public HeadTailList(T head)
{
_hasHead = true;
_head = head;
_tail = null;
Count = 1;
}
public HeadTailList(T head, HeadTailList <T> tail)
{
_hasHead = true;
_head = head;
_tail =
tail == null || tail.IsEmpty
? null
: tail;
Count = 1 + (tail?.Count ?? 0);
}
private static T[] ToArray(HeadTailList <T> list, T[] array, int currentIndex)
{
if (!list._hasHead)
{
return(array);
}
array[currentIndex] = list._head;
if (!(list._tail?._hasHead ?? false))
{
return(array);
}
return(ToArray(list._tail, array, currentIndex + 1));
}
private static T GetItem(HeadTailList <T> list, int currentIndex, int index)
{
var head =
list._hasHead
? list._head
: throw new ArgumentOutOfRangeException(nameof(index), index, "Argument is out of range.");
if (currentIndex == index)
{
return(head);
}
var tail =
list._tail?._hasHead ?? false
? list._tail
: throw new ArgumentOutOfRangeException(nameof(index), index, "Argument is out of range.");
return(GetItem(list._tail, currentIndex + 1, index));
}
public void Deconstruct(out T head, out HeadTailList <T> tail)
{
head = Head;
tail = Tail;
}
public HeadTailListEnumerator(HeadTailList <T> list)
{
_original = list;
_current = null;
}
