Upgrading to PHP 5

PHP/FI had a quirky function declaration syntax:

function sum $a, $b ( return($a + $b); );

This was changed in PHP 3, but you could continue to use the old form in PHP 3 and PHP 4 if you declared your function as an old_function :

old_function sum $a, $b ( return($a + $b); );

Alas, after six years , this backward compatibility feature is now gone. Another nostalgic remnant of PHP/FI has passed away.