Regexp lookahead and lookbehind and match between certain characters

Question

Currently I have this regexp to detect strings between double curly brackets and it work's wonderfully.

$str = "{{test}} and {{test2}}";
preg_match_all('/(?<={{)[^}]*(?=}})/', $str, $matches);
print_r($matches);

Returns:
Array
(
[0] => Array
    (
        [0] => test
        [1] => test2
    )

)

Now I need to expand it to only match stuff between ]] and [[

$str = "{{dont match}}]]{{test}} and {{test2}}[[{{dont match}}";

I've been trying to modify the regex but the lookahead and lookbehind is making it too difficult for me. How can I get it to match stuff inside ]] and [[ only?

Also I would like to match the whole string between ]] and [[ and then I would like to match each individual string between {{ }} inside it.

For example:

$str = "{{dont match}}]]{{test}} and {{test2}}[[{{dont match}}";

Would return:
Array
(
[0] => Array
    (
        [0] => {{test}} and {{test2}}
        [1] => test
        [2] => test2
    )

)

Answer 1

Piggyback using preg_replace_callback :

$str = "{{dont match}}]]{{test}} and {{test2}}[[{{dont match}}";
$arr = array();
preg_replace_callback('/\]\](.*?)\[\[/', function($m) use (&$arr) {
            preg_match_all('/(?<={{)[^}]*(?=}})/', $m[1], $arr); return true; }, $str);
print_r($arr[0]);

Output:

Array
(
    [0] => test
    [1] => test2
)