Lack of ulUnicodeRange Bit for Adlam

[Richard Wordingham via Unicode]

On Tue, 27 Feb 2018 11:45:36 -0500
Neil Patel via Unicode <unicode at unicode.org> wrote, under topic heading
"Re: Unicode Digest, Vol 50, Issue 20":

> Does the ulUnicodeRange bits get used to dictate rendering behavior or
> script recognition?
> 
> I am just wondering about whether the lack of bits to indicate an
> Adlam charset can cause other issues in applications.

(Answering in case the problem is still relevant - I had misfiled this
post.)

The lack is unlikely to cause any problems in anything recent enough to
understand the concept of "Adlam" - the bits were not added for blocks
newer than Unicode 5.1.

As Adlam was only added in Version 9.0, there is a significant risk of
rendering engines not supporting cursive joining.  On the other hand,
the Adlam characters have been right-to-left since Version 5.2.  (It
shouldn't matter whether one of the characters switched from right to
left to NSM.)

Richard.