Markdown presentation with the new ltx-talk class

[michal-h21]

Joseph Wright uploaded a new presentation class, ltx-talk to CTAN. It should fix some internal Beamer issues. It still misses most Beamer features, but it can be enough for simple presentations.

I've installed the development version and tried, if I will be able to use the following Markdown syntax:

## Slide title

- foo
- bar 
---

## Another slide
foo
---

I've tried that in the past with Beamer, and it didn't work too well. The idea is to redefine the second level heading to read all following text until the next break, and to typeset the content inside the frame environment, with the section title as \frametitle:

\long\def\markdownRendererHeadingTwo#1#2\markdownRendererThematicBreak{
\begin{frame}
\frametitle{#1}
#2
\end{frame}
}

This works for simple content, like:

## Sample frame

hello *world*
---

But it fails with compilation errors for itemized or enumerated blocks. So I had to redefine some Markdown commands to get them work:

% Fix commands that cause errors with ltx-talk
\def\markdownRendererUlBeginTight{\itemize}
\def\markdownRendererUlEndTight{\enditemize}
\def\markdownRendererUlItemPrototype{\item}
\def\markdownRendererOlBeginTight{\enumerate}
\def\markdownRendererOlEndTight{\endenumerate}
% I get label=<number> if I use \item[#1]. why?
\def\markdownRendererOlItemWithNumber#1{\item}
% line blocks use the verse environment, but that too adds some unwanted text to the output
\def\markdownRendererLineBlockBegin{\begingroup\parindent=0pt}
\def\markdownRendererLineBlockEnd{\endgroup}

With this change, it seems to work. Here is a full example:

\DocumentMetadata{tagging = on}
\documentclass{ltx-talk}
\usepackage[lineBlocks]{markdown}


\long\def\markdownRendererHeadingTwo#1#2\markdownRendererThematicBreak{
  \begin{frame}
    \frametitle{#1}
	#2
	\end{frame}
}


\long\def\markdownRendererHeadingThree#1#2\markdownRendererInterblockSeparator{
  \begin{block}{#1}
  #2 
  \end{block}
}

% Fix commands that cause errors with ltx-talk
\def\markdownRendererUlBeginTight{\itemize}
\def\markdownRendererUlEndTight{\enditemize}
\def\markdownRendererUlItemPrototype{\item}
\def\markdownRendererOlBeginTight{\enumerate}
\def\markdownRendererOlEndTight{\endenumerate}
% I get label=<number> if I use \item[#1]. why?
\def\markdownRendererOlItemWithNumber#1{\item}
% line blocks use the verse environment, but that too adds some unwanted text to the output
\def\markdownRendererLineBlockBegin{\begingroup\parindent=0pt}
\def\markdownRendererLineBlockEnd{\endgroup}


\title{Writing Beamer Slides with Markdown}
\author{Michal}

\begin{document}

\maketitle


\begin{frame*}
\begin{markdown}
- hello 
- world
\end{markdown}
\end{frame*}


\begin{markdown}
# Hello

## Another slide

- hello

| Here is a 
| line block

---

## Hello

> What about blockquotes?
> This is a blockquote.

This was a blockquote.

---

## This is a test slide

- some stuff
- more stuff 

1. first item
2. second item
---

## What about verbatim?

    \section{Hello}
    \textit{hello verbatim}
---

## What about blocks?
 
### This is a block title 

This is blocks contents. It seems that we need to leave out `---` after the block, there would be 
a blank slide with horizontal rule otherwise.
***

## Last slide

- will be there an empty slide?
---

\end{markdown}
\end{document}

It needs to be compiled using lualatex-dev.

So I am positively surprised that it works pretty well. I hope that ltx-talk will implement the ignorenonframetext from Beamer in the future, so we can mix slides and supporting text for handout articles. But for simple presentations, it is usable already.

[Witiko]

That's great news! If there ever is a Markdown theme for ltx-talk, I would be happy to link it from the contributions/ folder. There, you can also find other successful attempts to use the Markdown package for slides, such as 37c3-beamer from @TeXhackse.

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