Re: [Sedate] A syntax proposal: floating and future times

["Martin J. Dürst" <[e-mail]>]

Hello Shane, others,

On 2021-11-09 00:41, Shane Carr wrote:
> Two issues about storing a floating time with a time zone but not an offset
> are (1) ambiguities around summer time transitions and (2) summer time
> rules are subject to change.  Storing an offset along with the time zone
> solves these issues, but introduces another: should the offset or the time
> zone "win" in the case of a conflict?

To be more precise, with (1), are you referring to the 'doubled' one 
hour when switching back from summer time to normal time that results 
because clocks have to be switched back by one hour? So as a specific 
example, this would allow to distinguish

2021-10-31T02:30:00+02:00[Europe/Zurich] (before setting clocks back)
and
2021-10-31T02:30:00+01:00[Europe/Zurich] (after setting clocks back)
which both actually existed. In this case, wouldn't it be more 
straightforward to just denote these two instants in time as
2021-10-31T02:30:00+02:00 and 2021-10-31T02:30:00+01:00 ?

Also, with (2), are you referring to cases where the rules suddenly 
change on short notice? In that case, is the purpose of having both 
pieces of information to distinguish between "this is according to the 
old rules, before the sudden rule change" and "this is according to the 
new rules" ? Again, wouldn't it be easier to just have the actual 
information?


> In Temporal, we solve this via an API option
> <https://tc39.es/proposal-temporal/docs/zoneddatetime.html#from> called
> "offset" to declare the intent.  There is a further "disambiguation" option
> to handle the summer time conflict.
> 
> However, would it be useful if there were an annotation to declare the
> intent within the datetime string?  Something like
> 
> 2022-11-26T20:00:00+11:00[Australia/Melbourne][offset=ignore]
> 2022-11-26T20:00:00+11:00[Australia/Melbourne][offset=prefer]

Why give two (possibly conflicting) pieces of information to then say 
which one actually counts? Isn't it much easier to just give the 
information you want to be used, and leave the other part out?
So insteaf of

 > 2022-11-26T20:00:00+11:00[Australia/Melbourne][offset=ignore]
just write 2022-11-26T20:00:00[Australia/Melbourne],
and instead of
 > 2022-11-26T20:00:00+11:00[Australia/Melbourne][offset=prefer]
just write 2022-11-26T20:00:00+11:00 ?

Regards,   Martin.