# File lib/html5/treewalkers.rb, line 7
      def [](name)
        case name.to_s.downcase
        when 'simpletree'
          require 'html5/treewalkers/simpletree'
          SimpleTree::TreeWalker
        when 'rexml'
          require 'html5/treewalkers/rexml'
          REXML::TreeWalker
        when 'hpricot'
          require 'html5/treewalkers/hpricot'
          Hpricot::TreeWalker
        else
          raise "Unknown TreeWalker #{name}"
        end
      end