Re: Ligatures

[Yuri Khan]

> > (And putting multiple diacritics over a single base character in> > various 
> > orders is a thing, it is the subject of the Unicode
> > Canonical Order subsection in Unicode standard.)
>
> Canonical order of diacritics is indeed important for jobs such as
> comparison, searching, etc.  But we are talking about display, and for
> display there's a requirement that the order should not matter as long
> as the base character comes first.  AFAIR, HarfBuzz supports that
> requirement, but not every other shaping engine does.

I meant, the Canonical Order spec could be a lot simpler (“just sort
all diacritics according to their codepoint value” rather than “take
great care to only swap two adjacent diacritics if their combining
classes differ and ordered wrongly”) if diacritics order did not
matter. But it does; <a> <acute> <diaeresis> is different from <a>
<diaeresis> <acute>, so the use case of putting point between the base
character and its following diacritic in order to insert a different
one is somewhat important. Indeed, toggling auto-composition-mode
solves that.