One day, I would love to generalize the web-based playground so that you could edit the grammars. But it's complicated, because we use C as our output language,

One day, I would love to generalize the web-based playground so that you could edit the grammars. But it's complicated, because we use C as our output language, so you would always need to recompile the C after changing the grammar. So, I would say that it's not on our near-term roadmap.