$re = '/MyFunction(\((?>\((?<c>)|[^()]+|\)(?<-c>))*(?(c)(?!))\))/m';
$str = 'MyFunction(23)
MyFunction(\'Sekret\')
MyFunction( 23, \'Sekret\', Date() )
MyFunction( Encrypt(\'Sekret\'), Date() )
logger.info("MyFunction( Encrypt(\'Sekret\'), Date() )")
';
preg_match_all($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