attr_reader and attr_writer on class instance

gistfile1.rb

class Magic

	def property types, method_name, property_name = nil
		property_name = method_name if property_name.nil?
	
		# reader
		self.class.send :define_method, method_name do
			value = read_value property_name
			raise unless types.any? do |type|
				value.is_a? type
			end
			value
		end
	
		# writer
		self.class.send :define_method, method_name + '=' do |value|
			raise unless types.any? do |type|
				value.is_a? type
			end
			change_value property_name, value
		end
	end

	property [String, Integer], :online_mode

end