[gdome]user_data and language bindings

[Tobias Peters <tpeters uni-oldenburg de>]

This just comes to my mind, but I am not sure about this (and don't have
the time to investigate it right now):

I think you cannot use the user_data field and at least some of the
language bindings of gdome simultaneously. Because some of the language
bindings use the user_data field for their own purpose, as does gdome2
with the _private field in the libxml nodes: to ensure that at any time at
most one object in the wrapper language corresponds to a given gdome2
node.

I only know for sure that at least early versions of my Ruby and C++
wrappers did not do this, and as a result you could not compare DOM nodes
based on the object identity of their wrapper nodes, but would have used a
isSameNode method as proposed by DOM level 3.

Now I cannot remember for sure if I just planned to use the user_data
field or if I already did it in the last release. I think the Perl wrapper
does something similar, as I remember vaguely to have read a mail from TJ
on that subject.

Tobias