Add new Gnus summary commands and keystrokes for "unseen" navigation

* doc/misc/gnus.texi (Choosing Commands): Document them.
* lisp/gnus/gnus-sum.el (gnus-summary-next-unseen-article)
(gnus-summary-prev-unseen-article): New commands and
keystrokes (bug#35213).

3 files changed, 56 insertions, 0 deletions

diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index 4c69c692926..8ab1cf9f68f 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -5347,6 +5347,20 @@ Go to the next article (@code{gnus-summary-next-article}).
 @findex gnus-summary-prev-article
 Go to the previous article (@code{gnus-summary-prev-article}).
 
+@item G u
+@itemx ]
+@kindex ] @r{(Summary)}
+@kindex G u @r{(Summary)}
+@findex gnus-summary-next-unseen-article
+Go to the next unseen article (@code{gnus-summary-next-unseen-article}).
+
+@item G U
+@itemx [
+@kindex [ @r{(Summary)}
+@kindex G U @r{(Summary)}
+@findex gnus-summary-prev-unseen-article
+Go to the previous unseen article (@code{gnus-summary-prev-unseen-article}).
+
 @item G C-n
 @kindex G C-n @r{(Summary)}
 @findex gnus-summary-next-same-subject
diff --git a/etc/NEWS b/etc/NEWS
index 3d8480cb461..f858c958317 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1047,6 +1047,13 @@ Of course it will still find it if you have it in '~/.ecompleterc'.
 ** Gnus
 
 +++
+*** Two new Gnus summary mode navigation commands have been added,
+bound to the '[' and ']' keys: `gnus-summary-prev-unseen-article' and
+`gnus-summary-next-unseen-article'.  These take you (respectively) to
+the previous unseen or next unseen article.  (These are the ones that
+are marked with "." in the summary mode lines.)
+
++++
 *** The Gnus user variable 'nnimap-expunge' supports three new values:
 'never' for never expunging messages, 'immediately' for immediately
 expunging deleted messages, and 'on-exit' to expunge deleted articles
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index 20f338eda16..b5d744843f0 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -1911,6 +1911,8 @@ increase the score of each group you read."
   "\M-p" gnus-summary-prev-unread-subject
   "." gnus-summary-first-unread-article
   "," gnus-summary-best-unread-article
+  "[" gnus-summary-prev-unseen-article
+  "]" gnus-summary-next-unseen-article
   "\M-s" gnus-summary-search-article-forward
   "\M-r" gnus-summary-search-article-backward
   "\M-S" gnus-summary-repeat-search-article-forward
@@ -2088,6 +2090,8 @@ increase the score of each group you read."
   "\M-p" gnus-summary-prev-unread-subject
   "f" gnus-summary-first-unread-article
   "b" gnus-summary-best-unread-article
+  "u" gnus-summary-next-unseen-article
+  "U" gnus-summary-prev-unseen-article
   "j" gnus-summary-goto-article
   "g" gnus-summary-goto-subject
   "l" gnus-summary-goto-last-article
@@ -2796,6 +2800,8 @@ gnus-summary-show-article-from-menu-as-charset-%s" cs))))
          ["Previous article same subject" gnus-summary-prev-same-subject t]
          ["First unread article" gnus-summary-first-unread-article t]
          ["Best unread article" gnus-summary-best-unread-article t]
+         ["Next unseen article" gnus-summary-next-unseen-article t]
+         ["Prev unseen article" gnus-summary-prev-unseen-article t]
          ["Go to subject number..." gnus-summary-goto-subject t]
          ["Go to article number..." gnus-summary-goto-article t]
          ["Go to the last article" gnus-summary-goto-last-article t]
@@ -3175,6 +3181,9 @@ The following commands are available:
                (:type list))
   number mark pos header level)
 
+(defun gnus-data-unseen-p (data)
+  (memq (gnus-data-number data) gnus-newsgroup-unseen))
+
 (define-inline gnus-data-unread-p (data)
   (inline-quote (= (gnus-data-mark ,data) gnus-unread-mark)))
 
@@ -8119,6 +8128,32 @@ Return nil if there are no unread articles."
         (gnus-summary-first-subject t))
     (gnus-summary-position-point)))
 
+(defun gnus-summary-next-unseen-article (&optional backward)
+  "Select the next unseen article."
+  (interactive)
+  (let* ((article (gnus-summary-article-number))
+         (articles (gnus-data-find-list article (gnus-data-list backward))))
+    (when (or (not gnus-summary-check-current)
+              (not (gnus-data-unseen-p (car articles)))
+              (not (gnus-data-unread-p (car articles))))
+      (setq articles (cdr articles)))
+    (while (and articles
+                (or (not (gnus-data-unseen-p (car articles)))
+                    (not (gnus-data-unread-p (car articles)))))
+      (setq articles (cdr articles)))
+    (if (not articles)
+        (if backward
+            (message "No previous unseen article")
+          (message "No next unseen article"))
+      (goto-char (gnus-data-pos (car articles)))
+      (gnus-summary-select-article)
+      (gnus-data-number (car articles)))))
+
+(defun gnus-summary-prev-unseen-article ()
+  "Select the previous unseen article."
+  (interactive)
+  (gnus-summary-next-unseen-article t))
+
 (defun gnus-summary-first-unseen-subject ()
   "Place the point on the subject line of the first unseen article.
 Return nil if there are no unseen articles."