nixpkgs/pkgs/build-support/emacs/setup-hook.sh
Robert Helgesson 2d2de743d0
emacs: improve setup hook
- Add packages installed in a sub-directory of site-lisp, such as
  mu4e, to EMACSLOADPATH.

- Add ELPA packages to EMACSLOADPATH.

- Add each package only once to EMACSLOADPATH. Before, each package
  would typically be added twice for each transitive dependency
  leading to a huge variable for a package having many dependencies.

Fixed #78680
2020-03-14 19:46:28 +01:00

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addEmacsVars () {
for lispDir in \
"$1/share/emacs/site-lisp" \
"$1/share/emacs/site-lisp/"* \
"$1/share/emacs/site-lisp/elpa/"*; do
# Add the path to the Emacs load path if it is a directory
# containing .el files and it has not already been added to the
# load path.
if [[ -d $lispDir && "$(echo "$lispDir"/*.el)" && ${EMACSLOADPATH-} != *"$lispDir":* ]] ; then
# It turns out, that the trailing : is actually required
# see https://www.gnu.org/software/emacs/manual/html_node/elisp/Library-Search.html
export EMACSLOADPATH="$lispDir:${EMACSLOADPATH-}"
fi
done
}
if [[ ! -v emacsHookDone ]]; then
emacsHookDone=1
# If this is for a wrapper derivation, emacs and the dependencies are all
# run-time dependencies. If this is for precompiling packages into bytecode,
# emacs is a compile-time dependency of the package.
addEnvHooks "$hostOffset" addEmacsVars
addEnvHooks "$targetOffset" addEmacsVars
fi