php_closure.php

#!/usr/bin/php
<?php

function closure_test(&$foobar) {

    // Repeat for some arbitrary number of executions
    $x = mt_rand(3, 10);
    while ($x > 0) {
        $foobar[] = $x;
        --$x;
    }

    $closure = function(&$foobar) {
        $foobar[mt_rand(0, count($foobar) - 1)] = "this row got changed!";
    };
    $closure($foobar);

}

$foobar = [];

closure_test($foobar);

print_r($foobar);