I would think that a private code point would be an ideal separator.

On 20/11/2007, Michael Kay <mike@xxxxxxxxxxxx> wrote:
> > Do you need to worry about the delimeter here?  Just using:
> >
> > concat(../@name, @name)
> >
> > should be fine for the grouping key
>
> This obviously creates the (probably small) risk that ("AB", "C") ends up in
> the same group as ("A", "BC").
>
> Michael Kay
> http://www.saxonica.com/