Re: Small i with/out dot and with arrow

On Wed, 1 Aug 2012 18:09:27 -0700
Leo Broukhis <leob_at_mailcom.com> wrote:

> No, 20D7 is not a Diacritic, it is Other_Math, therefore the dot
> should remain. In general, mathematical combining characters are not
> diacritics.

While not definitive, note that U+20D7 is in the 'Combining Diacritical
Marks for Symbols' block. I would certainly expect soft-dotted letters
to shed their dot for third or fourth derivatives written as fluxions,
U+20DB COMBINING THREE DOTS ABOVE and U+20DC COMBINING FOUR DOTS ABOVE.
(Mind you, I would arrange the dots in a triangle or square - am I
using different characters?)

>
> Renderers that treat "combining" as a synonym for "diacritic" and
> remove the dot are in error.
> UAX 44 says, "Characters that linguistically modify the meaning of
> another character to which they apply. Some diacritics are not
> combining characters, and some combining characters are not
> diacritics."

The definitive text would appear to be Section 3.13 Definition D138 and
Table 3-14, as confirmed by the usage in UCD file SpecialCasing.txt.
The key property is canonical combining class 230, so 'i' would lose
its dot for U+20D7, just as it should for a Hebrew accent or a Tai Tham
or Tai Viet tone mark, but not a Thai or Lao tone mark. (The odds of
getting reasonable, let alone compliant, rendering for any of these
mixed script combinations is fairly low.)

Richard.
Received on Thu Aug 02 2012 - 14:49:30 CDT