fix lambda

lib.nix

@@ -138,7 +138,18 @@ let
       ++ [ kw_end ])
     );
   func0 = fnName: func fnName [ ];
-  lambda = func "";
+
+  lambda = params: body:
+    (spaceBetween
+      ([
+        (concat [
+          kw_function
+          (wrapParen (join ", " (map raw params)))
+        ])
+      ]
+      ++ (validBlockBody body)
+      ++ [ kw_end ])
+    );
   lambda0 = lambda [ ];
 
   return = expr: spaceBetween ([ kw_return expr ]);

lib.test.nix

@@ -173,6 +173,10 @@ with nix2lua; pkgs.lib.runTests {
     expr = toLua (func "hello" [ "a" ] (call1 "h.world" (var "a")));
     expected = "function hello(a) h.world(a) end";
   };
+  "test returns defined lambda" = {
+    expr = toLua (lambda [ "a" ] (call1 "h.world" (var "a")));
+    expected = "function(a) h.world(a) end";
+  };
   "test returns if statement" = {
     expr = toLua (if' (eq 10 10) (call "print" [ 10 ]));
     expected = ''if (10 == 10) then print(10) end'';