default.nix

{ config, pkgs, lib, ... }:

with lib;

let
  cfg = config.programs.emacs.org-build;
in

{
  options.programs.emacs.org-build = {
    enable = mkEnableOption "Build init.el from Orgmode file";
    source = mkOption {
      type = types.path;
      description = ''
        The source orgfile to build as init.el
      '';
    };
  };

  config = mkIf cfg.enable {
    home.file.".emacs.d/init.el".source = import ./release.nix {
      inherit pkgs;
      ssource = cfg.source;
    };
  };
}

osx.nix

{ config, pkgs, ... }:

# Import hm-org-build channel.
# sudo nix-channel --add https://github.com/dustinlacewell/nix-hm-org-build/archive/master.tar.gz hm-org-build
# sudo nix-channel --update

{
  # Import org-build modules.
  imports = [ <hm-org-build> ];

  programs.emacs.enable = true;
  programs.emacs.org-build.enable = true;
}

release.nix

{ pkgs, source ? ./. }:

rec {
  build = let
    # the build uses emacs to perform the conversion
    env = { buildInputs = [ pkgs.emacs ]; };
    # call make-init-el to convert the file
    script = ''
      ln -s "${source}" ./init.org;
      emacs -Q --script "${./org-build.el}" -f make-init-el;
      cp ./init.el $out;
    '';
  in pkgs.runCommand "org-build" env script;
}