[NTG-context] Re: nested context/lua calls

29 Mar 2025

      Hi Mohammad,

On Sat, 2025-03-29 at 11:06 -0400, Mohammad Hossein Bateni wrote:
...
Is there a more elegant solution?
Ideally I want a way to start a TeX process under Lua, and
process the macros there before I get to the next line of Lua code.
One option is to use "publications.prerollcmdstring", which fully and
completely expands its arguments (it typesets the arguments in a box and
then parses the box's glyphs). Another option is to use
"context.stepwise", which lets you interleave TeX and Lua execution.

Demonstration:

    \define[1]\MakeSomething{%
        \setbox0=\hbox{#1}%
        \ifdim\wd0>12pt\relax%
            12%
        \else%
            X%
        \fi%
    }

    \newcount\mycounter
    \define\incrementmycounter{%
        \advance\mycounter by 1\relax%
    }

    \startluacode
    local function WorkWithSomething(data)
        local value = publications.prerollcmdstring(([[\MakeSomething{%s}]]):format(data))
        return ("<%s>"):format(value)
    end

    interfaces.implement {
        name = "WorkWithSomething",
        arguments = { "string" },
        actions = { WorkWithSomething, context },
        public = true,
    }

    for i=1, 10 do
        context.incrementmycounter()
        print(tex.count.mycounter)
    end

    context.stepwise(function()
        for i=1, 10 do
            context.incrementmycounter()
            context.step()
            print(tex.count.mycounter)
        end
    end)
    \stopluacode

    \startTEXpage
        \WorkWithSomething{.}
        \WorkWithSomething{XXX}
    \stopTEXpage

Thanks,
-- Max

[NTG-context] Re: nested context/lua calls

Max Chernoff