lua: loadstring returns compiled fn (errors propagate cleanly); parse-fail → (nil, err)

lib/lua/runtime.sx

@@ -1500,9 +1500,12 @@
 (define
   lua-loadstring
   (fn (src)
-    (let ((compiled (lua-transpile src)))
-      (fn (&rest args)
-        (eval-expr (list (make-symbol "let") (list) compiled))))))
+    (guard
+      (e (true (list (quote lua-multi) nil (str e))))
+      (let ((compiled (lua-transpile src)))
+        (let ((wrapped (list (make-symbol "fn") (list (make-symbol "&rest") (make-symbol "__args"))
+                             (list (make-symbol "let") (list) compiled))))
+          (eval-expr wrapped))))))
 
 (define loadstring lua-loadstring)
 (define load lua-loadstring)