What is the status, in terms of category codes, of all the Unicode letters above ASCII in XeTeX (using XeLaTex+fontspec) and LuaTeX (using ConTeXt)? Can I define a macro using Unicode characters (ex. \μακρο)?
I am asking that because I went mad when trying to type in a right to left language using ConTeXt, since the combination of the TeX commands (LTR) and the text itself (RTL) made the editor unusable, and I found out that something like
worked, but the subsequent \شق was not synthax-highlighted properly. So I want to know if that is a problem of the editor (TeXShop), or the engine was just being lax when allowing that.