On 11/03/2011, at 1:33 PM, Bruno Le Floch wrote:

> I'll give a try to various variants f-/x-/non-expandable this weekend,
> and benchmark them.

Thanks!

> Do we care about keeping braces surrounding an element in a sequence
> (I'd say yes, although it requires more care)?

Absolutely, yes.

Cheers,
-- Will