Re: master e4e1e268c8e 2/2: Set a default locale on Android

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: emacs-devel@gnu.org
> Date: Fri, 08 Dec 2023 18:30:51 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > If that encoding is consistent with the current system locale, Emacs
> > is expected to be able to decode it.
> 
> The system's locale is _always_ UTF-8.

Now I'm confused: if the above is true, then what is the below about?

    Emacs does not respect the locale configured for user applications
  in the system, for the selection of locales available there does not
  match that supplied by the C library.  When Emacs starts on Android
  5.0 or newer, the @code{LANG} environment variable is set to
  @code{en_US.utf8}, which induces subprocesses linked against the
  Android C library to print output sensibly.

My interpretation of this was that Android does support locales
"configured for user applications", but Emacs doesn't respect that.
If that interpretation is incorrect, then how should the above text be
interpreted?  And what does "locale configured for user application"
mean then?

> >> >   . what will be the default coding-systems in Emacs? will they always
> >> >     be UTF-8?
> >> 
> >> Yes.
> >> 
> >> >   . what will be the default dictionary for spell-checking? will it
> >> >     always be English?
> >> 
> >> Yes, unless the system's spell checker is being used.
> >> 
> >> >   . what will be the default language-environment in Emacs? will it
> >> >     always be UTF-8? if so, what would be the default input method to
> >> >     be turned on when the user types 'C-\' ?
> >> 
> >> It'll always be UTF-8, and typing C-\ should prompt the user for the
> >> input method to enable.
> >
> > Such behaviors are unacceptable.  We should fix them so that Emacs on
> > Android behaves like it does on other platforms, or else we cannot
> > release such an Android port.  Please work on fixing these glaring
> > omissions.
> 
> How can it be fixed, when there are only two locales (C and UTF-8) in
> existence?

Let's defer this question until we are on the same page wrt locales
and language settings on Android.  As an active user of Android
(though not of Emacs on Android), I know that there _are_
configuration settings for system language and for each application,
they are under Settings->General Management->Language and
Settings->General Management->App Languages.  There are also settings
for keyboard, which are conceptually part of the language-environment
in Emacs.  Some Android smartphones also have Regional Preferences.

> Android spell checkers are meant to provide their own means
> for detecting and applying the system's language preferences, because
> the system does not on their behalf.

How will that work with ispell.el in Emacs?