unicode-math with greek letters upright and latin letters italic

Question

I am using unicode-math to select math fonts in XeLaTeX. From the documentation, I see there are four options for math-style:

• ISO has all letters, Greek and Latin, italic
• TeX has all letters italic except uppercase Greek, which are upright
• french has all letters upright except lowercase latin, which are italic
• upright has all letters upright

Would it be possible to set all Latin letters italic and all Greek letters upright?

The reason I need this setting is that I'm using Garamond-Math and I don't like the italic Greek letters of this font, so an alternative solution could be taking Greek letters from another font, but I haven't been able to do it. Here is my setting:

\usepackage[math-style=ISO,bold-style=ISO]{unicode-math}
\setmathfont{Garamond-Math.otf}[StylisticSet={5,7,9}]
\setmathfont{TeX Gyre Termes Math}[range=it/{Greek,greek}]

Answer 1

You can set the booleans mentioned by David in the document. Be aware that this are internal commands of unicode-math, so it would be good to make a feature request for an official interface:

\documentclass{article}
\usepackage{unicode-math}
\ExplSyntaxOn
\bool_gset_false:N  \g__um_upGreek_bool %or true
\bool_gset_true:N   \g__um_upgreek_bool %or false
\bool_gset_true:N   \g__um_uplatin_bool %or false
%more if needed ...
\ExplSyntaxOff
\setmathfont{Garamond-Math.otf}[StylisticSet={5,7,9}]
\begin{document}
$a\alpha\Gamma$
\end{document}

Answer 2

The options you mention just set boolean flags so it should be easy enough to add another option with a different combination

      {ISO} {
             \bool_gset_false:N \g__um_bfliteral_bool
             \bool_gset_false:N \g__um_bfupGreek_bool
             \bool_gset_false:N \g__um_bfupgreek_bool
             \bool_gset_false:N \g__um_bfupLatin_bool
             \bool_gset_false:N \g__um_bfuplatin_bool
            }
      {TeX} {
             \bool_gset_false:N \g__um_bfliteral_bool
             \bool_gset_true:N  \g__um_bfupGreek_bool
             \bool_gset_false:N \g__um_bfupgreek_bool
             \bool_gset_true:N  \g__um_bfupLatin_bool
             \bool_gset_true:N  \g__um_bfuplatin_bool
            }
  {upright} {
             \bool_gset_false:N \g__um_bfliteral_bool
             \bool_gset_true:N  \g__um_bfupGreek_bool
             \bool_gset_true:N  \g__um_bfupgreek_bool
             \bool_gset_true:N  \g__um_bfupLatin_bool
             \bool_gset_true:N  \g__um_bfuplatin_bool
            }
  {literal} {
             \bool_gset_true:N  \g__um_bfliteral_bool
            }

Answer 3

Based on your comments, you might have an XY-problem. What you say you want is sans-serif math for captions. The problem you’re having is that unicode-math supports either range= or version=, but not both together. (There’s a warning about this buried in the manual.)

If that’s what you actually want, load a sans-serif math font with version=, and don’t use range=.

\documentclass{scrartcl}
\usepackage{unicode-math}
\setmainfont{KpRoman}
\setsansfont{KpSans}
\setmonofont{KpMono}
\setmathfont{KpMath-Regular}
\setmathfont{KpMath-Bold}[version=bold]
\setmathfont{KpMath-Sans}[version=sans]
\addtokomafont{disposition}{\mathversion{sans}}
\begin{document}
\section*{Isn’t (\mathbb{R}^3) Wonderful?}
Truly, (\mathbb{R}^3) is.
\end{document}

Unfortunately, you’re not spoiled for choice when it comes to sans-serif math fonts.

It’s trivial to define \sansversion analogous to \boldversion, and you can also adapt the \boldsymbol code from amsbsy.sty to a \sanssymbol command if you need to be able to switch to sans-serif math within an expression. Otherwise, set the formatting of captions and whatever else you want to be sans-serif to \sffamily\mathversion{sans}.

If you already knew this and you were just asking how you can change the Greek letters in your math font, without using range=, one way to do that would be to define a new \setmathfontface or math version= that selects your alternative Greek font.

\documentclass{article}
\tracinglostchars=2
\usepackage[math-style=ISO]{unicode-math}
\defaultfontfeatures{Scale=MatchLowercase}
\setmainfont{EBGaramond}[Scale=1.0]
\setsansfont{KpSans}
\setmonofont{KpMono}
\setmathfont{Garamond-Math}
\setmathfont{KpMath-Sans}[version=sans]
\setmathfontface{\altgreek}{GFS Olga}
\newcommand\altGamma{\altgreek{\mupGamma}}
\newcommand\altzeta{\altgreek{\mupzeta}}
\begin{document}
Truly, (\altGamma(\altzeta)) is wonderful.
\end{document}