[XeTeX] unicode-math package and \UnicodeMathSymbol command

[Ed Morehouse]

thanks, joel, for the reply.  i've been doing some testing and the situation
seems more complicated than i realized.  to answer your questions:

* i am not getting any error messages about \UnicodeMathSymbol being undefined.

* wrapping the math symbol declarations in "\makeatletter" ... "\makeatother"
does not have any noticable effect.

* adding "\let\UnicodeMathSymbol\um <at> mathsymbol <at> noparse" causes the
error, "Missing begin{document}".

* it is not quite correct for me to have said that adding these declarations
locally to the preamble of a document has no effect:  a local declaration for
inverted exclamation mark causes the glyph for that character to be drawn,
whereas without it, no glyph is drawn.  however, these local declarations do not
seem to be correctly setting the character class. for example, my local
declaration of vertical bar does not result in relation symbol spacing for that
character. (this is most mysterious to me)

* it's true that i could modify the unicode-math package to look for a local
file with my declarations, which is what i have done for the time being, but the
problem with this approach is that depending on the subject matter, the same
symbol can have different meanings.  for example, in set theory, "⊃" is often
taken to mean "superset", which is a relation (\mathrel); whereas  in logic, it
is sometimes used for "implies", which is a binary operator on logical formulas
(\mathbin).  having unicode-math consult a local file for math symbol
declarations means that each time i typeset a document, i have to fiddle with
that file to set the right character classes (or re-edit unicode-math to look
for a different file), and it also means that i can't use the same symbol in
different character classes within the same document (admittedly, generally a
bad idea but sometimes unavoidable).

anyway, i appreciate you taking the time to try to help and i second your
expression of appreciation to will.  being able to type "α → β" is *so* much
nicer than "\alpha \rightarrow \beta".  i hope that someday something like
unicode-math makes its way into xetex proper.

-ed morehouse