[cells-devel] laziness -- what does "once-asked" mean?

I understand (I think ...) what :once-asked *does*, I want to know what it *means*.

In other words, the other two options seem to answer the question "when is this cell lazy?" Well, an :always cell is always lazy -- it's not recalculated until and unless you ask for it. An :until-asked cell is lazy until you query it once, then it's non-lazy from then on.

"once-asked" seems to answer a *different* question, "when is this cell evaluated?" It's evaluated once, when created, and then only when queried.

Is there any single "question" that all three answer, or are they just inconsistent?

Thanks!

-- L