# File lib_ctrl/rucy/params.rb, line 901
    def path=(new_path)
      case (new_path)
      when String
        if (new_path !~ %"^/") then
          raise "not allowed path: #{new_path.inspect}"
        end
      when NilClass
        # checked at saving
      else
        raise "not String: #{new_path.inspect}"
      end
      @attrs[path_tag] = new_path
    end