/**
* Calculates the closure set for the given set of rules
*
* @param \Phparser\Rule\RulesCollection $set Set of rules
* @return array
*/
protected function _closure(RulesCollection $set)
{
$regex = implode('|', $this->variables());
$first = $this->first();
$hasChanged = true;
while ($hasChanged) {
$hasChanged = false;
foreach ($set as $rule) {
$rhs = $rule->rhs();
$result = preg_match('/\\.\\b(' . $regex . ')\\b/', $rhs, $matches);
if ($result) {
$rightSymbols = end(explode($matches[1], $rhs));
$variable = str_replace('.', '', $matches[1]);
foreach ($this->_rules as $r) {
$lhs = $r->lhs();
if ($lhs == $variable) {
$seq = trim($rightSymbols . ' ' . $rule->lookahead());
foreach ($this->_first($first, $seq) as $lookahead) {
$newRHS = '.' . $r->rhs();
$newPro = new Rule("{$variable} -> {$newRHS}");
$newPro->lookahead($lookahead);
if ($set->push($newPro)) {
$hasChanged = true;
}
}
}
}
}
}
}
return $set;
}
