Re: Problems with 8-bit headers

[jsbien@mimuw.edu.pl (Janusz S. Bien)]

Florian Weimer <fw@deneb.cygnus.argh.org> writes:

>Vladimir Volovich <vvv@vvv.vsu.ru> writes:
[...]
>> * possibility to set up preferred charsets to encode message bodies on
>>   a per-group basis.
>
>> * possibility to specify that the preferred charset to encode a
>>   message body should be the same as the charset used to encode the
>>   message (or mime part) i'm replying to.
>
>Currently, these two features are very hard to implement, at least
>in the general case, because Emacs unifies only ASCII characters in
>different MULE charsets.  For example, an ISO-8859-1 "=E4" and one in
>ISO-8859-2 are completely different characters from Emacs' view.  As a
>result, it is impossible to decide whether the preferred MIME charset
>can be used---without additional mapping tables.  

Could you please elaborate? When you save or write a buffer, Emacs
can decide whether the buffer content (e.g. input directly from the
keyboard) can be represented in the default buffer coding system; if
not, Emacs offers the choice of appropriate coding systems.  

Why do you think that an analogical treatment of the preferred MIME
charset it is impossible? What is wrong with such Emacs functions as
`select-safe-coding-system-function', `detect-coding-with-priority',
`detect-coding-region', `prefer-coding-system' etc.?

Regards

Janusz

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                     ,   
dr hab. Janusz S. Bien, prof. UW
Prof. Janusz S. Bien, Warsaw Uniwersity
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