On 19 Aug 2011, at 15:34, Shriramana Sharma wrote: > On 08/19/2011 07:43 PM, Doug Ewell wrote: >> My question would be why the PUA is designated as 'L' by default at all, >> instead of, say, 'ON'. >> ... >> do present the impression that these code points are somehow reserved >> for strong-LTR characters, and also for non-reordrant characters (i.e. >> no combining marks), neither of which is true. > > I entirely agree! There then should be an effort to officially change the BC > of these characters to ON, would you say? I mean, what kind of > implementations could such a change affect adversely?
There is plenty of space. There would be no difficulty in assigning some rows to a RTL PUA. Mucking about with the directionality of the existing PUA would be extremely unwise. > Conceivably certain closed user-groups could be using closed-distribution > rendering engines which would support bidi and glyph reordering or such for > PUA codepoints. Not everyone is a programmer and can devise a rendering engine. But lots of people can make fonts that could support a RTL conscript or some private Arabic characters. > In which case, the only change that needs to be done to affirm that the PUA > can be used for both LTR and RTL scripts is to change the BC of all those > characters to ON. I wouldn't support that. Michael Everson * http://www.evertype.com/
