tabs.rb

# This is half the implementation in the problem given to applicants...
class Tab
  attr_accessor :url, :name
  attr_reader :tabs
  
  include ActionController::UrlWriter
  
  def initialize(name=nil, url=nil, &block)
    @name, @url = name, url
    @tabs = []
    instance_eval(&block) if block_given?
  end
  
  def active?(current_url)
    current_url == url || tabs.any?{|c| c.active?(current_url)}
  end
  
  def tab(*args, &block)
    @tabs << Tab.new(*args, &block)
  end
  
  def active(current_url)
    @tabs.find{|t| t.active? current_url } || Tab.new
  end
  
  def each(&block)
    @tabs.each(&block)
  end
end