Question

I’m trying to dump elements of an object’s private property through an anonymous function – of course I could achieve this in any number of other ways, but this highlights a PHP conundrum I can’t solve off the top of my head, short of $foo = $this and using $foo – but THAT won’t give me the private stuff, so… suggestions ?

Sample code:

class MyClass
{
    private $payload = Array( 'a' => 'A element', 'b' => 'B element');

    static $csvOrder = Array('b','a');

    public function toCSV(){
        $values = array_map(
            function($name) use ($this) { return $this->payload[$name]; },  
            self::$csvOrder
        );
        return implode(',',$values);
    }
}

$mc = new MyClass();
print $mc->toCSV();

Answer 1

I believe there is absolutely no way to do directly what you propose.

However, you can work around it either by making the anonymous method a class method (this is not what you asked for, but it could be a practical solution) or pulling everything you need out of $this explicitly and passing the extracted values into the function:

class MyClass
{
    private $payload = Array( 'a' => 'A element', 'b' => 'B element');

    static $csvOrder = Array('b','a');

    public function toCSV(){
        $payload = $this->payload;
        $values = array_map(
            function($name) use ($payload) { return $payload[$name]; },  
            self::$csvOrder
        );
        return implode(',',$values);
    }
}