# File control/AliasMap/AliasMap.rb, line 37
  def up
    pos = @alias[:pos]
    if (1 <= pos && pos <= @alias_list.length - 1) then
      @alias_list.swap(pos, pos - 1)
      @control.set_aliases(@alias_list)
      @alias[:pos] = pos - 1
    end

    nil
  end