From ef1b005f5ce53cf099e5eaf1bb4630f4ea34f04a Mon Sep 17 00:00:00 2001
From: Case Duckworth
Date: Sat, 2 Jan 2021 22:52:00 -0600
Subject: Make anchors in Org more useful

---
 config.org | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/config.org b/config.org
index 65dc47a..93e136d 100644
--- a/config.org
+++ b/config.org
@@ -1488,6 +1488,47 @@ I’ve put org mode under Applications, as opposed to Writing, because it’s  m
       (add-hook 'emacs-lisp-mode-hook #'org-link-minor-mode)
     #+end_src
 
+*** Useful HTML Anchors
+
+    #+begin_src emacs-lisp
+      (defun my/ensure-headline-ids (&rest _)
+	"Ensure better headlines for Org trees.
+
+      Use CUSTOM_ID property, or barring that, a \"fixed\" title.
+
+      All non-alphanumeric characters are cleverly replaced with ‘-’.
+
+      If multiple trees end-up with the same id property, issue a
+      message and undo any property insertion thus far.
+
+      E.g., ↯ We'll go on a ∀∃⇅ adventure
+	 ↦  We'll-go-on-a-adventure
+      "
+	(interactive)
+	(let ((ids))
+	  (org-map-entries
+	   (lambda ()
+	     (org-with-point-at (point)
+	       (let ((id (org-entry-get nil "CUSTOM_ID")))
+		 (unless id
+		   (thread-last (nth 4 (org-heading-components))
+		     (s-replace-regexp "[^[:alnum:]']" "-")
+		     (s-replace-regexp "-+" "-")
+		     (s-chop-prefix "-")
+		     (s-chop-suffix "-")
+		     (setq id))
+		   (if (not (member id ids))
+		       (push id ids)
+		     (message-box "Oh no, a repeated id!\n\n\t%s" id)
+		     (undo)
+		     (setq quit-flag t))
+		   (org-entry-put nil "CUSTOM_ID" id))))))))
+
+      ;; Whenever html & md export happens, ensure we have headline ids.
+      (advice-add 'org-html-export-to-html   :before 'my/ensure-headline-ids)
+      (advice-add 'org-md-export-to-markdown :before 'my/ensure-headline-ids)
+    #+end_src
+
 ** Git
 
 #+begin_src emacs-lisp
-- 
cgit 1.4.1-21-gabe81