Re: Several serious problems

[Dave Love <d.love@dl.ac.uk>]

Kenichi Handa <handa@etl.go.jp> writes:

> In article <rzqlm6ybz38.fsf@albion.dl.ac.uk>,
>   Dave Love <d.love@dl.ac.uk> writes:
> > As far as I know, what's installed in the trunk behaves correctly, but
> > I'm not using that code
> 
> Why aren't you using that code?

I don't want to use an unstable Emacs with all sorts of things I don't
understand.

> I noticed those `fixme's.   Yes, it is better to solve all
> of them, but, for the moment, I want to concentrate on
> fixing the problem of RC.

I was trying to sort out RC, but I don't understand this problem.

> The safe-charsets property of utf-8 in RC is this:
> 
> ascii eight-bit-control eight-bit-graphic latin-iso8859-1
> mule-unicode-0100-24ff mule-unicode-2500-33ff
> mule-unicode-e000-ffff ethiopic tibetan thai-tis620
> katakana-jisx0201 ipa chinese-sisheng lao
> vietnamese-viscii-lower vietnamese-viscii-upper

I see:

 '((safe-charsets
    ascii
    eight-bit-control
    eight-bit-graphic
    latin-iso8859-1
    mule-unicode-0100-24ff
    mule-unicode-2500-33ff
    mule-unicode-e000-ffff)

in what appears to be revision 1.9.4.2 with sticky tag `EMACS_21_1_RC'.

> It doesn't contain latin-iso8859-[23...].

Indeed.

> The complaint is that the coding-system utf-8 can't encode
> latin-2 characters in RC even if loadup.el has these lines.

Indeed, but the complaint seemed to be that it could encode latin-2
and safe-charsets didn't say so.  That's why I thought someone had
changed it.

> The reason is, as far as I see, the ccl program
> `ccl-encode-mule-utf-8' doesn't have this line at the near
> to head.
> 
> 	   (translate-character ucs-mule-to-mule-unicode r0 r1))

Yes.  

> So, even if we setup the translation table
> `ucs-mule-to-mule-unicode' at loadup time, it is not used in
> utf-8.

Nor in other CCL coding systems.

> Hmmm, I think I realized the situation of RC.  It can unify
> charsets between iso-8859-X, but utf-8 can't encode
> iso-8859-X (intentionally), correct?

Yes.

> Richard, is it what you asked Dave to install for RC?

I'm pretty sure ucs-tables was only allowed to be installed because
just adding the file couldn't break anything.

> I think RC should also allow utf-8 to encode 8859-X
> correctly like in HEAD.  I see no harm in it.

I'm sure there's no harm in my Mule changes generally, but that's not
what everyone has been told, unfortunately.  

> > I think I unilaterally added some other things (a utf-8 language
> > environment and utf-16.el?) since they addressed somewhat misleading
> > entries in PROBLEMS and the arguments against the Unicode support are
> > either demonstrably wrong or spurious IMNSHO.
> 
> I don't oppose to that.

I didn't think you would.

> I found one problem with utf-16.
> It seems that utf-16-le/be can handle 8859-X correctly
> because of this line in ccl-encode-mule-utf-16-le/be,
>       (translate-character ucs-mule-to-mule-unicode r0 r1)

I guess that's an error, and I should have taken that out for
consistency with utf-8.

> > I'm afraid I've had enough of all this,
> 
> Yah, you have done the excellent hack!

I don't mean anything to do with useful work.  It's after being told
for so long it's impossible/broken/not wanted, wasting time, and then
having to sort out the situation in adverse circumstances.  It's very
unfortunate not to have an active maintainer for Mule generally.

> When I implemented translation table stuffs, I didn't expect that it
> can be used this thoroughly.

Strange!  I thought that was exactly what they were for, and the only
thing that was missing initially to satisfy the complaining Europeans
was char-coding-system-table.  The names were even
`...-unification-...' originally.

> I thought containing ucs-tables and etc in RC is at least
> for making unify-on-encoding the default INCLUDING utf-8.

I've no idea.  As far as I remember, it was due to pressure from users
of both Latin-1 and Latin-9 who must have actually tried it despite
what they were told.  I was surprised it was eventually allowed in.