Presentation Forms - was: Questions about proposed characters

From: Jonathan Rosenne (
Date: Mon May 31 1999 - 03:11:49 EDT


Arabic ligatures were brought into 10646 by Mr. Raymond Halil and Mr. Hekimi
as part of the effort to promote proper Arabic presentation and as a means
to document the requirements of automatic shape determination (ASD). As far
as I know, the original was handwritten by Raymond. I kept a copy, it was so

At the time, computers were much slower, and we had thought that under
certain circumstances it would be advantageous to store data in its
presentation form, so Arabic and Hebrew presentation forms were added to
10646. These forms were not supposed to be used for interchange.

Also, at the time, the computer manufacturers had refused to support these
ligatures, probably because they thought that they are similar in nature the
many ligatures of the Latin script that are no longer in use, because the
requirement was vague and undefined and because they overestimated the cost.
The Arabists thought that cataloguing them and including them in an
international standard will help convince the manufacturers that they are
needed and possible.


> -----Original Message-----
> From: Michael Everson []
> Sent: Sunday, May 30, 1999 10:24 PM
> To: Unicode List
> Subject: Re: Questions about proposed characters
> Ar 11:08 -0700 1999-05-30, scríobh John Cowan:
> >Michael Everson scripsit:
> >
> >> Many of the digraphs already there are either from legacy
> >> character sets (such as a lot of Arabic presentation forms as far as I
> >> know)
> >
> >The Arabic ligatures don't even have that much excuse. They were dragged
> >in for purely political reasons.
> Someone must have thought they were a good idea for some technical reason
> or other.
> --
> Michael Everson, Everson Gunn Teoranta **
> 15 Port Chaeimhghein Íochtarach; Baile Átha Cliath 2; Éire/Ireland
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