Function take_while 

pub fn take_while<I, E>(
    f: impl FnMut(I::Atom) -> bool,
    qty: impl TryInto<Repetition, Error = impl StdError>,
) -> impl Pipe<I, (I::Container,), E, I::Container>
where
    I: TakeAtom,
    Incomplete: Into<E>,

Returns the longest input that matches the predicate

If quantity condition is not attained an error is returned