Coalesce function for PHP?

There is a new operator in php 5.3 which does this: ?:

// A
echo 'A' ?: 'B';

// B
echo '' ?: 'B';

// B
echo false ?: 'B';

// B
echo null ?: 'B';

Source: http://www.php.net/ChangeLog-5.php#5.3.0