todo: write mail about pointer attributes at the rubyRule element

Hi all,

Yves and me found some potential issues with the ruby data category:


- Problem with rpPointer: we need two of them! One for opening
parenthesis, one for closing parenthesis, e.g. rpOpeningPointer, and
rpClosingPointer.

- General impression: We might need to mark the pointer attributes (or
at least the rbcPointer, rtcPointer and rbspanPointer attributes) as
"features at risk", because they produce implementation problems (too
many useless combinations of pointer attributes, espc. with complex
ruby) we have not solved, and their need seems to be unclear. We might
keep just the rubyRule element with the selector attribute and the
rubyText element.


Cheers,

Felix