Suckerfish

If you want to add a "suckerfish dropdown" to your views, this is a starting point.

In a controller, add the following. This will get you a one level dropdown:

class AnyController < ActionController::Base
  before_action :set_categories
  helper_method :suckerfish

  def set_categories
    @categories = Category.where(ancestry: nil)
  end

  def suckerfish(node)
    fuc = lambda do |nodes|
      return "" if nodes.empty?
      return "<ul>" +
        nodes.inject("") do |string, (node, children)|
          string + "<li rel='#{node.id}'>" +
          "<a href=#{polymorphic_url(node)}>#{node.name}</a>" +
          fuc.call(children) +
          "</li>"
        end +
        "</ul>"
    end
    fuc.call(node.descendants.arrange)
  end
end

And in your view, add something like this. It will get you close to the markup needed in those suckerfish examples:

<ul id="nav-categories">
  <% @categories.each do |node| %>
    <li>
      <%= link_to node.name, node %>
      <%= suckerfish(node).html_safe %>
    </li>
  <% end %>
</ul>

For Rails 3 & 4, if you want to use this method in views as a helper_method :suckerfish add view_context before link_to:

  view_context.link_to(node.name, node.path) +  # don't forget to set your path