bug#33309: Add flatten-list?

[Alex Branham]

On Mon 10 Dec 2018 at 15:36, Stefan Monnier <monnier@IRO.UMontreal.CA> wrote:

> I think we should document clearly what should happen with nil and with
> dotted pairs.

Thanks for checking those others. I think it makes sense to completely
"flatten" the tree. In other words, combine all dotted pairs. I'm less
sure about what to do with nil entries. It looks like most of the
existing implementations drop nil elements, so I guess we'll do that?

Alex