/// <summary> /// Iterates over the descendant elements for the specified markdown <see cref="Block" /> element and filters by the type {T}. /// </summary> /// <typeparam name="T">Type to use for filtering the descendants</typeparam> /// <param name="block">The markdown object.</param> /// <returns> /// An iteration over the descendant elements /// </returns> public static IEnumerable <T> Descendants <T>(this ContainerBlock block) where T : Block { // Fast-path an empty container to avoid allocating a Stack if (block.Count == 0) { yield break; } Stack <Block> stack = new Stack <Block>(); int childrenCount = block.Count; while (childrenCount-- > 0) { stack.Push(block[childrenCount]); } while (stack.Count > 0) { var subBlock = stack.Pop(); if (subBlock is T subBlockT) { yield return(subBlockT); } if (subBlock is ContainerBlock subBlockContainer) { childrenCount = subBlockContainer.Count; while (childrenCount-- > 0) { stack.Push(subBlockContainer[childrenCount]); } } } }
internal Enumerator(ContainerBlock block) { this.block = block; index = 0; current = null; }