# Function nom::bytes::streaming::take_while1

source · [−]

    pub fn take_while1<F, Input, Error: ParseError<Input>>(
        cond: F
    ) -> impl Fn(Input) -> IResult<Input, Input, Error> where
        Input: InputTakeAtPosition,
        F: Fn(<Input as InputTakeAtPosition>::Item) -> bool,

Expand description

Returns the longest (at least 1) input slice that matches the predicate.

The parser will return the longest slice that matches the given predicate (a function that takes the input and returns a bool).

It will return an `Err(Err::Error((_, ErrorKind::TakeWhile1)))` if the pattern wasn’t met.

## Streaming Specific

Streaming version will return a `Err::Incomplete(Needed::new(1))` or if the pattern reaches the end of the input.

## Example

    use nom::bytes::streaming::take_while1;
    use nom::character::is_alphabetic;

    fn alpha(s: &[u8]) -> IResult<&[u8], &[u8]> {
      take_while1(is_alphabetic)(s)
    }

    assert_eq!(alpha(b"latin123"), Ok((&b"123"[..], &b"latin"[..])));
    assert_eq!(alpha(b"latin"), Err(Err::Incomplete(Needed::new(1))));
    assert_eq!(alpha(b"12345"), Err(Err::Error(Error::new(&b"12345"[..], ErrorKind::TakeWhile1))));