Overrides on different sytems?

[TRPB]

I'd like to set a few different global variables on different systems (scaling, some paths configured in vim.g). This might be a documentation issue but I couldn't work out how to do it.

When loading the flake, it would be nice if I could override vim.g.foo variables.

I think we'd need to do something like

{

  inputs = {

    nixpkgs.url = "github:nixos/nixpkgs/release-24.05";
    nixvim.url = "github:account/repo";
  };

  outputs =
    {
      self,
      nixpkgs,
      nixvim,
      ...
    }@inputs:
    let
      pkgs = nixpkgs.legacyPackages.x86_64-linux;
    in
    {
      nixosConfigurations.systemname = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          nixvim.modules.nixvimConfig
          ./systemconfig.nix
        ];
      };
}

Then in a module call nixvim.settings.g.variablename = 'x';

I had a look through the code, it does export some modules but I don't think I can easily override settings.

I'd also like to do this on a machine with a different using nix run but I assume that's a different challenge (or home-manager but I don't know how to import flakes into the home manager config)

[traxys]

You could approach that by multiple means:

• If you use the standalone nixvim module the resulting package exposes a .extend { .... } function that allows to apply additional settings, so you could condition to the system
• You can use multiple nix files, one for your "common" code, and then different ones for each system. You can the include them in the modules
• You can use some.nixvim.option = mkIf (pkgs.stdenv.isAaarch64) { ..... } to enable something only for aarch64 systems

[MattSturgeon]

IMO it's best to keep this kinda logic internal to modual eval whenever possible, so I would recomend using pkgs.stdenv for this.

To expand on #2372 (comment), you can leverage several attrs:

pkgs.stdenv.__bootPackages            pkgs.stdenv.extraBuildInputs          pkgs.stdenv.isFreeBSD                 pkgs.stdenv.overrideDerivation
pkgs.stdenv.__extraImpureHostDeps     pkgs.stdenv.extraNativeBuildInputs    pkgs.stdenv.isLinux                   pkgs.stdenv.overrides
pkgs.stdenv.__hatPackages             pkgs.stdenv.extraSandboxProfile       pkgs.stdenv.isMips                    pkgs.stdenv.passthru
pkgs.stdenv.all                       pkgs.stdenv.fetchurlBoot              pkgs.stdenv.isOpenBSD                 pkgs.stdenv.preHook
pkgs.stdenv.allowedRequisites         pkgs.stdenv.hasCC                     pkgs.stdenv.isSunOS                   pkgs.stdenv.setup
pkgs.stdenv.args                      pkgs.stdenv.hostPlatform              pkgs.stdenv.isi686                    pkgs.stdenv.shell
pkgs.stdenv.bootstrapTools            pkgs.stdenv.initialPath               pkgs.stdenv.isx86_32                  pkgs.stdenv.shellDryRun
pkgs.stdenv.buildPlatform             pkgs.stdenv.is32bit                   pkgs.stdenv.isx86_64                  pkgs.stdenv.shellPackage
pkgs.stdenv.builder                   pkgs.stdenv.is64bit                   pkgs.stdenv.meta                      pkgs.stdenv.system
pkgs.stdenv.cc                        pkgs.stdenv.isAarch32                 pkgs.stdenv.mkDerivation              pkgs.stdenv.targetPlatform
pkgs.stdenv.defaultBuildInputs        pkgs.stdenv.isAarch64                 pkgs.stdenv.name                      pkgs.stdenv.tests
pkgs.stdenv.defaultNativeBuildInputs  pkgs.stdenv.isBSD                     pkgs.stdenv.out                       pkgs.stdenv.type
pkgs.stdenv.disallowedRequisites      pkgs.stdenv.isBigEndian               pkgs.stdenv.outPath
pkgs.stdenv.drvAttrs                  pkgs.stdenv.isCygwin                  pkgs.stdenv.outputName
pkgs.stdenv.drvPath                   pkgs.stdenv.isDarwin                  pkgs.stdenv.override

In particular, hostPlatform.system¹ will tell you the system string for the targeted platform. In addition there's several is* helpers, such as isDarwin, isLinux, isx86_64, is64bit, etc.

Footnotes

1. using pkgs.stdenv.hostPlatform.system is preferred over directly using pkgs.stdenv.system or pkgs.system for several reasons, in particular it allows for cross-compilation. ↩