nixpkgs/pkgs/build-support/emacs/wrapper.nix
Thomas Tuegel 32c30411cf emacsWithPackages: link packages into single load-path
This should provide a small speed improvement by avoiding having to set
hundreds of load-paths.
2016-01-20 12:53:11 -06:00

116 lines
3.4 KiB
Nix

/*
# Usage
`emacsWithPackages` takes a single argument: a function from a package
set to a list of packages (the packages that will be available in
Emacs). For example,
```
emacsWithPackages (epkgs: [ epkgs.evil epkgs.magit ])
```
All the packages in the list should come from the provided package
set. It is possible to add any package to the list, but the provided
set is guaranteed to have consistent dependencies and be built with
the correct version of Emacs.
# Overriding
`emacsWithPackages` inherits the package set which contains it, so the
correct way to override the provided package set is to override the
set which contains `emacsWithPackages`. For example, to override
`emacsPackagesNg.emacsWithPackages`,
```
let customEmacsPackages =
emacsPackagesNg.override (super: self: {
# use a custom version of emacs
emacs = ...;
# use the unstable MELPA version of magit
magit = self.melpaPackages.magit;
});
in customEmacsPackages.emacsWithPackages (epkgs: [ epkgs.evil epkgs.magit ])
```
*/
{ lib, lndir, makeWrapper, stdenv }: self:
with lib; let inherit (self) emacs; in
packagesFun: # packages explicitly requested by the user
let
explicitRequires =
if builtins.isFunction packagesFun
then packagesFun self
else packagesFun;
in
stdenv.mkDerivation {
name = (appendToName "with-packages" emacs).name;
nativeBuildInputs = [ emacs lndir makeWrapper ];
inherit emacs explicitRequires;
phases = [ "installPhase" ];
installPhase = ''
mkdir -p $out/bin
mkdir -p $out/share/emacs/site-lisp
local requires
for pkg in $explicitRequires; do
findInputs $pkg requires propagated-user-env-packages
done
# requires now holds all requested packages and their transitive dependencies
siteStart="$out/share/emacs/site-lisp/site-start.el"
# Begin the new site-start.el by loading the original, which sets some
# NixOS-specific paths. Paths are searched in the reverse of the order
# they are specified in, so user and system profile paths are searched last.
cat >"$siteStart" <<EOF
(load-file "$emacs/share/emacs/site-lisp/site-start.el")
(add-to-list 'load-path "$out/share/emacs/site-lisp")
EOF
linkPath() {
local pkg=$1
local path=$2
# Add the path to the search path list, but only if it exists
if [[ -d "$pkg/$path" ]]; then
lndir -silent "$pkg/$path" "$out/$path"
fi
}
# Add a package's paths to site-start.el
linkEmacsPackage() {
linkPath "$1" "bin"
linkPath "$1" "share/emacs/site-lisp"
}
# First, link all the explicitly-required packages.
for pkg in $explicitRequires; do
linkEmacsPackage $pkg
done
# Next, link all the dependencies.
for pkg in $requires; do
linkEmacsPackage $pkg
done
# Byte-compiling improves start-up time only slightly, but costs nothing.
emacs --batch -f batch-byte-compile "$siteStart"
# Wrap emacs and friends so they find our site-start.el before the original.
for prog in $emacs/bin/*; do # */
local progname=$(basename "$prog")
rm -f "$out/bin/$progname"
makeWrapper "$prog" "$out/bin/$progname" \
--suffix EMACSLOADPATH ":" "$out/share/emacs/site-lisp:"
done
mkdir -p $out/share
# Link icons and desktop files into place
for dir in applications icons info man; do
ln -s $emacs/share/$dir $out/share/$dir
done
'';
inherit (emacs) meta;
}