RE: Re: About section 8.2.4

At 10:34 98/01/28 +0900, UCHIDA akira wrote:
> Hello ISHIKAWA-sama.
> 
> Thank you for your advice.
> Please allow me to ask you more detail.
> 
> > > I think that the word "not" in the last 4 words is NOT needed.
> > > 
> > > > Because HTML uses the Unicode bidirectionality algorithm, conforming
> > > > documents encoded using ISO 8859-8 must be labeled as "ISO-8859-8-i".
> > > > Explicit directional control is also possible with HTML, but cannot b
> e
> > > > expressed with ISO 8859-8, so "ISO-8859-8-e" should not be used.
> > 
> > No, the word "not" IS needed.  As noted in the previous paragraph of
> > Section 8.2.4, "ISO-8859-8-i" denotes implicit bidirectionality, and
> > "ISO-8859-8-e" denotes explicit directionality.
> 
> Yes. I read RFC1556 to understand the usage of "-i" and "-e".
> 
> 
> > "Unicode bidirectionality algorithm" means implicit bidirectionality
> > algorithm, thus, "ISO-8859-8-e" should NOT be used.
> 
> I still have two questions.
> 
> (1) Are there many language that can be encoded by "-e" encoding or
>     only Hebrew and Arabic have "-e" (and "-i") encoding ?

There are many languages that use the Hebrew or Arabic script and
therefore need Bidi support. There are also some more scripts (mostly
historic) that are written right-to-left. In practice, only Hebrew
email uses both visual and implicit ordering. RFC 1556 was written
by somebody mostly familliar with Hebrew, but not so much with
Arabic. While Hebrew and Arabic have more or less the same problems
for Bidi, Arabic needs more work for character->glyph processing.
In actual practice and early implementations, Hebrew therefore mostly
was based on simple ASCII software, with some keyboard hacking and
a different font. This resulted in using visual ordering in the
data. On the other hand, for Arabic, a more sophisticated renderer
was needed anyway, so in most cases, Bidi was also built in. Therefore,
visual ordering is not much used for Arabic, while it was and still
is in use for Hebrew. In contrary to what RFC 1556 says, the "-e" and
"-i" was only used for Hebrew, but never took on for Arabic. This is
mentionned in the HTML 4.0 spec. As for the distinction between "-i"
and "-e", please see my previous mail. As far as I know, there are
some standards that allow explicit reordering combined with 8859-8,
but they never really came into much use, and are not relevant in
connection with HTML 4.0.


> (2) Now my understanding about section 8.2.4 with your help:
>     Section 8.2.4 says "we can use NO '-e' encodings to express
>     explicit directional control, because HTML uses the Unicode
>     'inolicit' bidirectionality algorithm only".
>     Is it right?

No, this is not right, as explained in my previous mail.


> 
> > P.S.  If you have some difficulty in translating into Japanese, maybe
> > 	I can help you.
> 
> By the way, could I write to you in both English and Japanese (by
> ISO-2022-JP) ?

No problem for me of Ishikawa-san. But maybe it is better not to send too
many ISO-2022-JP mails to the translators list.


Regards,   Martin.

Received on Wednesday, 28 January 1998 01:42:26 UTC