refactor: add lib.my for useful functions

flake.nix

@@ -104,11 +104,17 @@
 
       channelsConfig.allowUnfree = true;
 
+      lib = nixpkgs.lib.extend
+        (self: super: { my = import ./lib { lib = self; }; });
+
       ################
       ### Overlays ###
       ################
 
-      overlay = import ./overlays { inherit inputs; };
+      overlay = import ./overlays {
+        inherit inputs;
+        inherit (self) lib;
+      };
 
       channels.nixpkgs.overlaysBuilder = channels: [
         inputs.emacs.overlays.default
@@ -134,8 +140,8 @@
         ./modules/profiles/gaming.nix
         ./modules/profiles/desktop.nix
       ];
-
-      hostDefaults.modules = [
+      hostDefaults = {
+        modules = [
           ./modules/default.nix
           self.nixosModules.base
           inputs.home-manager.nixosModule
@@ -150,6 +156,7 @@
           inputs.agenix.nixosModules.age
           inputs.howdy.nixosModules.default
         ];
+      };
 
       hosts.nixos-laptop.modules = [
         ./hosts/nixos-laptop

lib/default.nix

@@ -0,0 +1,16 @@
+{ lib, ... }:
+
+lib.makeExtensible (self: rec {
+  mkDate = longDate: lib.concatStringsSep "-" [
+    (builtins.substring 0 4 longDate)
+    (builtins.substring 4 2 longDate)
+    (builtins.substring 6 2 longDate)
+  ];
+  mkVersionSrc = src: "unstable-" + builtins.substring 0 7 src.rev;
+  mkVersionInput = input:
+    let
+      date = mkDate (input.lastModifiedDate or "19700101");
+      rev = input.shortRev or "dirty";
+    in
+    "unstable-${date}_${rev}}";
+})