RE: fdo77985 Calc function NETWORKDAYS

Hi Eike,

> I'd avoid changing existing Add-In functions, it's a source of hassle ;-) 

Fine, I prefer to keep away from the add-in code, too.

> Rather implement an ODFF compliant NETWORKDAYS function at the interpreter [...]

OK, then there will be 3 NETWORKDAYS functions: Add-in, OOXML and ODFF:
Add-in is a subset of ODFF as Add-in misses the 4th argument (defining weekend days);
OOXML differs from ODFF as the 3rd and 4th argument are the other way round and the weekend day 
argument for OOXML uses a 7-character string of 0 and 1, whereas ODFF uses a list of numbers (0 and 
not 0).

The difference between OOXML and ODFF doesn't concern me, that I can solve easily in the code.
The difference between Add-in and ODFF looks problematic to me when using ODFF NETWORKDAYS with 2 
arguments and saving to xls.
And how about compatibility with documents saved before introduction of ODFF NETWORKDAYS? Are these 
regarded as Add-inn?

A solution (which I don't like) could be to assume that NETWORKDAYS with 2 or 3 arguments is 
Add-in, and with 4 arguments is ODFF. I don't know if this can be implemented.

I will start making the ODFF NETWORKDAYS function and rename the Add-in function to NETWORKDAYS_ADD.

Winfried