Re: What is a preferred charset?

[Eli Zaretskii <eliz@gnu.org>]

> From: Stephen Berman <stephen.berman@gmx.net>
> Cc: schwab@suse.de,  emacs-devel@gnu.org
> Date: Wed, 21 Nov 2018 23:44:55 +0100
> 
> >> > In the case of HELLO, each hello phrase was given the 'charset'
> >> > property corresponding to its language's script, so as to instruct
> >> > Emacs to choose the most appropriate font for that greeting.
> >> 
> >> ...this seems to be a different criterion for preferred, not the highest
> >> priority as defined above
> >
> > Not a different criterion, it's just that the 'charset' text property
> > overrides the charset priority order (as you'd expect).
> 
> But why override the priority order if the preferred charset by that
> criterion (namely unicode, in this case) works (i.e. the character is
> correctly displayed)?  I guess because there are cases where the
> preferred charset according to priority order fails?

It is not a question of success or failure: every charset which
supports the character "succeeds".  We choose one of them in order to
produce the effect (such as select a font for displaying it) that
suits best what this particular user in this particular case expects.
When text comes from an encoding that specifies its charset (such as
Latin-N), we can determine that charset from the encoding; if not, we
use the charset-priority order that is determined by the locale, as
fallback.