Function seq_pairs_satisfy

utils/src/misc.rs:18–36

Ensures that each sequence pair satisfy provided predicate.

(mut validate: F)

/// Ensures that each sequence pair satisfy provided predicate.
pub fn seq_pairs_satisfy<I, F>(mut validate: F) -> impl FnMut(&I) -> Option<InvalidPair<I>>
where
    I: Clone,
    F: FnMut(&I, &I) -> bool,
{
    let mut last = None;

    move |item: &I| -> Option<InvalidPair<I>> {
        if let Some((prev, _)) = last
            .replace(item.clone())
            .zip(last.as_ref())
            .filter(|(prev, cur)| !validate(prev, cur))
        {
            Some(InvalidPair(prev, item.clone()))
        } else {
            None
        }
    }
}

/// Produces a function which will check for each item to be equal previous plus `n` starting from the supplied value.
pub fn seq_inc_by_n_from<N>(