nested UL tree from hierarchical db

Hi all, I'm playing around with "Modified Preorder Tree Traversal" as discussed in an article on sitepoint <http://www.sitepoint.com/article/hierarchical-data-database/>, which includes this function: <?php function display_tree($root) {

     // retrieve the left and right value of the $root node
     $result = mysql_query('SELECT lft, rgt FROM tree '.
                            'WHERE title="'.$root.'";');
     $row = mysql_fetch_array($result);

     // start with an empty $right stack
     $right = array();

     // now, retrieve all descendants of the $root node
     $result = mysql_query('SELECT title, lft, rgt FROM tree '.
                            'WHERE lft BETWEEN '.$row['lft'].' AND '.
                            $row['rgt'].' ORDER BY lft ASC;');

     // display each row
     while ($row = mysql_fetch_array($result)) {
         // only check stack if there is one
         if (count($right)>0) {
             // check if we should remove a node from the stack
             while ($right[count($right)-1]<$row['rgt']) {
                 array_pop($right);
             }
         }

         // display indented node title
         echo str_repeat('  ',count($right)).$row['title']."\n";

         // add this node to the stack
         $right[] = $row['rgt'];
     }

} ?> This is outputting a text-based tree of the data in the database, but what I'd like to do is modify it to output a series of nested ul's (unordered lists) to describe the nesting, rather than relying on spaces and newlines. I've had a couple of attempts, with no luck... can someone shed some light on how this might be achieved? --- Justin French http://indent.com.au