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 Re: Behaviour of \SplitArgument with missing input Michiel Helvensteijn <[log in to unmask]> Tue, 30 Apr 2013 19:20:11 +0200 text/plain (40 lines) On Tue, Apr 30, 2013 at 4:06 PM, Joseph Wright <[log in to unmask]> wrote: > On where '-NoValue-' 'lives', ...etc... Your problem is that xparse has been trying to cater to two different target groups. It's meant to create document-level commands. But it's not clear what kind of environment it's meant to create them from. On the one hand, the LaTeX3 methodology recommends the use of xparse for document level commands (rather than the LaTeX2 \newcommand or the TeX \def). On the other hand, xparse doesn't offer a LaTeX3 syntax! It was obviously designed to be used independently from expl3. I do understand. The xparse functionality is useful to both LaTeX3 programmers and other LaTeXers. As I see it, the 'correct' way to go about this is to follow your own methodology (I'm a fan of self-reference): * Create a LaTeX3 library which provides xparse functionality; let's call it l3xparse. I'd expect to see functions like \xparse_new_document_command:Nnn, \xparse_split_argument:nn, \xparse_if_no_value:n(TF). Actually, a lot of potential \xparse_... functions probably already exist under a different name, like \bool_if:n(TF) for \IfBoolean(TF). * Expose l3xparse with a thin layer of document-level commands. The result will be what you now call xparse. The cool thing is, you can actually use l3xparse to create that thin layer around itself. Whether the 'no value' placeholder should be different between the two packages is a separate issue. Syntax wise it doesn't matter, since it should never be visible in the code. But I'd probably still make it different, if only to make bugs easier to trace. Cheers! -- www.mhelvens.net