Coding solutions that require substantial support across implementations
are successful, if (and I argue, only if) you can't successfully sell
your implementation in a given market without support for that feature.
Mathematical layout is not needed by the majority of users, but those
users that do need it, can't be accommodated with a substitute. Hence,
anyone trying to sell into that market has to make a decent job of it.
Looks like there are enough people in that market that even general
purpose software, like Word, has a decent (nay, excellent) equation editor.
Arabic shaping is so essential to the script that you either support it,
or you don't support Arabic.
Placing accents on Latin characters is widely needed, but the most
widely needed cases are covered by precomposed legacy characters. Hence.
the support for this feature is spotty. Curiously, this remains the
case, even though, taken together, the diverse users of particular
combinations of letters and accents for the Latin/Greek/Cyrillic
probably reach substantial numbers, and a common solution would seem to
support all of them.
Support for Ideographic Variation Sequences is needed for all sorts of
high-end CJK work. It can be expected to be supported in those market
areas, but probably not necessarily in mainstream implementations. Time
will tell.
And so on.
The chances that any form of meta encoding for symbols (including
ligation) will ever reach critical mass in support is less than for
Latin/Greek/Cyrillic accents, because - as of today - there's no
established use for any of these schemes.
All of these things remain solutions in search of a problem.
The interesting thing I note is the level of enthusiasm with which these
are discussed here, when, at the same time, a lowly single character
currency symbol, with no special meta-coding, layout support, algorithm
changes, etc. was so roundly dismissed - despite all the evidence that
not supporting it in face of user demands would impact the ability of
implementers to sell into a not insubstantial market.
Sometimes I wonder what's going on ...
A./
