/**
* Returns the iterator for the next sequence, or NULL if the end of
* the outer iterator has been reached.
*
* @return php.Iterator
*/
protected function sequence()
{
while ($this->it->valid()) {
$value = $this->it->current();
$seq = $value instanceof Sequence ? $value->getIterator() : Sequence::of($value)->getIterator();
$seq->rewind();
if ($seq->valid()) {
return $seq;
} else {
$this->it->next();
}
}
return null;
}
