From: Sinnathurai Srivas (sisrivas@blueyonder.co.uk)
Date: Tue Aug 23 2005 - 14:47:49 CDT
I think PUA is used on an experimental basis and will be moved to character
code, once approved.
I like to hear technical views other than the temporary use of PUA, and the
discussions on weather it will be officially encoded or not, which can be
discussed at a later date. This will help avoid the stability trap that all
other languages find themselves in.
Sinnathurai
----- Original Message -----
From: "John Hudson" <tiro@tiro.com>
Cc: "Unicode List" <unicode@unicode.org>
Sent: Monday, August 22, 2005 10:35 PM
Subject: Re: 28th IUC paper - Tamil Unicode New
> Richard Wordingham wrote:
>
>>> GSUB tables don't handle the reordering in Indic languages. It's the
>>> responsibility of the OpenType Layout processor, e.g. Uniscribe.
>
>> So how do I get it to live up to its 'responsibility' to support an Indic
>> conlang living in the PUA? I'm not even sure that Burmese is supported
>> yet.
> ...
>
>> While it clearly looks like good practice to have a single per-script
>> definition of necessary re-orderings, in practice it is very inconvenient
>> if the user (or system administrator) cannot update the definitions. For
>> example, Microsoft has little incentive to modify Uniscribe to treat
>> independent Devanagari vowels as consonants (or, to be pedantic,
>> consonant-vowel ligatures).
>
> If you want something supported, you have to take it through the standards
> process and get it approved as part of Unicode or another standard that
> the software company in question is committed to supporting. If the
> behaviour you want to see for Devanagari becomes part of Unicode's
> processing requirements for that script, then you can expect Microsoft to
> support it.
>
>
> A shaping engine has no 'responsibility' to support an Indic conlang
> living in the PUA, because the shaping engine has no way of knowing that a
> string of PUA codepoints is text in an Indic conlang.
>
> The very nature of the PUA effectively makes it a dead end for most
> language processing, unless you have a very simple script in which there
> is a one-to-one correspondence between characters and glyphs and simple
> sequential, left-to-right display. Shaping engines simply don't know what
> to do when you pass them a PUA codepoint, because it could be *anything*.
> This is why using non-standard, PUA codepoints for any language processing
> is such a bad idea.
>
> John Hudson
>
> --
>
> Tiro Typeworks www.tiro.com
> Vancouver, BC tiro@tiro.com
>
> Currently reading:
> Lords of the horizons, by Jason Goodwin
> Dining on stone, by Iain Sinclair
>
>
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