Re: (LC_ALL=C; set -x 128 129; printf "%s\n" ${(#)@} | hexdump -C)

["Jun. T" <takimoto-j@kba.biglobe.ne.jp>]

> 2023/08/31 4:45, Bart Schaefer <schaefer@brasslantern.com> wrote:
> 
> Doc for (#) says:
> 
>     If the MULTIBYTE option is set and the number is greater than 127
>     (i.e.  not an ASCII character) it is treated as a Unicode
>     character.

It seems that this translation succeeds only if UTF-8 locale is in use.
The translation is done in function substevalchar(), but in C locale it
fails to convert and fallbacks to 'no translation':

$ LC_ALL=C zsh -f
% n=128
% printf "%s\n" ${(#)n} | hexdump -C
00000000  80 0a                                             |..|
00000002

substevalchar() calls getkeystring() for the conversion, and
wctomb() (utils.c:6983) fails (returns -1), and zerr() sets
errflag.

If we use an array instead of sclar:

% a=( 128 129 )
% printf "%s\n" ${(#)a} | hexdump -C
00000000  22 0a 22                                          |"."|
00000003

In this case, errflag is set when translating a[0]=128, but it is
not reset and still set to 1 when substevalchar() is called for a[1].
Then substevalchar() immediately returns NULL (subst.c:1496).

Now paramsubst() sets haserr=1 (subst.c:3592) and returns NULL at
line 3609 (although errflag is reset at line 3606), 
and stringsubst() also returns NULL (line 327),
and prefork() quits at line 146 (probably before removing " " from
t"%s\n").

So we need to reset (or save/restore) errflag somewhere...

And, with multibyte option on but with C locale, what is the
correct behavior of ${(#)n} for n > 127 ?