[PUSHED][PATCH] fdo#44456 added calc function DATEDIF as in ODF 1.2

[Eike Rathke]

Hi Winfried,

On Tuesday, 2012-05-15 08:09:37 +0200, Winfried Donkers wrote:

> You did a lot of work! I expected some or a lot of comments on my interpretations
> of ODF1.2 as i don't have Excel to compare with, but you did all the work yourself!
>  I'm a volunteer, I don't mind cleaning up (my own) mess :)

Heh, sorry for having taken away the work from you :-)
I'll keep that in mind for next time.

I thought I'd get that algorithm solved because I quite know the date
calculation area and the quirks that may be lurking there.


> > Some detailed nitpicks in commit comments :-)
> 
> If I'm correct, the main changes are that  my interpretation of ignore years/months were not right.

Hm, yes. I wouldn't say it's your fault though, the ODFF definition is
a bit weak to implement that from scratch if one is not familiar with
the area.

> There is one thing I am not very happy about: DATEDIF in calc now does
> not accept date1 to be later (larger) than date2. IMHO this should be
> possible as it is a very normal possibilty. It looks as if DATEDIF
> does not accept this condition because Excel doesn't/can't. I thought
> calc conforms to ODF and can export to xls(x) but with possible loss
> of functionality. Now it is like LibreOffice is an open source copy of
> MS Office.

Usually for spreadsheet functions we strive for Excel interoperability.
(Actually they implemented this function because Lotus 1-2-3 had it the
same way, anyway...)  If we allowed reversed date arguments, importing
a document in Excel would give different results, errors in this case.
The ODFF definition lacks a constraint that date1 must be <= date2,
seems we didn't think of that back then, I'll submit a comment. Also
Gnumeric implemented it the same.

> I would very much like to adjust the code to make it possible again
> for date1 to be later (larger) than date2, both to increase its use :)
> and because I don't want to be a follower of MS Office :(

I'd rather stick with the current implementation for the above reasons.

> And a big thank you for all your corrections/inprovements!
> I hope to be able to send in more formula based patches, I like this area:)

Great! I'm looking forward. Do you have already an idea what you'll pick
next?

  Eike

-- 
LibreOffice Calc developer. Number formatter stricken i18n transpositionizer.
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