// 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"(?mx)^(?!.*THIRD.*(?:SECOND|FIRST)) # SECOND or FIRST cannot appear after THIRD
(?!.*SECOND.*FIRST) # SECOND cannot appear before FIRST
(?!.*THIRD.*THIRD)
(?!.*SECOND.*SECOND)
(?!.*FIRST.*FIRST)
(?=.*FIRST).*").unwrap();
let string = "FIRST
FIRST SECOND
FIRST SECOND THIRD
SECOND THIRD FIRST
SECOND FIRST THIRD
THIRD SECOND FIRST
FIRST FIRST
SECOND FIRST THIRD
FIRST SECOND SECOND
The word FIRST is mandatory ; it can appear only once
The word SECOND can appear zero or one time
The word THIRD can appear zero or one time
Order: FIRST, then SECOND then THIRD";
// result will be an iterator over tuples containing the start and end indices for each match in the string
let result = regex.captures_iter(string);
for mat in result {
println!("{:?}", mat);
}
}
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/