“Old” math font commands (\mathrm etc.) and unicode-math (“range” option)

Question

I’m trying to use unicode-math’s capabilities (\setmathfont[range=…]) to use a non-math font in math mode. For example:

\documentclass{scrartcl}

\usepackage{unicode-math}

\setmainfont{FreeSans}
\setsansfont{FreeSans}

\setmathfont{Latin Modern Math}
\setmathfont{FreeSans}[range=up/{greek,Greek,latin,Latin,num}]
\setmathfont{FreeSans Oblique}[range=it/{greek,Greek,latin,Latin,num}]
\setmathfont{FreeSans Bold}[range=bfup/{greek,Greek,latin,Latin,num}]

\begin{document}

abc123

\textit{abc123}

\textbf{abc123}

\bigskip

\begin{tabular}{ll}
    math        & $abc123$ \\
    mathit      & $\mathit{abc123}$ \\
    mathrm      & $\mathrm{abc123}$ \\
    mathup      & $\mathup{abc123}$ \\
    mathbf      & $\mathbf{abc123}$ \\
    mathbfup    & $\mathbfup{abc123}$
\end{tabular}

\end{document}

With this document, I would expect all text to be in FreeSans and the lines with mathrm and mathup as well as mathbf and mathbfup to be the same. However, my result is this:

So, I have two questions about what is happening:

1. Why are \mathit and \mathup different from \mathbfup? \mathbfup works as it should, producing text in FreeSans Bold. The other two, on the other hand, produce the default of Latin Modern Math.
2. How do I get all of these commands to use FreeSans, just like \mathbfup does? I know about unicode-math’s command \setmathfontface⟨command⟩{⟨font name⟩}[⟨font features⟩], but that doesn’t let me specify a range like range=up/{greek,Greek,latin,Latin,num}, as far as I can tell. And shouldn’t unicode-math’s own commands like \mathup work correctly “out of the box”, anyway?

Version info: TeX Live 2017, LuaTeX v1.0.4, unicode-math 2017/01/27 v0.8d.

Answer 1

It you want really to change \mathbf and similar: This is done easily by (re)declaring the math alphabets.

The problem starts if you want to adapt the \symXX commands which normally map chars to the glyphs on the mathematical plan. Here the implementation is rather broken. It works more or less if you set your fonts as the last "math font", but this breaks various mathematical font dimens. If you reset them by setting a real math font as the last font, then the symXX fonts break. See also this issue https://github.com/wspr/unicode-math/issues/331.

\documentclass{scrartcl}

\usepackage{unicode-math}

\setmainfont{FreeSans}[NFSSFamily=FreeSans]
\setsansfont{FreeSans}

\setmathfont{Latin Modern Math}



\setmathfont{FreeSans}[range=up/{greek,Greek,latin,Latin,num}]
\setmathfont{FreeSans Bold}[range=bfup/{greek,Greek,latin,Latin,num}]
\setmathfont{FreeSans Oblique}[range=it/{greek,Greek,latin,Latin}]

% better a real math font at the end, but breaks the ranges above:
\setmathfont{Latin Modern Math}[range=\int]

 %Or with `\setmathfontface`, see documentation
\DeclareMathAlphabet{\mathrm}{TU}{FreeSans}{m}{n}
\DeclareMathAlphabet{\mathbf}{TU}{FreeSans}{bx}{n}
\DeclareMathAlphabet{\mathit}{TU}{FreeSans}{m}{it}
\let\mathbfup\mathbf


\begin{document}

abc123 αβ

\textit{abc123 αβ}

\textbf{abc123 αβ}

\bigskip

\begin{tabular}{ll}
    math        & $abc123$ \\
    mathrm      & $\mathrm{abc123αβ}$ \\
    mathup      & $\mathup{abc123αβ}$ \\
    mathbf      & $\mathbf{abc123αβ}$ \\
    mathbfup    & $\mathbfup{abc123αβ}$\\
    symup       & $\symup{aα} \mupalpha $\\
    symit       & $\symit{a}\symit{α}\symit{β} \mita  \mitalpha  \mitvarTheta $\\
    symbf       & $\symbf{a}\symbf{b}\symbf{c}\symbf{α}\symbf{β} \mbfa \mbfb \mbfc \mbfvarTheta \mbfalpha \mbfbeta$ \\
\end{tabular}

\end{document}