Problem with loose typing

Consider the following: function test() { static $i = 0; $i++; $retval = ( $i <= 10 ) ? $i : ''; return $retval; } while( $bob = test()) { echo $bob . '<br>'; } You would expect the while loop to go on forever just looking at the above code. However, what's happening is that when the empty string is getting returned due to $i being > 10, the while loop is resolving FALSE when $bob is set to the value of the empty string. Is there any way that I can force this not to happen? That the while loop resolves as FALSE only when the function actually returns a (boolean) FALSE value? thnx, Chris