From 122ace858ba94e11d1b2713d0816b3a7d7e2a323 Mon Sep 17 00:00:00 2001
From: Stefan Kangas <stefan@marxist.se>
Date: Wed, 28 Oct 2020 16:43:32 +0100
Subject: [PATCH] Add shortdoc navigation commands

* lisp/emacs-lisp/shortdoc.el (text-property-search): Require.
(shortdoc-mode): New major mode.
(shortdoc-mode-map): New variable.
(shortdoc--goto-section): New macro.
(shortdoc-next, shortdoc-previous, shortdoc-next-section)
(shortdoc-previous-section): New commands.
(shortdoc-display-group): Use new shortdoc-models.  Propertize
section header.
(shortdoc--display-function): Propertize function header.
---
 lisp/emacs-lisp/shortdoc.el | 56 +++++++++++++++++++++++++++++++++++--
 1 file changed, 53 insertions(+), 3 deletions(-)

diff --git a/lisp/emacs-lisp/shortdoc.el b/lisp/emacs-lisp/shortdoc.el
index 59c8c7794cf..ebc7e3f61b1 100644
--- a/lisp/emacs-lisp/shortdoc.el
+++ b/lisp/emacs-lisp/shortdoc.el
@@ -25,6 +25,7 @@
 ;;; Code:
 
 (require 'seq)
+(require 'text-property-search)
 (eval-when-compile (require 'cl-lib))
 
 (defgroup shortdoc nil
@@ -1065,7 +1066,7 @@ There can be any number of :example/:result elements."
   (let ((inhibit-read-only t)
         (prev nil))
     (erase-buffer)
-    (special-mode)
+    (shortdoc-mode)
     (button-mode)
     (mapc
      (lambda (data)
@@ -1076,7 +1077,8 @@ There can be any number of :example/:result elements."
            (insert "\n"))
          (insert (propertize
                   (concat (substitute-command-keys data) "\n\n")
-                  'face '(variable-pitch (:height 1.3 :weight bold)))))
+                  'face '(variable-pitch (:height 1.3 :weight bold))
+                  'shortdoc-section t)))
         ;; There may be functions not yet defined in the data.
         ((fboundp (car data))
          (when prev
@@ -1091,7 +1093,8 @@ There can be any number of :example/:result elements."
         (start-section (point))
         arglist-start)
     ;; Function calling convention.
-    (insert "(")
+    (insert (propertize "("
+                        'shortdoc-function t))
     (if (plist-get data :no-manual)
         (insert (symbol-name function))
       (insert-text-button
@@ -1201,6 +1204,53 @@ Example:
         (setq slist (cdr slist)))
       (setcdr slist (cons elem (cdr slist))))))
 
+(defvar shortdoc-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map (kbd "n") 'shortdoc-next)
+    (define-key map (kbd "p") 'shortdoc-previous)
+    (define-key map (kbd "C-c C-n") 'shortdoc-next-section)
+    (define-key map (kbd "C-c C-p") 'shortdoc-previous-section)
+    map)
+  "Keymap for `shortdoc-mode'")
+
+(define-derived-mode shortdoc-mode special-mode "shortdoc"
+  "Mode for shortdoc.")
+
+(defmacro shortdoc--goto-section (arg sym &optional reverse)
+  `(progn
+     (unless (natnump ,arg)
+       (setq ,arg 1))
+     (while (< 0 ,arg)
+       (,(if reverse
+             'text-property-search-backward
+           'text-property-search-forward)
+        ,sym t)
+       (setq ,arg (1- ,arg)))))
+
+(defun shortdoc-next (&optional arg)
+  "Move cursor to next function."
+  (interactive "p")
+  (shortdoc--goto-section arg 'shortdoc-function))
+
+(defun shortdoc-previous (&optional arg)
+  "Move cursor to previous function."
+  (interactive "p")
+  (shortdoc--goto-section arg 'shortdoc-function t)
+  ;; FIXME: Why is this needed?
+  (backward-char 1))
+
+(defun shortdoc-next-section (&optional arg)
+  "Move cursor to next section."
+  (interactive "p")
+  (shortdoc--goto-section arg 'shortdoc-section))
+
+(defun shortdoc-previous-section (&optional arg)
+  "Move cursor to previous section."
+  (interactive "p")
+  (shortdoc--goto-section arg 'shortdoc-section t)
+  ;; FIXME: Why is this needed?
+  (forward-line -2))
+
 (provide 'shortdoc)
 
 ;;; shortdoc.el ends here
-- 
2.39.2