From: Ernest Cline (email@example.com)
Date: Sun Mar 28 2004 - 00:11:28 EST
> [Original Message]
> From: <firstname.lastname@example.org>
> Asmus Freytag wrote,
> > Uninterpreted VS characters should *not* turn into black blobs. If we
> > wanted that to happen, we would have coded different characters.
> U+E000 COMBINING BLACK BLOB? Censors would probably love it.
> > >What does the collation standard say to do with unassigned codepoints
> > >anyhow?
> > Variation selectors are not unassigned characters.
> But, they might be regarded as such by any application predating VSs.
> likewise for any VS sequences approved after the application was created.
For a an application that predates the addition of that Variation Selector
character yes, but not for an unrecognized variation selector sequence.
The standard is quite clear that if a Variation Selector is recognized, but
the sequence it is, then it should be treated the same as if no selector was
This is one reason why transferring some or all of the Variation Selectors
on the SSP to Private Use is a possibility if they are not going to have
any official uses. Any Unicode 4.0 compliant software would
degrade the presentation of such data gracefully.
The only reason I can see for having 256 Variation Selectors is to
enable round trip encoding of data using legacy 8 bit character sets
that has data which is either invalid or unknown in Unicode. Then
either U+001A or U+FFFD followed by a variation selector could be
used to record the original octet for the round trip. Freeing up the
240 SSP variation selectors for private use except for a few defined
algorithmic uses such as this would seem to make sense I find it
doubtful that any non-algorithmic uses of Variation Selectors will
require even as many as 16 such selectors for official sequences.
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