<?php

class Point {
    protected $x;
    protected $y;

    public function __construct($x, $y) {
        $this->x = $x;
        $this->y = $y;
    }

    public function toArray() {
        return (array)$this;
    }
}

$p = new Point(4, 5);
var_dump($p->toArray()); // ["*x" => 4, "*y" => 5]