Opentype features in fallback math font (e. g. EB Garamond) in ConTeXt

Question

Preamble: In a document I want to use EB Garamond for both text and maths and I don't want to install anything that doesn't come with TeX Live (i. e. no Garamond Math and no URW Garamond).

So here's my typescript thing for that (sorry for the long listing, it is the minimal working example i could make):

\definefontfeature
    [eb-garamond-be-normal]
    [default]
    [onum=yes]
\starttypescriptcollection[ebgaramond-be]
    \starttypescript [serif] [ebgaramond-be]
        \loadfontgoodies[ebgaramond]
        \setups[font:fallback:serif]
        \definefontsynonym [Serif] [file:ebgaramond-regular] [features=eb-garamond-be-normal]
        \definefontsynonym [SerifItalic] [file:ebgaramond-italic] [features=eb-garamond-be-normal]
    \stoptypescript
    \definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Regular.otf] [digitsnormal] [force=yes]
    \definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Regular.otf] [lowercasenormal] [force=yes]
    \definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Regular.otf] [uppercasenormal] [force=yes]
    \definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Italic] [lowercasenormal] [offset=lowercaseitalic,force=yes]
    \definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Italic] [0x00068] [offset=0x0210E,force=yes] 
    \definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Italic] [uppercasenormal] [offset=uppercaseitalic,force=yes]    
    \starttypescript [math] [ebgaramondandbonum] 
        \definefontsynonym [MathRoman] [texgyrebonummath] [features={math,mathextra},fallbacks=ebgaramondmathtext]
    \stoptypescript 
    \starttypescript [ebgaramond-be]
        \definetypeface[ebgaramond-be] [rm] [serif] [ebgaramond-be] [default] [designsize=auto]
        \definetypeface[ebgaramond-be] [mm] [math] [ebgaramondandbonum] [default]
    \stoptypescript 
\stoptypescriptcollection

It does work:

\setupbodyfont[ebgaramond-be]

\starttext
text: {\it abcde123}

math: $abcde123$
\stoptext

but I want lining figures in math mode, instead of oldstyle ones. I tried to create separate feature set with lnum=yes,onum=no using \definefontfeature and add it alongside with {math,mathextra} to the main math font with no luck. Even worse: when I make lnum=yes for the main text font, it affects only text mode, leaving oldstyle figures in math mode:

Is it possible to set opentype features (like lnum, for example) to fallback fonts? Or, maybe, there are some other solutions?

Upd:

In the comments Metafox posted a solution. First there should be a fontfeature that does not rely on default

\definefontfeature [EBGM] [lnum=yes]

and then this feature can be referenced using * after file name in the fallback definition:

\definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Regular.otf*EBGM] [digitsnormal] [force=yes]

Answer 1

Features in math mode can only be changed when you’re in base mode but in your example you create a new feature based on the default set which uses node mode.

The easiest way to achieve this by creating a new feature without an mode settings because (ligatures etc. aren needed for symbols in math mode):

\definefontfeature [ebgaramond-math] [lnum=yes]

Another problem in your example is that you never apply the feature to your fallback font for the digits, to do this can either apply the feature with the font file in the \definefontfallback command, e.g.

\starttypescript [math] [ebgaramondandbonum]
  \definefontfallback [ebgaramondmathtext] [file:EBGaramond12-Regular*ebgaramond-math] [digitsnormal] [force=yes]
  \definefontsynonym [MathRoman] [texgyrebonummath] [features={math,mathextra},fallbacks=ebgaramondmathtext]
\stoptypescript 

or you use a two-step-method where you create a font synonym where you can use the third argument to set the features and load afterwards the synonym in the font fallback, e.g.

\starttypescript [math] [ebgaramondandbonum]
  \definefontsynonym  [EBGaramondFallback-Regular] [file:EBGaramond12-Regular] [features=ebgaramond-math]
  \definefontfallback [ebgaramondmathtext] [EBGaramondFallback-Regular] [digitsnormal] [force=yes]
  \definefontsynonym  [MathRoman] [texgyrebonummath] [features={math,mathextra},fallbacks=ebgaramondmathtext]
\stoptypescript 

The complete code to replace the digits from the math font with digits from EB Garamond would look like this:

\definefontfeature [ebgaramond-text] [default] [lnum=yes]
\definefontfeature [ebgaramond-math]           [lnum=yes]

\starttypescript [serif] [ebgaramond-be]
  \setups[font:fallback:serif]
  \loadfontgoodies[ebgaramond]
  \definefontsynonym [Serif]       [file:ebgaramond-regular] [features=ebgaramond-text]
  \definefontsynonym [SerifItalic] [file:ebgaramond-italic]  [features=ebgaramond-text]
\stoptypescript

\starttypescript [math] [ebgaramondandbonum]
  \definefontsynonym  [EBGaramondFallback-Regular] [file:EBGaramond12-Regular] [features=ebgaramond-math]
  \definefontfallback [ebgaramondmathtext] [EBGaramondFallback-Regular] [digitsnormal] [force=yes]
  \definefontsynonym [MathRoman] [texgyrebonummath] [features={math,mathextra},fallbacks=ebgaramondmathtext]
\stoptypescript 

\starttypescript [ebgaramond-be]
  \definetypeface[ebgaramond-be] [rm] [serif] [ebgaramond-be] [default] [designsize=auto]
  \definetypeface[ebgaramond-be] [mm] [math] [ebgaramondandbonum] [default]
\stoptypescript 

\setupbodyfont[ebgaramond-be]

\starttext

text: {\it abcde123}

math: $abcde123$

\stoptext