Recognizes one or more ASCII numerical characters: '0'..='9'

Complete version: Will return an error if there's not enough input data, or the whole input if no terminating token is found (a non digit character).

[Partial version][crate::_topic::partial]: Will return Err(winnow::error::ErrMode::Incomplete(_)) if there's not enough input data, or if no terminating token is found (a non digit character).

Effective Signature

Assuming you are parsing a &str [Stream]:

# use winnow::prelude::*;;
pub fn digit1<'i>(input: &mut &'i str) -> ModalResult<&'i str>
# {
#     winnow::ascii::digit1.parse_next(input)
# }

Example

# use winnow::prelude::*;
# use winnow::ascii::digit1;
fn parser<'s>(input: &mut &'s str) -> ModalResult<&'s str> {
    digit1.parse_next(input)
}

assert_eq!(parser.parse_peek("21c"), Ok(("c", "21")));
assert!(parser.parse_peek("c1").is_err());
assert!(parser.parse_peek("").is_err());

# use winnow::prelude::*;
# use winnow::{error::ErrMode, error::ContextError, error::Needed};
# use winnow::Partial;
# use winnow::ascii::digit1;
assert_eq!(digit1::<_, ErrMode<ContextError>>.parse_peek(Partial::new("21c")), Ok((Partial::new("c"), "21")));
assert!(digit1::<_, ErrMode<ContextError>>.parse_peek(Partial::new("c1")).is_err());
assert_eq!(digit1::<_, ErrMode<ContextError>>.parse_peek(Partial::new("")), Err(ErrMode::Incomplete(Needed::new(1))));

Parsing an integer

You can use digit1 in combination with Parser::try_map to parse an integer:

# use winnow::prelude::*;
# use winnow::ascii::digit1;
fn parser<'s>(input: &mut &'s str) -> ModalResult<u32> {
  digit1.try_map(str::parse).parse_next(input)
}

assert_eq!(parser.parse_peek("416"), Ok(("", 416)));
assert_eq!(parser.parse_peek("12b"), Ok(("b", 12)));
assert!(parser.parse_peek("b").is_err());