Re: Time string format

[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.

> 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"