rlatexyamlpandocligature

Enable ligatures with Fira Code in PDF output of Rmarkdown

The following code enables me to use Fira Code as mono font.

---
monofont: "Fira Code"
output: 
  pdf_document:
    latex_engine: xelatex
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r}
x <- 1:5
x != 2
```

This produces the desired ligature for != but not for <-.

enter image description here

The solution detailed in the accepted answer in this post works when done in LaTeX, e.g., 

\documentclass{article}

\usepackage{mathspec}
\setmonofont[Contextuals={Alternate}, Scale=0.75, Ligatures=TeX]{Fira Code}
\makeatletter
\def\verbatim@nolig@list{}
\makeatother

\begin{document}

\begin{verbatim}
x <- 1:5
x != 2
\end{verbatim}

\end{document}

enter image description here

The following YAML does not work. 

---
monofont: "Fira Code"
output: 
  pdf_document:
    latex_engine: xelatex
header-includes: |
  \makeatletter
  \def\verbatim@nolig@list{}
  \makeatother
---

Can enabling ligatures be done directly in the YAML?

Solution

  • If you look at the generated LaTeX output you see that the curly braces have been quoted: \def\verbatim@nolig@list\{\}. This quoting issue has been discussed in several issues on github, and there seems to be a fix available (c.f. this issue), but I have not tested it since my Debian testing machine still uses pandoc 1.19.2.4. As a workaround you can place the necessary commands into a separate file, say preamble.tex:

    \makeatletter
\def\verbatim@nolig@list{}
\makeatother

    and then use

    ---
monofont: "Fira Code"
output: 
  pdf_document:
    latex_engine: xelatex
    include:
      in_header: preamble.tex
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r}
x <- 1:5
x != 2
```