Re: "Missing character" glyph

From: Martin Kochanski (unicode@cardbox.net)
Date: Thu Aug 01 2002 - 12:38:39 EDT


At 08:42 01/08/02 -0700, Doug Ewell wrote:
>Martin Kochanski <unicode at cardbox dot net> wrote:
>
>> To look at it another way, virtually the only action that the Unicode
>> Consortium needs to take to define UNRENDERED CHARACTER is to promise
>> never to define a character at that code point.
>
>I think this is exactly what they have done by creating the
>"noncharacters" from U+FDD0 through U+FDEF. These code points are
>guaranteed never to be assigned to real characters.

First - thank you very much for the suggestion! I was looking in the printed book, where of course these things aren't mentioned (they arrived in 3.0.1).

Google led me to the UTC 84 / L2 181 Minutes, where Motion 84-M6 says of not-a-characters:
- they are not to be publicly transmitted
- they can be deleted without an impact of the interpretation of the text
- they should be removed in normalization
- their presence may also indicate corrupted text.

which suggests that putting them on a web page ought not to be allowed and might not work.

But - given that it would require a positive effort from a programmer to implement any of these restrictions, I think we're pretty safe in assuming that none of it will be enforced in practice, and so using U+FDD0 in online help or web pages ought to be safe. In any case, it wouldn't be catastrophic if things changed one day.

It also means that I don't have to write any proposals or make committee meetings longer than they already are!

[Unless Asmus Freytag, who proposed motion 84-M7 that made FDD0-FDEF not-a-characters has anything to add about the safety of using one of these characters in this way?]



This archive was generated by hypermail 2.1.2 : Thu Aug 01 2002 - 10:44:17 EDT