* gnus-util.el (gnus-add-text-properties-when): New function.

(gnus-remove-text-properties-when): Ditto.

* gnus-cite.el (gnus-article-hide-citation): Use them.
(gnus-article-toggle-cited-text): Use them.

* gnus-art.el (gnus-signature-toggle): Use them.
(gnus-article-show-hidden-text): Ditto.
(gnus-article-hide-text): Ditto.

* gnus-art.el (gnus-article-describe-key): Use prompt.
(gnus-article-describe-key-briefly): Ditto.

4 files changed, 197 insertions, 112 deletions

diff --git a/lisp/gnus/ChangeLog b/lisp/gnus/ChangeLog
index 00f5cb5b345..326d346b9a8 100644
--- a/lisp/gnus/ChangeLog
+++ b/lisp/gnus/ChangeLog
@@ -1,3 +1,18 @@
+2000-12-20  ShengHuo ZHU  <zsh@cs.rochester.edu>
+
+        * gnus-util.el (gnus-add-text-properties-when): New function.
+        (gnus-remove-text-properties-when): Ditto.
+
+        * gnus-cite.el (gnus-article-hide-citation): Use them.
+        (gnus-article-toggle-cited-text): Use them.
+        
+        * gnus-art.el (gnus-signature-toggle): Use them.
+        (gnus-article-show-hidden-text): Ditto.
+        (gnus-article-hide-text): Ditto.
+
+        * gnus-art.el (gnus-article-describe-key): Use prompt.
+        (gnus-article-describe-key-briefly): Ditto.
+
 2000-12-19  ShengHuo ZHU  <zsh@cs.rochester.edu>
 
         * mm-util.el (mm-charset-synonym-alist): Fix a typo.
diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index 517a16d745a..c1d7a62df57 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -1053,11 +1053,12 @@ Initialized from `text-mode-syntax-table.")
 
 (defsubst gnus-article-hide-text (b e props)
   "Set text PROPS on the B to E region, extending `intangible' 1 past B."
-  (add-text-properties b e props)
+  (gnus-add-text-properties-when 'article-type nil b e props)
   (when (memq 'intangible props)
     (put-text-property
      (max (1- b) (point-min))
      b 'intangible (cddr (memq 'intangible props)))))
+
 (defsubst gnus-article-unhide-text (b e)
   "Remove hidden text properties from region between B and E."
   (remove-text-properties b e gnus-hidden-properties)
@@ -1976,24 +1977,16 @@ means show, 0 means toggle."
         'hidden
       nil)))
 
-(defun gnus-article-show-hidden-text (type &optional hide)
+(defun gnus-article-show-hidden-text (type &optional dummy)
   "Show all hidden text of type TYPE.
-If HIDE, hide the text instead."
-  (save-excursion
-    (let ((buffer-read-only nil)
-          (inhibit-point-motion-hooks t)
-          (end (point-min))
-          beg)
-      (while (setq beg (text-property-any end (point-max) 'article-type type))
-        (goto-char beg)
-        (setq end (or
-                   (text-property-not-all beg (point-max) 'article-type type)
-                   (point-max)))
-        (if hide
-            (gnus-article-hide-text beg end gnus-hidden-properties)
-          (gnus-article-unhide-text beg end))
-        (goto-char end))
-      t)))
+Originally it is hide instead of DUMMY."
+  (let ((buffer-read-only nil)
+        (inhibit-point-motion-hooks t))
+    (gnus-remove-text-properties-when 
+     'article-type type
+     (point-min) (point-max) 
+     (cons 'article-type (cons type
+                               gnus-hidden-properties)))))
 
 (defconst article-time-units
   `((year . ,(* 365.25 24 60 60))
@@ -2639,6 +2632,8 @@ If variable `gnus-use-long-file-name' is non-nil, it is
   ">" end-of-buffer
   "\C-c\C-i" gnus-info-find-node
   "\C-c\C-b" gnus-bug
+  "\C-hk" gnus-article-describe-key
+  "\C-hc" gnus-article-describe-key-briefly
 
   "\C-d" gnus-article-read-summary-keys
   "\M-*" gnus-article-read-summary-keys
@@ -3836,26 +3831,58 @@ Argument LINES specifies lines to be scrolled down."
           (switch-to-buffer summary 'norecord))
         (setq in-buffer (current-buffer))
         ;; We disable the pick minor mode commands.
-        (if (setq func (let (gnus-pick-mode)
-                         (lookup-key (current-local-map) keys)))
+        (if (and (setq func (let (gnus-pick-mode)
+                              (lookup-key (current-local-map) keys)))
+                 (functionp func))
             (progn
               (call-interactively func)
-              (setq new-sum-point (point)))
-          (ding))
-        (when (eq in-buffer (current-buffer))
-          (setq selected (gnus-summary-select-article))
-          (set-buffer obuf)
-          (unless not-restore-window
-            (set-window-configuration owin))
-          (when (eq selected 'old)
-            (article-goto-body)
-            (set-window-start (get-buffer-window (current-buffer))
-                              1)
-            (set-window-point (get-buffer-window (current-buffer))
-                              (point)))
-          (let ((win (get-buffer-window gnus-article-current-summary)))
-            (when win
-              (set-window-point win new-sum-point))))))))
+              (setq new-sum-point (point))
+              (when (eq in-buffer (current-buffer))
+                (setq selected (gnus-summary-select-article))
+                (set-buffer obuf)
+                (unless not-restore-window
+                  (set-window-configuration owin))
+                (when (eq selected 'old)
+                  (article-goto-body)
+                  (set-window-start (get-buffer-window (current-buffer))
+                                    1)
+                  (set-window-point (get-buffer-window (current-buffer))
+                                    (point)))
+                (let ((win (get-buffer-window gnus-article-current-summary)))
+                  (when win
+                    (set-window-point win new-sum-point))))    )
+          (switch-to-buffer gnus-article-buffer)
+          (ding))))))
+
+(defun gnus-article-describe-key (key)
+  "Display documentation of the function invoked by KEY.  KEY is a string."
+  (interactive "kDescribe key: ")
+  (gnus-article-check-buffer)
+  (if (eq (key-binding key) 'gnus-article-read-summary-keys)
+      (save-excursion
+        (set-buffer gnus-article-current-summary)
+        (let (gnus-pick-mode)
+          (push (elt key 0) unread-command-events)
+          (setq key (if (featurep 'xemacs)
+                        (events-to-keys (read-key-sequence "Describe key: "))
+                      (read-key-sequence "Describe key: "))))
+        (describe-key key))
+    (describe-key key)))
+
+(defun gnus-article-describe-key-briefly (key &optional insert)
+  "Display documentation of the function invoked by KEY.  KEY is a string."
+  (interactive "kDescribe key: \nP")
+  (gnus-article-check-buffer)
+  (if (eq (key-binding key) 'gnus-article-read-summary-keys)
+      (save-excursion
+        (set-buffer gnus-article-current-summary)
+        (let (gnus-pick-mode)
+          (push (elt key 0) unread-command-events)
+          (setq key (if (featurep 'xemacs)
+                        (events-to-keys (read-key-sequence "Describe key: "))
+                      (read-key-sequence "Describe key: "))))
+        (describe-key-briefly key insert))
+    (describe-key-briefly key insert)))
 
 (defun gnus-article-hide (&optional arg force)
   "Hide all the gruft in the current article.
@@ -4509,9 +4536,15 @@ specified by `gnus-button-alist'."
     (set-buffer gnus-article-buffer)
     (let ((buffer-read-only nil)
           (inhibit-point-motion-hooks t))
-      (if (get-text-property end 'invisible)
-          (gnus-article-unhide-text end (point-max))
-        (gnus-article-hide-text end (point-max) gnus-hidden-properties)))))
+      (if (text-property-any end (point-max) 'article-type 'signature)
+          (gnus-remove-text-properties-when
+           'article-type 'signature end (point-max)
+           (cons 'article-type (cons 'signature
+                                     gnus-hidden-properties)))
+        (gnus-add-text-properties-when
+         'article-type nil end (point-max)
+         (cons 'article-type (cons 'signature
+                                   gnus-hidden-properties)))))))
 
 (defun gnus-button-entry ()
   ;; Return the first entry in `gnus-button-alist' matching this place.
diff --git a/lisp/gnus/gnus-cite.el b/lisp/gnus/gnus-cite.el
index fcddb0b76fa..ef659175b14 100644
--- a/lisp/gnus/gnus-cite.el
+++ b/lisp/gnus/gnus-cite.el
@@ -468,57 +468,63 @@ always hide."
   (gnus-set-format 'cited-closed-text-button t)
   (save-excursion
     (set-buffer gnus-article-buffer)
-    (cond
-     ((gnus-article-check-hidden-text 'cite arg)
-      t)
-     ((gnus-article-text-type-exists-p 'cite)
-      (let ((buffer-read-only nil))
-        (gnus-article-hide-text-of-type 'cite)))
-     (t
       (let ((buffer-read-only nil)
-            (marks (gnus-dissect-cited-text))
+            marks
             (inhibit-point-motion-hooks t)
             (props (nconc (list 'article-type 'cite)
                           gnus-hidden-properties))
-            beg end start)
-        (while marks
-          (setq beg nil
-                end nil)
-          (while (and marks (string= (cdar marks) ""))
-            (setq marks (cdr marks)))
-          (when marks
-            (setq beg (caar marks)))
-          (while (and marks (not (string= (cdar marks) "")))
-            (setq marks (cdr marks)))
-          (when marks
+            (point (point-min))
+            found beg end start)
+        (while (setq point 
+                     (text-property-any point (point-max) 
+                                        'gnus-callback
+                                        'gnus-article-toggle-cited-text))
+          (setq found t)
+          (goto-char point)
+          (gnus-article-toggle-cited-text
+           (get-text-property point 'gnus-data) arg)
+          (forward-line 1)
+          (setq point (point)))
+        (unless found
+          (setq marks (gnus-dissect-cited-text))
+          (while marks
+            (setq beg nil
+                  end nil)
+            (while (and marks (string= (cdar marks) ""))
+              (setq marks (cdr marks)))
+            (when marks
+              (setq beg (caar marks)))
+            (while (and marks (not (string= (cdar marks) "")))
+              (setq marks (cdr marks)))
+            (when marks
             (setq end (caar marks)))
-          ;; Skip past lines we want to leave visible.
-          (when (and beg end gnus-cited-lines-visible)
-            (goto-char beg)
-            (forward-line (if (consp gnus-cited-lines-visible)
-                              (car gnus-cited-lines-visible)
-                            gnus-cited-lines-visible))
-            (if (>= (point) end)
-                (setq beg nil)
-              (setq beg (point-marker))
-              (when (consp gnus-cited-lines-visible)
-                (goto-char end)
-                (forward-line (- (cdr gnus-cited-lines-visible)))
-                (if (<= (point) beg)
-                    (setq beg nil)
+            ;; Skip past lines we want to leave visible.
+            (when (and beg end gnus-cited-lines-visible)
+              (goto-char beg)
+              (forward-line (if (consp gnus-cited-lines-visible)
+                                (car gnus-cited-lines-visible)
+                              gnus-cited-lines-visible))
+              (if (>= (point) end)
+                  (setq beg nil)
+                (setq beg (point-marker))
+                (when (consp gnus-cited-lines-visible)
+                  (goto-char end)
+                  (forward-line (- (cdr gnus-cited-lines-visible)))
+                  (if (<= (point) beg)
+                      (setq beg nil)
                   (setq end (point-marker))))))
-          (when (and beg end)
-            ;; We use markers for the end-points to facilitate later
-            ;; wrapping and mangling of text.
-            (setq beg (set-marker (make-marker) beg)
-                  end (set-marker (make-marker) end))
-            (gnus-add-text-properties beg end props)
-            (goto-char beg)
-            (unless (save-excursion (search-backward "\n\n" nil t))
-              (insert "\n"))
-            (put-text-property
-             (setq start (point-marker))
-             (progn
+            (when (and beg end)
+              ;; We use markers for the end-points to facilitate later
+              ;; wrapping and mangling of text.
+              (setq beg (set-marker (make-marker) beg)
+                    end (set-marker (make-marker) end))
+              (gnus-add-text-properties-when 'article-type nil beg end props)
+              (goto-char beg)
+              (unless (save-excursion (search-backward "\n\n" nil t))
+                (insert "\n"))
+              (put-text-property
+               (setq start (point-marker))
+               (progn
                (gnus-article-add-button
                 (point)
                 (progn (eval gnus-cited-closed-text-button-line-format-spec)
@@ -526,42 +532,51 @@ always hide."
                 `gnus-article-toggle-cited-text
                 (list (cons beg end) start))
                (point))
-             'article-type 'annotation)
-            (set-marker beg (point)))))))))
+               'article-type 'annotation)
+              (set-marker beg (point))))))))
 
-(defun gnus-article-toggle-cited-text (args)
-  "Toggle hiding the text in REGION."
+(defun gnus-article-toggle-cited-text (args &optional arg)
+  "Toggle hiding the text in REGION.
+ARG can be nil or a number.  Positive means hide, negative
+means show, nil means toggle."
   (let* ((region (car args))
          (beg (car region))
          (end (cdr region))
          (start (cadr args))
          (hidden
-          (text-property-any
-           beg (1- end)
-           (car gnus-hidden-properties) (cadr gnus-hidden-properties)))
+          (text-property-any beg (1- end) 'article-type 'cite))
          (inhibit-point-motion-hooks t)
          buffer-read-only)
-    (funcall
-     (if hidden
-         'remove-text-properties 'gnus-add-text-properties)
-     beg end gnus-hidden-properties)
-    (save-excursion
-      (goto-char start)
-      (gnus-delete-line)
-      (put-text-property
-       (point)
-       (progn
-         (gnus-article-add-button
-          (point)
-          (progn (eval
-                  (if hidden
-                      gnus-cited-opened-text-button-line-format-spec
-                    gnus-cited-closed-text-button-line-format-spec))
-                 (point))
-          `gnus-article-toggle-cited-text
-          args)
-         (point))
-       'article-type 'annotation))))
+    (when (or (null arg)
+              (zerop arg)
+              (and (> arg 0) (not hidden))
+              (and (< arg 0) hidden))
+      (if hidden
+          (gnus-remove-text-properties-when
+           'article-type 'cite beg end 
+           (cons 'article-type (cons 'cite
+                                     gnus-hidden-properties)))
+        (gnus-add-text-properties-when
+         'article-type nil beg end 
+         (cons 'article-type (cons 'cite
+                                   gnus-hidden-properties))))
+      (save-excursion
+        (goto-char start)
+        (gnus-delete-line)
+        (put-text-property
+         (point)
+         (progn
+           (gnus-article-add-button
+            (point)
+            (progn (eval
+                    (if hidden
+                        gnus-cited-opened-text-button-line-format-spec
+                      gnus-cited-closed-text-button-line-format-spec))
+                   (point))
+            `gnus-article-toggle-cited-text
+            args)
+           (point))
+         'article-type 'annotation)))))
 
 (defun gnus-article-hide-citation-maybe (&optional arg force)
   "Toggle hiding of cited text that has an attribution line.
diff --git a/lisp/gnus/gnus-util.el b/lisp/gnus/gnus-util.el
index 0e037154d05..8fa0068b085 100644
--- a/lisp/gnus/gnus-util.el
+++ b/lisp/gnus/gnus-util.el
@@ -974,6 +974,28 @@ Entries without port tokens default to DEFAULTPORT."
       (while (search-backward "\\." nil t)
         (delete-char 1)))))
 
+(defun gnus-add-text-properties-when
+  (property value start end properties &optional object)
+  "Like `gnus-add-text-properties', only applied on where PROPERTY is VALUE."
+  (let (point)
+    (while (and start 
+                (setq point (text-property-not-all start end property value)))
+      (gnus-add-text-properties start point properties object)
+      (setq start (text-property-any point end property value)))
+    (if start
+        (gnus-add-text-properties start end properties object))))
+
+(defun gnus-remove-text-properties-when
+  (property value start end properties &optional object)
+  "Like `remove-text-properties', only applied on where PROPERTY is VALUE."
+  (let (point)
+    (while (and start 
+                (setq point (text-property-not-all start end property value)))
+      (remove-text-properties start point properties object)
+      (setq start (text-property-any point end property value)))
+    (if start
+        (remove-text-properties start end properties object))))
+
 (provide 'gnus-util)
 
 ;;; gnus-util.el ends here