public static IEnumerable Partition(bool all, int size, int step, IEnumerable pad, IEnumerable seq)
{
if (size <= 0)
{
throw new LispException("Invalid size: {0}", size);
}
if (step <= 0)
{
throw new LispException("Invalid step: {0}", step);
}
// We never need more than size-1 pad elements
var source = Runtime.Append(seq, Take(size - 1, pad));
var v = new Vector();
while (source != null)
{
while (source != null && v.Count < size)
{
v.Add(Car(source));
source = Cdr(source);
}
if (all || v.Count == size)
{
yield return(AsList(v));
}
if (source != null)
{
if (step < size)
{
v.RemoveRange(0, step);
}
else if (size < step)
{
source = Runtime.Drop(step - size, source);
v.Clear();
}
else
{
v.Clear();
}
}
}
}
