private function process()
{
//echo "Processing postfix notation:\n\n";
$tempStack = new Stack();
while ($token = $this->rpnNotation->dequeue()) {
if ($token instanceof Number) {
$tempStack->push($token);
} elseif ($token instanceof Operator || $token instanceof Funct) {
/** @var $token Operator|Funct */
if ($tempStack->count() < $token->numOfArgs()) {
throw new Exception(sprintf('Required %d arguments, %d given.', $token->numOfArgs(), $tempStack->count()));
}
$arg = $tempStack->popMultiple($token->numOfArgs());
$tempStack->push($token->execute(array_reverse($arg)));
}
}
return $tempStack->pop()->value;
}
