On 11/24/10 5:50 AM, Patrik Fältström wrote:
On 24 nov 2010, at 02.26, Doug Barton wrote:
no _technical_ reason that TLD labels should be all-alphabetic
FWIW, when you display internationalized domain names, and mixed RTL and LTR contexts
(overall, in a label etc), you can get "interesting" results when characters
that have not directionality (like numbers) are displayed adjacent to punctuation.
digits in the U0030..U0039 (latin script digits), U0660..U669 (arabic
script arabic-indic digits) and U06F0..U06F9 (arabic script eastern
arabic-indic digits) have directionality properties. i know this was a
casual error and paf is caffine-free slovenia at the moment.
See http://stupid.domain.name/node/681 for an example.
the example shows that the bidi algorithm used, correctly, if the
sequence of encoded values is "text", incorrectly, if the sequence of
encoded values is a dns label, render a directionality property of "."
restated, "." has a property which is dependent upon the
directionality of the proximal character(s), according to the authors
of the idn bidi algorithm. this may come as a surprise to applications
that assume that "." is a separator, semantically unaffected by the
properties of adjacent character(s).
the net of the unicadette usage advice to the dns weenies is don't put
digits in identifiers, um, don't put digits in identifiers composed
from characters with a rtl directionality property, um, don't mix
scripts with differing directionality properties, at least, not in
sight of dots or children, not because these are not "proper words" in
(some language), the point of view advanced by an important, but
mistaken on this point, group of arabic script and arabic language
(but not arabic script and farsi/urdu/... language) users, but because
Ox2E in US-ASCII, a standard published in 1963, has a property unknown
to the the authors of that sequence of standards.
one could summarize the unicadette's point of view that the choice of
"." as a label separator was an error in 952 and that ken, mary and
jake blew it, but the real blame should go to jon who blew it in 921
(required reading for the no-digits advacates). we're all lucky that
820's use of 0x2E has not yet been discovered by the unicadettes.
-e
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