///<summary>A modified copy with more incremental rebuilding performed (in order to eventually discard garbage).</summary>
private DropCollectStack <T> IterRebuild()
{
return
// iteratively transfer from _itemsTraverser to _partialReversedItems
(!_itemsTraverser.IsEmpty ? With(
itemsTraverser: _itemsTraverser.Pop(),
partialReversedItems: _partialReversedItems.Push(_itemsTraverser.Peek))
// then iteratively transfer from _partialReversedItems to _partialRebuiltItems
: !_partialReversedItems.IsEmpty ? With(
partialReversedItems: _partialReversedItems.Pop(),
partialRebuiltItems: _partialRebuiltItems.Push(_partialReversedItems.Peek()))
// then, if there are new items, place them in _itemsTraverser for iterative transfer
: _items.Count > _partialRebuiltItems.Count ? With(
itemsTraverser: _items.Pop().KeepOnly(_items.Count - _partialRebuiltItems.Count - 1),
partialReversedItems: _partialReversedItems.Push(_items.Peek))
// if there were no new items, then we've finished rebuilding and can use the result
: new DropCollectStack <T>(_partialRebuiltItems, _partialRebuiltItems));
}
///<summary>A modified copy with some more rebuilding work done.</summary>
private Queue <T> IterRebuild()
{
switch (_incomingTraverser.Count)
{
case 0: return(With(ready: _partialOutgoing, reStack: DropStack <T> .Empty, reFeed: _incoming.UnderlyingStack));
case 1: return(With(ready: _partialOutgoing.Push(_incomingTraverser.Peek), reStack: DropStack <T> .Empty, reFeed: _incoming.UnderlyingStack));
default: return(With(reStack: _partialOutgoing.Push(_incomingTraverser.Peek), reFeed: _incomingTraverser.Pop()));
}
}