Will Robertson <[log in to unmask]> wrote:

>  From the way things look to me, that will basically be impossible.
> The changes between LaTeX3 and LaTeX2e are much greater than between
> 2e and 2.09. Perhaps a strict subset of LaTeX2e documents will be able
> to be processed with LaTeX3, but I think we'll end up with two
> distinct document processing systems. That is, I doubt that LaTeX2e
> will ever be "replaced" by LaTeX3 -- people who need backwards
> compatibility will have to use the old code.

i fear you're probably right.

> On the other hand, it might be possible to detect when a 2e document
> is being processed and "drop down" into the old code automatically,
> but it's probably too early to say since we're not even building a
> separate LaTeX3 format at this stage (well, I'm not, at least).
> 
> We could probably write a "frequently asked questions" page to address
> questions like this.

i have an answer (which is currently pretty waffly, and largely
content-free) about latex 3 in the uk faq.
http://www.tex.ac.uk/cgi-bin/texfaq2html?label=LaTeX3

any suggestions for something i could say, or pages i might reference
(e.g., joseph's thing we looked at yesterday) would be welcome.  (after a
period of manic work on the catalogue, i'm trying to produce a new
version of the faq in odd minutes in the corner.)

robin