Referencing $this in a closure works :S

closure.php

<?php

class Called
{
    public function doThis($callback)
    {
        $callback('this is not a love song');
    }
}

class Output
{
    public function write($message)
    {
        echo $message.PHP_EOL;
    }
}

class Caller
{
    private $output;
    
    public function __construct()
    {
        $this->output = new Output();
    }
    
    public function doThat()
    {
        $called = new Called();
        $action = function($message) use ($output) {
            $this->output->write($message);
        };
        
        $called->doThis($action);
    }
}

$caller = new Caller();
$caller->doThat();