if http(req, resp), and method(req) == GET, and addr(req) == src, and status(resp) == 200, and body(resp) == doc, and doc contains a reference (type, ref), and resolve(html-base(doc) or http-base(resp) or src, ref) = abs-ref, then there is a link from src to dest@@.
@@destination @@path @@follow: visit the document associated with the destination of a link, as a result of activating its source anchor.
An anchor src is connected to an anchor dest if there is a path from src to dest.