So what you are asking about is a directional control character that would assign subsequent characters a BC of 'AL', right?
You don't want to call this a LANGUAGE MARK or anything else that implies language identification, because of the existence of "real" language identification mechanisms and the history of Unicode and language tagging. -- Doug Ewell • [email protected] Sent via BlackBerry by AT&T -----Original Message----- From: Richard Wordingham <[email protected]> Sender: [email protected] Date: Mon, 22 Aug 2011 03:19:39 To: Unicode Mailing List<[email protected]> Subject: Re: RTL PUA? On Sun, 21 Aug 2011 23:55:46 +0000 "Doug Ewell" <[email protected]> wrote: > What's a LANGUAGE MARK? There are *three* strong directionalities - 'L' left-to-right, 'AL' right-to-left as in Arabic, 'R' right-to-left (as in Hebrew, I suspect). 'AL' and 'R' have different effects on certain characters next to digits - it's the mind-numbing part of the BiDi algorithm. With one a $ sign after a string of European (or is it Arabic?) digits appears on the left and in the other it appears on the right. I can't remember whether 'higher-level protocols' have an effect on this logic. LRM has a BC of L, RLM has a BC of R, but no invisible character has a BC of AL. That's why I tentatively raised the notion of ARABIC LANGUAGE MARK. Incidentally, an RLO gives characters with a temporary BC of R, not AL. Richard.
