On 17/02/2010 15:05, Joseph Wright wrote:
> I should add that the issue was *if* you could include verbatim input
> using \NewDocumentCommand (as the last argument). The problem is not so
> much getting things right for one argument but dealing with the various
> cases:
> - Several arguments with only the last optional
> - Verbatim w.r.t. only some characters (some can be handled with
> \scantokens, some cannot)
> - Dealing entirely properly with nested functions (and making sure that
> the limitations are clear).

I should also add that perhaps having something like 
\DeclareVerbatimCommand is at least as sensible as 
\DeclareExpandableDocumentCommand.  If others agree I'm sure we can look 
at it (starting with the suggested code and then trying to break it!).
Joseph Wright