From 0da38f08349e4f5b52aed3ef359be29efd121770 Mon Sep 17 00:00:00 2001
From: Gerard Vermeulen <gerard.vermeulen@posteo.net>
Date: Sun, 21 Jan 2024 17:29:41 +0100
Subject: [PATCH] Add a section on "Buffer properties" with tools to handle
 those.

---
 README.org | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/README.org b/README.org
index 2ca5e07..b1206ed 100644
--- a/README.org
+++ b/README.org
@@ -2965,6 +2965,60 @@ to add =HTML+CSS+JS= for ~mhtml-mode~:
 )
 #+end_src
 
+*** [[info:org#In-buffer Settings][Buffer properties]]
+:PROPERTIES:
+:CUSTOM_ID: sec:buffer-properties
+:END:
+
+#+caption[Buffer properties]:
+#+caption: Buffer properties.
+#+name: lst:buffer-properties
+#+begin_src emacs-lisp -n
+(with-eval-after-load 'org
+  (defconst prop-comments-link-re
+    "\\( :comments link$\\)\\|\\( *$\\)"
+    "Regexp to find \"#+property:\" \":comments link\".")
+
+
+  (defconst prop-ha-re-template
+    (format "\\(?:^[[:blank:]]*#\\+%s:[[:blank:]]+%s:%s\\+*\\)+"
+            "property" "header-args" "%s")
+    "Regexp template to find `#+property:' header-args:any-language.")
+
+  (defconst prop-emacs-lisp-ha-re
+    (format prop-ha-re-template "emacs-lisp")
+    "Regexp to find `#+property:' Emacs Lisp header arguments.")
+
+  (defconst prop-python-ha-re
+    (format prop-ha-re-template "python")
+    "Regexp to find `#+property:' Python header arguments.")
+
+  (defun prop-python-link-comments-toggle ()
+    (interactive)
+    (save-excursion
+      (goto-char (point-min))
+      (if (re-search-forward prop-python-ha-re nil 'noerror)
+          (if (re-search-forward prop-comments-link-re nil t)
+              (if (match-string 1)
+                  (replace-match " ")
+                (replace-match " :comments link"))
+            (user-error "Found no python link comment"))
+        (user-error "Found no python header arguments property")))
+    (move-beginning-of-line 1)
+    (org-ctrl-c-ctrl-c))
+
+  (defun org-get-buffer-properties ()
+    "Get all properties in buffer."
+    (org-element-map (org-element-parse-buffer) 'keyword
+      (lambda (el)
+        (and ;; Use (upcase "property"), else it fails.
+         (string= (org-element-property :key el) "PROPERTY")
+         (let* ((strings (split-string (org-element-property :value el)))
+                (value (string-join (cdr strings) " "))
+                (name (car strings)))
+           (cons name value)))))))
+#+end_src
+
 ***  [[info:org#Column View][Column View (info)]] and [[info:org#Property Syntax][Property Syntax (info)]]
 :PROPERTIES:
 :CUSTOM_ID: sec:using-properties