Formatting code fragments extracted from file with minted

Question

I would like to use the catchfilebetweentags package to grab code snippets from a source file and use minted to highlight them.

Imagine I have the following in program.scala:

//<a
def someFunctionA = {
  // some code
}
//a>

def aFunctionIDontCareAbout = {
  // irrelevant stuff
}

//<b
def someFunctionB = {
  // important code!
}
//b>

and the following LaTeX document:

\documentclass{article}
\usepackage{minted}
\usepackage{catchfilebetweentags}

\begin{document}

% Nicely formatted snippet:
\begin{minted}{scala}
  def someNicelyHighlightedFunction = {
    // not from the file
  }
\end{minted}

% Expanding, but unformatted snippet:
\CatchFileBetweenDelims{\a}{program.scala}{<a}{//a>}
\a

% Non-expanding snippet inside minted environment:
\CatchFileBetweenDelims{\b}{program.scala}{<b}{//b>}
\begin{minted}{scala}
  \b
\end{minted}

\end{document}

Is there any way I can get \b to expand inside the verbatim environment used by minted?

(I am not committed to catchfilebetweentags or to minted in particular, but I do need Pygments highlighting on extracted code fragments.)

Answer 1

catchfilebetweentags will get tricky with catcodes. Since you already have fancyvrb loaded, already have \write18 enabled (shell escape), and have Python (to use Pygments), I would suggest a pure Python solution. This is designed for tags that don't need to be escaped by either LaTeX or Python, though it could be adapted.

The basic idea is to use fancyvrb's VerbatimOut to create a Python script that will read your code and save the relevant portion in a temporary file. This script is executed automatically via \write18. Then the temporary file is read in via minted's \inputminted.

\documentclass{article}
\usepackage{minted}

\begin{VerbatimOut}{minted_delim.py}
import sys
codefile = sys.argv[1]
delim1 = sys.argv[2]
delim2 = sys.argv[3]
f = open(codefile)
code = f.read()
f.close()
f = open(codefile + '.snippet', 'w')
try:
    f.write(code.split(delim1, 1)[1].split(delim2, 1)[0])
except:
    f.write('MINTED DELIM ERROR')
f.close()
\end{VerbatimOut}

\newcommand{\inputmintedbetweendelims}[5][]{%
  \immediate\write18{python minted_delim.py "#3" "#4" "#5"}%
  \inputminted[#1]{#2}{#3.snippet}%
}

\begin{document}

\begin{minted}{scala}
  def someNicelyHighlightedFunction = {
    // not from the file
  }
\end{minted}

\inputmintedbetweendelims{scala}{program.scala}{<b}{//b>}


\end{document}