I've been working lately on a font with Greek in it. I decided to take the plunge and make polytonic characters for it. But the coding, argh, the coding! I read through these two threads on the topic—http://www.typophile.com/node/83725, http://typophile.com/node/15982—to get the gist of the issue. The take-home messages I got were:
—A principle that one should stick by is to make all changes reversible. So, if a user presses a button to capitalize the glyph ῴ, your font shouldn't turn it into two separate characters Ώ+ι or Ώ+Ι, because then if the user tries to turn that letter back to the original lowercase, it turns into ώ+ι.
—When you set Greek in all-caps, the accents disappear, except for the dialytika (¨). And you get an extra dialytika on a (bare) Iota if the vowel before it has an accent, so that ρωμέικα becomes ΡΩΜΕΪΚΑ.
But I still have some questions about how I need to go ahead.
Since I'm kind of a low-tech guy and couldn't think of an easy way to do it better, I handwrote the questions and scanned them. (You can disregard question 1d, because after I wrote it and scanned it, I looked again at the thread in the first link, and realized the question was answered there.) So, here they are.