Method feed

crates/stdlib/src/posixsubprocess.rs:531–536

(&mut self, c: u8)

struct NonDigit;
impl IntParser {
    fn feed(&mut self, c: u8) -> Result<(), NonDigit> {
        let digit = (c as char).to_digit(10).ok_or(NonDigit)?;
        self.num *= 10;
        self.num += digit as i32;
        Ok(())
    }
}