Passing a block into a helper

dropdown_to.rb

  # Creates a Bootstrap dropdown
  # Ex:
  # = dropdown_to "Auctions", auctions_path do
  #   %li= link_to 'Upcoming Auctions', auctions_path
  #   %li= link_to 'Past Auctions', past_auctions_path
  #
  # Returns:
  #   <li class="dropdown">
  #    <a class="dropdown-toggle" data-toggle="dropdown" href="/auctions">
  #      <span>Auction</span>
  #      <b class="caret"></b>
  #    </a>
  #    <ul class="dropdown-menu">
  #      <li><a href="/auctions">Upcoming Auctions</a></li>
  #      <li><a href="/auctions/past">Past Auctions</a></li>
  #    </ul>
  #   </li>
  def dropdown_to(title, path, options = {},  &block)
    link_options     = options.has_key?(:link)     && options[:link].is_a?(Hash)     ? options[:link] :     {}
    dropdown_options = options.has_key?(:dropdown) && options[:dropdown].is_a?(Hash) ? options[:dropdown] : {}
    li_options       = options.has_key?(:li)       && options[:li].is_a?(Hash)       ? options[:li] :       {}

    link = content_tag(:a, { :href => path, :class => 'dropdown-toggle', :data => { :toggle => 'dropdown' } }.merge(link_options) ) do
      content_tag(:span, title).concat( content_tag(:b, '', :class => 'caret') )
    end 
    dropdown_list = content_tag(:ul, { :class => 'dropdown-menu' }.merge(dropdown_options) ) do
      capture &block if block_given?   
    end
    content_tag(:li, { :class => 'dropdown' }.merge(li_options) ) do
      link.concat(dropdown_list)
    end
  end