You can use the array functions on a object of a class that implements ArrayAccess using the __invoke magic method in this way:
<?php
class ArrayVar implements ArrayAccess
{
private $data = [];
public function __invoke()
{
return $this->data;
}
}
?>
Now you can use it in this way:
<?php
$arrayar = new ArrayVar();
$arrayar['one'] = 'primer';
$arrayar['two'] = 'segon';
$arrayar['three'] = 'tercer';
$keys = array_keys($arrayar());
var_dump($keys);
$diff = array_diff($arrayar(), [ 'two' => 'segon']);
var_dump($diff);
?>