@TruffleBoundary protected static Object encodeArgumentPairList(RArgsValuesAndNames args, String symbolName) { Object list = RNull.instance; for (int i = args.getLength() - 1; i >= 0; i--) { String name = args.getSignature().getName(i); list = RDataFactory.createPairList( args.getArgument(i), list, name == null ? RNull.instance : RDataFactory.createSymbolInterned(name)); } list = RDataFactory.createPairList(symbolName, list); return list; }