# File lib/hashery/linked_list.rb, line 145
    def push(v)
      if @lookup.has_key?(v)
        n = @lookup[v]
        node_delete(n)
        node_join(@tail.prev_node,n)
        node_join(n,@tail)
      else
        n = Node.new(v,v,@tail.prev_node,@tail)
        node_join(@tail.prev_node,n)
        node_join(n,@tail)
        @lookup[v] = n
      end
      v
    end