Re: Time-zone in dates

[francois@avalenn.eu]

Hello,

On Fri, Jun 26, 2015 at 09:20:00PM +0200, Nicolas Goaziou wrote:
> Time zone information is interesting when users of different areas are
> exchanging Org documents.
> 
> I think it would be useful to have:
> 
>  - a keyword to specify time zone per document. This time zone would
>    apply to every time stamp not defining their own time zone. Default
>    value could be `local' so we would be backward compatible.
> 
>  - a way to specify a time zone per time stamp, overriding the previous
>    keyword.
> 
> I think it would require to define a proper API for timestamps in order
> to ensure, e.g., comparisons are done right.

Timezones are strange beasts to deal with.

It is really simpler programmatically to deal with time offsets
instead. The downside is that you cannot manage DST and other similar
peculiarities but the API is much simpler to write.

Just please don't confuse timezones and time offsets especially in
documentation as it is not the same thing and it can lead to
confusion.

I reread from time to time this note from W3C which explains the
difference and why it matters :
http://www.w3.org/TR/2005/NOTE-timezone-20051013/#d2e226 

Regards,
François