[3.1.1 类型定义](3.1.1%E7%B1%BB%E5%9E%8B%E5%AE%9A%E4%B9%89.md) [3.1.2 类型格式化](3.1.2%E7%B1%BB%E5%9E%8B%E6%A0%BC%E5%BC%8F%E5%8C%96.md)