public function run()
{
$result = $this->firstOperand->run();
foreach ($this->otherOperands as $otherOperand) {
$operator = $otherOperand['operator'];
$command = $otherOperand['command'];
switch ($operator) {
case self::ADD_OPERATOR:
$result = $result + $command->run();
break;
case self::MULTIPLY_OPERATOR:
$result = $result * $command->run();
break;
case self::SUBTRACT_OPERATOR:
$result = $result - $command->run();
break;
case self::DIVIDE_OPERATOR:
$result = $result / $command->run();
break;
}
}
return $result;
}
