WIP: add a Val struct as an input/output when calling a function

src/generator.h

@@ -975,6 +975,7 @@ void Generator::Generate()
 	ResizeStack();
 	ResizeBlockStack();
 	ResizeEzcFrameStack();
+	InitializeTmpStreams();
 	filter_index = 0;
 	stack_index  = 0;
 	ezc_frames_stack_index = 0;