Red Box Around Question-Mark Operator in Minted Erlang Code

highlightingminted

I'm trying to include some Erlang code samples in a document using the minted package which include the ? operator to denote a message being received from a process. The code

\documentclass{minimal}
\usepackage{minted}
\begin{document}
\begin{minted}{erlang}
A ! Msg1,
receive
    A ? Msg2 ->
        ok
\end{minted}
\end{document}

produces the following output:

LaTeX output

with the ? operator being treated differently to the ! operator, and having a red box drawn around it. How can I remove this box and have it treated in the same way as the ! operator? I presumed pygmentize would treat them similarly in this context. Is there any way I can check that this assertion is true, and if it's not, modify how pygmentize treats it accordingly?

Best Answer

Normally the red box indicates syntax errors in your source code (here Erlang). However, the language specific parsers used by Pygments (which in turn is used by minted) are incomplete. Apparently the Erlang parser cannot cope with the question mark as an identifier.

The best course of action is to file a bug with the maintainer of the Erlang lexer, Jeremy Thurgood or the Pocoo team who maintain Pygments.

Or you can fix the error yourself in your local Pygments installation by modifying pygments/lexers/functional.py – the error is probably just a missing question mark on line 659.

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Do you want to achieve something like this?

enter image description here

Do you mean you want to put a frame around your code? You have to use the frame option. You can choose from the values none (the default), leftline, topline, bottomline, lines, single.

\documentclass[]{article}
\usepackage{minted}

%opening

\begin{document}

\begin{listing}[H]
\begin{minted}[frame=single]{js}
var http = require("http");
    http.createServer(function(request, response) {
        response.writeHead(200, {"Content-Type": "text/plain"});
        response.end();
    }).listen(8080);
\end{minted}
\caption{Example of a listing.}
\end{listing}

\end{document}

Minted Environment – How to Add a Box Around Minted Environment

As mentioned by Torbjørn T. minted has some options to add a frame. However minted doesn't do the frame. This is done by the package fancyvrb. The possibilities of frames with fancyvrb are limited. If you want e.g. round corners you can use another package like tcolorbox or mdframed.

The example below shows you the usage of tcolorbox. I am using the advantages of etoolbox to add a frame around every minted environment.

\documentclass[a5paper]{article}
\usepackage[]{minted}
\usepackage{tcolorbox}
\usepackage{etoolbox}
\BeforeBeginEnvironment{minted}{\begin{tcolorbox}}%
\AfterEndEnvironment{minted}{\end{tcolorbox}}%
\begin{document}
\begin{minted}{latex}
%Preamble
\usepackage[]{minted}
\usepackage{tcolorbox}
\usepackage{etoolbox}
\BeforeBeginEnvironment{minted}%
     {\begin{tcolorbox}}%
\AfterEndEnvironment{minted}
   {\end{tcolorbox}}%
\end{minted}
\end{document}

enter image description here

EDIT: If you want to have automatic line breaks with fancyvrb you can use the following. Please note line breaks only occur at spaces. A line break has pre hook in form of $\rightarrow$ . You can change it, of course. To get the symbol in front of a line I used lineno.

\documentclass[a5paper]{article}
%\pagestyle{empty}
\usepackage[T1]{fontenc}
\usepackage[]{minted}
\usepackage{tcolorbox}
\usepackage{lineno}
\def\gobble#1{}
\renewcommand\DeleteFile[1]{}
\usepackage{xparse}
\ExplSyntaxOn
\box_new:N \l_fvrb_box
\tl_new:N \l_fvrb_tl

\RenewDocumentCommand \FancyVerbFormatLine { m }
 {
   \hbox_set:Nn \l_fvrb_box { #1 }
    \dim_compare:nNnTF { \box_wd:N \l_fvrb_box }>{ \linewidth }
      {%box to big 
       \tl_set:Nn \l_fvrb_tl { #1 }
       \fvrb_use_tl:N \l_fvrb_tl
      } 
      {%box fits
       \box_use:N \l_fvrb_box
      }
 }

\cs_new:Npn \fvrb_use_tl:N  #1
 {
  \group_begin:
   \null\hfill\vbox_set:Nn \l_fvrb_box
     {\hsize=\linewidth
      \renewcommand\thelinenumber
           {
             \ifnum\value{linenumber}=1\relax\else
                  $\rightarrow$
             \fi
           }
      \begin{internallinenumbers}
        \advance\hsize by -2em
        \hspace*{-2em}\tl_use:N #1
      \end{internallinenumbers}
     }
   \box_use:N \l_fvrb_box
  \group_end:
}

\ExplSyntaxOff


\usepackage{etoolbox}
\BeforeBeginEnvironment{minted}{\begin{tcolorbox}}%
\AfterEndEnvironment{minted}{\end{tcolorbox}}%
\begin{document}
\begin{minted}{latex}
%Preamble
\usepackage[]{minted}
\usepackage[fancyvrb=true]{listings}
\usepackage{tcolorbox}
\usepackage{etoolbox}
\BeforeBeginEnvironment {minted} { \begin{tcolorbox} } \AfterEndEnvironment {minted} { \end{tcolorbox} }%
\usepackage{lipsum}
\end{minted}
\end{document}

enter image description here

Best Answer

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