d_o_s

# File lib/rexml/xpath_parser.rb, line 477
    def d_o_s( p, ns, r )
      nt = nil
      ns.each_index do |i|
        n = ns[i]
        x = expr( p.dclone, [ n ] )
        nt = n.node_type
        d_o_s( p, n.children, x ) if nt == :element or nt == :document and n.children.size > 0
        r.concat(x) if x.size > 0
      end
    end