Ah, especially after your edit, I think I understand. So there's no problem if I leave comments like that (for my own learning enforcement, really) but mark them as spoilers?

Cheers, akar-0. No harm intended. I was just trying to leave a note on my own submitted solution regarding what I subsequently learned from someone else's submitted solution. Is this a bad way to do it, then? Should I not do this here at all, or should I do it but mark it as a spoiler, or...? I wasn't worried about really spoiling because I was commenting on my own submitted solution to the same problem. I'm new here; please advise, and I'll do it right from now on! :)

Is there a compelling reason for calling that particular identifier "expos"?

Excellent. Thank you for spelling this out for me.