Luatex pass variable amount of arguments from tex to lua (comma separated and escaped)

Question

How can you pass multiple arguments from a tex command to a lua function, whilst also escaping them

Or how do I modify

(imports)

\usepackage{luacode}

\newcommand{\example}[1]{
    \directlua{
        function debug(...)
            local arr = {...}
            for i, v in pairs(arr) do
                print(v)
            end
        end
        debug(#1)
    }
}

such that

\example{\notDefined, aNilValue, 5}

produces standard output of

\notDefined
aNilValue
5

instead of throwing

• Undefined control sequence (latex error)
• or printing nothing because the variable aNilValue is not defined

I've tried using \luastring{\unexpanded{...}} with \docsvlist but i keep getting runaway arguments

EDIT Clearification, all passed arguments should be strings so local arr = {...} should equal in the example {"\\notDefined", "aNilValue", "5"}

Answer 1

It could take more care of white space but this makes a lua string of the whole list then splits on commas so every item is interpreted as a string.

\newcommand{\example}[1]{%
    \directlua{
        function debug(s)
            for v in string.gmatch(s,'[^,]*') do
                print(v)
            end
        end
        debug("\luaescapestring{\detokenize{#1}}",",")
    }%
}

\typeout{}

\example{\notDefined, aNilValue, 5}

\stop

produces terminal output

\notDefined 
 aNilValue
 5

Answer 2

This solution uses LaTeX3's comma separated list. The arguments of \example will be written to the log file.

\documentclass{article}
\usepackage{expl3}

\directlua{
  function debug(...)
      local arr = {...}
      for i, v in pairs(arr) do
          texio.write_nl(v)
      end
  end
}

\ExplSyntaxOn
\newcommand{\example}[1]{
  % construct comma separated list
  \clist_set:Nn \l_tmpa_clist {#1}
  % construct lua string for each component
  % and store them in a sequence
  \seq_clear:N \l_tmpa_seq
  \clist_map_inline:Nn \l_tmpa_clist {
    \str_set:Nn \l_tmpa_str {##1}
    \seq_put_right:Nx \l_tmpa_seq {"\luaescapestring{\l_tmpa_str}"}
  }
  \directlua{debug(\seq_use:Nn \l_tmpa_seq {,})}
}
\ExplSyntaxOff

\begin{document}
\example{\notDefined, aNilValue, 5}
\end{document}