PHP如何在这里避免无限递归? [英] How does PHP avoid infinite recursion here?

问题描述

考虑此类:

class test
{
    public function __set($n, $v)
    {
        echo "__set() called\n";
        $this->other_set($n, $v, true);
    }

    public function other_set($name, $value)
    {
        echo "other_set() called\n";    
        $this->$name = $value;
    }

    public function t()
    {
        $this->t = true;
    }
}

我正在重载PHP的魔术方法 __set() 方法.每当我在test类的对象中设置属性时，它都会调用__set()，后者又调用other_set().

I am overloading PHP's magic __set() method. Whenever I set a property in an object of the test class, it will call __set(), which in turn calls other_set().

$obj = new test;
$test->prop = 10;

/* prints the following */
__set() called
other_set() called

但是other_set()具有以下行$this->$name = $value.这不应该导致对__set()的调用，从而导致无限递归吗?

But other_set() has the following line $this->$name = $value. Shouldn't this result in a call to __set(), causing infinite recursion?

我的理论是，仅当在类外设置内容时，它才会调用__set().但是，如果调用方法t()，则可以清楚地看到它也通过__set().

I theorized that it would call __set() only when setting things outside the class. But if you call the method t() you can see it clearly goes through __set() too.

推荐答案

__set is only called once per attempt for a given property name. If it (or anything it calls) attempts to set the same property, PHP won't call __set again -- it'll just set the property on the object.

这篇关于PHP如何在这里避免无限递归?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！