chore: initial commit

lib/attrs/default.nix

@@ -0,0 +1,36 @@
+{ core-inputs
+, user-inputs
+, snowfall-lib
+}:
+
+let
+  inherit (core-inputs.nixpkgs.lib)
+    assertMsg
+    mapAttrsToList
+    flatten
+    fold
+    recursiveUpdate
+    mergeAttrs;
+in
+{
+  attrs = {
+    # Map and flatten an attribute set into a list.
+    # Type: (a -> b -> [c]) -> Attrs -> [c]
+    # Usage: map-concat-attrs-to-list (name: value: [name value]) { x = 1; y = 2; }
+    #   result: [ "x" 1 "y" 2 ]
+    map-concat-attrs-to-list = f: attrs:
+      flatten (mapAttrsToList f attrs);
+
+    # Recursively merge a list of attribute sets.
+    # Type: [Attrs] -> Attrs
+    # Usage: merge-deep [{ x = 1; } { x = 2; }]
+    #   result: { x = 2; }
+    merge-deep = fold recursiveUpdate { };
+
+    # Merge the root of a list of attribute sets.
+    # Type: [Attrs] -> Attrs
+    # Usage: merge-shallow [{ x = 1; } { x = 2; }]
+    #   result: { x = 2; }
+    merge-shallow = fold mergeAttrs { };
+  };
+}