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There are different types of “registers” in LuaTeX. With totcount package, you can save counter (number) from any place in a document and get its value also in any place in a document with the help of .aux file (maybe other extension). But is there any way to use this exact (or similar) feature with (Unicode) strings (in Lua)?

For example, I have calculated something at the end which shouldn't be precalculated (i. g., in the preamble) because that will make a big mess and will be much less readable. And then I need to use this result at the beginning (like a \hyperref of some sort, but just for string values). And of course this should be possible with multiple strings at the same time.

Andrew15_5
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    see how table of contents are implemented, write to a file, or the aux file and then read at begin document on the next run – David Carlisle Dec 17 '22 at 18:17
  • @DavidCarlisle, thank you for the advice. I was just hoping that there is already some sort of implementation for that in Lua(La)TeX. – Andrew15_5 Dec 17 '22 at 19:36
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    it's a standard feature of latex, at the end \immediate\write\@auxout{\gdef\noexpand\wibble{my string]} then on the next run \wibble will be defined from begin document to be my string – David Carlisle Dec 17 '22 at 20:26

1 Answers1

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Thanks to David Carlisle, I made an extensive example of what I wanted to achieve:

\documentclass{article}
\newcommand\lua[1]{\directlua{#1}}

\usepackage{fontspec}


% https://tex.stackexchange.com/questions/572212/
% substituting-fonts-for-emojis-in-lualatex/572220#comment1662059_572220
\lua{luaotfload.add_fallback("FallbackFonts", {
  "Noto Color Emoji:mode=harf",
  "Noto Sans CJK JP:"
})}
\setmainfont{Times New Roman}[RawFeature={fallback=FallbackFonts}]


% Get (command if defined)
\newcommand\Get[1]{\csname #1\endcsname}


% Lua get (if variable is not defined or
% argument is empty then nothing will be printed)
\newcommand\LGet[1]{\lua{tex.print(#1)}}


\makeatletter
% Global definition
\newcommand\Gdef[2]{\immediate\write@auxout{%
  \unexpanded{\expandafter\gdef\csname #1\endcsname{#2}}%
}}


% Global Lua definition
\newcommand\GLdef[2]{\immediate\write@auxout{%
  \unexpanded{\lua{#1 = #2}}%
}}


% Global Lua string definition
\newcommand\GLsdef[2]{\immediate\write@auxout{%
  \unexpanded{\lua{#1 = "#2"}}%
}}
\makeatother
\begin{document}


After 2nd run we get:


\Get{super@ cool!!}


\setlength\parskip{1ex}


\ifdefined\simplename
  \simplename
\fi


\LGet{this1}


\LGet{that2}


% Added nil check
\LGet{complex and complex.foo}


\LGet{complex and complex.bar}


% Later in document...


\GLdef{this1}{69}


\GLsdef{that2}{my Unicode string. やった！}


\GLdef{complex}{{foo = 123, bar = "string"}}


\Gdef{super@ cool!!}{%
  Any string that I want
  asdf
  asdfasd
  fasdfas


df asdf
  as df \
  sdf
   asf a sdfs
}


\Gdef{simplename}{Can be used without the use of additional command. But will
give an error if not checked for definition (during the 1st run).}
\end{document}

Which will create PDF (with lualatex) after 1st run:

nothing

And after 2nd run we get:

everything

Andrew15_5
  • 161