Re: [office-formula] http://tools.oasis-open.org/issues/browse/OFFICE-2248

[robert_weir@us.ibm.com]

OK.  Settlement Date.  Let me explain the concept.

With securities you have the trade date and the settlement date.  The 
former is the date you contact to buy or sell the security, and when the 
price is agreed to.  And then the settlement date is when (in the old 
days) the security was actually delivered, typically three business days 
after the trade date.

I think we have two ways of dealing with functions like this:

A) Define everything in mathematical terms

If we do this, the name of the parameters is arbitrary.  We could just as 
well call it "fred" as call it "settlement".  The return value is defined 
purely in terms of fundamental mathematical operations.

That said, settlement date is just a date, and the functions should be 
defined in such a way that they would return the same results if we called 
it "fred".  If we do this, we don't need to ascribe any meaning to the 
parameters.


B) Define everything in terms of conventional semantics or external 
reference

If we do this, then we define the function parameters to a degree that the 
reader of the specification can determine how to calculate the required 
value.


I think in most cases we are going for style-A functions.  But some may 
require us to go with style-B.  For example, suppose we had a function to 
calculate the date of Easter for a given year, as was proposed earlier. 
Giving the exact formula, although it could be done, would be rather 
cumbersome.  But we could say "Returns the date of Gregorian Easter for 
given year" and know that this is sufficiently described and permits the 
use of pre-calculated table look-ups as well as algorithmic approaches.

On the financial function side, we have a few functions -- generally for 
bond coupon calculations -- where we have given neither style definition 
adequately.  I'll push to get find some domain experts to review these 
functions once we have the rest of the spec cleaned up a bit more.  So I'd 
move these questions to CD 2.

-Rob

Patrick Durusau <patrick@durusau.net> wrote on 02/01/2010 05:14:54 PM:

> [office-formula] http://tools.oasis-open.org/issues/browse/OFFICE-2248
> 
> Rob,
> 
> The last note on this item says you and I will work on it.
> 
> Should it be CD-1 or CD-2?
> 
> Patrick