> Of course it would have been possible to handle the "Astral Planes" > > uniformly by making every character in them a legal Char, but not a > valid name character or name start character. This would have avoided > silliness like elements named after the musical symbol for a six > string fretboard or the damage of using undefined characters in XML > documents. It also would have been much more compatible with existing > parsers and tools. :-(
This would have created the opposite silliness of perfectly sensible name start characters being arbitrarilly disallowed. I'd like to see the musical symbol for a six string fretboard disallowed because we *know* what it is and we *know* it is category So and hence not an appropriate character for such use. Similarly we know U+400FE will never be assigned, so I'd prefer to see it disallowed as such, from Char and from all other productions. With unassigned characters (but not non-characters) doing anything other than allowing them would cause forwards-compatibility issues. However they (along with the private-use characters) are probably characters that should not be used for interchange.
