On 03/01/2011, at 8:34 PM, Arno Trautmann wrote:

>> Based on my experience with Texinfo, my comment is that robust parsing
>> of arguments delimited by end-of-line is essentially impossible.  I
>> fully agree with Joseph: I wouldn't go there. 
> What about an non-robust solution? ;)
> No, seriously: Would it be aceptable (generally spoken) to offer
> non-robust solutions istead of no solution at all?

Not for xparse, no. We have steered away from offering features that will work sometimes but not always (with the exception of the expandable optional argument parsing, which is in a bit of a funny spot -- I lean toward suggesting it should be moved to another package).

Another example of a non-robust solution we did not include is to offer arguments that allow verbatim material inside, such as \verb inside \footnote. While this can be done for commands that are not placed inside other commands, the techniques fall down for things like \caption{abc\footnote{\verb|%|}}.

But rolling your own is fine since you are confident of how you'll be using the material -- you just can't use xparse to do it :)

-- Will