chore: initial commit

lib/module/default.nix

@@ -0,0 +1,48 @@
+{ core-inputs
+, user-inputs
+, snowfall-lib
+}:
+
+let
+  inherit (builtins) baseNameOf;
+  inherit (core-inputs.nixpkgs.lib) assertMsg foldl;
+
+  user-modules-root = snowfall-lib.fs.get-file "modules";
+in
+{
+  module = {
+    # Create flake output modules.
+    # Type: Attrs -> Attrs
+    # Usage: create-modules { src = ./my-modules; overrides = { inherit another-module; default = "my-module"; }; }
+    #   result: { another-module = ...; my-module = ...; default = ...; }
+    create-modules =
+      { src ? user-modules-root
+      , overrides ? { }
+      }:
+      let
+        user-modules = snowfall-lib.fs.get-default-nix-files-recursive src;
+        create-module-metadata = module: {
+          name = builtins.unsafeDiscardStringContext (snowfall-lib.path.get-parent-directory module);
+          path = module;
+        };
+        modules-metadata = builtins.map create-module-metadata user-modules;
+        merge-modules = modules: metadata:
+          modules // {
+            ${metadata.name} = metadata.path;
+          };
+        modules-without-default = foldl merge-modules { } modules-metadata;
+        default-module =
+          if overrides.default or null == null then
+            { }
+          else if builtins.isAttrs overrides.default then
+            { default = overrides.default; }
+          else if modules-without-default.${overrides.default} or null != null then
+            { default = modules-without-default.${overrides.default}; }
+          else
+            { };
+        overrides-without-default = builtins.removeAttrs overrides [ "default" ];
+        modules = modules-without-default // default-module // overrides-without-default;
+      in
+      modules;
+  };
+}