On Thu, Jan 22, 2009 at 08:52:43PM +0000, Joseph Wright wrote: > Will Robertson 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. > > > > 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). > > I'd imagine that LaTeX3 documents will start with something other than > \documentclass (let's call it \documenttype, for arguments sake). Given > the likely size of a LaTeX3 kernel, essentially the entire 2e kernel > could also be included without making it all that much bigger. If the > first line of the file is \documenttype, the 2e stuff is never used. On > the other hand, if \documentclass is found, the new kernel "bails out", > runs the current 2e code and the file is processed as a 2e document. In theory. In practice, you can or sometimes even must have some stuff before \documentclass/\documenttype. Example: \RequirePackage{cmap}% before the class loads fonts \documentclass{myclass} Yours sincerely Heiko <[log in to unmask]>