Using otf-libertinus with ConTeXt for typesetting math

Question

I'm trying to use Libertinus Serif font for typesetting both text and math.

\starttypescript [libertinusserif]
\setups[font:fallback:serif]          % security: if not found==> back to defaults
% \definefontsynonym[ConTeXt basics name] [Human readable]       [features=default]
  \definefontsynonym[Serif]                 [LibertinusSerif-Regular]       [features=default]
  \definefontsynonym[SerifItalic]           [LibertinusSerif-Italic]        [features=default]
  \definefontsynonym[SerifBold]             [LibertinusSerif-Semiold]           [features=default]
  \definefontsynonym[SerifBoldItalic]       [LibertinusSerif-SemiboldItalic]    [features=default]
\stoptypescript

\starttypescript [libertinusserif]
  \definetypeface [libertinusserif]    [rm] [serif] [libertinusserif]    [default]
\stoptypescript

\setupbodyfont[libertinusserif, 14pt]

\starttext
Just some text.

Some text with \m{m+a_{th}} in it.

\stoptext

and it drops out with the following error:

Math error: parameter \Umathsub_shift_down\textstyle is not set


\m_syst_action_nop ...artimath #1\normalstopimath 
                                                  \fi 
l.21 Some text with \m{m+a_{th}}
                               in it.

(Note: when I comment out the line with math or do not set the body font, the output is produced.)

Answer 1

I think one problem (the error you get) is that you do not define a math font.

If you use the standalone version, you just have to be sure to have the fonts on your system where it can be found (my $OSFONTDIR is set to $HOME/.fonts). It seems that this is not your problem, since you get the fonts when you comment out the math.

Thus, you will have these nice fonts working by adding

\setupbodyfont[libertinus]

to your setup. The definitions seems to be taken from

tex/texmf-context/tex/context/fonts/mkiv/type-imp-libertinus.mkiv