Accessing 'parent' in PHP Anonymous Function (and possible bug)

Question

Does anyone know how to get access to a function on the parent class from inside an anonymous function defined in a class? Is this actually meant to be possible? I would presume not and that I would have to get a reference to the parent class into the anonymous function with the "use" keyword somehow.

However, if I run the following code on a local apache server running on windows with version 5.4.12 of php it works and b and a are outputted.

If I run it on a apache server running on linux with php version 5.3.10-1ubuntu3.11 with Suhosin-Patch (cli) I get the error Fatal error: Cannot access parent:: when no class scope is active on line 17.

echo("PHP version: ".phpversion()."<br /><br />");

class A {

    public function fn() {
        echo("in A");
    }   

}

class B extends A {

    public function fn() {
        echo("in B");

        $anonFn = function() {
            parent::fn(); // this causes the error (sometimes)
        };
        $anonFn();
    }

}


$b = new B();
$b->fn();

If you paste the above code into http://writecodeonline.com/php/ the error still occurs.

So my questions are,

should this work or not, do I need to file a php bug report?
If it should always throw the error it is throwing, how do I actually get a reference to 'parent' in an anonymous function?

Thanks!

I think this is one of the enhancements in PHP 5.4 -- class scope is saved in closures, so you can use $this and parent::. — Barmar
– Barmar, Commented May 23, 2014 at 10:38
See this related question: stackoverflow.com/questions/23819597/… — Barmar
– Barmar, Commented May 23, 2014 at 10:39
That would make sense. It's just it doesn't seem to mention in any of those explicitly that it is $this and parent::, only $this. In the changelog on the anonymous functions page they say $this can be used in anonymous functions. Maybe this should be changed to include 'and parent::' as well? Makes sense though, I'll get php updated. Thanks! — Tom Jenkinson
– Tom Jenkinson, Commented May 23, 2014 at 10:46
@Barmar if you post it as an answer I'll accept it. I presume that's the reason. — Tom Jenkinson
– Tom Jenkinson, Commented May 23, 2014 at 16:00

Barmar · Accepted Answer · 2014-05-23 16:04:30Z

3

PHP 5.4 includes class scope in closures, PHP 5.3 doesn't.

answered May 23, 2014 at 16:04

Barmar

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