# File lib/iq_rdf/collection.rb, line 32
    def build_xml(xml, elements = nil, &block)
      elements ||= @elements.dup
      block.call({},
        lambda {
          xml.rdf :List do
            elements.shift.build_xml(xml) do |*args|
              xml.rdf(:first, *args)
            end
            if elements.size > 0
              build_xml(xml, elements) do |opts, block|
                xml.rdf :rest do
                  block.call
                end
              end
            else
              xml.rdf :rest, "rdf:resource" => Rdf.nil.full_uri
            end
          end
        }
      )
    end