On Wed, Sep 17, 2008 at 4:49 PM, Joseph Wright
<[log in to unmask]> wrote:
> I've been giving a little thought to how I might implement something
> like siunitx in expl3.  An initial assessment points to two support
> packages: array and amstext.  Both strike me as pretty much essential
> for LaTeX3, so I wondered if it is likely that either functionality
> might make it into the new kernel?

Good question :)
I suspect the underlying interface to tabular material will remain
rather similar. (Although I'd like to write a better *user* interface,
one day.)

Either way, I can't see anything happening in the near future since
porting array would be a big job and maths is all rather up in the air
at the moment. (breqn is taking form but it's very early days yet;
it's current incarnation on CTAN is probably the last that *won't* use
the expl3 bundle, though.)

But there's no problem, of course, using their "LaTeX2e" macros in your package.