# File lib/html.rb, line 19
  def render_template template_name, extra_binding={}
    if extra_binding.empty?
      @@erbs ||= {}
      @@erbs[template_name] ||= ERB.new IO.read(File.join(@template_dir, "#{template_name}.rhtml"))
      @@erbs[template_name].result binding
    else
      clone_for_binding(extra_binding).render_template template_name
    end
  end