scribu/wp-posts-to-posts — pull request #128 by tnorthcutt (2012-03-13 20:18:46+00:00)
Title: Add optional separator argument to p2p_list_posts()

...he first in the list with the separator, after $before_item. This allows for building a comma separated list with p2p_list_posts(), much like get_the_category_list() in WP core.