class Nokogiri::XML::Document

def tdiff(tree,&block)
  return enum_for(:tdiff,tree) unless block
  tdiff_recursive(tree,&block)
  return self
end

def tdiff_unordered(tree,&block)
  return enum_for(:tdiff_unordered,tree) unless block
  tdiff_recursive_unordered(tree,&block)
  return self
end