Doug Ewell via Unicode
unicode at unicode.org
Tue Jan 29 11:10:31 CST 2019
Martin J. Dürst wrote:
> Here's a little dirty secret about these tag characters: They were
> placed in one of the astral planes explicitly to make sure they'd use
> 4 bytes per tag character, and thus quite a few bytes for any actual
> complete tags. See https://tools.ietf.org/html/rfc2482 for details.
> Note that RFC 2482 has been obsoleted by
> https://tools.ietf.org/html/rfc6082, in parallel with a similar motion
> on the Unicode side.
I don't recall anyone mentioning Plane 14 language tags per se in this
thread. The tag characters themselves were un-deprecated to support
emoji flag sequences. But more on language tags in a moment.
> These tag characters were born only to shoot down an even worse
> proposal, https://tools.ietf.org/html/draft-ietf-acap-mlsf-01. For
> some additional background, please see
> The overall tag proposal had the desired effect: The original proposal
> to hijack some unused bytes in UTF-8 was defeated, and the tags itself
> were not actually used and therefore could be depreciated.
I agree that the ACAP proposal was awful, for many reasons and on many
levels. But in general, introducing a new standardized mechanism SO THAT
it can be deprecated is a crummy idea. It engenders bad feelings and
distrust among loyal users of the standard. Major software vendors, one
in particular starting with M, have been castigated for decades for
employing tactics similar to this.
> Bad ideas turn up once every 10 or 20 years. It usually takes some
> time for some of the people to realize that they are bad ideas. But
> that doesn't make them any better when they turn up again.
The suggestions over the past three weeks to encode basic styling in
plain text (I'm not saying I'm for or against that) have some
similarities with Plane 14 language tags: many people consider both
types of information to be meta-information, unsuitable for plain text,
and many of the suggested mechanisms are stateful, which is an anti-goal
of Unicode. But these are NOT the same idea, and the fact that they both
use Plane 14 tag characters doesn't make them so.
Doug Ewell | Thornton, CO, US | ewellic.org
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