Combining characters

[Martin J. Dürst]

On 2025-12-15 08:07, Alex Shpilkin via Unicode wrote:
> 
> On Sun, Dec 14 2025 at 14:02:41 -08:00:00, Asmus Freytag via Unicode 
> <unicode at corp.unicode.org> wrote:
>> To make matters more complex, some combining marks are defined to not 
>> reorder. Those can be in any order defined by the author and could 
>> lead to duplicate encoding for the same display. The reasons behind 
>> supporting that are a bit complex, but generally it's done for scripts 
>> other than Latin.
> 
> Amusingly, study of literal Latin, the language, uses two combining 
> marks of the same CCC together as a matter of course: dictionaries mark 
> a vowel with (what in NFD would be) the sequence COMBINING MACRON, 
> COMBINING BREVE to tell the reader that a syllable’s length either 
> varies or cannot be determined.

These two characters are indeed not reordered, but that's not a problem, 
because they are stacked. The sequence COMBINING MACRON, COMBINING BREVE 
will have the macron between the character and the breve, whereas the 
sequence COMBINING BREVE, COMBINING MACRON will have the macron above 
the breve. Not an expert, but my assumption is that only the first one 
is customary for Latin.

Regards,   Martin.