Re: iso-8859-1 and non-latin-1 chars

[Kenichi Handa <handa@m17n.org>]

In article <rzqhedrp0f5.fsf@albion.dl.ac.uk>, Dave Love <d.love@dl.ac.uk> writes:
> Richard Stallman <rms@gnu.org> writes:
>>  Emacs normally does warn when the coding system doesn't handle all the
>>  characters in the file.  Is there a common scenario where that warning
>>  is bypassed?

> I don't know how common, but for example: broken code (Gnus at times,
> I'd bet) or customizations (select Latin-1 for your BBDB database) and
> C-x RET c.  Basically whenever the coding system is actually specified
> rather than selected from the set of somehow-preferred coding systems.

Even if we write out a proper escape seqeucne for
unencodable characters in a file, those people who are not
familiar with handling coding systems can't read the file
correctly.  If he reads it without C-x RET c, it will be
read as iso-2022-7bit or something like that, not as
iso-latin-1-with-esc.  If he doesn't notice it, he will be
in a big confusion.  If he reads it with C-x RET c
iso-latin-1, the escape sequence is not decoded, thus he
will see raw ESC codes.

So, my conclusion was that writing out those escape
sequences not only violates the commonly accepted concept
about a coding system, but also doesn't help people that
much.

Richard Stallman <rms@gnu.org> writes:
> If you specify a coding system with C-x RET c, and it doesn't
> handle all the text, should Emacs warn about that?

I think that is better, but, can we distinguish these cases
in Fwrite_region.
  (1) coding system is specified by C-x RET c.
  (2) coding system is specified by a code:
	 (let ((coding-system-for-write ...)) ...)

Or, do you think we should warn in both cases?

---
Ken'ichi HANDA
handa@m17n.org