[luatex] Use Math Glyphs from Text Font

[C. Comren]

> \ExplSyntaxOn
> \fontspec_set_family:Nnn \myfont {} {MyFont}
> \ExplSyntaxOff
> \DeclareSymbolFont{EU2}{mysymfont}{\myfont}{m}{n}
> \DeclareMathSymbol{A}{\mathalpha}{mysymfont}{`A}

After getting an error, I changed it to

\DeclareSymbolFont{mysymfont}{EU2}{\myfont}{m}{n}

and it works perfectly. Thanks.

Now I just need a way to change the Greek alphabet.

Best,
CC