🌒 Quarto/Pandoc filter to create columns

Introduction

A Pandoc Pandoc Lua filter that provides an easier notation to create columns in documents, especially for Beamer or reveal.js presentations.

In Quarto, the traditional way of creating columns in a markdown document is by using the special fenced Div .columns :

:::: {.columns}

::: {.column width="40%"}
Left contents...
:::

::: {.column width="60%"}
Right contents...
:::

::::

This special Quarto syntax contains several customization options and is an effective way to produce two-column sections inside documents (HTML, LaTeX) or slides (Beamer).

However, it is somewhat cumbersome in the sense that the user should pay extra attention to the number of consecutive colons (:) starting the div blocks, in this case 4 for .columns and 3 for .column, but any consistently different number can be applied to both.

This filter simplifies this notation using a new div called twocol and an horizontal rule as the column separator. For instance, the code above turns into:

::: twocol

Left contents...

---

Right contents...

:::

Line 1
The block name

Line 5
The column delimiter is a horizontal rule

Formatting can be changed by passing the options align or width. These should be given by a comma-separated string, with the left and right columns' values, respectively. In this case, the Div syntax is the following:

::: {.twocol width="40%,60%" align="l,r"}

Left contents...

* * *

Right contents...

:::

Note

Also, notice the alternative way to represent the horizontal rule (at least three - or * with optional spaces within).

The parameters are:

Parameter	Description
align	l=Left, r=Right, c=Center, d=Default
width	Column width percentage e.g “30%,70%”

Other parameters included are forwarded to the column environment.

Installation and execution

Pandoc

Save the file twocol to ~/.pandoc/filters (default directory for pandoc filters) or any other directory. Run using one of the following syntaxes:

pandoc -s test.md -t html -L twocol.lua
pandoc -s test.md -t html --lua-filter=twocol.lua
pandoc -s test.md -t html -L ~/myfilters/twocol.lua

The last alternative refers to the filter installed in a custom location.

Quarto

quarto install extension gpappasunb/twocol

Add the filter to the document metadata:

---
filters:
  - twocol.lua
---

Author

Prof. Georgios Pappas Jr
Computational Genomics group
University of Brasilia (UnB) - Brazil