How to reference declared variable in application config?

Help
1

Hello, using NixOS Unstable with Flakes/Home-Manager

I am trying to set some variable so abstract some of the configuration between programs. Setting the variables seems simple enough, that is no problem and I have ECHO’d to confirm they are working.

However, when I set my variable as a binding in Hyprland for example I am not having any luck. This is probably a simple problem to solve but I can’t find the proper information.

I have it set as such in home.nix

  home = {
    username = "cmde";
    homeDirectory = "/home/cmde";
    stateVersion = "23.11";
  
    sessionPath = [ "~/.env" ];
    sessionVariables = {
    EDITOR = "hx";

    MOD = "SUPER";

    LEFT  = "n";
    DOWN  = "e";
    UP    = "i";
    RIGHT = "o";
    };
  
  };

and the offending line in hyprland.nix

    "$MOD, $RIGHT, layoutmsg, cyclenext"

Is there some syntax I need to use to delimiter or import the variables manually somehow? Thanks in advance.

2

Nix cannot read environment variables at build time. The variables won’t be set until the configuration is already running.

Either set the variables in a custom option to use them during the build, or use whatever functionality hyprland has to read environment variables when it’s running.