Re: lisp/ChangeLog coding system

[Stephen J. Turnbull]

>>>>> "Stefan" == Stefan Monnier <monnier+gnu/address@hidden> writes:

    >> One aspect is making better guesses about desired coding
    >> systems.

    Stefan> I'm not sure what kind of improvements you're thinking
    Stefan> about.

Well, in the version (mid-January, maybe?) of GNU Emacs I have, when I
tried saving a buffer with mixed ascii, latin-1, and latin-2 in it, it
gave me an abominably long list of coding systems including mule
internal, all the -with-esc systems, and iso-2022-jp-2.  But all of
the characters used in the buffer are in ISO-8859-2, it's just Mule
making false distinctions.

At the very least, the defaults in Emacs should be to identify
identical characters (eg, those from the Latin-## subsets) and to
distinguish those where unification is controversial (the Han
ideographs).

    Stefan> non-MIME coding-systems should be in the "unlikely" list, tho.

There is no unique "the unlikely list".

For example, if I were Croatian, I probably would want the buffer
described above saved in ISO-8859-2 without being asked, but a German
would probably want to save it in UTF-8 (or maybe ISO-2022-7 if she
were an Emacs developer), or be queried, defaulting to ISO-8859-2.
And some of the "universal" coding systems (UTF-32, mule internal, all
the -with-esc systems) should probably not even be offered to most
users; they should have to ask for them by name.  But people with
special needs should be able to configure them for regular use.

And what's a "non-MIME coding system"?  AFAIK MIME has nothing to do with
coding systems except that the notation "the preferred MIME name" is a
useful convention.  But KOI8-R and all the Windows-125x sets are MIME
registered.

    Stefan> Looking at the README, I have the impression that most of
    Stefan> the functionality is already part of the Emacs CVS code
    Stefan> (mostly thanks to Dave's ucs-tables.el).  Someone should
    Stefan> try and figure out the details.

As for most functionality being in Emacs, yes, that's why I said I'd
help refactor; relative to ucs-tables.el the contribution is all UI.
My duplication[1] of ucs-tables is straightforward, not terribly
efficient code; all the meat is devoted to the question of "how do we
know which coding systems to offer the user".  Specifically I address
the issues of preferred unibyte systems and preferred universal
systems described above.


Footnotes: 
[1]  XEmacs 21.5 has built-in support for Unicode.  The UCS tables are
loaded at startup from (a local copy of) the Unicode Consortium
tables, and an API is provided to reload if desirable.  The code
predates the release of Emacs 21, and so is different from
ucs-tables.el, unfortunately.  The duplicative parts are for 21.4.

-- 
Institute of Policy and Planning Sciences     http://turnbull.sk.tsukuba.ac.jp
University of Tsukuba                    Tennodai 1-1-1 Tsukuba 305-8573 JAPAN
 My nostalgia for Icon makes me forget about any of the bad things.  I don't
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