Minimal example of handling escape characters.

main.rs

fn main() {
    for arg in std::env::args().skip(1) {
        println!("{}", unescape(arg.as_ref()));
    }
}

/// Takes a string and replaces escape sequences with the characters they represent.
fn unescape(data: &str) -> String {
    let mut result = String::with_capacity(data.len());
    let mut iterator = data.chars();
    while let Some(c) = iterator.next() {
        // Push character and continue if it's not the start of an escape sequence.
        if c != '\\' {
            result.push(c);
            continue;
        }

        // Otherwise, match the next char.
        if let Some(next) = iterator.next() {
            let escaped = match next {
                '\'' => Some('\''),
                '\"' => Some('\"'),
                'n' => Some('\n'),
                'r' => Some('\r'),
                't' => Some('\t'),
                '0' => Some('\0'),
                _ => None,
            };

            if let Some(escaped) = escaped {
                // Push the escaped char instead.
                result.push(escaped);
            } else {
                // Just push unrecognized escape sequences
                result.push(c);
                result.push(next);
            }
        } else {
            result.push(c);
        }
    }

    result
}