You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: bases.rs
    path of file: ./repos/tao-of-rust-codes/src/ch08
    
    the code of the file until where you have to start completion: /// # 字符串编码
///
/// Base usage: 从Unicod
    
/// fn main() {
///     let tao = '道';
///     let tao_u32 = tao as u32;
///     assert_eq!(36947, tao_u32);
///     println!("U+{:x}", tao_u32); // U+9053
///     println!("{}", tao.escape_unicode());  //\u{9053}
///     assert_eq!(char::from(65), 'A');
///     assert_eq!(std::char::from_u32(0x9053), Some('道'));
///     assert_eq!(std::char::from_u32(36947), Some('道'));
///     assert_eq!(std::char::from_u32(12901010101), None); // 该数字并不是一个有效的Unicode标量值
/// }