Import filters and Features

Hi Fridrich,

it was great talking to you at the Linux Tag in Berlin on Saturday.  I
hope you don't mind me CCing the mailing list, in case somebody else
finds it interesting and could provide some info.

Inspired by your talk about import filters, I would like to ask what is
the usual strategy to addressing impedance mismatch between features
covered in an input file format and LibreOffice internal representation?
E.g. when a feature is missing in the ODF format?

For example, MS Word have list numbering restarts which ODF doesn't
have.  In such cases the documents don't import and export correctly.  I
guess you hit similar issues with your import filters even though they
were less about word processing and more about picture drawing iirc.  In
case of my example, I figured out that I can parse the exported DOC file
(e.g. using <http://logand.com/sw/cl-olefs.html> which I wrote based on
MS spec and which gives me as a bonus file positions for every data
record), find out where the numbering restart bit is located in the DOC
file and set it accordingly.  It would be better though if no such
postprocessing was needed.  In such case, is it permissible to
accomodate the "feature" in the internal LibreOffice representation or
is the internal representation strictly dictated/limited by the ODF
spec?  If the later, I guess input filters can never be made to work
correctly?

Thank you,

Tomas