Re: [office-formula] Constraints and infix ^

[Andreas J Guelzow <aguelzow@math.concordia.ab.ca>]

On Wed, 2009-01-21 at 08:55 -0500, Patrick Durusau wrote:
> Andreas,
> 
> Andreas J Guelzow wrote:
> > On Wed, 2009-01-21 at 06:25 -0500, Patrick Durusau wrote:
> >   
> >>> "Implementation-defined" means that the implementation is free to
> >>> pick from a set of possibilities, as long as that selection meets the 
> >>> other requirements of the spec.  If the spec limits the set of 
> >>> permissible returns, then it must be one of those possible returns.
> >>>
> >>>       
> >> Oh, no, sorry, at least as I experience standards writing that simply 
> >> isn't true.
> >>
> >> If I wanted to say that, I would say:
> >>
> >> "There are three (or whatever number) answers to X. Those answers are: 
> >> (list here). For purposes of this standard, each of these answers is 
> >> equivalent to the others for all purposes."
> >>
> >> That gets you applications that recognize all the possible answers while 
> >> allowing them to return which ever one they prefer. But they have to 
> >> recognize the others.
> >>     
> >
> > All of this arose from the discussion which value the formula 0^0 should
> > return. In this context"recognizing the oterhs doesn't make any sense
> > whatsoever.
> >
> >   
> Well, I am assuming that an application can recognize the case where the 
> formula 0^0 occurs in order for us to say anything about it at all.
> 
> If that is the case, then surely an application can also recognize one 
> of the three results that David wants to define.

Of course it should be able to recognize 0, 1, and ERROR.

> 
> That is if an application gets a document with the formula 0^0 and the 
> *recorded* result #1, or #2, or #3, why can't it recognize that result 
> as being one of the three that we define?
> 
> Unless you are presuming that all formulas will be calculated every time 
> a document is loaded, which seems like a lot of overhead to me.

If the program _can_ at any time recalculate the formula, then it _must_
recalculate all formulas when it opens the file. It would be greatly
disturbing to the user if the results in the spreadsheet change just
because something triggered recalculation:

say A1 is 1 and A2 contains =IF(A1=0;7;0^0)

then it would be disturbing if the value of A2 changed just because A1
was changed to 2.

In fact, if an application ever wanted to recognize erroneous results
stored in a file it would need to be able to recalculate the whole file
with all "possible" results.  

> 
> Or really for that matter, we could say that since all three results are 
> the same, simply replace whatever is found with the one your application 
> prefers.

which would likely trigger recalculation of other cells too.

But of course as I said above, a spreadsheet program will likely need to
recalculate on opening anyways if the file format allows various
versions.
 
> 
> Well, but I do suspect there are places where substitution may not be 
> appropriate but if that is the case, then we need to fall back to 
> implementation defined and let it go at that.
> 
> What am I missing?

I don't know...

Have a nice day too,

Andreas
> 
-- 
Andreas J. Guelzow
Concordia University College of Alberta