There are times when you need to input modified variables with diacritical marks, or superscripts.
Seems like declare_index_properties allows doing it at the stage of display print. But it is neither simple, nor very useful in formulas.
is there a simple way of adding hats, umlauts, and ', "strokes on top of a symbol, making it distinguishable from the symbol without such mark both to interpreter and to human eye?
Maxima doesn't have a notion of declaring a symbol to have diacritical marks or other combining marks on it. However, Maxima allows Unicode characters in symbol names if the underlying Lisp implementation allows Unicode; almost all of them allow Unicode. GCL is the only Lisp implementation, so far as I know, which doesn't handle Unicode correctly.
WxMaxima appears to allow Unicode characters to be input. At least, it worked that way when I tried some examples. Command-line Maxima allows Unicode if the terminal it is running in allows Unicode.
I think any Unicode character should be OK in a string. For symbols, any character which passes ALPHA-CHAR-P (a build-in Lisp function) can be part of a symbol name. Also, any character which is declared to be alphabetic (via declare("x", alphabetic) where x is the character in question) can be part of a symbol name.
I think wxMaxima has some capability to allow the user to select characters with diacritical marks from a menu; I haven't tried it. When I want to use Unicode characters, I end up just pasting them from a web page or something. I have used https://www.w3.org/2001/06/utf-8-test/UTF-8-demo.html as a source of characters in the past.
