example refactor snowflake module system

nix/snow/flake/outputs/nixosConfigurations.nix

@@ -0,0 +1,67 @@
+# {
+#   _module = { ... };
+#   _type = "configuration";
+#   class = null;
+#   config = { ... };
+#   extendModules = «lambda extendModules @ /nix/store/9hfp0agnm43kz72l5lpfn9var5p0x2fa-source/lib/modules.nix:340:9»;
+#   graph = [ ... ];
+#   options = { ... };
+#   type = { ... };
+# }
+    nixosConfigurations = mapNodes nodes (
+      {
+        base,
+        lib,
+        name,
+        node,
+        groupModules,
+        ...
+      }: let
+        homeManager =
+          if node.homeManager != null
+          then node.homeManager
+          else if nodes.homeManager != null
+          then nodes.homeManager
+          else
+            warn ''
+              [snowflake] Neither `nodes.homeManager` nor `nodes.nodes.${name}.homeManager` were specified!
+              [snowflake] home-manager will NOT be used! User configuration will be ignored!
+            ''
+            null;
+
+        userArgs = nodes.args // node.args;
+        ceruleanArgs = {
+          inherit systems root base nodes node;
+          inherit (node) system;
+          inherit (this) snow;
+          hostname = name;
+
+          _cerulean = {
+            inherit inputs userArgs ceruleanArgs homeManager;
+            specialArgs = userArgs // ceruleanArgs;
+          };
+        };
+        specialArgs = assert (userArgs
+          |> attrNames
+          |> all (argName:
+            ! ceruleanArgs ? argName
+            || abort ''
+              `specialArgs` are like super important to Cerulean my love... </3
+              But `args.${argName}` is a reserved argument name :(
+            ''));
+          ceruleanArgs._cerulean.specialArgs;
+      in
+        lib.nixosSystem {
+          inherit (node) system;
+          inherit specialArgs;
+          modules =
+            [
+              self.nixosModules.default
+              (this.findImport /${root}/hosts/${name})
+            ]
+            ++ (groupModules root)
+            ++ node.modules
+            ++ nodes.modules;
+        }
+    );
+