This discussion has focused pretty tightly on the *default* properties of PUA code points, without really addressing the issue of specifying new properties to override those defaults, and I think that's a mistake.
After all, if you're going to define Private Use characters, it really isn't enough to specify only the glyphs. You also need to indicate the type of character (letter, number, space, etc.), directionality, numeric properties, combining class, maybe case, and so forth. This is Unicode, after all, where a character is defined as much by its properties as anything else. As a reminder, I do believe in the PUA for the purpose of exchanging rare, personal, or ideosyncratic *TEXT CHARACTERS* in a Unicode environment (note to William: I still owe you a response). My invented script at [1] is an example: it does not, and will never, qualify for standardization in Unicode; but I have sent and received private e-mails in it, using a privately defined agreement, exactly what the PUA was intended for. The page at [2] includes a full list of Unicode properties for each character in my invented script. This includes not only directionality, but everything else that would be listed for a standardized Unicode character in UnicodeData.txt. (I've wanted to do a complete list like this for all of CSUR, but it's waaaay down on my list of priorities.) I could imagine someone, somewhere... possibly me... writing a Unicode subsystem that actually read in UnicodeData.txt (or a compiled version of it) and used that to derive its information about character properties. Now, if someone defined PUA characters and *actually went to the trouble of specifying their properties*, as I did in [2], and if this subsystem was able to use that data as an adjunct to UnicodeData.txt, then things would work the way Peter Kirk wants. The default LTR directionality and other default properties of PUA characters would not matter; they would be overridden. But Ken and Rick are absolutely right that very few companies are going to see a business opportunity in this. Even SC UniPad, which has implemented many comparatively arcane features of Unicode, has never done anything with the PUA, though it has been on their "future versions" list for 6 years now. [1] http://users.adelphia.net/~dewell/ewellic.html [2] http://users.adelphia.net/~dewell/ew-props.html -Doug Ewell Fullerton, California http://users.adelphia.net/~dewell/
