From: Richard Wordingham <>
Date: Mon, 22 Aug 2011 03:18:41 +0100

On Sun, 21 Aug 2011 16:37:34 -0700
Asmus Freytag <> wrote:

> Treating PUA characters as ON is very problematic - their display
> would become context sensitive in unintended ways. No users of CJK
> characters would think of using LRM characters, but if text is
> inserted or viewed in RTL context, it could behave randomly.

I think a problem would be immediately obvious. Also, the CJK PUA
characters would usually be guarded by non-PUA CJK characters.

> In contrast, always supplying a RLO override for RTL text (containing
> PUA characters) would be a simple thing to remember and to get right.

So long as you remembered to pop before digits. This could easily go
wrong if the text were amended. For example, if two paragraphs were
merged, one could easily delete a PDF, and then digits at the bottom of
the second paragraph, quite possibly off-screen at the time, would
suddenly flip.

Received on Sun Aug 21 2011 - 21:23:12 CDT

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