Pandoc lua filter to move image caption at the end of the document

Question

I'm totally new to Lua pandoc filter so this problem is over my level.

Starting from a markdown document, I want to collect all figures in the manuscript, remove the latex call to display them, capture their captions and display them in a block at the end called Figures.

For example, figures are rendered in the intermediate .tex as:

\begin{figure}
  \includegraphics[width=1\linewidth]{figure1} \caption{Figure 1. Caption.}\label{fig:figure1}
\end{figure}

I want to remove the afore mentioned block, take the caption and move it in the (existing) Figure section with this structure:

\section*{Figures}
  \begin{figure}[h!]
    \caption{Figure 1. Caption.}
  \end{figure}

  \begin{figure}[h!]
    \caption{Figure 2. Caption.}
  \end{figure}

I want to stress that the figures should not be shown anymore in the final document. This structure is required by the journal I'm sending the .tex to, which require the pictures to be loaded separately and just keep a reference to them in the manuscript.

I tried some Lua coding with no luck. But then I discovered that lua was not seeing at all my images.

I put this into the .md file:

\begin{figure}
  \includegraphics[width=1\linewidth]{figure1} \caption{Figure 1. Caption.}\label{fig:figure1}
\end{figure}

and then trying to check how it was seen by Lua with:

function Para (el) print(pandoc.utils.stringify(el)) end

But no reference to the image was printed (the other elements were printed, as a test). I tried substituting Para for Str, Inline, Image, Pandoc but nothing.

So I am not even able to catch the figure in the AST...

Answer 1

Instead of actually moving the figures, you can just tell latex to show the captions at the end:

\usepackage{figcaps}