README.org

@@ -59,7 +59,7 @@ you to install a selected set of packages.  Quit Emacs and invoke Emacs again.
 #+name: lst:prepare-user-emacs-directory-with-https
 #+begin_src shell :noeval :tangle no
 cd ~
-git clone https://forge.chapril.org/gav451/emacs.d.git .emacs.d
+git clone https://forge.chapril.org/gav451/emacs.d.git
 make --directory=.emacs.d init
 emacs &
 #+end_src
@@ -69,7 +69,7 @@ emacs &
 #+name: lst:prepare-user-emacs-directory-with-ssh
 #+begin_src shell :noeval :tangle no
 cd ~
-git clone ssh://gitea@forge.chapril.org:222/gav451/emacs.d.git .emacs.d
+git clone ssh://gitea@forge.chapril.org:222/gav451/emacs.d.git
 make --directory=.emacs.d init
 emacs &
 #+end_src
@@ -267,6 +267,8 @@ The [[info:emacs#Init File][init file (info)]] does not load the ~custom-file~ a
                  (hyperbole . "gnu-devel")
                  (marginalia . "gnu-devel")
                  (org . "gnu-devel")
+                 ,(when (version< emacs-version "28.9.9")
+                    '(python . "gnu-devel"))
                  (queue . "gnu")
                  (rainbow-mode . "gnu")
                  (spinner . "gnu")
@@ -281,10 +283,14 @@ The [[info:emacs#Init File][init file (info)]] does not load the ~custom-file~ a
 (custom-set-variables
  '(package-selected-packages
    `,(delq nil `(async              ; asynchroneous processing
+                 auctex             ; Aalborg University Center TeX
                  debbugs            ; access the GNU bug tracker
                  no-littering       ; keep `user-emacs-directory' clean
                  org                ; thought organizer
-                 wgrep))))          ; open a writable grep buffer
+                 ,(when (version< emacs-version "28.9.9")
+                    'python)        ; major mode to edit Python files
+                 wgrep              ; open a writable grep buffer
+                 xr))))             ; undo rx to grok regular expressions
 #+end_src
 
 #+caption[Customize the fourth set of Emacs variables]:
@@ -397,7 +403,7 @@ the contents of packages and allows to update packages to the latest version.
 #+caption: Customize Emacs Tree-sitter.
 #+name: lst:customize-emacs-tree-sitter
 #+begin_src emacs-lisp
-(when (require 'treesit nil 'noerror)
+(when (require 'treesit nil t)
   ;; https://lists.gnu.org/archive/html/emacs-devel/2022-11/msg01372.html
   (let ((tselp (expand-file-name "~/VCS/tree-sitter-module/dist/")))
     (when (file-exists-p tselp)
@@ -1638,22 +1644,6 @@ suggestions on those pages.
      '(xref-search-program 'ugrep))))
 #+end_src
 
-** [[https://github.com/mattiase/xr#readme][XR - Emacs regexp parser and analyzer]]
-:PROPERTIES:
-:CUSTOM_ID: sec:ensure-xr-installation
-:END:
-
-[[https://github.com/mattiase/xr#readme][XR]] converts Emacs regular expressions to the structured =rx= form, thus being an
-inverse of =rx=. It can also find mistakes and questionable constructs inside
-regexp strings.
-
-#+caption[Ensure =xr= installation]:
-#+caption: Ensure =xr= installation.
-#+name: lst:ensure-xr-installation
-#+begin_src emacs-lisp
-(when (ensure-package-installation 'xr))
-#+end_src
-
 * [[info:emacs#Version Control][Version Control (info)]]
 :PROPERTIES:
 :CUSTOM_ID: sec:version-control
@@ -1858,8 +1848,8 @@ elisp library file has no autoload cookie.  Without prior loading of =tex.el=,
 Emacs will complain that ~TeX-master~ is no safe local variable in case it reads
 a LaTeX file that sets ~TeX-master~.  The list below summarizes the main [[https://en.wikipedia.org/wiki/AUCTeX][AUCTeX]]
 configuration objectives:
-1. Listing [[lst:require-tex]] ensures installation of [[https://en.wikipedia.org/wiki/AUCTeX][AUCTeX]] and initializes [[https://en.wikipedia.org/wiki/AUCTeX][AUCTeX]]
+1. Listing [[lst:require-tex]] initializes [[https://en.wikipedia.org/wiki/AUCTeX][AUCTeX]] properly for =LuaTeX= or
-   properly for =LuaTeX= or =LuaLaTeX=.
+ =LuaLaTeX=.
 2. Listing [[lst:require-tex]] also enables [[https://git.savannah.gnu.org/cgit/auctex.git/patch/?id=f464242eab092e610dda6b654e6fd197ef649d3eAA][indenting between square brackets]]
    which is a recent feature.
 3. Listing [[lst:update-lualatex-opentype-font-name-database]] defines a function to
@@ -1875,18 +1865,17 @@ configuration objectives:
 #+caption: Require and configure =TeX=.
 #+name: lst:require-tex
 #+begin_src emacs-lisp
-(when (ensure-package-installation 'auctex)
+;; Use `require' to make `TeX-master' a safe local variable.
-  ;; Use `require' to make `TeX-master' a safe local variable.
+(when (require 'tex nil 'noerror)
-  (when (require 'tex nil 'noerror)
+  (custom-set-variables
-    (custom-set-variables
+   '(TeX-auto-save t)
-     '(TeX-auto-save t)
+   '(TeX-engine 'luatex)
-     '(TeX-engine 'luatex)
+   '(TeX-indent-close-delimiters "]")
-     '(TeX-indent-close-delimiters "]")
+   '(TeX-indent-open-delimiters "[")
-     '(TeX-indent-open-delimiters "[")
+   '(TeX-install-font-lock #'font-latex-setup)
-     '(TeX-install-font-lock #'font-latex-setup)
+   '(TeX-parse-self t)
-     '(TeX-parse-self t)
+   ;; Disable `TeX-electric-math' to prevent collisions with `smartparens'.
-     ;; Disable `TeX-electric-math' to prevent collisions with `smartparens'.
+   '(TeX-electric-math nil)))
-     '(TeX-electric-math nil))))
 #+end_src
 
 #+caption[Update the =LuaLaTeX OpenType Font=  name database]: