[Gambas-user] Best way converting dates into strings forth and back

[Jussi Lahtinen]

>  E.g., my laundry will be done in 85 minutes.
> That's an alarm which is not influenced by the earth's orbit, my timezone
> transgressions or politics.
>

Yes, if you set 85 minutes and just count down.
Easy, I agree.



> The time is of course understood by my potential employer and me to
> be whatever the local time is on that day.


Yes, when we do no conversions it is simple. It doesn't matter when we make
the appointment (summer or winter)
"10.12.2021 13:00" is always the correct local time when we meet. Even when
it changes relative to UTC. We ignore it, if UTC is not the local time.
Gambas doesn't really give that option in an intuitive and easy way.



> Alternatively, we may write "12:00 CEST" to fix a reference timezone.
>

Yes, that also works and again, it is something not supported by Gambas. It
has local time (which may not be CEST) and UTC.
However, I think it would be simplest to just assume the given time is in
the correct local time. All conversions would be done by the user.



> I see no other solution to scheduling calendar datetime alarms than to
> rely on your operating system to always be up to date enough on these
> matters and then to regularly check the current datetime in your program.
>

Yes, this is exactly what I have tried to do. The problem is when I have a
date stored in a dataype Date at some point, the conversion happens
automatically when the timezone changes. Or alternatively you need to do
weird unintuitive things like pretend the local time is in UTC and never
rely on the actual localization. It gets messy very quickly.



> Timezone is still a bit of a headache, especially when you're traveling.
> Can we have a meetig on 27 March 2022 at 2:30am?
> People in the US can, people in Germany can't. The week after it's the
> opposite.
>

Well, these are exceptions I'm willing to leave to the user to worry.



> Basically, if you want to solve this properly (meaning without literally
> once-in-400-years edge cases), keep a stringified version of your appoint-
> ment datetime, rely on your operating system / NTP daemon and evaluate
> that string representation in the way a human would do in a high enough
> frequency to check if your appointment is SOON ENOUGH for all factors
> influencing the interpretation of the datetime to have settled. Then you
> may convert it to a point in time and set a Timer for it.
>

By using only strings and never date type, you will lose a lot of
functionality. But I guess that could work.
I just hope there would be a clean way to stop all the automatic
conversions for dates. Perhaps by forcing Gambas to assume the system clock
is in UTC.


Jussi
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