/**
* @return PaccSet<PaccLRItem>
*/
private function closure(PaccSet $items)
{
if ($items->getType() !== 'PaccLRItem') {
throw new InvalidArgumentException('Bad type - expected PaccSet<LRItem>, given PaccSet<' . $items->getType() . '>.');
}
do {
$done = TRUE;
$itemscopy = clone $items;
foreach ($items as $item) {
if (!(count($item->afterDot()) >= 1 && current($item->afterDot()) instanceof PaccNonterminal)) {
continue;
}
$newitems = new PaccSet('PaccLRItem');
$beta_first = new PaccSet('integer');
if (count($item->afterDot()) > 1) {
$beta_first->add(next($item->afterDot())->first);
$beta_first->delete($this->grammar->epsilon->index);
}
if ($beta_first->isEmpty()) {
$beta_first->add($item->terminalindex);
}
$B = current($item->afterDot());
foreach ($this->grammar->productions as $production) {
if ($B->__eq($production->left)) {
foreach ($beta_first as $terminalindex) {
$newitems->add(new PaccLRItem($production, 0, $terminalindex));
}
}
}
if (!$newitems->isEmpty() && !$itemscopy->contains($newitems)) {
$itemscopy->add($newitems);
$done = FALSE;
}
}
$items = $itemscopy;
} while (!$done);
return $items;
}
