Re: [luatex] searching a "marktobase" lookup example

[Max Chernoff via luatex]

Hi Werner,

On Tue, 2025-09-16 at 08:02 +0000, Werner LEMBERG wrote:
> > Attached is an improved version.
>
> As usual: right after sending an improved version I find a problem :-)
>
> The old version only checked the first lookup of a 'mark' feature;
> this is now fixed.

Looks good to me. One other tip is that you can fake a "continue"
statement with "goto", which will let you reduce the amount of nested
"if"s:

    for _, step in ipairs(sequence.steps) do
        local coverage = step.coverage
        if not coverage then
            goto continue
        end

        local coverage_mark = coverage[uni_mark]
        if not coverage_mark then
            goto continue
        end

        mark_glyph_in_coverage = true
        local coverage_base = coverage_mark[1][uni_base]
        if not coverage_base then
            goto continue
        end

        base_glyph_in_coverage = true
        for i, baseclass in ipairs(step.baseclasses) do
            if baseclass[uni_base] then
                report("log", 0, "add_to_mark",
                                "found base-mark glyph combination '%s+%s'"
                                .. " in 'mark' feature of font '%s'",
                                base, mark, filename)
                -- Report OpenType value for anchor class, not
                -- the one used in luatex.
                report("log", 0, "add_to_mark",
                                "adding glyph '%s' to anchor class %d",
                                acc, i - 1)
                coverage[uni_acc] = {baseclass, {x, y}}
                return
            end
        end
        ::continue::
    end

Another suggestion is to use a more descriptive name for your
"luaotfload.patch_font" callback, since "patch-fonts" isn't the most
informative. "add-to-mark" would probably be a good name.

But otherwise, this looks great.

Thanks,
-- Max