Can you interpret macro parameters as verbatim?

Question

Basically I want to define a macro whose parameter should be treated as a "script", meaning that I want to print it in a verbatim way including line breaks and special characters. Furthermore, I want to use this parameter in a second way, namely as an input to create a qrcode (using the qrcode package). A very minimal example is the following:

\documentclass{article}
\usepackage{qrcode}

\newcommand{\script}[1]{
    #1\qrcode{#1}
}

\begin{document}
    \script{test}
\end{document}

When I do it like this, the parameter is obviously not interpreted as verbatim. Since I need the parameter at two different places (both interpreted in verbatim mode), I cannot use an environment either -- such as a listings environment -- since the body text cannot (directly) be used as parameter.

I played around with the environ package (see my earlier question: Is it possible to "scan" the text within an environment?) to capture the body text of an environment, but, again, didn't succeed to make it verbatim.

I also tried to work with \obeylines and \StrSubstitute, but it gets quite ugly really soon, and it didn't actually work well.

It looks rather easy, but I'm struggling with this for a long time now. Any suggestions?

Answer 1

I am not entirely sure that I understood what you want. However, your MWE can easily be achieved with xparse and its v type argument:

\documentclass{article}
\usepackage{qrcode,xparse}

\NewDocumentCommand{\script}{v}{%
  \texttt{#1} \qrcode{#1}%
}

\begin{document}

\script{test} \script{&$\#$}

\end{document}

Keep in mind, though, that now since now the argument is read in verbatim in the first place \script{&$\#$} gives a different qrcode than using \qrcode{&$\#$} directly. If that is not what you want, then maybe

\NewDocumentCommand{\script}{v}{%
  \texttt{#1} \scantokens{\qrcode{#1}\ignorespaces}\relax
}

would be a solution.

The output with the first version (qrcode of verbatim input):

The output with the second version (qrcode like in direct use of \qrcode):

---

Idea for an environment doing similar things using listings (and its writefile aspect) and catchfile – the idea is to write the contents of the environment to an external file and then use it to produce the qrcode:

\documentclass{article}
\usepackage{qrcode,listings,catchfile}

\makeatletter
\lst@RequireAspects{writefile}
\lstnewenvironment{script}[1][]
  {%
    \lstset{#1}%
    \lst@BeginAlsoWriteFile{\jobname.script}%
  }
  {%
    \lst@EndWriteFile
    \CatchFileDef\script@tmp{\jobname.script}{}%
    \expandafter\qrcode\expandafter{\script@tmp}%
  }
\makeatother

\begin{document}

\begin{script}[basicstyle=\ttfamily,columns=fullflexible,gobble=2]
  foo bar

  baz
\end{script}

\qrcode{foo bar

baz
}

\end{document}