Eszett

John C Klensin klensin at jck.com
Sun Jul 12 01:21:26 CEST 2009



--On Sunday, July 12, 2009 00:04 +0100 Michael Everson
<everson at evertype.com> wrote:

> On 11 Jul 2009, at 23:20, Vint Cerf wrote:
> 
>> long ago the working group decided that eszett "ß" would be
>> a PVALID   character and thus allowed for registration and
>> lookup.
>> 
>> I see no utility in re-visiting that now.
> 
> That's splendid, Vint, but there are two.
> 
> U+00DF ß LATIN SMALL LETTER SHARP S
> U+1E9E ẞ LATIN CAPITAL LETTER SHARP S.
> 
> Are both PVALID?

No capital letter in a multiple-case script is PVALID.   Not
U+1E9E and not "A" (U+0041), "Å" (U+00C5), "Β" (U+0392), etc.

>...
>I would make ss and SS and ß and ẞ equivalent.

If we support (whether as a recommendation or a requirement)
lower-casing or case mapping of any other flavor, I certainly
hope that U+1E9E will be mapped into U+00DF.   It appears from
my reading of the Mapping draft and UnicodeData.txt that mapping
(and the mapping from "S" to "s" will happen without making any
special provisions, so we should be ok.

     john



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