lib/gtfs_reader/configuration.rb
def parameter(*names)
      names.each do |name|
        define_singleton_method(name) do |*values|
          if (value = values.first)
            instance_variable_set("@#{name}", value)
          else
            instance_variable_get("@#{name}")
          end
        end
      end
    end
def parameter(*names)
      names.each do |name|
        define_singleton_method(name) do |*values|
          if (value = values.first)
            instance_variable_set("@#{name}", value)
          else
            instance_variable_get("@#{name}")
          end
        end
      end
    end
Creates simple configuration parameters which may be set by the user
 @param names [Array<Symbol>] the names of the parameters to create