From 706d5d71cdf1ed2528664bdaf714aad6bd15af6c Mon Sep 17 00:00:00 2001
From: Psionik K <73710933+psionic-k@users.noreply.github.com>
Date: Wed, 10 Jan 2024 23:15:26 +0900
Subject: [PATCH] org.el: introducing org-fill-buffer

* lisp/org.el: (org-fill-buffer) this command walks the tree and will
call fill-paragraph on every paragraph or plain-list element, enabling
the user to quickly cycle between hard newlines or visual-line-mode.
They can also adjust the fill, such as after removing indentation.
---
 lisp/org.el | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/lisp/org.el b/lisp/org.el
index 57379c26..1becc394 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -21901,6 +21901,38 @@ modified."
 		      (org-do-remove-indentation))))))))
     (funcall unindent-tree (org-element-contents parse-tree))))
 
+(defun org-fill-buffer ()
+  "Fill all paragraph and plain-list elements.
+This command can be used to add hard newlines or to remove them.
+To add hard newlines for text filling, set `fill-column' to the
+desired with.  To remove hard newlines, such as to prepare the
+contents for `visual-line-mode', set `fill-column' to
+`most-positive-fixnum'."
+  (interactive)
+  (unless (and  (eq major-mode 'org-mode))
+    (user-error "Cannot fill a buffer not in Org mode"))
+  (letrec ((parse-tree (org-element-parse-buffer 'greater-element nil 'defer))
+           (fill-tree
+	    (lambda (contents)
+	      (dolist (element (reverse contents))
+                (let ((type (org-element-type element)))
+		  (if (member type  '(headline section))
+		      (funcall fill-tree (org-element-contents element))
+		    (save-excursion
+		      (save-restriction
+		        (narrow-to-region
+		         (org-element-begin element)
+		         (org-element-end element))
+                        (goto-char (point-min))
+                        (pcase type
+                          (`paragraph (fill-paragraph))
+                          (`plain-list
+                           (mapc (lambda (i)
+                              (goto-char (car i))
+                              (fill-paragraph))
+                            (reverse (org-list-struct)))))))))))))
+    (funcall fill-tree (org-element-contents parse-tree))))
+
 (defun org-make-options-regexp (kwds &optional extra)
   "Make a regular expression for keyword lines.
 KWDS is a list of keywords, as strings.  Optional argument EXTRA,
-- 
2.42.0