regexide.com/rust/src/main.rs

fn main_regex() {
    let re = regex::Regex::new(r"<!--([\s\S]*?)-->").unwrap();

    let mut str = "<!--";
    let mut _str = format!("{}{}", str, str);
    let mut rept: u32 = 1;
    for _i in 1..25 {
        _str = format!("{}{}", str, str);
        str = _str.as_str();
        rept *= 2;
    }

    for _j in 1..8 {
        let start_time = std::time::Instant::now();

        let _caps = re.captures(str);

        let elapsed_time = start_time.elapsed();
        println!("{}: {:?}", rept, elapsed_time);
        _str = format!("{}{}", str, str);
        str = _str.as_str();
        rept *= 2;
    }
}

fn main_regress() {
    let re = regress::Regex::new(r"<!--([\s\S]*?)-->").unwrap();

    let mut str = "<!--";
    let mut _str = format!("{}{}", str, str);
    let mut rept: u32 = 1;
    for _i in 1..8 {
        _str = format!("{}{}", str, str);
        str = _str.as_str();
        rept *= 2;
    }

    for _j in 1..11 {
        let start_time = std::time::Instant::now();

        let _caps = re.find(str);

        let elapsed_time = start_time.elapsed();
        println!("{}: {:?}", rept, elapsed_time);
        _str = format!("{}{}", str, str);
        str = _str.as_str();
        rept *= 2;
    }
}

fn main() {
    //main_regress();
    main_regex();
}