email.zh.md

电子邮件地址提取登录名，并验证

[![regex-badge]][regex] [![lazy_static-badge]][lazy_static] [![cat-text-processing-badge]][cat-text-processing]

验证电子邮件地址的格式是否正确，并提取@符号之前的所有内容。

#[macro_use]
extern crate lazy_static;
extern crate regex;

use regex::Regex;

fn extract_login(input: &str) -> Option<&str> {
    lazy_static! {
        static ref RE: Regex = Regex::new(r"(?x)
            ^(?P<login>[^@\s]+)@
            ([[:word:]]+\.)*
            [[:word:]]+$
            ").unwrap();
    }
    RE.captures(input).and_then(|cap| {
        cap.name("login").map(|login| login.as_str())
    })
}

fn main() {
    assert_eq!(extract_login(r"I❤[email protected]"), Some(r"I❤email"));
    assert_eq!(
        extract_login(r"[email protected]"),
        Some(r"sdf+sdsfsd.as.sdsd")
    );
    assert_eq!(extract_login(r"More@Than@[email protected]"), None);
    assert_eq!(extract_login(r"Not an email@email"), None);
}