/// <summary>
/// Flatten <paramref name="node"/> to key lines.
/// </summary>
/// <param name="node"></param>
/// <param name="lineAppender">(optional) overriding appender</param>
/// <returns></returns>
public static IEnumerable <ILine> ToLines(this ILineTree node, ILineFactory lineAppender = default)
{
Queue <(ILineTree, ILine)> queue = new Queue <(ILineTree, ILine)>();
queue.Enqueue((node, node.Key));
while (queue.Count > 0)
{
// Next element
(ILineTree, ILine)current = queue.Dequeue();
// Yield values
if (current.Item2 != null && current.Item1.HasValues)
{
foreach (ILine value in current.Item1.Values)
{
yield return(current.Item2.Concat(value));
}
}
// Enqueue children
if (current.Item1.HasChildren)
{
foreach (ILineTree child in current.Item1.Children)
{
if (lineAppender != null)
{
ILine childKey = lineAppender.Concat(lineAppender.Clone(current.Item2), child.Key);
queue.Enqueue((child, childKey));
}
else
{
ILine childKey = current.Item2 == null ? child.Key : current.Item2.Concat(child.Key);
queue.Enqueue((child, childKey));
}
}
}
}
}