Re: • instead of \

From: Philippe Verdy <verdy_p_at_wanadoo.fr>
Date: Fri, 25 Oct 2013 01:18:17 +0200

For ISO 646 and all variants of ASCII (incluing JIS, HKCS, GB...) may be,
but this should hve never affected the UCS. These were separate encoding sta
ndards, that have clear distinctive mppings of their code position 5C to
the correct codepoints in the UCS.
MSDOS anywy did not use the UCS but one of these legcy encodings. Even today
if you use the console apps in Windows, they use the setting of the codepage
with CHCP, to determine how Windows will map these codepages to the UCS for
rendering with its UCS-encoded fonts.

There's no excuse for fonts embedding an Unicode mapping to use the wrong
code points in their glyph mappings, even if they include also a
separate mapping
for legacy codepages specific to some OS. Those fonts are incorrect.

2013/10/24 Koji Ishii <kojiishi_at_gluesoft.co.jp>

> A bit of more history to supplement Asmus.
>
> When ISO defined their 7-bit standard ISO 646 BCT[1] based on ASCII, they
> defined 12 code points national standards can change: 23, 24, 40, 5B, 5C,
> 5D, 5E, 60, 7B, 7C, 7D, 7E.
>
> European needed most of these code points to define diacritic characters,
> but East Asians needed only a couple, so Japanese and Korean standard body
> chose probably least oftenly used code points: 5C and 7E.
>
> It was an unfortunate coincident that MS-DOS 2.0 chose 5C as the directory
> separator in 1983. All Japanese books at the point Unicode was implemented
> say YEN is the directory separator character. I was actually surprised when
> I learned that non-Japanese MS-DOS uses backslash as the directory
> separator. Also during the transition period, Unicode applications needed
> backwards compatibility with non-Unicode applications for their currency
> symbols.
>
> Hence there wasn't a clear solution that is Unicode compliant and also
> suffices backwards compatibility.
>
> [1] http://en.wikipedia.org/wiki/ISO/IEC_646
>
> -----Original Message-----
> From: unicode-bounce_at_unicode.org [mailto:unicode-bounce_at_unicode.org] On
> Behalf Of Asmus Freytag
> Sent: Wednesday, October 23, 2013 4:23 AM
> To: jf_at_colson.eu; unicode_at_unicode.org
> Subject: Re: • instead of \
>
> On 10/22/2013 11:38 AM, Jean-FranÁois Colson wrote:
> > Hello.
> >
> > I know that in some Japanese encodings (JIS, EUC), \ was replaced by a •.
> >
> > On my computer, there are some Japanese fonts where the characters
> > seems coded following Unicode, except for the \ which remained a •.
> >
> > Is that acceptable from a Unicode point of view?
> >
> > Are such fonts Unicode considered compliant?
>
> It's one of those things where there isn't a clean solution that's also
> backwards compatible.
>
> A./
> >
> > Thanks.
> >
>
>
>
>
>
Received on Thu Oct 24 2013 - 18:21:50 CDT

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