Re: Country specific add-on package

On Aug 27, 2004, at 2:26, Olivier Hallot wrote:
> I concede that OpenGroupware was conceived with a German-centric  
> scope.  But when it comes to use OGo in other countries/TZ and  
> hemisphere, things change.

At least in this case this is wrong and that you raise that as an  
argument is really disappointing! libFoundation wasn't even written by  
a German nor was the OpenStep specification it is based on.

Please understand: you have a different definition of the term  
"timezone" than what is used in computing. You just refer to  
"geographical" timezones which are basically useless for software  
applications.
Timezones used to compute dates are _always_ "political" timezones  
which _must_ include DST information. This is especially true for Unix  
like operating systems which store all times in UTC and need to  
translate back and forth to the real time.

Again: the term "timezone" as used in computing, Linux,  
libFoundation/OGo or all other software is _always_ for "political"  
timezones.

If you are interested, you can read more about libFoundation timezone  
internals over here:
    
http://developer.apple.com/documentation/Cocoa/Reference/Foundation/ 
ObjC_classic/Classes/NSTimeZone.html

>> If your country doesn't have a specified timezone, you need to  
>> workaround by using GMTxxx. I don't know why Brazil does that, but it  
>> results in inconvinience for the user.
> Sure. Brasil has a TZ, namely GMT-03:00. And no, I don't need a  
> workaround, as I showed in the TZ paper I put in docs.

Hu? In
   http://docs.opengroupware.org/Members/olivier/tz2/view
you actually create a new timezone called Brazil. QED.

>   I am using "Brasilia" as an alias for GMT-3. Works perfectly.

No, you don't. In your text on docs the timezone abbreviation is
   "Horário de Brasília"
   (which is wrong, it should be a proper _abbreviation_)
and the timezone name is
   "Brasilia"

No alias. QED.

>> The technically correct way to make calendaring systems work in this  
>> setup, is to make a _new_ timezone (America/Brazil) with _all_ the  
>> historical data.
> That is what I explained how to do in the above mentioned paper.  
> However I had not put any data (=DST shift dates) before 2003 since  
> past calendar data is of very seldom use and I am lazy to get this  
> data.

Si.

>> In addition - without DST information you can't create cyclic  
>> appointments which go into the future.
> That I was unaware... Then I have an issue here, since I don't know  
> when DST will start.

Actually you can't make _any_ appointments in the future which has DST.  
See above and try to understand why.

I'm not aware of any computer system which could handle this (I would  
be interested if someone knows one). One would basically need to invent  
a new datatype called "NSUnsureDate" which is displayed in the UI as  
"might be at 12:00" and has an associated  
"NSNotYetKnownTimezoneDetail".

>> Again: a proper (political) timezone is strictly required! (whether  
>> or not you can predict them ;-)
> You talk on time zones ( w.r.t. GMT shift) and I am talking on  their  
> multiple aliases.

A timezone as used in libFoundation cannot have aliases. A timezone in  
libFoundation is:
- a name and an abbreviation
- an arbitary offset to UTC
- a set of rules for exceptions (eg DST)
It doesn't make sense to call anything else a "timezone" if we are  
discussing OGo.

> These aliases are purely cultural and thus country specific.

Yes, they are cultural, no they are not country specific.


OK, lets close the thread now. If the above doesn't sufficiently  
explain how timezones on Unix machines work, I have no idea how to make  
it transparent.
I understand that Brazil has quite an unusual way to handle DST (there  
is certainly a reason for that), but its a matter of fact that this  
breaks any application using the "Unix way" of handling times in UTC.

Helge
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