Zero-Width Joiner U+200D

[Peter Constable]

From Unicode 15, section 9.2 (p. 375):

“The Non-joiner and the Joiner. The Unicode Standard provides two user-selectable for[1]matting codes: U+200C zero width non-joiner and U+200D zero width joiner. The use of a joiner adjacent to a suitable letter permits that letter to form a cursive connection without a visible neighbor. This provides a simple way to encode some special cases, such as exhibiting a connecting form in isolation, as shown in Figure 9-2.”

Later in that section (p. 383), ZWJ is listed in the Join_Causing set of Arabic joining types

It seems to me the text is describing the original intent as Asmus described.


Peter

From: Unicode <unicode-bounces at corp.unicode.org> On Behalf Of Jukka K. Korpela via Unicode
Sent: Tuesday, February 21, 2023 4:56 AM
To: Asmus Freytag <asmusf at ix.netcom.com>
Cc: unicode at corp.unicode.org
Subject: Re: Zero-Width Joiner U+200D

 Asmus Freytag via Unicode (unicode at corp.unicode.org<mailto:unicode at corp.unicode.org>) wrote:

I think we need to look at whether the language accurately reflects what we were trying to say. I do know that it was revised at one point, when the use of ZWJ was generalized beyond cursive connection.

It seems that this took place as early as in Unicode 2.

The interpretation you suggest may be an inadvertent result of that change, or someone had found out why the usage that I always understood as intended is for some reason problematic. In that case, it should be excluded more explicitly, in my view.

In fact, reading chapter 23 onwards, I now see the use of ZWJ’s around a character to ask for isolated form. It was just so far from the place that described ZWJ and ZWNJ between adjacent characters, giving the impression that this is their only use. Perhaps it would help to remove the word “adjacent” from “U+200D zero width joiner is intended to produce a more connected rendering of adjacent characters than would otherwise be the case, if possible.

The text describes the use of ZWJ for isolated form and shows this in example 23-1. Sorry for the confusion I caused.

So the answer to Andreas’ question is “yes, it should”, with the value of “should” roughly as “is intended to, according to the Unicode standard, but a program that renders Unicode characters is not required to obey, or even understand, such rendering suggestions”

Jukka
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