On 16/02/2011 16:04, Bruno Le Floch wrote: >> If it's as good as it seems then it allows all sorts of expandable things, >> such as optional argument parsing and expandable nested mapping. > > We had a short discussion with Joseph about optional argument parsing. > The obvious constraint is that the last argument must be mandatory, so > we can just look for its opening delimiter. Then it is in principle > possible, but argument specifications like {oom} become quite tricky, > since #{ has to be used when grabbing each of these arguments. I > haven't looked at the implementation of xparse in detail, though. In this discussion I did say that whether fully-expandable arguments should be limited to 'om'-like cases was an open question. If it's more sensible over all then I'm happy with this: that part of xparse is very much 'experimental'. > I've put the code for \fullyexpand online for those interested, as > well as a very primitive macro expander. ( > http://users.aims.ac.za/~bruno/LaTeX/ULcase/ ) Another thing to read after work :-) -- Joseph Wright