svmono with 'draft' causes lstlistings to produce no output

Question

Why does the following produce no output?

\documentclass[draft]{svmono}
\usepackage{listings}
\begin{document}

\begin{lstlisting}
  theorem :: GROUP_10:14
    for G being finite Group,
    p being prime (natural number) holds
      (for H being Subgroup of G st
           H is_p-group_of_prime p holds
\end{lstlisting}

\end{document}

(Obviously it is easy to fix this issue by switching off 'draft' -- but I would like to understand what is happening.)

Answer 1

It is unrelated to svmono. Class options are global options so it gets passed to listings the draft option of listings suppresses file handling as far as I can see. The listings documentation says

draft
     The package prints no stand alone files, but shows the captions and defines
     the corresponding labels. Note that a global \documentclass-option draft
     is recognized, so you don't need to repeat it as a package option.