pub fn successors<T, F>(first: Option<T>, succ: F) -> Successors<T, F> ⓘ
Expand description
Creates an iterator which, starting from an initial item, computes each successive item from the preceding one.
This iterator stores an optional item (Option<T>
) and a successor closure (impl FnMut(&T) -> Option<T>
).
Its next
method returns the stored optional item and
if it is Some(val)
calls the stored closure on &val
to compute and store its successor.
The iterator will apply the closure successively to the stored option’s value until the option is None
.
This also means that once the stored option is None
it will remain None
,
as the closure will not be called again, so the created iterator is a FusedIterator
.
The iterator’s items will be the initial item and all of its successors as calculated by the successor closure.