Re: [office-formula] 6.9.13 NETWORKDAYS

[robert_weir@us.ibm.com]

Eric Patterson <ericpa@exchange.microsoft.com> wrote on 02/23/2009 
07:47:51 PM:

> 
> Reading the definition of the NETWORKDAYS() function in the current 
> draft of the specification, I see that the function definition 
> includes an optional 4th parameter.  Microsoft Excel's definition of
> this function only includes 3 parameters.
> 
> I'm trying to understand the implications of this.  If the intent of
> OpenFormula is to create a portable syntax how should differences 
> like this be handled?  Implementers that only use the first 3 
> parameters could share documents, but what is expected if the 4th 
> parameter is included in a document?  I would expect it to return an
> error value to provide a warning to the user.
> 
> What effect would implementing only the first 3 parameters have on 
> application and document conformance?
> 

The level of granularity is the function.  Think of it like a .NET 
interface.  You either implement it or you don't.  The contract is 
IEnumerable and if you want to say you implement IEnumerable then you 
implement all of IEnumerable.  Same with NETWORKDAYS().  You either 
implement it or you don't.  There is no 75% conformance at the level of a 
function.

IMHO, user expectations are (in order):

1) That the spreadsheet will calculate properly in Excel, to give the same 
results it did in the original application.

2) That if Excel lacked a particular function or parameter in the 
function, that it would fail in an obvious (noticeable) way rather than 
silently give a wrong answer.

Of course, you are free to be conformant and meet user expectations at the 
same time.  Simply add support for that 4th parameter.  I know we've heard 
from users, especially in the Middle East, that the work-week assumptions 
of the 3-parameter Excel function did not work well for them, since their 
legally-defined weekend was Th/Fr or Fr/Sa and the 3-parameter function 
would yield incorrect results for them.

-Rob