Re: Variation Selectors

From: Andrew West (
Date: Wed Mar 29 2006 - 03:49:17 CST

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    On 28/03/06, Kent Karlsson <> wrote:
    > Andrew West wrote:
    > > determined by the rendering system (e.g. for Mongolian where
    > > particular glyph forms may be used for writing foreign words)
    > Sounds to me that they deserve separate encoding rather than
    > using the hack of FVS.

    It's not that they are special glyph forms used only for writing
    foreign words. If that were the case, yes they should have been
    encoded as separate characters, and indeed that is the case for U+1827
    MONGOLIAN LETTER EE which represents the form of the letter E used
    exclusively for writing foreign words (it is used contrastively with
    U+1821 MONGOLIAN LETTER E, which is used exclusively for writing
    Mongolian words).

    The sort of case I am thinking of is that in which a letter L may have
    two contextual forms, L1 and L2 which are selected in different
    contexts (e.g. L1 before one set of vowels and L2 before another set
    of vowels). However, when writing a foreign word L2 is always used,
    regardless of context. In such a case a VS may be required to tell the
    rendering system not to apply the normal contextual glyph
    substitution. I do not think that this sort of usage of variation
    selectors is a hack, any more than using ZWJ or ZWNJ are.

    > Since Mongolian and Phags-Pa are cursive scripts, I guess ZWJ/ZWNJ
    > has a role for these two scripts too...

    Indeed, ZWJ and ZWNJ are used to override positional forms of letters
    in both Mongolian and Phags-pa (although in Phags-pa only vowels have
    distinct positional forms).


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