emacs: Add more documentation to site-start.el

`site-start.el` is the file loaded on startup, containing nix-specific
customizations like adding paths in `NIX_PROFILES` to the
emacs-specific search-path (`load-path`) or making man-pages in these
directories discoverable.
This commit is contained in:
Moritz Ulrich 2018-01-04 11:16:35 +01:00
parent 6484eac5b2
commit 1543c8cc01
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@ -1,18 +1,28 @@
;;; NixOS specific load-path
(defun nix--profile-paths ()
"Returns a list of all paths in the NIX_PROFILES environment
variable, 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'
(setq load-path
(append (reverse (mapcar (lambda (x) (concat x "/share/emacs/site-lisp/"))
(split-string (or (getenv "NIX_PROFILES") ""))))
(append (mapcar (lambda (x) (concat x "/share/emacs/site-lisp/"))
(nix--profile-paths))
load-path))
;;; Make `woman' find the man pages
(eval-after-load 'woman
'(setq woman-manpath
(append (reverse (mapcar (lambda (x) (concat x "/share/man/"))
(split-string (or (getenv "NIX_PROFILES") ""))))
(append (mapcar (lambda (x) (concat x "/share/man/"))
(nix--profile-paths))
woman-manpath)))
;;; Make tramp work for remote NixOS machines
(eval-after-load 'tramp
;; 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
@ -22,9 +32,9 @@
;;; from: /nix/store/<hash>-emacs-<version>/share/emacs/site-lisp/site-start.el
;;; to: /nix/store/<hash>-emacs-<version>/share/emacs/<version>/src/
(let ((emacs
(file-name-directory ;; .../emacs/
(directory-file-name ;; .../emacs/site-lisp
(file-name-directory load-file-name)))) ;; .../emacs/site-lisp/
(file-name-directory ; .../emacs/
(directory-file-name ; .../emacs/site-lisp
(file-name-directory load-file-name)))) ; .../emacs/site-lisp/
(version
(file-name-as-directory
(concat