Re: StandardizedVariants.txt error?

I agree with that analysis.

Mark <https://plus.google.com/114199149796022210033>
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*— Il meglio è l’inimico del bene —*
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On Mon, Nov 26, 2012 at 1:53 PM, Whistler, Ken <ken.whistler_at_sap.com> wrote:

> Actually, I think the omission here is the word "canonical". In other
> words, Section 16.4 should probably read:
>
> "The base character in a variation sequence is never a combining character
> or a *canonical* decomposable character."
>
> Note that with this addition, StandardizedVariants.txt poses no
> contradiction, because all of the decomposable character instances noted
> are compatibility decomposable characters.
>
> The main concern here with this restriction is to ensure that one doesn't
> end up with conundrums involving canonical decompositions into sequences
> followed by a variation selector.
>
> In the case of compatibility decompositions, there already is no
> expectation that neither the appearance nor the interpretation of the text
> will change. With a decomposition mapping like "<font> 0069", the
> decomposition is already indicating a typically different appearance. If
> you decompose U+2139 to U+0069, you have already lost information about
> appearance and interpretation. So it isn't that much of a stretch to assume
> that any relevant variation sequences will also lose their interpretation.
>
> But I think it might make sense, in addition to the above textual fix, to
> add a note to the standard to indicate that variation sequences preserve
> their validity across *canonical* normalization forms, but that there is no
> guarantee that variation sequences will remain valid for any compatibility
> normalization.
>
> --Ken
>
> > 2012-11-24 8:12, Masatoshi Kimura wrote:
> >
> > > According to TUS v6.2 clause 16.4,
> > > http://www.unicode.org/versions/Unicode6.2.0/ch16.pdf#page=15
> > >> The base character in a variation sequence is never a
> > >> combining character or a decomposable character.
> > > However, the following base characters appearing in
> > > http://unicode.org/Public/6.2.0/ucd/StandardizedVariants.txt
> > > have a decomposition mapping.
> >
> > There seems to be a contradiction here. “Decomposable character” is
> > defined in clause 3.7 as follows:
> >
> > “A character that is equivalent to a sequence of one or more other
> > characters, according to the decomposition mappings found in the Unicode
> > Character Database, and those described in Section 3.12, Conjoining Jamo
> > Behavior.”
> >
> > I suppose the intended meaning in clause 16.4, given its context, is to
> > say that the base character is neither a combining character nor a
> > character with a decomposition that contains a combining character.
> >
> > Yucca
> >
> >
>
>
>
>
Received on Mon Nov 26 2012 - 16:23:35 CST