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Re: 'x-' prefix on charset names

From: Martin Duerst <duerst@w3.org>
Date: Tue, 22 Oct 2002 11:33:30 +0900
Message-Id: <>
To: Dan Chiba <dan.chiba@oracle.com>, www-international@w3.org

Hello Dan,

Many thanks for your question.

At 14:11 02/10/21 -0700, Dan Chiba wrote:

>I have a question regarding the 'x-' convention used to
>indicate that a charset is not registered at the IANA registry.
>Is it prohibited to use a unregistered charset at one's own risk?
>According to the latest CharMod paper, the convention is
>discouraged as follows (Excerpt from Section 3.6.2):
>   [S] The 'x-' convention for unregistered character encoding
>   names SHOULD NOT be used, having led to abuse in the past.
>   ('x-' was used for character encodings that were widely used,
>   even long after there was an official registration.)
>My question is about the intent of this is. If an unregistered
>charset was used, you will be forced to avoid the convention
>for complience. I think there are good reasons to avoid it, but
>what should be the options to take?
>Among the following viable alternatives that I can think of, I
>understand W3C is in the position of recommending option a and b.
>  a. Use a registered charset instead (May or maynot be feasible)
>  b. Get the charset registered (May take time)
>  c. Use the unregistered charset (Need bilateral agreement)
>It is not clear to me if W3C intend to prohibit option c. Could
>somebody clarify the intent, please?

I think your reading of what the Character Model says is correct.
Opinion c) is not completely prohibited, but I think the cases
where it could be used are very limited. I can imagine the

- Some researchers are working on an encoding for Egyptian Hieroglyphs.
   They want to work out the details before registering. So they
   create something like x-hiero-test-1, x-hiero-test-2, and so on.
   Once they think they know what they need, they register it, and
   use the registered name.

- A company wants to test their software with dummy data, and dummy
   'charset's, e.g. to check how they can upgrade their software to
   deal with new 'charset's. In this case, using x-dummy-1,... would
   come in handy.

There may be other, similar cases. But in general, go for a) or b).
b) may indeed take some time, but it can be as short as two weeks
(a minimum period of 2 weeks is necessary to give everybody a
chance to comment).

Regards,   Martin.
Received on Monday, 21 October 2002 22:42:29 UTC

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