Function combine::char::oct_digit

pub fn oct_digit<I>() -> OctDigit<I> where
    I: Stream<Item = char>,
    I::Error: ParseError<I::Item, I::Range, I::Position>, 

Parses an octal digit.

use combine::Parser;
use combine::char::oct_digit;
assert_eq!(oct_digit().parse("7"), Ok(('7', "")));
assert!(oct_digit().parse("8").is_err());