(require-library "macro.ss")

(define-signature mzlib:nntp^
  ((struct communicator (sender receiver server port))
    connect-to-server disconnect-from-server
    open-news-group
    head-of-message body-of-message
    make-desired-header extract-desired-headers

    (struct nntp ())
    (struct unexpected-response (code text))
    (struct bad-status-line (line))
    (struct premature-close (communicator))
    (struct bad-newsgroup-line (line))
    (struct non-existent-group (group))
    (struct article-not-in-group (article))
    (struct no-group-selected ())
    (struct article-not-found (article))))