是否可以在 PHP 中重载运算符？
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Is it possible to overload operators in PHP?
提问by chadgh
Specifically, I would like to create an Array class and would like to overload the [] operator.
具体来说，我想创建一个 Array 类并想重载 [] 运算符。
采纳答案by cbeer
If you are using PHP5 (and you should be), take a look at the SPL ArrayObjectclasses. The documentation isn't too good, but I think if you extend ArrayObject, you'd have your "fake" array.
如果您使用的是 PHP5（您应该使用），请查看SPL ArrayObject类。文档不太好，但我认为如果您扩展 ArrayObject，您将拥有“假”数组。
EDIT: Here's my quick example; I'm afraid I don't have a valuable use case though:
编辑：这是我的快速示例；不过，恐怕我没有有价值的用例：
class a extends ArrayObject {
public function offsetSet($i, $v) {
echo 'appending ' . $v;
parent::offsetSet($i, $v);
}
}
$a = new a;
$a[] = 1;
回答by panicz
Actually, the optimal solution is to implement the four methods of the ArrayAccess interface: http://php.net/manual/en/class.arrayaccess.php
实际上，最佳的解决方案是实现ArrayAccess接口的四个方法：http://php.net/manual/en/class.arrayaccess.php
If you would also like to use your object in the context of 'foreach', you'd have to implement the 'Iterator' interface: http://www.php.net/manual/en/class.iterator.php
如果您还想在“foreach”的上下文中使用您的对象，则必须实现“Iterator”接口：http: //www.php.net/manual/en/class.iterator.php
回答by grammar31
PHP's concept of overloading and operators (see Overloading, and Array Operators) is not like C++'s concept. I don't believe it is possible to overload operators such as +, -, [], etc.
PHP 的重载和运算符的概念（请参阅重载和数组运算符）与 C++ 的概念不同。我认为不可能重载 +、-、[] 等运算符。
Possible Solutions
可能的解决方案
- Implement SPL ArrayObject(as mentioned by cbeer).
- Implement Iterator(if
ArrayObjectis too slow for you). - Use the PECL operatorextension (as mentioned by Benson).
- 实现SPL ArrayObject（如cbeer 所述）。
- 实现迭代器（如果
ArrayObject对你来说太慢了）。 - 使用PECL 运算符扩展（如Benson 所述）。
回答by Fabien Sa
For a simple and clean solution in PHP 5.0+, you need to implements the ArrayAccessinterfaceand override functions offsetGet, offsetSet, offsetExists and offsetUnset. You can now use the object like an array.
为了在 PHP 5.0+ 中获得简单干净的解决方案，您需要实现ArrayAccess接口和覆盖函数 offsetGet、offsetSet、offsetExists 和 offsetUnset。您现在可以像使用数组一样使用该对象。
Example:
例子：
<?php
class A implements ArrayAccess {
private $data = array();
public function offsetGet($offset) {
return isset($this->data[$offset]) ? $this->data[$offset] : null;
}
public function offsetSet($offset, $value) {
if ($offset === null) {
$this->data[] = $value;
} else {
$this->data[$offset] = $value;
}
}
public function offsetExists($offset) {
return isset($this->data[$offset]);
}
public function offsetUnset($offset) {
unset($this->data[$offset]);
}
}
$obj = new A;
$obj[] = 'a';
$obj['k'] = 'b';
echo $obj[0], $obj['k']; // print "ab"
回答by Benson
回答by dirtside
Put simply, no; and I'd suggest that if you think you need C++-style overloading, you may need to rethink the solution to your problem. Or maybe consider not using PHP.
简单地说，不；我建议，如果您认为需要 C++ 风格的重载，您可能需要重新考虑问题的解决方案。或者考虑不使用 PHP。
To paraphrase Jamie Zawinski, "You have a problem and think, 'I know! I'll use operator overloading!' Now you have two problems."
套用 Jamie Zawinski 的话来说，“您遇到问题并想，'我知道！我将使用运算符重载！' 现在你有两个问题。”
