public override IValue Subtract(Context context, IValue value)
{
if (value is ListValue)
{
SetValue set = new SetValue(this.ItemType);
value = set.Add(context, value);
}
if (value is SetValue)
{
HashSet <IValue> excluded = ((SetValue)value).items;
HashSet <IValue> values = new HashSet <IValue>();
foreach (IValue item in items)
{
if (!excluded.Contains(item))
{
values.Add(item);
}
}
return(new SetValue(ItemType, values));
}
else
{
throw new SyntaxError("Illegal : List - " + value.GetType().Name);
}
}
public IValue Subtract(Context context, IValue value)
{
if (value is ListValue)
{
SetValue set = new SetValue(this.ItemType);
value = set.Add(context, value);
}
if (value is SetValue)
{
ListValue result = new ListValue(ItemType);
result.AddRange(this);
result.RemoveAll(item => ((SetValue)value).HasItem(context, item));
return(result);
}
else
{
throw new SyntaxError("Illegal : List - " + value.GetType().Name);
}
}
