LyX - automatic glyph substitution in preamble?

Question

I use LyX to write documents with a mix of Hebrew, English, and mathematics. The fonts I use are specific: David CLM (for Serif), Simple CLM (for Sans Serif), and Miriam Mono CLM (for Typewriter).

When compiling a document (via XeTeX), I get a warning of some missing glyphs; specifically, bullets:

Missing character: There is no • (U+2022) in font David CLM Medium/OT:script=he

I seem to recall there is a way to hardcode specific glyphs to use different fonts, but for the life of me I can't find it.

Apparently, TeX itself supports automatic substitution of companion symbols since 2020 ("Providing all text companion symbols by default"), this seems like an ideal solution.

How would I implement this, or \DeclareFontFamilySubstitution, in the preamble? My goal is to use David CLM for all available symbols, and fall back to Liberation Serif for unavailable ones.

Answer 1

How to do this with LyX is beyond my knowledge.

If you have

\newfontfamily{\lastresort}{Liberation Serif}

you can load

\usepackage{newunicodechar}

and do

\newunicodechar{•}{\mbox{\lastresort •}}}

so any appearance of • in the document will use the glyph from Liberation Serif. Do the same for all other characters you want to substitute the font for. Using \mbox should avoid problems with text direction.