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

[Larry Clapp]

On Fri, Aug 29, 2008 at 07:40:03AM -0400, Kenny Tilton wrote:
> Kenny Tilton wrote:
> >Larry Clapp wrote:
> >
> > > 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?
> >
> >
> > Once-asked would be "un-lazy until you query it once" (ie,
> > consistent) but it also looks to be vestigial: all code seems to
> > treat it the same as always.
> > 
> > If I missed it in my brief scan of the code, it would have to do
> > with model instance initialization. 
> 
> Yeah, looks like I missed it, because the code looks for other than
> :once-asked to break off initialization and I was just searching on
> once-asked.

Ah, so they all *do* answer the same question, "when is this cell
lazy?", but with the clarification that creation => asking.

once-asked: Lazy once you ask for it (creating asks)
until-asked: Lazy until you ask for it (creating does not ask)
always: Lazy always (creating does not ask)

This is probably one of those things that would have become clear once
I got more experience with Cells, but I'm lazy, so I asked.  :)

Thanks for the quick answer!

-- L