From: John Cowan <cowan@ccil.org>
To: Mark H Weaver <mhw@netris.org>
Cc: 33044@debbugs.gnu.org, tdevries@suse.de
Subject: bug#33044: Guile misbehaves in the "ja_JP.sjis" locale
Date: Tue, 16 Oct 2018 08:52:59 -0400 [thread overview]
Message-ID: <CAD2gp_RLS5PcWsN3EpfVh3zCf+dWWFio_BLUd+Ur3JGdpBtA9g@mail.gmail.com> (raw)
In-Reply-To: <87tvlmo4mw.fsf@netris.org>
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At this point, I'm inclined to believe that Shift_JIS is not suitable as
> a locale encoding on POSIX systems, and that we should not try to
> support it in Guile.
>
> What do you think?
>
> Can you tell me how backslash and tilde are represented in Shift JIS?
>
They aren't: iconv is right. Japanese Windows users are used to seeing
Windows pathnames that look like "C:¥foo¥bar", and when writing C, to
strings like "first line¥nsecond line." So what is happening is that the
character at #\x5C is *functionally* a backslash that is *displayed* as a
yen sign. This is reinforced by the fact that the round-trip mapping from
Shift_JIS #\x5C is U+005C BACKSLASH, whereas U+00A5 YEN SIGN is mapped only
from Unicode (or other encodings) to Shift_JIS, never the other way around.
This is the last survivor of the "national characters" concept of ISO 646,
whereby certain 7-bit characters were interpreted differently in different
countries. For Scandinavian programmers, for example, blocks in C began
with æ and ended with å rather than { and } respectively, and the logical
OR operator was ø. In the same way, British and Irish programmers used £
instead of # at the beginning of comments in awk and shell programs. With
the arrival of Latin-{1,2,3,4} this concept was eventually abandoned, and
all systems converged on ISO-646-IRV (the same as US-ASCII) *except*
Japanese systems.
So I recommend that you do what everyone else does and ignore the issue in
JIS-based encodings, of which Shift_JIS is the only one in practical use
(and it _is_ heavily used in Japan, where it is almost the only encoding
for documents on desktops). Just ignoring the encoding is not an option
in Japan: see the comments by Joel Rees, Norman Diamond, and Ryan Thompson
at the bug you pointed to.
--
John Cowan http://vrici.lojban.org/~cowan cowan@ccil.org
In might the Feanorians / that swore the unforgotten oath
brought war into Arvernien / with burning and with broken troth.
and Elwing from her fastness dim / then cast her in the waters wide,
but like a mew was swiftly borne, / uplifted o'er the roaring tide.
--the Earendillinwe
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next prev parent reply other threads:[~2018-10-16 12:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-15 8:44 bug#33044: Invalid read access of chars of wide string in scm_seed_to_random_state Tom de Vries
2018-10-15 14:20 ` bug#33044: Reproduced using guile binary Tom de Vries
2018-10-21 16:24 ` Tom de Vries
2018-10-15 18:59 ` bug#33044: Analysis and proposed patch Tom de Vries
2018-10-16 1:57 ` bug#33044: Guile misbehaves in the "ja_JP.sjis" locale Mark H Weaver
2018-10-16 5:13 ` Mark H Weaver
2018-10-16 12:52 ` John Cowan [this message]
2018-10-16 23:38 ` Tom de Vries
2018-10-17 7:00 ` Tom de Vries
2018-10-16 23:27 ` Tom de Vries
2018-10-18 1:56 ` Mark H Weaver
2018-10-18 10:26 ` Tom de Vries
2018-10-20 2:24 ` Mark H Weaver
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