If the point of personal projects is to push yourself and learn, you've done that in spades, you should feel proud of your effort. I think it's normal for a pro

If the point of personal projects is to push yourself and learn, you've done that in spades, you should feel proud of your effort. I think it's normal for a project like lily to wind down after a time. Particularly if there's little or no uptake or contribution from others. I (and many others I wager) have a much poorer language implementation in my archives, only difference is I never made mine public, as you did on github. Kudos for that as well, putting it out there for public scrutiny. Re closure implementation, I suggest taking a look a how they're implemented in the Lua source code. Also, the documentation for Guile has a lot of really nice implementation detail. They're not trivial to implement, kudo's on doing your own thing, but this is an instance where I think studying the work of others can pay huge dividends.