Move programs to modules

lib/options.nix

@@ -0,0 +1,35 @@
+{ lib, ... }:
+
+let
+  inherit (lib) mkOption types;
+in
+rec {
+  mkOpt = type: default:
+    mkOption { inherit type default; };
+
+  mkOpt' = type: default: description:
+    mkOption { inherit type default description; };
+
+  mkBoolOpt = default: mkOption {
+    inherit default;
+    type = types.bool;
+    example = true;
+  };
+
+  mkStringOpt = default: mkOption {
+    inherit default;
+    type = types.lines;
+    example = "";
+  };
+
+  mkListOfStringOpt = default: mkOption {
+    inherit default;
+    type = types.listOf types.lines;
+    example = [ "a" "b" "c" ];
+  };
+
+  mkPath = path:
+    if path != null
+    then toString path
+    else "";
+}