is there a PHP function that would create a (deep) array key from an array ? It's quite difficult to explain, see that example:

function mysterious_function($input,$keys,$value){
    //...
    return $output;
}

$array = array(
    'hello'=>array(
        'im'=>'okay'
    )
);

$array = mysterious_function($array,array('hello','youre'),'beautiful');
$array = mysterious_function($array,array('ilove','the'),'haircut');

//would output

array(
    'hello'=>array(
        'im' =>         'ok',
        'youre' =>      'beautiful',
    ),
    'ilove'=>array(
        'the' =>        'haircut'
    )
);

I don't know if this could help you:

function mysterious_function($array,$keys,$value){

    $stack = "";
    foreach($keys as $k){
        $stack .= "['{$k}']";
    }
    eval("\$array{$stack} = \$value;");

    return $array;

}

Yes, it's brutal :-D

Demo: http://sandbox.onlinephpfunctions.com/code/3091e831982df4f4fafca6f7e1fd05c31cdee526

Edit:

Often eval() is evil. Often there is another way to do this; by the way I hope this could help you.