2 files changed, 20 insertions, 0 deletions
diff --git a/lib/default.nix b/lib/default.nix
index 803a614a1..4c54f60aa 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -1,6 +1,9 @@
 let
   nixpkgs-lib = import <nixpkgs/lib>;
   lib = with lib; nixpkgs-lib // builtins // {
+
+    evalSource = import ./eval-source.nix;
+
     git = import ./git.nix { inherit lib; };
     shell = import ./shell.nix { inherit lib; };
     types = nixpkgs-lib.types // import ./types.nix { inherit lib; };
diff --git a/lib/eval-source.nix b/lib/eval-source.nix
new file mode 100644
index 000000000..de5f0b43c
--- /dev/null
+++ b/lib/eval-source.nix
@@ -0,0 +1,17 @@
+with import <stockholm/lib>;
+let
+  eval = _file: source: evalModules {
+    modules = singleton {
+      inherit _file;
+      options.source = mkOption {
+        type = types.attrsOf types.source;
+        default = {};
+      };
+      config = {
+        inherit source;
+      };
+    };
+  };
+in
+  # This function's return value can be used as pkgs.populate input.
+  _file: source: (eval _file source).config.source