Find last visual post in a discussion

During setting custom styling to the forum, I found out that I could really use an indicator for the last post in a discussion. Not the chronologically last post but the last one to be displayed.

I came up with this code that I added at the end of forum_get_all_discussion_posts() after the $posts array has been rearranged.

$lastpost = false;

// start with the last child of the first post

$post = &$posts[reset($posts)->id];

while (!$lastpost) {

    if (!isset($post->children)) {

        $post->lastpost = true;

        $lastpost = true;

    }

    else // go to the last child of this post

        $post = &$posts[end($post->children)->id];

}

Later on, when building the HTML, if isset($post->lastpost) is true I add the "lastpost" class (same syntax as "firstpost" that's already in the code).

This improvement is purely for the benefit of the front-end output and I believe it will come in handy when working with styling and script writing.