Unescaped underscores in code rendering as italics in xaringan

[machow]

I think this may be more likely to pop up in python, since you can use _ as a variable name 😬. I'm using knitr v1.30.

Rmarkdown code:

---
title: "code examples"
output:
  xaringan::moon_reader:
    lib_dir: libs
    nature:
      ratio: '16:9'
      countIncrementalSlides: false

---


```{python test}
a = 1
_ = 2
_ = 3
```

```{r}
library(flair)
decorate("test") %>% flair("a")
```

Output (note italics in very bottom 2 lines):

Looking at the source, it seems that html tags are escaped (for remarkjs?), but underscores are left as is.

[machow]

It looks like this traces back to htmltools::htmlEscape (used by xaringan).

> htmltools::htmlEscape("< _")
[1] "&lt; _"

Underscores don't need to be escaped in html, but I'm guessing remarkjs does markdown rendering early on?

See these issues:

• xaringan escapes html and remarkjs sort of puts it back together (< and > gets converted into &lt; and &gt; yihui/xaringan#12)
• someone hit a similar issue with math formatting (Xaringan requires escaping of underscores for subscripts in math formulas in some cases yihui/xaringan#146)

[machow]

I just tossed in a quick gsub. Not pretty, but seems to work!

Changed here:

flair/R/with_flair.R

Lines 96 to 99 in ab67c7d

	} else if (doc_type == "xaringan::moon_reader") {
	x <- paste0("<code class ='r hljs remark-code'>", x, "</code>")

Original

    x <- paste0("<code class ='r hljs remark-code'>", x, "</code>")

New

    x <- paste0("<code class ='r hljs remark-code'>",  gsub("([_*])", "\\\\\\1", x), "</code>")

[shannonpileggi]

a +1 for underscore support 😊

https://community.rstudio.com/t/xaringan-flair-character-strings-with-underscores/135029