1 files changed, 18 insertions, 0 deletions
diff --git a/tests/lang/lib.nix b/tests/lang/lib.nix
new file mode 100644
index 000000000000..f888453ffbea
--- /dev/null
+++ b/tests/lang/lib.nix
@@ -0,0 +1,18 @@
+rec {
+
+  fold = op: nul: list:
+    if list == []
+    then nul
+    else op (builtins.head list) (fold op nul (builtins.tail list));
+
+  concat =
+    fold (x: y: x + y) "";
+
+  flatten = x:
+    if builtins.isList x
+    then fold (x: y: (flatten x) ++ y) [] x
+    else [x];
+
+  sum = fold (x: y: builtins.add x y) 0;
+
+}