[lltx] luaotfload: Adjusting OpenType math parameters

[Graham Douglas]

Hi All

I'm just starting to explore LuaTeX's OpenType math typesetting
capabilities and would like to adjust some of the OpenType parameter
values to fine-tune some spacing. Just out of curiosity I wrote a tiny
aux library function so that I can explore the values (details below if
anyone interested).

My question is, what is the safest or "official" way via luaotfload to
make adjustments to OpenType math parameters which will minimize risk of
breaking something?

Many thanks in advance.

Best wishes
Graham

Note:  I'm using
luaotfload: 2016/06/16 v2.7 unicode-math 2015/09/24 v0.8c I'm on Windows
7 using LuaTeX, Version 0.96.0 (TeX Live 2016) which I compiled from
source code.
======================================================

--- aux function
local get_identifiers = function ()
  return identifiers
end

aux.get_identifiers = get_identifiers

In the TeX document, then loop over "identifiers" to dump out the values
of the mathparameters and MathConstants tables

\directlua{
local t=luaotfload.aux.get_identifiers()
for i,j in pairs(t) do
    if (j.nomath==false) then
        tex.print(j.name..string.char(92).."par")
        for a,b in pairs(j.mathparameters) do
        j.mathparameters[a]=(j.mathparameters[a])*2
        print("mathparameters", a,b, "difference=",
j.MathConstants[a]-j.mathparameters[a]..string.char(92).."par")
        end
        for a,b in pairs(j.MathConstants) do
        print("MathConstants", a,b)
        end
    end
end
}