Thank you. I was aware of that, but was just being plain lazy.. I didn't consider refactoring my whole config to fix that until now[1], so thanks :)
Here's the improved code:
(let* ((bin-dir (when (and invocation-directory
(file-exists-p invocation-directory))
(file-truename invocation-directory)))
(prefix-dir (when bin-dir ;Because bin-dir = prefix-dir + "bin/"
(file-name-directory (directory-file-name bin-dir))))
(share-dir (when (and prefix-dir
(file-exists-p prefix-dir))
(file-name-as-directory (expand-file-name "share" prefix-dir))))
(emacs-dir (when (and share-dir
(file-exists-p share-dir))
(file-name-as-directory (expand-file-name "emacs" share-dir))))
(version-dir (when emacs-dir
;; Possibility where the lisp dir is something like
;; ../emacs/26.0.50/lisp/. If `emacs-version' is x.y.z.w,
;; remove the ".w" portion. Though, this is not needed
;; for emacs 26+, and also will do nothing in that case.
;;
http://git.savannah.gnu.org/cgit/emacs.git/commit/?id=22b2207471807bda86534b4faf1a29b3a6447536 (let* ((version (replace-regexp-in-string "\\([0-9]+\\.[0-9]+\\.[0-9]+\\).*" "\\1" emacs-version))
(version-dir-1 (file-name-as-directory (expand-file-name version emacs-dir))))
(if (file-exists-p version-dir-1)
version-dir-1
;; Possibility where the lisp dir is something like
;; ../emacs/25.2/lisp/. If `emacs-version' is x.y.z,
;; remove the ".z" portion.
(setq version (replace-regexp-in-string "\\([0-9]+\\.[0-9]+\\).*" "\\1" emacs-version))
(setq version-dir-1 (file-name-as-directory (expand-file-name version emacs-dir)))
(when (file-exists-p version-dir-1)
version-dir-1)))))
(lisp-dir (file-name-as-directory (expand-file-name "lisp" version-dir))))
(defvar modi/default-share-directory (when (file-exists-p share-dir)
share-dir)
"Share directory for this Emacs installation.")
(defvar modi/default-lisp-directory (when (file-exists-p lisp-dir)
lisp-dir)
"Directory containing lisp files for the Emacs installation.
This value must match the path to the lisp/ directory of the
Emacs installation. If Emacs is installed using
--prefix=\"${PREFIX_DIR}\" this value would typically be
\"${PREFIX_DIR}/share/emacs/<VERSION>/lisp/\"."))
I think it would be useful to include the share/ and lisp/ dirs stored in some variable in emacs core, just like invocation-directory.
[1]:
https://github.com/kaushalmodi/.emacs.d/commit/64b0c3fbf3372bd96a32d1f24d9adeb9112abd08