Markdown syntax for beamer "\alert"

[gjherbiet]

Hello,

This issue can be thought as a reverse of #4091 : would it be possible to have a Markdown syntax element that translates to LaTeX Beamer \alert command.

For instance, using !! as delimiter, this would give:

$ echo "This text has an !!alert part with *emphasis*!!." | pandoc -f markdown -t beamer
\begin{frame}

This text has an \alert{alert part with \emph{emphasis}}.

\end{frame}

Ideally, this would support nested formatting, as in the example.

[mb21]

You can simply write raw TeX, e.g. \alert inside your markdown document. I think adding special markdown syntax for such a rarely-used command is out of scope for pandoc.

[cagix]

You could also use (blabla){.alert} and translate the resulting span with a short lua-filter ...

[CLRafaelR]

@gjherbiet

You can use the following lua filter (say, alert.lua) when you produce a beamer presentation.

if FORMAT:match 'beamer' then
    function Span(el)
        if el.classes[1] == "alert" then
            table.insert(el.content, 1, pandoc.RawInline("latex", "\\alert{"))
            table.insert(el.content, pandoc.RawInline("latex", "}"))
        end
        return el
    end
    return { { Span = Span } }
end

In an md file, [what you want to highlight]{.alert} is the command to produce a text with an alert. Note that you need to enclose the text with square bracket [...], not (...).

## frame header

- This is important
- This is also important
- This is [the most important]{.alert} line

Then, your md is converted into a beamer presentation pdf with alerts.

pandoc --lua-filter=alert.lua -t beamer presentation.md -o presentation.pdf