err

用于与 FromError 一起工作的宏集合，其中最有用的是 error_enum!

#[macro_use]
extern crate err;

error_enum! {
	enum MyError {
		bare SomethingCustom(&'static str),
		auto Io(std::io::Error)
	}

	enum MyOtherError {
		auto MyError(MyError)
	}
}

// An all the elements marked `auto` have auto-generated FromError
// implimentations created with the assumption that they are simple wrappers
// around a type.

限制

• 不支持无参数枚举元素
• 不支持枚举元素末尾的逗号