dot notation to array in php

test.php

<?php

class test
{
    protected $data;

    public function set($key, $value) 
    {
        $points = explode(".", $key);
        $tmp =& $this->data;
        foreach ($points as $p) {
            if (!isset($tmp[$p])){
                $tmp[$p] = [];
            }
            $tmp =& $tmp[$p];
        }
        $tmp = $value;
    }

    public function get($key) 
    {
        $tmp =& $this->data;
        $points = explode(".", $key);
        foreach ($points as $p) {
            if (isset($tmp[$p])) {
                $tmp =& $tmp[$p];
            }
        }

        return $tmp;
    }

    public function getData()
    {
        return $this->data;
    }
}

$t = new test;

$t->set("user.name", "yunus");
$t->set("user.surname", "oksuz"); 
$t->set("user.school.name", "SDU"); 

var_dump($t->get("user"));
var_dump($t->get("user.school"));
//
var_dump($t->getData());