Perhaps this question has been asked already, but my search efforts were unsuccessful.
Is it necessary to have ASCII characters (i.e. letters basically [a..z,A..Z], special characters such as
\( etc are not important for this question) for a macro name or is it possible to say, e.g. with cyrillic letters
or with any other alphabet not being the (western) Latin Alphabet?
This is somehow connected to input encoding, but on the other hand it is not connected to it, since I am not interested what (La)TeX generates of ordinary words entered in another alphabet/encoding, say я не понимаю, generating the corresponding output using the correct font.
How's the situation with LaTeX 3, or ConTeXt, Xe/LuaLaTeX?