TODO XXX's algorithm.
There is a book on fonts: Fonts & Encodings by Yannis Haralambous. [Hara]. Despite the raving review, I was underwhelmed by it. I wanted to find out if it is possible to encode the vowel/cantillation placement logic into an OpenType font - and did not find the answer in the book.
Which is not really surprising, since the book's author is also the author of Omega project (Unicode in TeX), about which a very informative text about printing Unicode in 2002 says:
However, Omega is very much a failure. Its creators have been guided by Principles. They were conscious of the Desirability of Flexibility. They Knew about the Demands of Fine Typesetting of Complex Scripts. ... You cannot run to the manual, because the manual is a very interesting piece of academic prose about the difficulty of the task, but useless for a mere user.
I did find out about a useful tool for OpenType font jobs: TTX [TTX].
Does kerning work through vowels?