pandoc.md

A converter between many formats.

Lua filter

Pandoc supports passing the text through Lua filter with --lua-filter=filter.lua. It gets passed an internal AST, made out of staff like Para (for Paragraph), Space, BulletList, etc. To see the AST use --to=native option, it's immensely useful for debugging the filter.

To process specific type of elements you declare a function similarly named, e.g. function Para for Para types.

Example of surrounding paragraphs containing the emoji with an html tag:

function Para(elem)
   local text = pandoc.utils.stringify(elem)
   if text:find("📝 ") then
      return pandoc.Plain({pandoc.RawInline('html', '<span class="notes">')}
                          .. elem.content
                          .. {pandoc.RawInline('html', '</span>')})
   end
end

Examples

Converting a Markdown to PDF

Most of the stuff I took from this post; and a bit from an answer on SO.

I use this command pandoc -H preamble.tex -V geometry:"top=2cm, bottom=1.5cm, left=2cm, right=2cm" -V colorlinks -V urlcolor=NavyBlue --pdf-engine=lualatex -s ~/document.md -o document.pdf

And preamble is:

\usepackage{fontspec}
\directlua{luaotfload.add_fallback
   ("emojifallback",
    {
      "NotoColorEmoji:mode=harf;"
    }
   )}

% set fallback for the main font.
\setmainfont{Ubuntu Mono}[
  RawFeature={fallback=emojifallback}
]

% change background color for inline code in
% markdown files. The following code does not work well for
% long text as the text will exceed the page boundary
\definecolor{bgcolor}{HTML}{E0E0E0}
\let\oldtexttt\texttt

\renewcommand{\texttt}[1]{
  \colorbox{bgcolor}{\oldtexttt{#1}}
  }

You can also use csv for styling, and then create an html with pandoc -c /tmp/github-pandoc.css -V colorlinks -V urlcolor=NavyBlue -s ./document.md -o document.html. pdf later then can be created with a browser by "printing to a file". NOTE: the css file has to be included with absolute path, otherwise browser won't find it.