/// <summary>
/// Returns the elements within the given elements (using depth-first
/// pre-order traversal) that match the selectors with the given scope.
/// </summary>
/// <param name="selector">A selector object.</param>
/// <param name="elements">The elements to take as source.</param>
/// <param name="scope">The element to take as scope.</param>
/// <returns>The collection containing the resulting elements.</returns>
public static IHtmlCollection <IElement> MatchAll(this ISelector selector, IEnumerable <IElement> elements, IElement?scope)
{
var result = new List <IElement>();
selector.MatchAll(elements, scope, result);
return(new HtmlCollection <IElement>(result));
}