Reading/ Writing GNU XML format

[Steve Swann <swannhome xsinet co za>]

I have recently discovered Gnumeric and am very impressed. I mainly use 
WinXP and so do my users (school teachers) and have been very impressed 
at the responsiveness of Gnumeric. Currently I am  using the 
gnumeric-1.9.1-win32-20080625.exe install. This seems to equate to  
Gnumeric 1.6.3

I am using Gnumeric as a generalised capture front end for teachers to 
capture marks, see some results and then upload a .GNU file to a 
Webserver. The users need to be able to capture data offline as they 
have sporadic access to the internet. Typically they store the 
spreadsheet on a flash for use at home or work.

Once I receive the file at the Webserver I intend to read the XML file 
and upload the spreadsheet contents to a database. I piloted this 
approach and all seemed to go very well until I discovered that formula 
are represented in the cell element value as only a formula descriptor . 
The problem with that is that I cannot easily determine the value of the 
cell. So for example if Cell(row=10, col=20) = "=C4" and the value of 
the cell is 200 then all I get for the cell element value is "=C4". Is 
there anyway a value pair can be provided, the formula and the cell 
value at the time the spreadsheet was saved.

Alternatively is there an API that I can call from an external Python 
program that will allow me to easily determine the value of the cell 
content when it has a formula. I have written a lot of interfaces to 
Excel where this is possible, but it then requires the server to run 
Windows and Excel so that I have access to the Excel object model. As I 
much prefer to run a Linux based server and not all teachers have access 
to Excel is there a solution to this problem.

If you have an alternate approach to this problem please let me know.

Thanks very much.
Steve