从调用属性的位置获取变量

Question

For some user-level debugging I would like to know from which variable a certain property from a class was called. All classes are stdClass, so I can't look for an answer in that direction.

Let's say I have a class Person with properties Name and Sex. The setup looks like $oPerson = new Person(). When I call $oPerson->FirstName = 'Jack'; I would like to figure out the call was made from $oPerson. Can this be achieved?

Answer 1

This isn't perfect (see here for my inspiration and why it's not), but it's a start:

class Person {
    var $name;
    var $sex;

    function Person() {
        $this->name = "Jon";
        $this->sex = "male";
    }

    function __get($name) {
        $var_name = "";
        foreach ($GLOBALS as $key => $val) {
            if ($val === $this) {
                $var_name = $key;
                break;
            }
        }

        echo "Getting undefined '$name' from '\$$var_name'.
";

        $trace = debug_backtrace();
        trigger_error(
            'Undefined property via __get(): ' . $name .
            ' in ' . $trace[0]['file'] .
            ' on line ' . $trace[0]['line'],
            E_USER_NOTICE);

        return null;
    }
}

$oPerson = new Person();
$name = $oPerson->name;
$fullname = $oPerson->fullname;

For example, the following won't work:

class Nerd {
    var $person;

    function Nerd() {
        $person = new Person();
        $nerd_fullname = $person->fullname;
    }
}

because the $person property of Nerd is not global, so it doesn't appear in $GLOBALS, nor is it within the scope of Persons's magic function __get().