lua-implementation of pdf@shellescape should be reconsidered.

[u-fischer]

Starting from a question on tex.sx
https://tex.stackexchange.com/questions/354830/lualatex-compilation-fails-when-sorting-text-using-luacode
the following minimal example was created. It fails with the error

)...xlive/2016/texmf-dist/tex/luatex/lualibs/lualibs-lua.lua:195: standard outpu
t file is closed

The error is caused by the faulty definition of sort_tdo which doesn't restore correctly the output handler but also leads to the question if the lua implementation of \pdf@shellescape in oberdiek.pdftexcmds.lua should be reconsidered to use a less fragile method.

\documentclass{article}

\directlua{
   function sort_tdo (jobname)
    file=io.open(jobname.."sorted", "w")
    % zz=io.output() %store output
    io.output(file)
    io.close(file)
    % io.output(zz)  %restore output
   end
}

\directlua{
 function shellescape()
  if os.execute then
   tex.write(os.execute())
  end
end}



\directlua{sort_tdo("\jobname.tdo")}

\makeatletter 
%\def\pdf@shellescape{\directlua{tex.sprint(status.shell_escape .. " ")}} %works
\def\pdf@shellescape{\directlua{shellescape()}}% breaks
\ifnum\pdf@shellescape>0 %
  \show\x
\fi
\begin{document}
\end{document}

[davidcarlisle]

On 21 February 2017 at 10:25, u-fischer ***@***.***> wrote: Starting from a question on tex.sx https://tex.stackexchange.com/questions/354830/lualatex- compilation-fails-when-sorting-text-using-luacode the following minimal example was created. It fails with the error )...xlive/2016/texmf-dist/tex/luatex/lualibs/lualibs-lua.lua:195: standard outpu t file is closed The error is caused by the faulty definition of sort_tdo which doesn't restore correctly the output handler but also leads to the question if the lua implementation of ***@***.*** in oberdiek.pdftexcmds.lua should be reconsidered to use a less fragile method. \documentclass{article} \directlua{ function sort_tdo (jobname) file=io.open(jobname.."sorted", "w") % zz=io.output() %store output io.output(file) io.close(file) % io.output(zz) %restore output end } \directlua{ function shellescape() if os.execute then tex.write(os.execute()) end end} \directlua{sort_tdo("\jobname.tdo")} \makeatletter ***@***.***{\directlua{tex.sprint(status.shell_escape .. " ")}} %works ***@***.***{\directlua{shellescape()}}% breaks ***@***.***>0 % \show\x \fi \begin{document} \end{document}

Thanks yes. Also I suspect it could be better as \protected\edef\pdf@shellescape{\directlua{tex.sprint(status.shell_escape .. " ")}} so you only do it once, at a point known to be safe. this is read only so can't change during a run anyway or perhaps \protected\edef\pdf@shellescape{\numexpr\directlua{tex.sprint(status.shell_escape)}\relax} To avoid the slightly risky space and so \the\pdf@shellescape works

[davidcarlisle]

the new pdf@shellescape is in the last ctan release, thanks for the comment.