Function conrod_core::utils::iter_diff

pub fn iter_diff<'a, A, B>(a: A, b: B) -> Option<IterDiff<B::Item, B::IntoIter>> where
    A: IntoIterator<Item = &'a B::Item>,
    B: IntoIterator,
    B::Item: PartialEq + 'a, 

Compares every element yielded by both elems and new_elems in lock-step.

If the number of elements yielded by b is less than the number of elements yielded by a, the number of b elements yielded will be returned as IterDiff::Shorter.

If the two elements of a step differ, the index of those elements along with the remaining elements are returned as IterDiff::FirstMismatch.

If a becomes exhausted before b becomes exhausted, the remaining b elements will be returned as IterDiff::Longer.

This function is useful when comparing a non-Clone Iterator of elements to some existing collection. If there is any difference between the elements yielded by the iterator and those of the collection, a suitable IterDiff is returned so that the existing collection may be updated with the difference using elements from the very same iterator.