Re: environment variable don't get coding conversion

["Ehud Karni" <ehud@unix.mvs.co.il>]

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On Sat, 25 Jan 2003 14:22:27 -0500, Richard Stallman <rms@gnu.org> wrote:
>
> "make non-ascii usable" is not specific enough for me to understand.
> I cannot be sure if there is a real problem.

I'd say "Make non-ASCII usable" means that the env var should be usable
in Emacs sub shell. i.e. getenv in program run in subshell will get the
proper value (usually an 8 bit characters for ISO-8859-x).

> Please show me a specific problem case so I can judge if there is a
> significant problem.

We have many variables containing Hebrew strings (ISO-8859-8). They
are accessed by programs and scripts. They are represented by 8 bit
values in process-environment.
e.g. HUSER is set to "דוהא", is stored as "HUSER=\343\345\344\340".

If I do (setenv "HUTST" "דוהא") it is stored as "HUTST=דוהא". Now,
when a subshell is accessing the the HUTST variable it gets
ˆדˆוˆהˆא (i.e. \210 before each Hebrew character).
Here is the output of "env | grep "^HU" | cat -v" run from Emacs:
HUTST=M-^HM-cM-^HM-eM-^HM-dM-^HM-`
HUSER=M-cM-eM-dM-`

The way to overcome it in Emacs is to set the env var like this:
  (setenv "HUTST" (encode-coding-string "דוהא" 'hebrew-iso-8bit))

>     If you have a non-ASCII variable name, you can't sensibly use M-x
>     getenv with it;
>
> getenv could decode the variable name, if that is useful.

You can set non-ASCII variable name, e.g.
  (setenv (encode-coding-string "Hםש" 'hebrew-iso-8bit)
          (encode-coding-string "ינרק" 'hebrew-iso-8bit))
and you can use them in subprocesses. To use them in Emacs itself,
You have to use the encoded Hebrew name, i.e.
  (getenv (encode-coding-string "Hםש" 'hebrew-iso-8bit))

I agree that to use non-ASCII environment variable name is not
practical, so this problem is not really important, but the non-ASCII
values are used a lot, and the practical way for ISO-8859-x is to
have them in unibyte.

The `process-environment' can hold the values in multibyte but
`child_setup' and `getenv_internal' (in callproc.c) should transform
the values to unibyte (or whatever necessary for other coding systems
like CJK and utf-8).

Ehud.


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