Rust Programming By Example

Implementing the SYST command

First, let's add a new entry into the Command enum (I won't do this every time, but the steps will remain the same):

enum Command {
    Auth,
    Syst,
    Unknown(String),
}

Then, let's update the as_ref implementation:

impl AsRef<str> for Command {
    fn as_ref(&self) -> &str {
        match *self {
            Command::Auth => "AUTH",
            Command::Syst => "SYST",
            Command::Unknown(_) => "UNKN",
        }
    }
}

Finally, let's update the Command::new method:

impl Command {
    pub fn new(input: Vec<u8>) -> io::Result<Self> {
        let mut iter = input.split(|&byte| byte == b' ');
        let mut command = iter.next().expect("command in  input").to_vec(); to_uppercase(&mut command); let data = iter.next(); let command = match command.as_slice() { b"AUTH" => Command::Auth, b"SYST" ...