Make lyluatex work with LilyPond v2.25.5 and newer

[fanninpm]

I was tracking down the source of a bug having to do with typeface preferences not getting transmitted to LilyPond. I came across #309, which seems to match up with the symptoms I'm observing with LilyPond v2.25.11 (the version I got when I installed LilyPond using brew install lilypond --HEAD to dodge another LilyPond bug in v2.24.2 having to do with GhostScript). Unfortunately, the fix supplied by @lemzwerg in that issue no longer works as of LilyPond v2.25.6 because of two changes I found:

• In LilyPond v2.25.5 and above, instead of fonts.roman, it needs to be fonts.serif, according to this patch.
• In LilyPond v2.25.6 and above, instead of fonts.{serif,sans,typewriter}, it probably needs to be property-defaults.fonts.{serif,sans,typewriter}, according to this patch.

---

I'm not a Lua expert, but if I had to guess at what the code would look like, this would be it:

Lua code at function Score:ly_fonts()

function Score:ly_fonts()
    if self['pass-fonts'] then
        local fonts_def
        if self:lilypond_version() >= ly.v{2, 25, 6} then
            fonts_def = [[property-defaults.fonts.serif = "%s"
    property-defaults.fonts.sans = "%s"
    property-defaults.fonts.typewriter = "%s"]]
        else if self:lilypond_version() >= ly.v{2, 25, 5} then
            fonts_def = [[fonts.serif = "%s"
    fonts.sans = "%s"
    fonts.typewriter = "%s"]]
        else if self:lilypond_version() >= ly.v{2, 25, 4} then
            fonts_def = [[fonts.roman = "%s"
    fonts.sans = "%s"
    fonts.typewriter = "%s"]]
        else
            fonts_def = [[
#(define fonts
    (make-pango-font-tree "%s"
                          "%s"
                          "%s"
                          (/ staff-height pt 20)))
]]
        end
        return fonts_def:format(self.rmfamily, self.sffamily, self.ttfamily)
    else
        return '%% fonts not set'
    end
end

---

Workaround

It's possible to define a \paper block in the LilyPond code itself. For example,

\paper {
    property-defaults.fonts.serif = "Alegreya"
}