Re: ZWJ and Latin Ligatures (was Re: (long) Re: Chromatic font research)

From: Kenneth Whistler (
Date: Mon Jul 01 2002 - 17:47:33 EDT

James Kass said:

> One problem with TR28 is that it is worded so that it appears to
> be "in addition" to earlier guidelines.

It is. The way this works is as follows: The original decision
about the ZWJ as request for ligation was documented in the
Unicode 3.0.1 update notice. That documentation was rolled forward
into UAX #27 (Unicode 3.1), where it was explicitly cast as text
to replace the Unicode 3.0 text on p. 318 re Controlling Ligatures,
including an update of the example table. The additional text in
UAX #28 is just that -- an *addition* to the Unicode 3.1 text,
not a replacement for it.

This will all become more apparent when we can finally publish
Unicode 4.0, which will roll all of the textual additions, once
again, into a single published document.

> This implies that the examples
> used in TR27, for one, are still valid.

They are.

> In TR27, font developers are
> urged to add things like "f+ZWJ+i" to existing tables where "f+i"
> is already present.

That recommendation still stands -- and, as John pointed out,
is being implemented by vendors.

> Another problem with TR28 is that its date is earlier than the date
> on TR27. This suggests that TR27 is more current.

I don't understand this claim.

The date on UAX #27 is: 2001-05-16

The date on UAX #28 is: 2002-03-07

Please check that you are referring to the most recent (and only
valid) versions of each.

Otherwise, regarding the substance of this thread, I find myself
in violent agreement with John, who it seems to me is quite ably
stating the case for the current treatment as decided by the UTC.


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