Time string format

Time string format

[Eli Zaretskii]

time.el:display-time-string-forms believes that the right format for
displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
is not necessarily TRT in languages other than English, because
putting the month name before the day of the month does not
necessarily read well in other languages.

Would it be a good idea to have an element of language-info-alist that
provides a proper format for this?

Re: Time string format

[Lennart Borgman]

On Fri, Nov 19, 2010 at 7:42 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> time.el:display-time-string-forms believes that the right format for
> displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
> is not necessarily TRT in languages other than English, because
> putting the month name before the day of the month does not
> necessarily read well in other languages.
>
> Would it be a good idea to have an element of language-info-alist that
> provides a proper format for this?

Maybe, but why not use ISO format?§

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Fri, 19 Nov 2010 19:51:40 +0100
> Cc: emacs-devel@gnu.org
> 
> On Fri, Nov 19, 2010 at 7:42 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> > time.el:display-time-string-forms believes that the right format for
> > displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
> > is not necessarily TRT in languages other than English, because
> > putting the month name before the day of the month does not
> > necessarily read well in other languages.
> >
> > Would it be a good idea to have an element of language-info-alist that
> > provides a proper format for this?
> 
> Maybe, but why not use ISO format?§

I don't understand what exactly do you mean and how it would solve the
issue I was talking about.  Please explain more.

Re: Time string format

[Lennart Borgman]

On Fri, Nov 19, 2010 at 8:03 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Lennart Borgman <lennart.borgman@gmail.com>
>> Date: Fri, 19 Nov 2010 19:51:40 +0100
>> Cc: emacs-devel@gnu.org
>>
>> On Fri, Nov 19, 2010 at 7:42 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> > time.el:display-time-string-forms believes that the right format for
>> > displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
>> > is not necessarily TRT in languages other than English, because
>> > putting the month name before the day of the month does not
>> > necessarily read well in other languages.
>> >
>> > Would it be a good idea to have an element of language-info-alist that
>> > provides a proper format for this?
>>
>> Maybe, but why not use ISO format?§
>
> I don't understand what exactly do you mean and how it would solve the
> issue I was talking about.  Please explain more.

There is an ISO format for displaying time. See the doc string of
format-time-string, at the bottom.

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Fri, 19 Nov 2010 20:36:06 +0100
> Cc: emacs-devel@gnu.org
> 
> There is an ISO format for displaying time. See the doc string of
> format-time-string, at the bottom.

I don't see any relevance of the ISO format to the issue at hand.

Re: Time string format

[Lennart Borgman]

On Fri, Nov 19, 2010 at 11:15 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Lennart Borgman <lennart.borgman@gmail.com>
>> Date: Fri, 19 Nov 2010 20:36:06 +0100
>> Cc: emacs-devel@gnu.org
>>
>> There is an ISO format for displaying time. See the doc string of
>> format-time-string, at the bottom.
>
> I don't see any relevance of the ISO format to the issue at hand.

Why not? Is not the ISO time format relevant for all languages? Or do
you think of right-to-left languages?

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Sat, 20 Nov 2010 02:25:16 +0100
> Cc: emacs-devel@gnu.org
> 
> On Fri, Nov 19, 2010 at 11:15 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> >> From: Lennart Borgman <lennart.borgman@gmail.com>
> >> Date: Fri, 19 Nov 2010 20:36:06 +0100
> >> Cc: emacs-devel@gnu.org
> >>
> >> There is an ISO format for displaying time. See the doc string of
> >> format-time-string, at the bottom.
> >
> > I don't see any relevance of the ISO format to the issue at hand.
> 
> Why not? Is not the ISO time format relevant for all languages?

No.  You cannot force a culture to use ISO.  The ISO format, as I
understand it, is mainly for machine-readable output, not for humans.

> Or do you think of right-to-left languages?

That too, but not just.

Re: Time string format

[Lennart Borgman]

On Sat, Nov 20, 2010 at 10:43 AM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Lennart Borgman <lennart.borgman@gmail.com>
>> Date: Sat, 20 Nov 2010 02:25:16 +0100
>> Cc: emacs-devel@gnu.org
>>
>> On Fri, Nov 19, 2010 at 11:15 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> >> From: Lennart Borgman <lennart.borgman@gmail.com>
>> >> Date: Fri, 19 Nov 2010 20:36:06 +0100
>> >> Cc: emacs-devel@gnu.org
>> >>
>> >> There is an ISO format for displaying time. See the doc string of
>> >> format-time-string, at the bottom.
>> >
>> > I don't see any relevance of the ISO format to the issue at hand.
>>
>> Why not? Is not the ISO time format relevant for all languages?
>
> No.  You cannot force a culture to use ISO.  The ISO format, as I
> understand it, is mainly for machine-readable output, not for humans.

It was invented for paper format from the beginning. The purpose was
mainly avoiding misunderstandings. (But US did not adapt it so the
misunderstandings continued.)

>> Or do you think of right-to-left languages?
>
> That too, but not just.

Don't they have a common standardized time format?

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Sat, 20 Nov 2010 13:08:19 +0100
> Cc: emacs-devel@gnu.org
> 
> Don't they have a common standardized time format?

They do, but that's not relevant for this issue.

Re: Time string format

[Lennart Borgman]

On Sat, Nov 20, 2010 at 1:38 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Lennart Borgman <lennart.borgman@gmail.com>
>> Date: Sat, 20 Nov 2010 13:08:19 +0100
>> Cc: emacs-devel@gnu.org
>>
>> Don't they have a common standardized time format?
>
> They do, but that's not relevant for this issue.

I think you are wrong. I do not know the RL standard but the ISO 8601
format is for computer user interface. The purpose is to avoid
confusion.

In my opinion we should use the international standard when it is
possible. Standard helps free software since it requires less
resources.

Re: Time string format

[Lennart Borgman]

On Sat, Nov 20, 2010 at 2:34 PM, Lennart Borgman
<lennart.borgman@gmail.com> wrote:
> On Sat, Nov 20, 2010 at 1:38 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>>> From: Lennart Borgman <lennart.borgman@gmail.com>
>>> Date: Sat, 20 Nov 2010 13:08:19 +0100
>>> Cc: emacs-devel@gnu.org
>>>
>>> Don't they have a common standardized time format?
>>
>> They do, but that's not relevant for this issue.
>
> I think you are wrong. I do not know the RL standard but the ISO 8601
> format is for computer user interface. The purpose is to avoid
> confusion.

Forgot: here are some links for those who want to learn about it:

  http://www.cl.cam.ac.uk/~mgk25/iso-time.html
  http://www.iso.org/iso/date_and_time_format

> In my opinion we should use the international standard when it is
> possible. Standard helps free software since it requires less
> resources.
>

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Sat, 20 Nov 2010 14:36:47 +0100
> Cc: emacs-devel@gnu.org
> 
>   http://www.cl.cam.ac.uk/~mgk25/iso-time.html
>   http://www.iso.org/iso/date_and_time_format

These explain that the ISO format resolves the ambiguity in numerical
specifications of dates.  Therefore, it's irrelevant to the issue in
this thread, which is how to display non-numerical dates.  There's no
ambiguity in "20 Nov 2010".  Not to mention that the date format
discussed here is specific to a locale's language, whereas the ISO
format is agnostic to the locale.

Re: Time string format

[Lennart Borgman]

On Sat, Nov 20, 2010 at 4:39 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Lennart Borgman <lennart.borgman@gmail.com>
>> Date: Sat, 20 Nov 2010 14:36:47 +0100
>> Cc: emacs-devel@gnu.org
>>
>>   http://www.cl.cam.ac.uk/~mgk25/iso-time.html
>>   http://www.iso.org/iso/date_and_time_format
>
> These explain that the ISO format resolves the ambiguity in numerical
> specifications of dates.  Therefore, it's irrelevant to the issue in
> this thread, which is how to display non-numerical dates.  There's no
> ambiguity in "20 Nov 2010".  Not to mention that the date format
> discussed here is specific to a locale's language, whereas the ISO
> format is agnostic to the locale.

We are discussing the time string format for the mode line. ISO is
perfect for local formatting because it is the same for all locales.

My impression is that you do not like the format I suggest and
therefore say it is irrelevant. You are entitled to your opinion but
not to dismissing relevant information as irrelevant.

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Sat, 20 Nov 2010 17:17:00 +0100
> Cc: emacs-devel@gnu.org
> 
> We are discussing the time string format for the mode line.

Not in the mode line, in a tooltip that pops up when the mouse hovers
above the time string.

> My impression is that you do not like the format I suggest and
> therefore say it is irrelevant.

It's not I who doesn't like that, it's time.el.

Re: Time string format

[Óscar Fuentes]

Lennart Borgman <lennart.borgman@gmail.com> writes:

> We are discussing the time string format for the mode line. ISO is
> perfect for local formatting because it is the same for all locales.

How can a fixed format be perfect for *local* formatting? The user wants
to see dates on a format that is familiar to him. So ISO is just another
format.

[snip]

Re: Time string format

[Stephen J. Turnbull]

Óscar Fuentes writes:

 > How can a fixed format be perfect for *local* formatting? The user wants
 > to see dates on a format that is familiar to him. So ISO is just another
 > format.

+1

Re: Time string format

[Lennart Borgman]

On Sun, Nov 21, 2010 at 2:53 PM, Stephen J. Turnbull <stephen@xemacs.org> wrote:
> Óscar Fuentes writes:
>
>  > How can a fixed format be perfect for *local* formatting? The user wants
>  > to see dates on a format that is familiar to him. So ISO is just another
>  > format.
>
> +1

"2010-11-21" - in what local is that not perfectly valid? Do we really
have Emacs users that do not understand this standard ISO format?

Re: Time string format

[Stephen J. Turnbull]

[-- Attachment #1: Type: text/plain, Size: 490 bytes --]

Lennart Borgman writes:
 > On Sun, Nov 21, 2010 at 2:53 PM, Stephen J. Turnbull <stephen@xemacs.org> wrote:
 > > Óscar Fuentes writes:
 > >
 > >  > How can a fixed format be perfect for *local* formatting? The user wants
 > >  > to see dates on a format that is familiar to him. So ISO is just another
 > >  > format.
 > >
 > > +1
 > 
 > "2010-11-21" - in what local is that not perfectly valid? Do we really
 > have Emacs users that do not understand this standard ISO format?

[-- Attachment #2: Type: text/plain, Size: 167 bytes --]


Who cares what they do or don't understand?  What matters is
presenting what they want to see to them.  I personally want to see ２
０１０年１０月２１日.

Re: Time string format

[Lennart Borgman]

2010/11/21 Stephen J. Turnbull <stephen@xemacs.org>:
> Lennart Borgman writes:
>  > On Sun, Nov 21, 2010 at 2:53 PM, Stephen J. Turnbull <stephen@xemacs.org> wrote:
>  > > Óscar Fuentes writes:
>  > >
>  > >  > How can a fixed format be perfect for *local* formatting? The user wants
>  > >  > to see dates on a format that is familiar to him. So ISO is just another
>  > >  > format.
>  > >
>  > > +1
>  >
>  > "2010-11-21" - in what local is that not perfectly valid? Do we really
>  > have Emacs users that do not understand this standard ISO format?
>
>
> Who cares what they do or don't understand?  What matters is
> presenting what they want to see to them.  I personally want to see ２
> ０１０年１０月２１日.

I think it matters if they understand. If they understand the ISO time
format that makes it possible to have that as default. (Though as
someone noticed ISO 8601 does not have a format that mixes week day
with a common time string like "2010-11-21 18:20". That is quite bad
in my opinion, but does not prevent the use of the standard in the
time string without week day.)

Having the possibility for a local time string like the one you want
is of course not bad.

Re: Time string format

[Stephen J. Turnbull]

Lennart Borgman writes:

 > I think it matters if they understand. If they understand the ISO time
 > format that makes it possible to have that as default.

Nobody but you is talking about the default, though.  Everybody else
is talking about more or less customized date/time formats.

Re: Time string format

[Lennart Borgman]

On Mon, Nov 22, 2010 at 5:19 AM, Stephen J. Turnbull <stephen@xemacs.org> wrote:
> Lennart Borgman writes:
>
>  > I think it matters if they understand. If they understand the ISO time
>  > format that makes it possible to have that as default.
>
> Nobody but you is talking about the default, though.  Everybody else
> is talking about more or less customized date/time formats.

Ok, thanks.

Re: Time string format

[Harald Hanche-Olsen]

+ Lennart Borgman <lennart.borgman@gmail.com>:

> "2010-11-21" - in what local is that not perfectly valid? Do we really
> have Emacs users that do not understand this standard ISO format?

Quick: What weekday is 2012-04-27?

Anyhow, some users might even wish to have today's date represented as
2010W467 (also part of ISO 8601:2001, and as far as I know the only
variant that includes the day of the week).

- Harald

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Sat, 20 Nov 2010 14:34:45 +0100
> Cc: emacs-devel@gnu.org
> 
> In my opinion we should use the international standard when it is
> possible. Standard helps free software since it requires less
> resources.

This discussion goes nowhere, because you are missing the issue at
hand.  The issue at hand is how to correctly display a date with the
names of the month and the week-day spelled out as strings in the
locale's language.  By contrast, "%Y-%m-%d" produces a numerical date,
which is not what we want in time.el.

Re: Time string format

[Lennart Borgman]

On Sat, Nov 20, 2010 at 4:30 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Lennart Borgman <lennart.borgman@gmail.com>
>> Date: Sat, 20 Nov 2010 14:34:45 +0100
>> Cc: emacs-devel@gnu.org
>>
>> In my opinion we should use the international standard when it is
>> possible. Standard helps free software since it requires less
>> resources.
>
> This discussion goes nowhere, because you are missing the issue at
> hand.  The issue at hand is how to correctly display a date with the
> names of the month and the week-day spelled out as strings in the
> locale's language.  By contrast, "%Y-%m-%d" produces a numerical date,
> which is not what we want in time.el.

The week day is a problem, but why do we want the month spelled out?
Doesn't it save our time not spell it out? Are there any Emacs users
out there that can not understand the ISO time format?

Re: Time string format

[Eli Zaretskii]

> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Sat, 20 Nov 2010 16:39:36 +0100
> Cc: emacs-devel@gnu.org
> 
> The week day is a problem, but why do we want the month spelled out?

Because it's a nice-looking display, and there's no reason not to
provide it.

Re: Time string format

[Deniz Dogan]

2010/11/19 Eli Zaretskii <eliz@gnu.org>:
> time.el:display-time-string-forms believes that the right format for
> displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
> is not necessarily TRT in languages other than English, because
> putting the month name before the day of the month does not
> necessarily read well in other languages.
>
> Would it be a good idea to have an element of language-info-alist that
> provides a proper format for this?
>
>

In the docstring for `format-time-string':

%c is the locale's date and time format.
%x is the locale's "preferred" date format.
%X is the locale's "preferred" time format.
%EX is a locale's alternative version of %X;
%OX is like %X, but uses the locale's number symbols.

One of these or a combination of multiple formats seems ideal to me.

-- 
Deniz Dogan

Re: Time string format

[Eli Zaretskii]

> From: Deniz Dogan <deniz.a.m.dogan@gmail.com>
> Date: Sat, 20 Nov 2010 03:49:24 +0100
> Cc: emacs-devel@gnu.org
> 
> 2010/11/19 Eli Zaretskii <eliz@gnu.org>:
> > time.el:display-time-string-forms believes that the right format for
> > displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
> > is not necessarily TRT in languages other than English, because
> > putting the month name before the day of the month does not
> > necessarily read well in other languages.
> >
> > Would it be a good idea to have an element of language-info-alist that
> > provides a proper format for this?
> >
> >
> 
> In the docstring for `format-time-string':

Granted, I've read that ;-)

> %c is the locale's date and time format.
> %x is the locale's "preferred" date format.
> %X is the locale's "preferred" time format.
> %EX is a locale's alternative version of %X;
> %OX is like %X, but uses the locale's number symbols.
> 
> One of these or a combination of multiple formats seems ideal to me.

I think you are missing the point.  The issue is not what each of the
format specifiers produce, the issue is their order in a
_well-formatted_and_short_date_ string.  When viewed from this POV, I
think you will agree with me that

  . %x is inappropriate, because in most (if not all) locales it
    returns a numerical date, like 11/22/33, while time.el wants to
    produce human-readable names of the month and the week-day

  . %X, %EX, and %OX are irrelevant, because I was talking about
    the date, not the time

  . %c is inappropriate, because it shows the time together with the
    date

  . any combination of the above will be inappropriate for the same
    reasons the individual specifiers are

It is therefore a small wonder that time.el does not use any of these,
but instead attempts to define its own format.  The problem is that
the result is not correct for some locales/languages.  I was asking
about a good way of having that fixed.

Re: Time string format

[David De La Harpe Golden]

On 19/11/10 18:42, Eli Zaretskii wrote:
> time.el:display-time-string-forms believes that the right format for
> displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
> is not necessarily TRT in languages other than English,

Or even in English... Americans speak an English dialect but have that 
awkward habit of putting the month first.  But that's mainly an issue 
when they use all-numeric dates, I expect an American could cope with
"%a %d %b %Y" which is used by a lot of locales including  english 
speaking ones - and in fact we see the "en_US.UTF-8" locale on my system 
apparently uses that order in its %c, unlike the "C" locale.

> Would it be a good idea to have an element of language-info-alist that
> provides a proper format for this?

Probably not? language-info-alist is AFAICS a list of emacs' "language 
environments", which are not at all 1:1 to locales.  Emacs does 
auto-pick its language env based on your locale, unless you set one 
explicitly (I always just set current-language-environment to UTF-8...), 
but e.g. it picks the same language env "English" for several locales 
that happen to be english-speaking, but which have different D_FMTs.


# just some example locale info
# nl_langinfo(D_T_FMT) is just what strftime uses for %c,
# nl_langinfo(D_FMT) for %x and nl_langinfo(T_FMT) for %X
# a.out just being a program that calls nl_langinfo and strftime

$ export LC_ALL=C
$ ./a.out '%c || %X || %x'
nl_langinfo(D_T_FMT): "%a %b %e %H:%M:%S %Y"
nl_langinfo(T_FMT): "%H:%M:%S"
nl_langinfo(D_FMT): "%m/%d/%y"
strftime("%c || %X || %x"): "Sat Nov 20 03:16:15 2010 || 03:16:15 || 
11/20/10"

$ export LC_ALL=en_US.UTF-8
$ ./a.out '%c || %X || %x'
nl_langinfo(D_T_FMT): "%a %d %b %Y %r %Z"
nl_langinfo(T_FMT): "%r"
nl_langinfo(D_FMT): "%m/%d/%Y"
strftime("%c || %X || %x"): "Sat 20 Nov 2010 03:16:29 AM GMT || 03:16:29 
AM || 11/20/2010"

$ export LC_ALL=en_IE.UTF-8
$ ./a.out '%c || %X || %x'
nl_langinfo(D_T_FMT): "%a %d %b %Y %T %Z"
nl_langinfo(T_FMT): "%T"
nl_langinfo(D_FMT): "%d/%m/%y"
strftime("%c || %X || %x"): "Sat 20 Nov 2010 03:16:38 GMT || 03:16:38 || 
20/11/10"

$ export LC_ALL=ga_IE.UTF-8
$ ./a.out '%c || %X || %x'
nl_langinfo(D_T_FMT): "%a %d %b %Y %T %Z"
nl_langinfo(T_FMT): "%T"
nl_langinfo(D_FMT): "%d.%m.%y"
strftime("%c || %X || %x"): "Sath 20 Samh 2010 03:17:04 GMT || 03:17:04 
|| 20.11.10"

$ export LC_ALL=fr_FR.UTF-8
$ ./a.out '%c || %X || %x'
nl_langinfo(D_T_FMT): "%a %d %b %Y %T %Z"
nl_langinfo(T_FMT): "%T"
nl_langinfo(D_FMT): "%d/%m/%Y"
strftime("%c || %X || %x"): "sam. 20 nov. 2010 03:17:15 GMT || 03:17:15 
|| 20/11/2010"

$ export LC_ALL=de_DE.UTF-8
$ ./a.out '%c || %X || %x'
nl_langinfo(D_T_FMT): "%a %d %b %Y %T %Z"
nl_langinfo(T_FMT): "%T"
nl_langinfo(D_FMT): "%d.%m.%Y"
strftime("%c || %X || %x"): "Sa 20 Nov 2010 03:17:23 GMT || 03:17:23 || 
20.11.2010"

$ export LC_ALL=ja_JP.UTF-8
$ ./a.out '%c || %X || %x'
nl_langinfo(D_T_FMT): "%Y年%m月%d日 %H時%M分%S秒"
nl_langinfo(T_FMT): "%H時%M分%S秒"
nl_langinfo(D_FMT): "%Y年%m月%d日"
strftime("%c || %X || %x"): "2010年11月20日 03時17分43秒 || 03時17分43秒 
|| 2010年11月20日"

Re: Time string format

[Eli Zaretskii]

> Date: Sat, 20 Nov 2010 03:47:13 +0000
> From: David De La Harpe Golden <david@harpegolden.net>
> 
> On 19/11/10 18:42, Eli Zaretskii wrote:
> > time.el:display-time-string-forms believes that the right format for
> > displaying the date in the mode-line tooltip is "%a %b %e, %Y".  This
> > is not necessarily TRT in languages other than English,
> 
> Or even in English... Americans speak an English dialect but have that 
> awkward habit of putting the month first.  But that's mainly an issue 
> when they use all-numeric dates, I expect an American could cope with
> "%a %d %b %Y" which is used by a lot of locales including  english 
> speaking ones - and in fact we see the "en_US.UTF-8" locale on my system 
> apparently uses that order in its %c, unlike the "C" locale.

That's correct, but we could still leave the current default in
time.el in the absence of a locale-specific format, because it is
appropriate to the "C" locale.

> > Would it be a good idea to have an element of language-info-alist that
> > provides a proper format for this?
> 
> Probably not? language-info-alist is AFAICS a list of emacs' "language 
> environments", which are not at all 1:1 to locales.

That's true, but since I was only talking about a _date_, does it
really matter?  See below.

> Emacs does 
> auto-pick its language env based on your locale, unless you set one 
> explicitly (I always just set current-language-environment to UTF-8...), 
> but e.g. it picks the same language env "English" for several locales 
> that happen to be english-speaking, but which have different D_FMTs.

I wasn't talking about D_FMT, mind you.  D_FMT is what %x produces,
and time.el rightfully doesn't want to use that, because it produces a
numeric date in most locales (as your sample clearly shows).

> $ export LC_ALL=en_US.UTF-8
> $ ./a.out '%c || %X || %x'
> nl_langinfo(D_T_FMT): "%a %d %b %Y %r %Z"
> nl_langinfo(T_FMT): "%r"
> nl_langinfo(D_FMT): "%m/%d/%Y"
> strftime("%c || %X || %x"): "Sat 20 Nov 2010 03:16:29 AM GMT || 03:16:29 
> AM || 11/20/2010"
> 
> $ export LC_ALL=en_IE.UTF-8
> $ ./a.out '%c || %X || %x'
> nl_langinfo(D_T_FMT): "%a %d %b %Y %T %Z"
> nl_langinfo(T_FMT): "%T"
> nl_langinfo(D_FMT): "%d/%m/%y"
> strftime("%c || %X || %x"): "Sat 20 Nov 2010 03:16:38 GMT || 03:16:38 || 
> 20/11/10"

Note that, in both these en_* locales, the date part of %c is the
same: "Sat 20 Nov 2010".  Are there any en_* locales (or any other
locales that share the same language) which differ in that part?  If
there aren't, then we can use the language alone as the key.

Also note that we already have languages such as "Brazilian
Portuguese", which are really locale-specific variations of other
languages; we could use the same trick for the date format, should we
need that (if the answer to the previous questions is YES).

If we want to use the locale as the key after all, we could add the
format to locale-language-names instead, but that sounds less clean to
me.

Re: Time string format

[David De La Harpe Golden]

On 20/11/10 10:28, Eli Zaretskii wrote:

> Note that, in both these en_* locales, the date part of %c is the
> same: "Sat 20 Nov 2010".
>  Are there any en_* locales (or any other
> locales that share the same language) which differ in that part?

[I have to reconfigure my system to spit out that information, it's 
presently only generating a small subset of locales, might take a bit
longer than I thought, bah]

Re: Time string format

[David De La Harpe Golden]

[-- Attachment #1: Type: text/plain, Size: 1996 bytes --]

On 20/11/10 18:10, David De La Harpe Golden wrote:
> On 20/11/10 10:28, Eli Zaretskii wrote:
>
>> Note that, in both these en_* locales, the date part of %c is the
>> same: "Sat 20 Nov 2010".
>> Are there any en_* locales (or any other
>> locales that share the same language) which differ in that part?
>
> [I have to reconfigure my system to spit out that information, it's
> presently only generating a small subset of locales, might take a bit
> longer than I thought, bah]


Attached please find dump of the raw info from my system.
("%a %d %b %Y" covers a lot and is quite likely still comprehensible by 
a lot of the others).

There are some locales that differ in that part despite being the
same language (following by visual inspection only, and n.b. just in 
case: this is only a list of the locales where the langauge is the same 
but the date part of the d_t_fmt different, this is not a list of 
locales differing from "%a %d %b %Y")

*Afar (aa):
- aa_DJ (Djibouti): "%a %d %b %Y"
- aa_ER (Eritrea):  "%A, %B %e, %Y"
- aa_ET (Ethiopia): "%A, %B %e, %Y"

*Arabic (ar):
mostly "%d %b, %Y", except:
- ar_IN (India): "%A %d %B %Y"
- ar_SA (Saudi Arabia): "%A %e %B %Y"

*English (en):
mostly "%a %d %b %Y"  (including US!) except:
numeric, Y-m-d ordering
- en_DK (Denmark):  "%Y-%m-%d"
month and day in full, month,day,year ordering:
- en_HK (Hong Kong): "%A, %B %d, %Y"
month and day in full, day,month,year ordering:
- en_IN (India):  "%A %d %B %Y"
- en_PH (Philippines): "%A, %d %B, %Y"
- en_SG (Sinqgapore): "%A %d,%B,%Y"

*Frisian (fy):
just dot after the %d in one and not the other.
- fy_NL: "%a %d %b %Y"
- fy_DE: "%a %d. %b %Y"

*Somali (so):
mostly "%A, %B %e, %Y", except:
- so_DJ (Djibouti): "%a %d %b %Y"

*Swedish (sv):
- sv_FI (Finland): "%a %e. %Bta %Y"
- sv_SE (Sweden): "%a %e %b %Y"

*Chinese (zh):
mosltly "%Y年%m月%d日 %A", except day in parens for:
- zh_TW (Taiwan R.O.C.): "%Y年%m月%d日 (%A)"



[-- Attachment #2: dump_locale_dtfmts --]
[-- Type: text/plain, Size: 425 bytes --]

#!/bin/bash

for L in C $(awk </etc/locale.gen '{print $1}'); do
   if [[ ! "$L" == "tt_RU@iqtelif.UTF-8" ]]; then # buggy locale
     export LC_ALL=$L
     C=$(locale charmap)
     if [[ ( "$1" == "-a" ) || ( "$C" == "UTF-8" ) || ( "$C" == "ANSI_X3.4-1968" ) ]]; then
        echo LC_ALL="\"$L\""
        locale -k language territory charmap d_t_fmt d_fmt t_fmt
        echo
     fi
   fi
done

export LC_ALL=$ORIG_LC_ALL



[-- Attachment #3: locale_dtfmts.all_mixedenc.txt.gz --]
[-- Type: application/x-gzip, Size: 6974 bytes --]

[-- Attachment #4: locale_dtfmts.utf8only.txt.gz --]
[-- Type: application/x-gzip, Size: 5050 bytes --]