Use dash instead of underscore

modules/writing.org

@@ -84,6 +84,34 @@ Configure custom keybindings behind =SPC r=.
   "rb" '(org-roam-buffer-toggle-display :which-key "Buffer"))
 #+end_src
 
+** File slugs
+
+The default behaviour of ~org-roam~ when creating a title slug is to replace any non alpha numerical (whitespace) to ~_~. I wanted to change this to use ~_~ and have done so here in my own definition. The only substantial difference from the original definition is the character used.
+
++ Define a new ~title-to-slug~ function
++ Override ~org-roam-title-to-slug-function~
+
+#+begin_src emacs-lisp
+(with-eval-after-load 'org-roam
+  (require 'cl-lib)
+  (defun dotfiles/title-to-slug (title)
+    "Convert TITLE to a filename-suitable slug."
+    (cl-flet* ((nonspacing-mark-p (char)
+                                  (eq 'Mn (get-char-code-property char 'general-category)))
+               (strip-nonspacing-marks (s)
+                                       (apply #'string (seq-remove #'nonspacing-mark-p
+                                                                   (ucs-normalize-NFD-string s))))
+               (cl-replace (title pair)
+                           (replace-regexp-in-string (car pair) (cdr pair) title)))
+      (let* ((pairs `(("[^[:alnum:][:digit:]]" . "-") ;; Convert anything not alphanumeric.
+                      ("--*" . "-")                   ;; Remove sequential dashes.
+                      ("^-" . "")                     ;; Remove starting dashes.
+                      ("-$" . "")))                   ;; Remove ending dashes.
+             (slug (-reduce-from #'cl-replace (strip-nonspacing-marks title) pairs)))
+        (downcase slug))))
+  (setq org-roam-title-to-slug-function #'dotfiles/title-to-slug))
+#+end_src
+
 ** Web visualizer
 
 Including the extension *Org roam server*[fn:5] will run a web application that visualizes the *Org roam*[fn:4] database. Available whenever the editor is running at https://localhost:8080. The image at the top of this page is an example of the application running.