# File control/SetupAlias/SetupAlias.rb, line 45
  def init_alias
    if (@pos < 0 || @alias_list.length < @pos) then
      raise 'out of range'
    end
    if (@pos == @alias_list.length) then
      @alias_list.push({ 'alias_path' => nil,
                         'orig_path' => nil,
                         'virtual_host' => nil
                       })
    end
    @alias = @alias_list[@pos]
    nil
  end