1 files changed, 21 insertions, 0 deletions
diff --git a/lib/modules.nix b/lib/modules.nix
new file mode 100644
index 000000000..248e638ea
--- /dev/null
+++ b/lib/modules.nix
@@ -0,0 +1,21 @@
+let
+  pkgs = import <nixpkgs> {};
+  inherit (pkgs.lib) concatMap hasAttr;
+in rec {
+
+  no-touch-args = {
+    config = throw "no-touch-args: can't touch config!";
+    lib = throw "no-touch-args: can't touch lib!";
+    pkgs = throw "no-touch-args: can't touch pkgs!";
+  };
+
+  # list-imports : path -> [path]
+  # Return a module's transitive list of imports.
+  # XXX duplicates won't get eliminated from the result.
+  list-imports = path:
+    let module = import path no-touch-args;
+        imports = if hasAttr "imports" module
+                    then concatMap list-imports module.imports
+                    else [];
+    in [path] ++ imports;
+}