Re: comments_popup_link
http://phpxref.ftwr.co.uk/wordpress/nav.html?wp-includes/comment-template.php.source.html
In WordPress, comments_popup_link()
takes three arguments that tell it how to format the output based on how many comments are present and runs a sprintf()
with the appropriate output after retrieving the comment count.
The equivalent to get_comments_number
in bbPress would be get_topic_posts
, the rest of the function is either WordPress-specific or would need slight tweaking (like what the posts page would actually be).