Joseph Wright a écrit :
> \xparse_process_comma_split:n { 1,2 } => {1} {2}
> 
> but what should happen with
> 
> \xparse_process_comma_split:n { 12 }
> 
> A the moment you get "{12} \NoValue" so that exactly two results are
> returned. Should you get perhaps just \NoValue, or something else?

IMO {12} \NoValue is the best solution: it conveys all the initial information,
is a form that is easy to use.

Manuel.