Macro with lstlisting inside

Question

I have been following this topic about using \NewDocuentCommand with lstlisting and the accepted answer is nice except it is too big and it doesn't quite work for me.

I came up with this example to test xparse:

\documentclass{article}
\usepackage{xparse}
\usepackage{listings}
\ExplSyntaxOn
\NewDocumentCommand{\code}{m +v}{
    \begin{lstlisting}[style=#1,numbers=none,xleftmargin=0.35cm,framesep=0mm]
        #2
    \end{lstlisting}
}
\ExplSyntaxOff
\begin{document}
\code{C}{
int x = 200;
unsigned int y = 0;
}
\end{document}

Like stated in the CTAN xparse documentation I first used m as a normal parameter and then +v as a multiline verbatim parameter, but it fails. It looks like I am still missing something...

You cannot wrap verbatim into macros. This doesn't change with LaTeX3. — Henri Menke, Jun 21 '17 at 07:34
@Henri Menke I need to create a command and not environment. In the example I provided they did it somehow... — 71GA, Jun 21 '17 at 07:53
@71GA you didn't provide an example: I guess you forgot to add the link… — cgnieder, Jun 21 '17 at 07:57
You can't use the v-argument for a multiline argument. It will complain with ! Verbatim argument of '\code ' ended by end of line.. — Ulrike Fischer, Jun 21 '17 at 08:03
@71GA »I need to create a command...« Wrong! You want to create a command but what you need and should use is an environment. — Henri Menke, Jun 21 '17 at 08:14
@Henri Menke I am working on a document which should be as easy as possible for the end user to input commands and it is easier for them to write \kodaB{C}{...} than \begin{kodaB}...\end{kodaB}. — 71GA, Jun 21 '17 at 08:57
@71GA it isn't easier to use a command than an environment, just different. In this case, especially when the code part spans several lines, an environment IMHO is both easier to input and makes the document source easier to read — cgnieder, Jun 21 '17 at 10:38

Henri Menke · Accepted Answer · 2022-07-27T06:51:29.950

5

You can just use Bruno's solution from the linked question (pretty smart I think).

\documentclass{article}
\usepackage{listings}
\usepackage{xparse}
\ExplSyntaxOn
\NewDocumentCommand{\code}{m +v}{
  \newlinechar=\endlinechar
  \exp_args:Nx \scantokens
  {
    \string\begin{lstlisting}[\unexpanded{language=#1,numbers=none,xleftmargin=0.35cm,framesep=0mm}]
      #2
    \string\end{lstlisting}
  }
}
\ExplSyntaxOff
\begin{document}
\code{C}{
int x = 200;
unsigned int y = 0;
}
\end{document}

But please, just use a new environment instead.

\documentclass{article}
\pagestyle{empty}
\usepackage{listings}
\lstnewenvironment{code}[1]{\lstset{language=#1,numbers=none,xleftmargin=0.35cm,framesep=0mm}}{}
\begin{document}
\begin{code}{C}
int x = 200;
unsigned int y = 0;
\end{code}
\end{document}

Output is similar.

edited Jul 27 '22 at 06:51

answered Jun 21 '17 at 08:12

Henri Menke

109,596

Thank you for the answer. One more thing is bugging me. In either of the cases you provided, code is moved one tab to the right if I move source code \begin{code}...\end{code} one tab right. So source code position affects the compiled code position. Any idea on how to solve this? – 71GA Jun 21 '17 at 08:47
@71GA See the gobble option in the documentation. – Henri Menke Jun 21 '17 at 09:22
@ Henri Menke In the first solution, if the content of the second argument(+v) locates at the same line where \code{ is, this part of content will not be typeset. Why and how to deal with that? – lyl Jul 26 '22 at 13:26
@lyl lstlisting environment ignores the content on its first line as well, so no surprise here. To deal with it insert an explicit ^^J at the end of the lines. – user202729 Jul 27 '22 at 04:29
@user202729 I tried with the above example of the first solution like this ... unsigned int y = 0; ^^J, but only get ... unsigned int y = 0; ^^J – lyl Jul 27 '22 at 04:40
@lyl No, insert in the command definition. Ensure that the ^^J get catcode other. \iow_newline: works as well. – user202729 Jul 27 '22 at 05:37
@user202729 Thank you for this wonderful proposal! And \code{% ... causes error. Why and how to do that? – lyl Jul 27 '22 at 05:50
@HenriMenke You forgot the \newlinechar=\endlinechar. (fortunately lstlisting happily ignores it in this case) – user202729 Jul 27 '22 at 05:56
@lyl Because of the above. – user202729 Jul 27 '22 at 05:56
@user202729 @HenriMenke It seems that combination of \newlinechar=\endlinechar and ^^J causes error. And \code{% ... causes the first line(int x = 200;) disappear. – lyl Jul 28 '22 at 08:17
@lyl Do understand what code does instead of just test out random things. By default xparse uses char 13 to separate lines, but to write to file/scantokens you need char \newlinechar which is 10 by default. Anyway "how to keep first line" isn't really in the focus of this question. – user202729 Jul 28 '22 at 08:24

Macro with lstlisting inside

1 Answers1

Linked