public OrderedSet <T> excluding(T element)
{
var copy = new OrderedSet <T>(this);
copy.remove(element);
return(copy);
}
public OrderedSet <T> minus(Set <T> other)
{
var result = new OrderedSet <T>(this);
foreach (T element in other)
{
result.remove(element);
}
return(result);
}
public virtual OrderedSet <T> append(T item)
{
var copy = new OrderedSet <T>(this);
if (this.Contains(item))
{
copy.remove(item);
}
copy.add(item);
return(copy);
}