Re: ZWJ and Latin Ligatures

From: John H. Jenkins (jenkins@apple.com)
Date: Mon Jul 01 2002 - 13:00:30 EDT


On Monday, July 1, 2002, at 10:16 AM, Michael Everson wrote:

> Some nice person just said to me privately:
>
>> Michael Everson wrote:
>>
>>> In my paper http://www.dkuug.dk/jtc1/sc2/wg2/docs/n2317.pdf I raised
>>> a lot of questions about exceptions and the use of these. I don't
>>> think they were ever all answered.My other papers, N2141 and N2147,
>>> show a number of examples of ligation which is not particularly
>>> predictable. That's what ZWJ us supposed to be for.
>>
>> That's because some people (not to mention any ad-hominem names; there
>> is more than one) are more interested in saying "This is a simple
>> problem, and the rendering systems of the future (or my Mac today) will
>> handle it automatically" than in answering the complex linguistic and
>> orthographic questions you raised.
>>

For the record, I (at least) have never asserted that Mac (or any other)
system software will ever gain the ability to handle ligation on a
completely automatic basis. In any event, the ZWJ/ZWNJ mechanism has no
advantage over any higher-level protocol when it comes to software support,
  since it's all being done via AAT/OpenType/Graphite or something similar
in any event.

I guess one thing that's frustrating for me personally in this perennial
discussion is the creation of this false dichotomy, that ligation control
either *must* be in plain text or *must* be expressly forbidden in plain
text. I would agree, Michael, that your arguments that some degree of
ligation control belongs in plain text were unanswerable. You did a good
job there. But at the same time, I've never heard you argue that the only
way to turn ligatures on or off is in plain text.

I feel compelled to reiterate my own feelings on the subject: Ligation in
Latin text is generally a matter of stylistic preference, and depends on
the specific typeface being used and its set of available ligatures.
There are exceptions, and these should be handled via the ZWJ/ZWNJ
mechanism. Where ligation is merely a matter of stylistic preference,
however, it should be handled by some other mechanism which can take the
specific capacities of a typeface into consideration. System and other
software can (and should) provide default ligation which the user should
be able to override.

And under no circumstances should new Latin ligatures be added to Unicode.

>> Personally I think your ZERO-WIDTH LIGATOR papers are among the best of
>> all your Unicode-related papers. I agreed with the decision to unify
>> the ligation function with ZWJ rather than creating a new character, but
>> your arguments about Latin, Greek, Runic, Old Hungarian, etc. ligation
>> were thorough and unassailable.
>
> Thank you, nice person. It's nice to know that someone else looked at the
> argument and came up with the same conclusion that I did.
>

For the record, Michael, this was the general feeling of the UTC when the
matter was debated there.

==========
John H. Jenkins
jenkins@apple.com
jenkins@mac.com
http://homepage.mac.com/jenkins/



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