Function parse_num

src/parser.rs:188–192

Next up is number parsing. We're keeping it simple here by accepting any number (> 1) of digits but ending the program if it doesn't fit into an i32.

(i: &'a str)

/// Next up is number parsing. We're keeping it simple here by accepting any number (> 1)
/// of digits but ending the program if it doesn't fit into an i32.
fn parse_num<'a>(i: &'a str) -> IResult<&'a str, Atom, VerboseError<&'a str>> {
    map_res(digit1, |digit_str: &str| {
      digit_str.parse::<usize>().map(Wrapping).map(Atom::Num)
    })(i)
}

/// Now we take all these simple parsers and connect them.
/// We can now parse half of our language!