Excerpts from Martin Bähr's message of 2015-12-09 02:43:35 +0100:
> Excerpts from EuanM's message of 2015-12-09 01:59:43 +0100:
> > http://www.unicode.org/reports/tr15/#Stable_Code_Points
> > Table 7, the discussion of Ligatures, (which uses the ligature of
> > "ffi" as its example)
> 
> ß is not a ligature of ss, but is a different character.

rereading this, i think i am wrong, in that this has nothing to do with ß vs ss.

looking at the standard i also don't understand your conclusion.

what the standard seems to say is, that the ffi ligature is not equivalent to
plain ffi because, if i write a string with the ligature, then it is a
different string than plain "ffi",  because both forms are printable.
on the other hand ä and a" (two different encodings for ä) are the same,
because the printed forms are always identical.

however that doesn't mean that they are sorted differently.
german sorting rules for example explicitly state that ß and ss are sorted the same.
(at least according to wikipedia :-)
and surely, ffi ligature and ffi are sorted the same too.

greetings, martin.

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