Midnight and noon in agendas

Midnight and noon in agendas

[Daniel J. Sinder]

I've noticed that '12pm' when used as a time-of-day specification
puts an entry at 24:00 in the agenda.  '12am' places the item at
noon in the agenda.

It is arguable whether 00:00 should be used instead of 24:00.
Personally, I prefer it the way it is, where midnight events are
placed at 24:00 because if I have something scheduled/due at
midnight, I'd like to see it on the agenda for the day *preceding*
the event/item.

However, the issue I differ on is the interpretation of 12am as noon
and 12pm as midnight.  Although they are both ambiguous, it seems
that 12am is more typically associated with midnight, while 12pm is
associated with noon.  One explanation goes like this:  Since the
24-hour clock runs from 00:00:00--23:59:59, then 00:00:00-11:59:59
is AM and 12:00:00-23:59:59 is PM.

Just curious....is the current mapping a deliberate choice or a bug?

Dan

Re: Midnight and noon in agendas

[Carsten Dominik]

Well, if this is the way things are normally interpreted,
then this is clearly a bug.  Thanks for explaining this to me.
Strange system.  Switching am to pm always makes the event happen 
later, except when the hour is 12.

However, I will not make items jump days because of a time 
specification.  This has first of all technical reasons:  Agenda 
entries are collected based on the date only. The time-of-day 
specification is only used later in the process to sort the entries on 
the day.  So given this restriction, what would you or other people 
here want:

Should 12am be listed as 0:00 or as 24:00?
Should 12:21am be listed as 0:21 or as 24:21?

It seems to me that the logic would be a bit better to schedule these 
show uo as 0:00 and 0:21.  If you wanted to put something at midnight 
at the end of the day you would then have to use 24:00 and 24:21.

Opinions?

- Carsten

On Jun 2, 2006, at 1:36, Daniel J. Sinder wrote:

> I've noticed that '12pm' when used as a time-of-day specification
> puts an entry at 24:00 in the agenda.  '12am' places the item at
> noon in the agenda.
>
> It is arguable whether 00:00 should be used instead of 24:00.
> Personally, I prefer it the way it is, where midnight events are
> placed at 24:00 because if I have something scheduled/due at
> midnight, I'd like to see it on the agenda for the day *preceding*
> the event/item.
>
> However, the issue I differ on is the interpretation of 12am as noon
> and 12pm as midnight.  Although they are both ambiguous, it seems
> that 12am is more typically associated with midnight, while 12pm is
> associated with noon.  One explanation goes like this:  Since the
> 24-hour clock runs from 00:00:00--23:59:59, then 00:00:00-11:59:59
> is AM and 12:00:00-23:59:59 is PM.
>
> Just curious....is the current mapping a deliberate choice or a bug?
>
> Dan
>
>
> _______________________________________________
> Emacs-orgmode mailing list
> Emacs-orgmode@gnu.org
> http://lists.gnu.org/mailman/listinfo/emacs-orgmode
>
>

--
Carsten Dominik
Sterrenkundig Instituut "Anton Pannekoek"
Universiteit van Amsterdam
Kruislaan 403
NL-1098SJ Amsterdam
phone: +31 20 525 7477

Re: Midnight and noon in agendas

[Jason F. McBrayer]

On Fri, 2006-06-02 at 07:15 +0200, Carsten Dominik wrote:

> It seems to me that the logic would be a bit better to schedule these 
> show uo as 0:00 and 0:21.  If you wanted to put something at midnight 
> at the end of the day you would then have to use 24:00 and 24:21.
> 
> Opinions?

That's probably the best way to do it.  Users should probably be
responsible for scheduling things on the correct day --- either 23:59
one day or 0:00 the next.

-- 
+-----------------------------------------------------------+
| Jason F. McBrayer                    jmcbray@carcosa.net  |
| A flower falls, even though we love it; and a weed grows, |
| even though we do not love it.            -- Dogen        |

Re: Midnight and noon in agendas

[J. David Boyd]

Carsten Dominik <dominik@science.uva.nl> writes:

>
> Should 12am be listed as 0:00 or as 24:00?
> Should 12:21am be listed as 0:21 or as 24:21?
>

I vote for 0:00 and 0:21

Dave in Largo, FL

Re: Midnight and noon in agendas

[Michael Olson]

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Carsten Dominik <dominik@science.uva.nl> writes:

> It seems to me that the logic would be a bit better to schedule these
> show uo as 0:00 and 0:21.  If you wanted to put something at midnight
> at the end of the day you would then have to use 24:00 and 24:21.
>
> Opinions?

That would have the nice effect of giving people more hours in a day.
I'm sure everyone could use that.  :^)

-- 
Michael Olson -- FSF Associate Member #652 -- http://www.mwolson.org/
Interests: Emacs Lisp, text markup, protocols -- Jabber: mwolson_at_hcoop.net
  /` |\ | | | IRC: mwolson on freenode.net: #hcoop, #muse, #PurdueLUG
 |_] | \| |_| Project involvement: Emacs, Muse, Planner, ERC, EMMS

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Re: Re: Midnight and noon in agendas

[Carsten Dominik]

On Jun 2, 2006, at 16:11, Michael Olson wrote:

> Carsten Dominik <dominik@science.uva.nl> writes:
>
>> It seems to me that the logic would be a bit better to schedule these
>> show uo as 0:00 and 0:21.  If you wanted to put something at midnight
>> at the end of the day you would then have to use 24:00 and 24:21.
>>
>> Opinions?
>
> That would have the nice effect of giving people more hours in a day.
> I'm sure everyone could use that.  :^)


Yes, indeed a funny effect.  However, it can be useful to schedule 
something at 24:21 or even at 26:00 or so.  because if you put such a 
date on your agenda for the next day, you might find out too late....

- Carsten

Re: Midnight and noon in agendas

[Christian Schlauer]

Carsten Dominik <dominik@science.uva.nl> writes:

> However, it can be useful to schedule something at 24:21 or even at
> 26:00 or so. because if you put such a date on your agenda for the
> next day, you might find out too late....

I see the problem, but I don't like these time formats at all. I'd
prefer if the agenda would show me things that are scheduled "early"
the next day (before 06:00, for example, should be configurable) on
the previous day already (and on the actual day).

Also, 26:00 is against the rules ;-)

,----[ http://en.wikipedia.org/wiki/ISO_8601 ]
| hh refers to an hour between 00 and 24, where 24 is only used to
| notate the midnight at the end of a calendar date
`----

,----[ http://en.wikipedia.org/wiki/24-hour_clock#Midnight_00:00_and_24:00 ]
| Time-of-day notations beyond 24:00 (such as 24:01 or 25:59) are
| neither commonly used nor covered by any relevant standards,
| although they have been seen on rare occasions in Japan.
`----

-- 
Christian Schlauer

Re: Re: Midnight and noon in agendas

[Carsten Dominik]

Hi Christian,

thanks for pointing to the relevant standards.

On Jun 2, 2006, at 19:24, Christian Schlauer wrote:
>
> I see the problem, but I don't like these time formats at all. I'd
> prefer if the agenda would show me things that are scheduled "early"
> the next day (before 06:00, for example, should be configurable) on
> the previous day already (and on the actual day).

I agree that this would be nice, but because the technical way in which 
the agenda is constructed, this would be hard to implement.  The way it 
works is like this:

1. The agenda collects all entries for the given date.
2. The it checks if the entry specifies a time-of day in any way.  
Org-mode is very tolerant in this.  Times may be specified as part of a 
timestamp, but also in many free-format ways.

To implement what you ask for, I would have to collect entries for two 
different dates, check for times, throw away the ones with the second 
date and either not time at all, or a time larger than your limit.  All 
this is possible, but has significant overhead.  The purpose of the 
week agenda is to show entries of the next day at least in close 
proximity to entries of the current day.

Still, this is a good idea, and I will put it on my todo list, 
scheduled for a long winter day evening :-)

> Also, 26:00 is against the rules ;-)

That is certainly true, but I see no reason to explicitly forbid them.  
This is something that can be easily left at a users discretion, don't 
you agree?

- Carsten



--
Carsten Dominik
Sterrenkundig Instituut "Anton Pannekoek"
Universiteit van Amsterdam
Kruislaan 403
NL-1098SJ Amsterdam
phone: +31 20 525 7477

Re: Midnight and noon in agendas

[Christian Schlauer]

Carsten Dominik <dominik@science.uva.nl> writes:

> On Jun 2, 2006, at 19:24, Christian Schlauer wrote:
>> Also, 26:00 is against the rules ;-)
>
> That is certainly true, but I see no reason to explicitly forbid them.

Of course not! The "format" is unusual, but very useful.

> This is something that can be easily left at a users discretion, don't
> you agree?

I do. Also, I like how it will look in the agenda: "+h:mm".

-- 
Christian Schlauer

Re: Midnight and noon in agendas

[Daniel J. Sinder]

Carsten Dominik wrote:
> Well, if this is the way things are normally interpreted,
> then this is clearly a bug.  Thanks for explaining this to me.
> Strange system.  Switching am to pm always makes the event happen later, 
> except when the hour is 12.

If 12am/00:00 is considered the start of the day, then the rule
holds -- switching 12am to 12pm makes the event later that same day,
at noon.

> Should 12am be listed as 0:00 or as 24:00?
> Should 12:21am be listed as 0:21 or as 24:21?
> 
> It seems to me that the logic would be a bit better to schedule these 
> show uo as 0:00 and 0:21.  If you wanted to put something at midnight at 
> the end of the day you would then have to use 24:00 and 24:21.

I like this idea (allowing times at 24:00 and beyond).  The user can
place things where they want: at the start or end of the day.  As a
bonus, if you work the night shift, you'll be able to see your daily
agenda all under one date at the start of your shift.

Re: Midnight and noon in agendas

[Carsten Dominik]

On Jun 2, 2006, at 21:45, Daniel J. Sinder wrote:
>
> If 12am/00:00 is considered the start of the day, then the rule
> holds -- switching 12am to 12pm makes the event later that same day,
> at noon.

Yes, you are right, of course.

>
>> Should 12am be listed as 0:00 or as 24:00?
>> Should 12:21am be listed as 0:21 or as 24:21?
>>
>> It seems to me that the logic would be a bit better to schedule these
>> show uo as 0:00 and 0:21.  If you wanted to put something at midnight 
>> at
>> the end of the day you would then have to use 24:00 and 24:21.
>
> I like this idea (allowing times at 24:00 and beyond).  The user can
> place things where they want: at the start or end of the day.  As a
> bonus, if you work the night shift, you'll be able to see your daily
> agenda all under one date at the start of your shift.

Thank you and the others on this thread for the input.
I am summarizing the result (at least what I extract of it):

- 12am is beginning of the day, same as 0:00
- 12pm is noon.
- Times like 24:13, 25:14, and even 13:12pm will be tolerated,
   mainly because the regular expression I have for finding times.
   matches them (it is something like [012]?[0-9].....
   The agenda will list such times after midnight.  You need to
   decide for yourself if this is more useful than confusing.
   The way these nonstandard times will show up in the agenda is:

     23:58
     23:59
     24:00
     +0:01
     +0:02
      ...

   The hard limit for this game is 29:59

- Carsten

--
Carsten Dominik
Sterrenkundig Instituut "Anton Pannekoek"
Universiteit van Amsterdam
Kruislaan 403
NL-1098SJ Amsterdam
phone: +31 20 525 7477