PHP 函数参数支持的类型有哪些？

function sumNumbers($a, $b) {
  if (is_int($a) && is_int($b)) {
    return $a + $b;
  } else {
    throw new Exception("Invalid argument types: $a and $b");
  }
}

$result = sumNumbers(10, 20);
echo $result; // 输出 30

function printArray($arr) {
  if (is_array($arr)) {
    foreach ($arr as $value) {
      echo $value . "<br>";
    }
  } else {
    throw new Exception("Invalid argument type: $arr");
  }
}

printArray([1, 2, 3]); // 输出 1<br>2<br>3<br>

class Person {
  public $name;
  public $age;

  public function greet() {
    echo "Hello, my name is $this->name and I'm $this->age years old.<br>";
  }
}

function introduce(Person $person) {
  if ($person instanceof Person) {
    $person->greet();
  } else {
    throw new Exception("Invalid argument type: $person");
  }
}

$person = new Person();
$person->name = "John Doe";
$person->age = 30;

introduce($person); // 输出 Hello, my name is John Doe and I'm 30 years old.<br>

function sumNumbers(int $a, int $b): int {
  return $a + $b;
}