string 类型约束的问题

[历努]

function foo(string $s) { 
	  echo $s;
}
foo("hello world");

报错Catchable fatal error: Argument 1 passed to foo() must be an instance of string, string given, called in
这是为什么？应该怎么写呢？

[xuzuning]

类型约束实际是一种倒退 类型约束只支持对象 和 数组两种类型。而不支持整型 和 字符串类型。

[码无边]

php是弱类型 对简单的类型是不支持的，一般就支持对象和数组

[一起混吧]

php 函数声明参数不需要指定类型

[历努]

settings.php
<settings>
<resolvedomains>false</resolvedomains>
</settings>
AddressManager.php
class AddressManager{
private $addresses = array("209.131.36.159","74.125.19.106");

function outputAddresses($resolve){
foreach($this->addresses as $address){
if(!is_bool($resolve)){
die("outputAdresses() requires a Boolean argument\n");
}
print "</br>";
}
}
}
$settings = simplexml_load_file("settings.xml");
$manager = new AddressManager();
$manager->outputAddresses((string)$settings->resolvedomains);
但是这里$manager->outputAddresses((string)$settings->resolvedomains);的类型约束是可以的

[历努]

好吧，非常
谢谢