%#!lualatex
\documentclass{article}
\usepackage[a4paper]{geometry}
\makeatletter

\usepackage{unicode-math}

\usepackage{luatexja-fontspec}
\setmainjfont{IPAGothic}
\setmathfont{XITSMath}

\ltj@alljachar %←全部の（>=U+0080な）文字を和文文字扱いに！
\setmainfont{TexGyreTermes}

\reDeclareMathAlphabet{\mathtestA}{\mathrm}{\mathmc}
\reDeclareMathAlphabet{\mathtestB}{\mathrm}{\mathtestb}
\reDeclareMathAlphabet{\mathtestC}{\mathtesta}{\mathmc}
\reDeclareMathAlphabet{\mathtestD}{\mathtesta}{\mathtestb}
\reDeclareMathAlphabet{\mathtestE}{\mathtestE}{\mathmc}
\begin{document}\makeatletter
\[
 \frac1{1^2}+\frac1{2^2}+\cdots=
\sum_{n=1}^\infty \frac1{n^s}=\zeta(2)=\frac{\pi^2}{6}
=\frac16\cdot \pi\times\pi,\qquad a_1,\dots,a_n.
\]

$\hslash$

○×○漢×漢\times え\ltjjachar`\“え\ltjalchar`\“え\textquotedblleft え“え←数式外では和文文字扱いのままになっている．

\kanjifamily{mc}\selectfont
$あいうえおabcde a^\mathrm{b}$

mathrm: $\mathrm{\alpha あいうえおabcde}^\mathrm{b}$

mathbf: $\mathbf{\alpha あいうえおabcde}$

mathmc: $\mathmc{\alpha あいうえおabcde}$

mathgt: $\mathgt{\alpha あいうえおabcde}$

\tt\meaning\mathtestA

\tt\meaning\mathtestB

\tt\meaning\mathtestC

\tt\meaning\mathtestD

\tt\meaning\mathtestE

\meaning\lfloor
\[
\lceil x\rceil + \lfloor x\rfloor +\hat a-\sqrt{a} - [\hbar]
\]
\end{document}
