python/PyXML hell (was: Re: some try-ark suggestions)

This message is the little I have to add on Berto's (et
al.'s) battle with Python and PyXML.  Jonathan has more than
admirably covered the bases on this one, as far as figuring
out the details.

Berto (et al.), we are *not* satisfied with the present "it
falls over horribly if you aren't very lucky" situation.
The goal is for it to Just Work (TM), and I'm sure we will
get there.

You may want to bear in mind the following:

* I don't know beans about PyXML.  We actually use just a
little tiny bit of it, and want to keep it that way :-)

  I really don't know about the weird twists and turns of
  compatibility and incompatibility in it, and what got into
  Python 2.x and what didn't.  And, hey, I *have* been on
  the right mailing list (xml-sig) for nearly two years...

  (For example, I didn't know about the xml.version_info
  variable (sorry) [not that it would've helped a lot].)

* I'd like the ARK stuff to Just Work (TM) with any faintly
  sensible Python (1.5.2 and up) and any faintly sensible
  PyXML (probably 0.5.x and up).  We don't *have* all of
  these combinations around, so there's some trial and error
  to be done...

* Ideally, we'd like it to work with nothing but your
  bog-standard Python distribution (2.x), i.e. no extra
  PyXML at all.

* At some point, the ARK core will require Python 2.  No
  time soon, though...

#1 - OK, here's hoping that the code in
ARK/arkbase/ark/xmlfile.py is now up to negotiating the
twists and turns of python/pyxml version...

#2 - Jonathan, could we expand
sidai/webpages/ark-boot.htma#pyxml to have a sanity-checking
section?  Along the lines of "invoke 'python' then type the
following at the prompt...  If you see <x>, then it's OK,
else send mail to ...".  Then we can add a link from the
try-ark page to this bit of advice.  Sound OK?

Berto, many thanks for your persistence through this
particular episode!  (And, Jonathan: nice work.)

Will