# File htree/traverse.rb, line 138
    def each_hyperlink_uri(base_uri=nil) # :yields: hyperlink, uri
      base_uri = URI.parse(base_uri) if String === base_uri
      links = []
      each_hyperlink_attribute {|elem, attr, hyperlink|
        if %r{\{http://www.w3.org/1999/xhtml\}(?:base)\z}i =~ elem.name
          base_uri = URI.parse(hyperlink.to_s)
        else
          links << hyperlink
        end
      }
      if base_uri
        links.each {|hyperlink| yield hyperlink, base_uri + hyperlink.to_s }
      else
        links.each {|hyperlink| yield hyperlink, URI.parse(hyperlink.to_s) }
      end
    end