That makes sense, but I still think the meta name is confusing. I mean, as a user the fact that it was implemented using metaprogramming techniques has no bearing, it's an implementation detail. Actually, my brain never thought to associate meta in this context with metaprogramming. Makes sense in hindsight, but still confusing.

But still, I can't really come up with a nicer name. VerbalDataFrames to match the dplyr verbs idiom?