Foo
  def vc_name
    'Hello'
  end
end

class Baz < Bar
  def vc_code
    'world'
  end
end

Bar.new.vc_name
Baz.new.vc_name
Baz.new.vc_code
# "vc_name called!"
# "vc_name called!"
# "vc_code called!"