Changed coding system priority (sort-coding-systems)

[Reiner Steib <reinersteib+gmane@imap.cc>]

Hi,

in Emacs 23, with (set-language-environment "Latin-1"), windows-1252
(and iso-8859-15, too) gets a higher priority than utf-8.  This wasn't
so in Emacs 22.  Is this an intended change?

I was surprised to see charset=windows-1252 in this message[1] because
in Emacs 22, Gnus won't use windows-1252 in outgoing message unless
`mm-coding-system-priorities' prefers it.

IMHO, windows-1252 should be tried before falling back to binary on
decoding (e.g. when reading a file).  On encoding (when saving to a
file or sending a mail message), utf-8 should be preferred.  Rational:
Encourage to use UTF-8 instead of M$ windows-1252, but display common
windows-1252 file/message correctly.

Is there a way to achieve this?  Or should we need to make a change in
Gnus (`mm-util.el')?

,----[ Emacs 22 ]
| ELISP> emacs-version
| "22.1.92.2"
| ELISP> (sort-coding-systems '(iso-8859-1 iso-8859-15 utf-8 windows-1252)) 
| (utf-8 iso-8859-1 iso-8859-15 windows-1252)
| ELISP> (set-language-environment "Latin-1")
| t
| ELISP> (sort-coding-systems '(iso-8859-1 iso-8859-15 utf-8 windows-1252))
| (iso-8859-1 utf-8 windows-1252 iso-8859-15)
`----

,----[ Emacs 23 ]
| ELISP> emacs-version
| "23.0.60.2"
| ELISP> (sort-coding-systems '(iso-8859-1 iso-8859-15 utf-8 windows-1252))
| (utf-8 iso-8859-1 iso-8859-15 windows-1252)
| ELISP> (set-language-environment "Latin-1")
| t
| ELISP> (sort-coding-systems '(iso-8859-1 iso-8859-15 utf-8 windows-1252))
| (iso-8859-1 iso-8859-15 windows-1252 utf-8)
`----

(Both tests with `LANG=en_US.UTF-8'.)

Hm, I guess this is the reason:

,----[ <f1> v language-info-alist RET ]
|   coding-system      value is a list of coding systems that are good
| 			for saving text written in this language environment.
| 			This list serves as suggestions to the user;
| 			in effect, as a kind of documentation.
|   coding-priority    value is a list of coding systems for this language
| 			environment, in order of decreasing priority.
| 			This is used to set up the coding system priority
| 			list when you switch to this language environment.
`----

,----[ Emacs 23 | <f1> v language-info-alist RET ]
|  ("Latin-1"
|  [...]
|   (coding-priority iso-latin-1)
|   (coding-system iso-latin-1 iso-latin-9 windows-1252)
`----

,----[ Emacs 22 | <f1> v language-info-alist RET ]
|  ("Latin-1"
|  [...]
|   (coding-priority iso-latin-1 windows-1252)
|   (coding-system iso-latin-1)
`----

Bye, Reiner.

[1]
,----
| From: Thien-Thi Nguyen [...]
| Subject: Re: Emacs Bazaar repository
| To: dhruva [...]
| Cc: emacs-devel[...]
| Date: Thu, 13 Mar 2008 10:04:54 +0100
| Message-ID: <874pbbyoy1.fsf@ambire.localdomain>
| Content-Type: text/plain; charset=windows-1252
`----
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/