Beamer Code Snippets Slide by Slide

Question

I would like my slide presentation to display one item at a time, where the codesnippet is considered another item. Here's what I have.

\documentclass{beamer}
\usetheme{Madrid}
\usepackage{listings}
\begin{document}

\begin{frame}[fragile]
    \frametitle{Test Slide}

    \defverbatim[colored]\codesnippet{
    \begin{lstlisting}[language=Python,basicstyle=\ttfamily,keywordstyle=\color{blue}]
        def main():
            <statements>
    \end{lstlisting}
    }

    \begin{itemize}
        \item<1-> test
        \item<2-> test
        \codesnippet
    \end{itemize}
\end{frame}

\end{document}

What happens with my current code is that item<1-> appears on the first slide, but then item 1 and item 2 appear on the second slide together with codesnippet. On slide 2, I just want item 1 and item 2 without the codesnippet, and then have item 1, item 2, and codesnippet appear on slide 3. If i try to nest codesnippet in another item like so, then I get an extra item after the code snippet.

\begin{itemize}
    \item<1-> test
    \item<2-> test
    \item<3->{\codesnippet}
\end{itemize}

How can I treat a code snippet like an item that can be added to the next slide? Thanks.

Answer 1

Well, I do not know why, but the problem seems to come from the definition of \codesnippet. If you replace it with the explicit expression of its content, it works fine. Do you really need to define this macro ?

\documentclass{beamer}
\usetheme{Madrid}
\usepackage{listings}
\lstset{language=Python,basicstyle=\ttfamily,keywordstyle=\color{blue}}
\begin{document}

\begin{frame}[fragile]
    \frametitle{Test Slide}


    \begin{itemize}
        \item<1-> test
        \item<2-> test
        \item<3-> 
        \begin{lstlisting}
def main():
    <statements>
        \end{lstlisting}
    \end{itemize}
\end{frame}

\end{document}