Tangle to ./site-lisp to zap user-emacs-directory' from load-path'

README.org

@@ -315,8 +315,6 @@ recommendation of [[info:emacs#Saving Customizations][saving customizations (inf
 #+caption: Set the third set of Emacs options: upgrade Org and transient.
 #+name: lst:3rd-setopt-call
 #+begin_src emacs-lisp -n
-;; To test my own stuff in my `emacs-user-directory:'
-(push (expand-file-name user-emacs-directory) load-path)
 ;; To use an Org git clone:
 (push (expand-file-name "~/VCS/org-mode/lisp") load-path)
 ;; Postpone (require 'org) after shadowing Org and sh-script faces below.
@@ -2246,8 +2244,9 @@ list detailing and motivating each listing:
 1. Listing [[lst:set-org-options]] handles basic [[https://orgmode.org/][Org-mode]] options.
 2. Listing [[lst:setup-org-babel]] handles basic [[https://orgmode.org/][Org-mode]] options specific to
    [[info:org#Working with Source Code][work with source code (info)]].
-3. Listing [[lst:ob-tangle-plus]] extends [[info:org#Noweb Reference Syntax][source code export (info)]] with user
-   friendly commands.
+3. Listing [[lst:ob-tangle-plus]] extends [[info:org#Noweb Reference Syntax][source code export (info)]] with the
+   possibility to tangle Emacs Lisp files into a directory specified by a
+   top-level variable.
 4. Listing [[lst:set-org-link-options]] handles [[https://orgmode.org/][Org-mode]] options specific to
    [[info:org#Hyperlinks][hyperlinks (info)]].
 5. Listing [[lst:setup-org-mode-map]] extends the =org-mode-map= with useful
@@ -2340,46 +2339,32 @@ list detailing and motivating each listing:
 #+name: lst:ob-tangle-plus
 #+begin_src emacs-lisp -n
 (with-eval-after-load 'emacs
-  (defun set-org-babel-language-activity (lang active)
-    "Set the `org-babel' activity of language LANG to ACTIVE.
+  ;; Modified from https://emacs.stackexchange.com/a/61364 which replies to
+  ;; https://emacs.stackexchange.com/questions/61359/
+  ;; "How to specify a directory to tangle all code blocks into".
+  (defvar post-tangle-hook-dir nil
+    "Destination directory used by `dir+org-babel-post-tangle'.
+May be changed by `toggle-post-tangle-hook-dir-usage'.")
 
-Let `org-babel-do-load-languages' load ob-LANG when ACTIVE is t or
-unbind the `org-babel' interface functions when ACTIVE is nil."
-    (if (locate-library (format "ob-%s" lang))
-        (or (org-babel-do-load-languages
-             'org-babel-load-languages
-             (cons (cons lang active)
-                   (assq-delete-all
-                    lang (default-toplevel-value 'org-babel-load-languages))))
-            org-babel-load-languages)
-      (warn "Can't locate `ob-%s', hence don't set `%s' activity" lang lang)))
+  (defun dir+org-babel-post-tangle ()
+    "Function to hook on `org-babel-post-tangle-hook'."
+    (when (and (bound-and-true-p post-tangle-hook-dir)
+               (derived-mode-p '(emacs-lisp-mode)))
+        (message "Tangle into `%S'" post-tangle-hook-dir)
+        (rename-file (buffer-file-name) post-tangle-hook-dir t)))
 
-  (defun activate-org-babel-language (lang)
-    "Activate LANG for `org-babel'."
-    (interactive "SActivate language: ")
-    (if (set-org-babel-language-activity lang t)
-        (message "Did activate `%s' for `org-babel'" lang)
-      (message "Can't activate `%s' for `org-babel'" lang)))
-
-  (defun deactivate-org-babel-language (lang)
-    "Activate LANG for `org-babel'."
-    (interactive "SDeactivate language: ")
-    (if (set-org-babel-language-activity lang nil)
-        (message "Did deactivate `%s' for `org-babel'" lang)
-      (message "Can't deactivate `%s' for `org-babel'" lang)))
-
-  ;; https://readingworldmagazine.com/emacs/2023-06-11-introducing-org-mode/
-  (defun org-babel-tangle-block()
-    "Tangle single source blocks."
+  (defun toggle-post-tangle-hook-dir-usage ()
+    "Toggle tangling to `post-tangle-hook-dir' by `dir+org-babel-post-tangle'."
     (interactive)
-    (let ((current-prefix-arg '(4)))    ;; C-u C-c C-v t
-      (call-interactively 'org-babel-tangle)))
-
-  (defun org-babel-tangle-collect()
-    "Collect all source blocks with the same target file and tangle."
-    (interactive)
-    (let ((current-prefix-arg '(16)))   ;; C-u C-u C-c C-v t
-      (call-interactively 'org-babel-tangle))))
+    (if (member 'dir+org-babel-post-tangle org-babel-post-tangle-hook)
+        (progn
+          (setq post-tangle-hook-dir nil)
+          (message "Disable tangling into `post-tangle-hook-dir'")
+          (remove-hook 'org-babel-post-tangle-hook #'dir+org-babel-post-tangle))
+      (setq post-tangle-hook-dir (org-entry-get nil "post-tangle-hook-dir" t))
+      (message "Enable tangling into `post-tangle-hook-dir' which equals `%S'"
+               post-tangle-hook-dir)
+      (add-hook 'org-babel-post-tangle-hook #'dir+org-babel-post-tangle))))
 #+end_src
 
 #+caption[Set =org-link= options]: