Re: What is a preferred charset?

[Stephen Berman <stephen.berman@gmx.net>]

On Thu, 22 Nov 2018 00:30:22 +0200 Eli Zaretskii <eliz@gnu.org> wrote:

>> From: Stephen Berman <stephen.berman@gmx.net>
>> Cc: emacs-devel@gnu.org
>> Date: Wed, 21 Nov 2018 17:48:37 +0100
>> 
>> > When text has the 'charset' property, we show its value as the
>> > highest-priority charset of the characters having that property.  This
>> > property is described in "Explicit Encoding".
>> 
>> On my system (where the value of locale-coding-system is utf-8-unix) the
>> first entries in charset-priority-list are: ascii iso-8859-1 unicode
>> latin-iso8859-1 ...  And calling char-charset on the character named
>> INVERTED EXCLAMATION MARK returns "unicode" here.  That accords with
>> what you both wrote above about highest priority, but...
>> 
>> > 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?  So then it is not
preferred.  But then preferred in that case does not mean according to
priority order.  So I'm still not clear about this...

Steve Berman