$re = '/(@?)({!\s*((?:(?!{!|!}).)*?)\s*!})/is';
$str = 'Hi, My name is {!first_name!}
and my family name is {!last_name!},
To sum it up, my name is {!full_name!}.
I am a {!job_title!}.
To use my function just write your vars like this @{!code!}';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php