bug#5235: 23.1; Unibyte keyboard input problem

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

>>> I'll try to explain why I need unibyte mode. I'm maintener of a C/C++
>>> source  code which has comments coded in cp1250 (polish language) but
>>> strings in code  are coded in cp852. So I have two different code
>>> pages in source code file.  This is old source code and it was
>>> developed in Windows (that's why comments  are in cp1250) but is
>>> compiled to work on MS-DOS (that's why strings are  coded in cp852).
>> So what happens if you read those files as binary (i.e. C-x RET
>> r binary RET)?
> At best, he'd end up silently screwing up his files even further, with
> cp1250, cp852 and now utf-8 encoded characters in them.  More likely he
> would still get prompted when saving, just as if he'd used cp1250 or cp852
> to read them.

That would be a bug: a file visited as `binary' (or as `raw-text')
should be placed in a unibyte buffer, so it should not screw anything up
more than was already the case to start with.

> The problem here is the files, not Emacs.  Basically the reason for using
> unibyte is that it allows the user to bury their head in the sand and
> pretend the problem does not exist.

Of course, but if you start with such files and can't (or don't want to)
recode the parts consistently, we can't do much better.

> I work on similar files in my day job, with Japanese comments in ShiftJIS
> and Chinese comments in GB2312. An easy method of fixing such files would be
> nice, but the best I can think of would be to provide a recode-region
> function, which would still be too much manual work to be worth it to me
> given that I can barely make sense of the Japanese comments and can't make
> any sense of the Chinese ones. The original poster might be more motivated
> to make use of such a function if it existed though.

I'm not sure what would be the best approach in general or in particular
cases, but we could certainly provide a command that recodes comments.
Or another one that looks for invalid byte sequences (i.e. decoded as
eight-bit-bytes) and tries to re-decode them with a secondary coding system.


        Stefan