Re: [office] Date and Timezone: draft text

[Leonard Mada <discoleo@gmx.net>]

Hello everyone,

Please see my comments below.

David A. Wheeler wrote:
> Dave Pawson:
> > Outsider view.
> > Not a solution. Just more of an interop problem.
> > Use iso8601 inclusive of TZ.
>
> We already use ISO 8601, which supports indicating timezones.
> Timezone information is _optional_ in ISO 8601, though,
> so _not_ indicating the timezone is _still_ compatible with ISO 8601.
>
> There is no timezone data in the built-in "Date" type of spreadsheets.
> Writing out a timezone marker (such as "Z" for UTC) would be WRONG,
> because there is NO such information in a spreadsheet.
>
> I think it'd be great to extend spreadsheets to provide proper
> support for timezones, but that turns out to be:
> 1. Nontrivial.
> 2. Implemented by NO spreadsheets
>
> I think it'd be inappropriate to do major surgery on a basic
> type when there's no experience with such changes.  Let's standardize
> on where there _IS_ agreement first.

Having NO support for time-zones is a little bit shortsighted in the age 
of globalisation.

Especially NOW() and TODAY() would be very prone in a spreadsheet 
traveling through different continents.

My biggest concern stems however from a different issue: *partial dates*.

Unfortunately, it is non-trivial to work with partial dates in 
spreadsheets. Actually you can't define one in the first place, however, 
most dates - in the field I work - are actually partial dates, e.g. the 
day is not known.

Calc would convert automatically 07/2008 to 01/07/2008, but this is 
plainly wrong. The bigger problem is in computing periods (differences) 
between 2 partial dates (or one partial date and a fully known one). 
They are perfectly defined up to the precision of the partial date, e.g.
 - between 2008-01 and 2008-05 are exactly 4 months,
   without counting 05 [but counting 01]
 - between 1999 and 2008-07-06 are exactly 9 years
   [the extra precision in one of the dates is removed]

The time period was defined by purpose in ISO 8601 because it is such an 
important feature in the industry.

Sincerely,

Leonard