What day is tomorrow?

[Luc]

Today is 23 so tomorrow is 24, no problem.

But if today was the 30th, how would I know what day tomorrow is?
The 31st or the 1st?

Easy. Just check what the month is.

But then I would need to maintain two lists:
30-day months and 31-day months.

And there is always February, of course. So I also have to check
if it's a leap year.

Or maybe I can just get today's Epoch, add 86400 seconds and get
the date corresponding to the resulting Epoch.

I can do all that by myself, but it definitely sounds like a wheel
that someone else has invented already.

Do you know of any? I would like to see what other tools there
might be in that toolbox.

I haven't found anything in Tcllib or Tclx.


--
Luc
>>

[Harald Oehlmann]

clock format [clock add [clock seconds] 1 day] -format %d

[Christian Gollwitzer]

Am 23.01.23 um 08:33 schrieb Harald Oehlmann:

> Am 23.01.2023 um 07:37 schrieb Luc:
>> Today is 23 so tomorrow is 24, no problem.
>>
>> But if today was the 30th, how would I know what day tomorrow is?
>> The 31st or the 1st?
>

> clock format [clock add [clock seconds] 1 day] -format %d
>

Or use the free-form clock parser:

clock format [clock scan tomorrow] -format %d

It also understands "now + 1 day" and similar things

Christian

[Harald Oehlmann]

Wow, I did not know this! You learn each day! Thanks,
Harald

[Arjen Markus]

You should be a bit careful with that: the free-form parser is a bit quirky, if I understand it correctly. One reason to stay with the more formal arithmetic.

Regards,

Arjen

[Harald Oehlmann]

Yes, and it is depreciated. So, maybe remove it in 9.0 ;-).
But the solution by Christian is just beautiful !

Take care,
Harald

[Ralf Fassel]

* Christian Gollwitzer <auri...@gmx.de>

But be aware of the subtle differences between "24 hours" and "1 day":

% clock format [clock scan "now"]
Mon Jan 23 10:53:41 CET 2023

% clock format [clock scan "now + 24 hours"]
Tue Jan 24 10:53:41 CET 2023

% clock format [clock scan "now + 1 day"]
Tue Jan 24 00:00:00 CET 2023

% clock format [clock scan tomorrow]
Tue Jan 24 00:00:00 CET 2023

% info patchlevel
8.6.13

I would have expected that "now + 1 day" produces the same result as
"now + 24 hours", since the docs state:

FREE FORM SCAN
relative time
A specification relative to the current time. The format is
number unit. Acceptable units are year, fortnight, month, week,
day, hour, minute (or min), and second (or sec). The unit can
be specified as a singular or plural, as in 3 weeks. These mod-
ifiers may also be specified: tomorrow, yesterday, today, now,
last, this, next, ago.

The actual date is calculated according to the following steps.

First, any absolute date and/or time is processed and converted. Using
that time as the base, day-of-week specifications are added. Next,
relative specifications are used.
!!! If a date or day is specified, and no absolute or relative
!!! time is given, midnight is used.
Finally, a correction is applied so that the correct hour of the
day is produced after allowing for daylight savings time
differences and the correct date is given when going from the end
of a long month to a short month.

(Emphasis by me)

HTH
R'

[Robert Heller]

It is built-in: the clock command will tell you.

clock add timeVal ?count unit...? ?-option value?


proc nextdate {month date year} {
return [clock format [clock add [clock scan \
[format {%04d-%02d-%02d} $year $month $date] \
-format {%Y-%m-%d}] 1 day] -format {%m %d %Y}]

Robert Heller -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software -- Custom Software Services
http://www.deepsoft.com/ -- Linux Administration Services
hel...@deepsoft.com -- Webhosting Services

[Gerald Lester]

Read the manual page for the clock command, pay attention to the section
on the clock add subcommend.

--
+----------------------------------------------------------------------+
| Gerald W. Lester, President, KNG Consulting LLC |
| Email: Gerald...@kng-consulting.net |
+----------------------------------------------------------------------+

[Christian Gollwitzer]

Am 23.01.23 um 11:00 schrieb Harald Oehlmann:

I know it is deprecated and I think it is a mistake to completely take
it away, since it has these nice features. If it is moved away, I think
it should go into something like
clock scan -format free "tomorrow"
or "clock guess tomorrow" or maybe into tcllib.

Christian