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liuser666
V2EX    Rust

rust 为什么用 Trait 需要手动引入 trait?

  •  1
     
  •   liuser666 2023-02-0 18:19:26 +08:00 2592 次点击
    这是一个创建于 979 天前的主题,其中的信息可能已经有所发展或是发生改变。

    use std::net::TcpListener; use std::io::{Read,Write};

    fn main(){ let listener = TcpListener::bind("127.0.0.1:4000").unwrap(); println!("Running on port 4000....");

    // let result = listener.accept().unwrap(); for stream in listener.incoming(){ let mut stream = stream.unwrap(); println!("connection established"); let mut buffer = [0; 1024]; stream.read(&mut buffer).unwrap(); } 

    } 为什么非要 use std::io::{Read,Write};显式地引入 Trait 呢? impl trait Read 的代码不是在 TcpListener 里已经有了吗?

    4 条回复    2023-06-13 12:29:58 +08:00
    serco
        1
    serco  
       2023-02-04 18:32:33 +08:00   1
    不同的 trait 可以定义同名 method ,所以需要引入
    beloved70020
        2
    beloved70020  
       2023-02-04 19:42:51 +08:00 via Android
    因为你也可以在自己的库里为其实现自己的 Read
    RiverRay
        3
    RiverRay  
       2023-02-05 11:10:52 +08:00   1
    The reasoning for this is that multiple traits can define methods with the same name/signature.If this rule was not in place and there were multiple traits defining get for Read,

    Except for fully qualifying the method call, but that would also require you to import the trait!
    NetLauu
        4
    NetLauu  
       2023-06-13 12:29:58 +08:00
    the
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