nixpkgs/pkgs/applications/editors/emacs/site-start.el
Caleb Chase a131be8f99 emacs: populate load-path recursively
Previous behavior only added <nix_profile>/share/emacs/site-lisp/ and
one level of subdirectories, whereas this commit adds all subdirectories
recursively using normal-top-level-add-subdirs-to-load-path. This
matches the behavior of Emacs on non-Nix distros, which include a
/usr/share/emacs/site-lisp/subdirs.el file with identical recursive
behavior.

See also: https://www.emacswiki.org/emacs/LoadPath
2022-02-22 20:03:35 -06:00

80 lines
3.5 KiB
EmacsLisp

;; -*- lexical-binding: t; -*-
(defun nix--profile-paths ()
"Return a list of all paths in NIX_PROFILES.
The list is ordered from more-specific (the user profile) to the
least specific (the system profile)"
(reverse (split-string (or (getenv "NIX_PROFILES") ""))))
;;; Extend `load-path' to search for elisp files in subdirectories of all folders in `NIX_PROFILES'.
;;; Non-Nix distros have similar logic in /usr/share/emacs/site-lisp/subdirs.el.
;;; See https://www.gnu.org/software/emacs/manual/html_node/elisp/Library-Search.html
(dolist (profile (nix--profile-paths))
(let ((default-directory (expand-file-name "share/emacs/site-lisp/" profile)))
(when (file-exists-p default-directory)
(setq load-path (cons default-directory load-path))
(normal-top-level-add-subdirs-to-load-path))))
;;; Remove wrapper site-lisp from EMACSLOADPATH so it's not propagated
;;; to any other Emacsen that might be started as subprocesses.
(let ((wrapper-site-lisp (getenv "emacsWithPackages_siteLisp"))
(env-load-path (getenv "EMACSLOADPATH")))
(when wrapper-site-lisp
(setenv "emacsWithPackages_siteLisp" nil))
(when (and wrapper-site-lisp env-load-path)
(let* ((env-list (split-string env-load-path ":"))
(new-env-list (delete wrapper-site-lisp env-list)))
(setenv "EMACSLOADPATH" (when new-env-list
(mapconcat 'identity new-env-list ":"))))))
(let ((wrapper-site-lisp (getenv "emacsWithPackages_siteLispNative"))
(env-load-path (getenv "EMACSNATIVELOADPATH")))
(when wrapper-site-lisp
(setenv "emacsWithPackages_siteLispNative" nil))
(when (and wrapper-site-lisp env-load-path)
(let* ((env-list (split-string env-load-path ":"))
(new-env-list (delete wrapper-site-lisp env-list)))
(setenv "EMACSNATIVELOADPATH" (when new-env-list
(mapconcat 'identity new-env-list ":"))))))
;;; Set up native-comp load path.
(when (featurep 'comp)
;; Append native-comp subdirectories from `NIX_PROFILES'.
(setq native-comp-eln-load-path
(append (mapcar (lambda (profile-dir)
(concat profile-dir "/share/emacs/native-lisp/"))
(nix--profile-paths))
native-comp-eln-load-path)))
;;; Make `woman' find the man pages
(defvar woman-manpath)
(eval-after-load 'woman
'(setq woman-manpath
(append (mapcar (lambda (x) (concat x "/share/man/"))
(nix--profile-paths))
woman-manpath)))
;;; Make tramp work for remote NixOS machines
(defvar tramp-remote-path)
(eval-after-load 'tramp-sh
;; TODO: We should also add the other `NIX_PROFILES' to this path.
;; However, these are user-specific, so we would need to discover
;; them dynamically after connecting via `tramp'
'(add-to-list 'tramp-remote-path "/run/current-system/sw/bin"))
;;; C source directory
;;;
;;; Computes the location of the C source directory from the path of
;;; the current file:
;;; from: /nix/store/<hash>-emacs-<version>/share/emacs/site-lisp/site-start.el
;;; to: /nix/store/<hash>-emacs-<version>/share/emacs/<version>/src/
(defvar find-function-C-source-directory)
(let ((emacs
(file-name-directory ; .../emacs/
(directory-file-name ; .../emacs/site-lisp
(file-name-directory load-file-name)))) ; .../emacs/site-lisp/
(version
(file-name-as-directory
emacs-version))
(src (file-name-as-directory "src")))
(setq find-function-C-source-directory (concat emacs version src)))