improve module system more

lib/default.nix

@@ -32,15 +32,14 @@ in rec {
   mkSystem = hostname:
     nixosSystem {
       system = "x86_64-linux";
-      modules = [
+      modules =
+        [
           ../modules/common.nix
-
-          # ({...}: nixpkgs.overlays = [ import ../overlays {}; ])
-          (_:
-            { nixpkgs.overlays = import ../overlays _ ++
-              [inputs.pinix.overlays.default]; })
+          ../overlays
         ]
-        ++ filter isNixFile (listFilesRecursive (../. + "/hosts/${hostname}"));
+        ++ filter
+        isNixFile
+        (listFilesRecursive (../. + "/hosts/${hostname}"));
 
       specialArgs = {inherit inputs mkRune;};
     };

overlays/default.nix

@@ -1,14 +1,18 @@
-# import all nix files in the current folder,
-# and execute them with args as parameters
-# The return value is a list of all execution results,
-# which is the list of overlays
-args:
-# execute and import all overlay files in the current
-# directory with the given args
-builtins.map
-# execute and import the overlay file
-(f: (import (./. + "/${f}") args))
-# find all overlay files in the current directory
-(builtins.filter
+{inputs, ...}: let
+  defaultOverlays =
+    # execute and import all overlay files in the current
+    # directory with the given args
+    builtins.map
+    # execute and import the overlay file
+    (f: (import (./. + "/${f}") {inherit inputs;}))
+    # find all overlay files in the current directory
+    (builtins.filter
       (f: f != "default.nix")
-  (builtins.attrNames (builtins.readDir ./.)))
+      (builtins.attrNames (builtins.readDir ./.)));
+in {
+  nixpkgs.overlays =
+    defaultOverlays
+    ++ [
+      inputs.pinix.overlays.default
+    ];
+}