// include the latest version of the regex crate in your Cargo.toml
extern crate regex;
use regex::Regex;
fn main() {
let regex = Regex::new(r"^(?!$)M{0,2}(?:M(?=CM(?:XC)?(?:IX)?$))?(?:C(?=M[^CD]*(?:XC)?[^CD]*$))?M?(?:C(?=D[^C]*(?:XC)?[^C]*$))?D?C{0,2}(?:C(?=XC(?:IX)?$))?(?:X(?=C[^X]*(?:IX)?[^X]*$)(?!.*L))?C?(?:X(?=L[^X]*(?:IX)?[^X]*$))?L?X{0,2}(?:X(?=IX$))?(?:I(?=[XV]$))?X?V?I{0,3}$").unwrap();
let string = "I
II
XXIX
XXXVIII
IV
XIV
XXXIX
LXXX
XL
CCCXCIX
DCCCXCIX
CDXC
MMMCMIX
MMMCMXCIX
MMMCM
(MMMCM)CMI
(I)";
// result will be a tuple containing the start and end indices for the first match in the string
let result = regex.captures(string);
let (start, end) = match result {
Some((s, e)) => (s, e),
None => {
// ...
}
};
println!("{}", &string[start, end]);
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Rust, please visit: https://docs.rs/regex/latest/regex/