[XeTeX] Xetex, Latex3, unicode-math and Math font not found

[Phelype Oleinik]

Hi Pierre,

On Wed, May 13, 2020 at 7:34 AM Pierre Dupond <76nemo76 at gmx.ch> wrote:
>
> \RequirePackage{expl3}
> \ProvidesExplPackage {test} {2020-05-12} {1.0}
>                      {to test some commands}
>
> \RequirePackage{fontspec}
> \RequirePackage{unicode-math}
> \tl_const:Nn \c__test_MathFont_tl {Asana-Math}
> \tl_const:Nn \c__test_MathFontSpec_tl {Extension=.otf,}
>
> \exp_args:Noo\setmathfont{\tl_use:N \c__test_MathFont_tl} { [ \tl_use:N \c__test_MathFontSpec_tl ] }

\tl_use:N doesn't fully expand with one expansion step, so you have to
use e or x (f could also be used, but that might consume a space at the
head of the token list).

With \exp_args:No \cmd { [ \tl_use:N \c_some_tl ] }, the \expandafter
will hit the [, and do nothing at all. x or e expansion will also do the
trick here:

\exp_args:Nxx \setmathfont
  { \tl_use:N \c__test_MathFont_tl }
  { [ \tl_use:N \c__test_MathFontSpec_tl ] }

or

\use:x
  {

    \setmathfont { \tl_use:N \c__test_MathFont_tl }
      [ \tl_use:N \c__test_MathFontSpec_tl ]
  }

Phelype