4 files changed, 64 insertions, 0 deletions
diff --git a/modules/default.nix b/modules/default.nix
new file mode 100644
index 0000000..0c1f907
--- /dev/null
+++ b/modules/default.nix
@@ -0,0 +1,7 @@
+{
+  imports = [
+    ./outputs.nix
+    ./pkgs.nix
+    ./sources.nix
+  ];
+}
diff --git a/modules/outputs.nix b/modules/outputs.nix
new file mode 100644
index 0000000..3ceaf7c
--- /dev/null
+++ b/modules/outputs.nix
@@ -0,0 +1,15 @@
+{ lib, ... }:
+
+let
+  outputsSubmodule = {
+    freeformType = lib.types.lazyAttrsOf lib.types.raw;
+  };
+in
+
+{
+  options.outputs = lib.mkOption {
+    type = lib.types.submodule outputsSubmodule;
+    default = { };
+    description = "Outputs to pass to the top-level file.";
+  };
+}
diff --git a/modules/pkgs.nix b/modules/pkgs.nix
new file mode 100644
index 0000000..d984859
--- /dev/null
+++ b/modules/pkgs.nix
@@ -0,0 +1,22 @@
+{ config, lib, ... }:
+
+{
+  options.pkgs = lib.mkOption {
+    type = lib.types.nullOr (lib.types.lazyAttrsOf lib.types.raw);
+    default =
+      if (config.sources ? "nixpkgs") then
+        import config.sources.nixpkgs {
+          config = { };
+          overlays = [ ];
+        }
+      else
+        null;
+    defaultText = "if (sources has nixpkgs) import sources.nixpkgs { ... } else null";
+    description = "The instance of `nixpkgs` to pass as a module argument.";
+    example = lib.literalExpression "import <nixpkgs> { config = { allowUnfree = true; }; }";
+  };
+
+  config = {
+    _module.args = { inherit (config) pkgs; };
+  };
+}
diff --git a/modules/sources.nix b/modules/sources.nix
new file mode 100644
index 0000000..6fb8d32
--- /dev/null
+++ b/modules/sources.nix
@@ -0,0 +1,20 @@
+{ config, lib, ... }:
+
+let
+  sourcesSubmodule = {
+    freeformType = lib.types.lazyAttrsOf lib.types.raw;
+  };
+in
+
+{
+  options.sources = lib.mkOption {
+    type = lib.types.submodule sourcesSubmodule;
+    default = { };
+    description = "Sources used across modules.";
+    example = lib.literalExpression "import ./npins";
+  };
+
+  config = {
+    _module.args = { inherit (config) sources; };
+  };
+}