Re: Ancient Greek (symbols versus letters and duplicate letters)

From: Kenneth Whistler (
Date: Thu Apr 10 2003 - 17:19:43 EDT

  • Next message: Andrew Cunningham: "Re: Variant Glyph Display"

    Chris Hopkins asked:

    > Many thanks for the explanation. So by mapping the archaic forms of a Greek
    > letter to the basic Unicode Greek codepoint, the sorting will be correct. I
    > think I see how this works for Variation Selectors (which must be officially
    > approved), but I don't see how it could work if using things I control, say,
    > OpenType unmapped glyphs with <aalt> or <salt> entries. Can these be sorted?

    They can, but you'd have to do some preprocessing and possibly some

    Effectively, you preprocess your OpenType unmapped glyphs through
    a filter to some character value. For example, if you were
    representing a square-theta-with-a-dot as an OpenType unmapped
    glyph, you could either filter that to convert it to a theta
    for sorting (in which case you wouldn't need tailoring for
    the collation table), or filter it to a private use code
    point, or to a theta plus a private use code point representing
    your own scheme for tracking variants. In the latter two cases,
    you'd need access to an implementation of Unicode collation
    which would allow you to tailor your table to incorporate
    your use of private use code points, appropriately. The
    ICU library implementation, for example, gives you a Unicode collation
    algorithm implementation and also has a public mechanism for
    tailoring, so with that you could accomplish what you need
    to do.


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