l3backend-dvips: embedding a file in stream doesn't work

[u-fischer]

This document doesn't embed the file but outputs parts of the arguments:

\documentclass{article}
\usepackage{l3pdf}
\begin{filecontents}[overwrite]{testinput.tex}
blub
\end{filecontents}
\begin{document}
\showoutput
abc
\ExplSyntaxOn
\pdf_object_new:nn {test} {fstream}
\pdf_object_write:nn {test}{
        {/Type/EmbeddedFile}
        {testinput.tex}
      }
\ExplSyntaxOff
\end{document}

The problem is that \__pdf_backend_object_write_fstream:nn is not define but used in a \use:c{}.

The following definitions seem to work.

Side remark: ps2pdf refuses to insert the file unless one uses the option -dNOSAFER or e.g. --permit-file-read=* . Also ps2pdf can not find files with kpathsea. These restrictions should perhaps be documented.

\cs_new_protected:Npn \__pdf_backend_object_write_fstream:nn #1#2
  {
    \exp_args:Nx
      \__pdf_backend_object_write_fstream:nnn {#1} #2
  }

\cs_new_protected:Npn \__pdf_backend_object_write_fstream:nnn #1#2#3
  {
    \__kernel_backend_literal:n
      { ps::[nobreak]~
        SDict ~ begin ~
        mark ~ #1 ~ << #2 >> /PUT ~ pdfmark ~
        mark ~ #1 ~ ( #3 )~ (r)~ file ~ /PUT ~ pdfmark ~
        end
      }
  }