Replace '\u{...}' with '<char>'

replace_char_codes.rs

use std::convert::TryFrom;
use std::io::{stdin, BufRead};
use std::process::exit;

use regex::{Captures, Regex};

fn main() {
    let re = Regex::new(r"'\\u\{([0-9A-Fa-f]+)\}'").unwrap();

    let stdin = stdin();
    for line in stdin.lock().lines() {
        let line = line.unwrap();
        let line = re.replace_all(&line, |captures: &Captures| {
            let num = captures.get(1).unwrap().as_str();

            let i = match u32::from_str_radix(num, 16) {
                Err(err) => {
                    eprintln!("Unable to parse {:?}: {}", num, err);
                    exit(1);
                }
                Ok(i) => i,
            };

            format!("{:?}", char::try_from(i).unwrap())
        });
        println!("{}", line);
    }
}