# File temp/parsers/xpathparser.rb, line 91
      def expand( path )
        path = path.kind_of?(String) ? parse( path ) : path
        string = ""
        document = false
        while path.size > 0
          op = path.shift
          case op
          when :node
            string << "node()"
          when :attribute, :child, :following, :following_sibling, 
                :ancestor, :ancestor_or_self, :descendant, :descendant_or_self,
                :namespace, :preceding, :preceding_sibling, :self, :parent
            string << "/" unless string.size == 0
            string << op.to_s.tr("_", "-")
            string << "::"
          when :any
            string << "*"
          when :qname
            prefix = path.shift
            name = path.shift
            string << prefix+":" if prefix.size > 0
            string << name
          when :predicate
            string << '['
            string << predicate_to_string( path.shift ) { |x| expand(x) }
            string << ']'
          when :document
            document = true
          else
            string << "/" unless string.size == 0
            string << "UNKNOWN("
            string << op.inspect
            string << ")"
          end
        end
        string = "/"+string if document
        return string
      end