From: Peter Kirk (peter.r.kirk@ntlworld.com)
Date: Wed Aug 06 2003 - 16:03:34 EDT
On 06/08/2003 03:38, Kent Karlsson wrote:
>Kenneth Whistler wrote:
>
>
>
>>Kent Karlsson said:
>>
>>
>>
>>>I see no particular *technical* problem with using WJ, though. In
>>>contrast
>>>to the suggestion of using CGJ (re. another problem)
>>>
>>>
>>anywhere else but
>>
>>
>>>at the end of a combining sequence. CGJ has combining class
>>>
>>>
>>0, despite
>>
>>
>>>being invisible and not ("visually") interfering with any other
>>>combining
>>>mark. Using CGJ at a non-final position in a combining sequence puts
>>>in doubt the entire idea with combining classes and normal forms.
>>>
>>>
>>Why?
>>
>>
>
>See above (I DID write the motivation!). Combining classes are generally
>assigned according to "typographic placement". Combining characters
>(except those that are really letters) that have the "same" placement,
>and "interfere typographically" are assigned the same combining class,
>while those that don't get different classes, ...
>
Not true, as we have seen for Hebrew. It's supposed to be true, but
isn't, and the problems can't be fixed.
>... and the relative order is
>then considered unimportant (canonically equivalent). How is then,
>e.g. <a, ring above, cgj, dot below> supposed to be different from
><a, dot below, cgj, ring above> (supposing all involved characters
>are fully supported), when <a, ring above, dot below> is NOT
>supposed to be much different from <a, dot below, ring above>
>(them being canonically equivalent)? ...
>
There is no difference when the characters really do not interfere
typographically. But when they do, there is a real and, in some
languages, meaningful distinction.
>...
>
>... the only ways out seem to be to either formally deprecate
>CGJ, or at least confine it to very specific uses. Other occurrences
>would not be ill-formed or illegal, but would then be non-conforming.
>
>
OK, let's confine it to those specific uses where it is really needed,
e.g. to get round the problem of combining characters with different
combining classes which actually do interact typographically, and
perhaps there was another one being suggested. I have no problem with
that - as long as the list of permitted uses is not set in stone, so
that new uses can be approved when they are discovered. But there is no
good reason to object to its use in those cases where it is needed,
simply because in many other cases it is not needed.
-- Peter Kirk peter.r.kirk@ntlworld.com http://web.onetel.net.uk/~peterkirk/
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