emacs-overlay/elisp.nix

68 lines
2 KiB
Nix

/*
Parse an emacs lisp configuration file to derive packages from
use-package declarations.
*/
{ pkgs }:
let
parse = pkgs.callPackage ./parse.nix { };
inherit (pkgs) lib;
in
{ config
# emulate `use-package-always-ensure` behavior (defaulting to false)
, alwaysEnsure ? null
# emulate `#+PROPERTY: header-args:emacs-lisp :tangle yes`
, alwaysTangle ? false
, extraEmacsPackages ? epkgs: [ ]
, package ? pkgs.emacs
, override ? (epkgs: epkgs)
}:
let
ensureNotice = ''
Emacs-overlay API breakage notice:
Previously emacsWithPackagesFromUsePackage always added every use-package definition to the closure.
Now we will only add packages with `:ensure`, `:ensure t` or `:ensure <package name>`.
You can get back the old behaviour by passing `alwaysEnsure = true`.
For a more in-depth usage example see https://github.com/nix-community/emacs-overlay#extra-library-functionality
'';
doEnsure = if (alwaysEnsure == null) then builtins.trace ensureNotice false else alwaysEnsure;
isOrgModeFile =
let
ext = lib.last (builtins.split "\\." (builtins.toString config));
type = builtins.typeOf config;
in
type == "path" && ext == "org";
configText =
let
type = builtins.typeOf config;
in
if type == "string" then config
else if type == "path" then builtins.readFile config
else throw "Unsupported type for config: \"${type}\"";
packages = parse.parsePackagesFromUsePackage {
inherit configText isOrgModeFile alwaysTangle;
alwaysEnsure = doEnsure;
};
emacsPackages = pkgs.emacsPackagesGen package;
emacsWithPackages = emacsPackages.emacsWithPackages;
mkPackageError = name:
let
errorFun = if alwaysEnsure then builtins.trace else throw;
in
errorFun "Emacs package ${name}, declared wanted with use-package, not found." null;
in
emacsWithPackages (epkgs:
let
overridden = override epkgs;
usePkgs = map (name: overridden.${name} or (mkPackageError name)) packages;
extraPkgs = extraEmacsPackages overridden;
in
usePkgs ++ extraPkgs)