pub fn digit<Input>() -> Digit<Input> where
<Input as StreamOnce>::Error: ParseError<<Input as StreamOnce>::Token, <Input as StreamOnce>::Range, <Input as StreamOnce>::Position>,
Input: Stream,
Input: Stream<Token = char>,
Expand description
Parses a base-10 digit.
use combine::Parser;
use combine::parser::char::digit;
assert_eq!(digit().parse("9"), Ok(('9', "")));
assert!(digit().parse("A").is_err());