Provide error messages if math or latex syntax is incorrect

[venpopov]

Description

I have an equation that was rendered just fine within visual editing mode of Rstudio:

But when I rendered the html, it was not:

I spend half an hour trying to solve until I decided to try rendering it to pdf and I got this error message:

Removing the # symbol from the equation resolved the issue and it was rendered in the html output. But it would have saved me a lot of time if I got that error message during the html rendering, rather than just a weird output.

[mcanouil]

Unfortunately, we can't use screenshots.
Please share a small reproducible code and please indicate which version of Quarto and RStudio you are using.

You can share a Quarto document using the following syntax, i.e., using more backticks than you have in your document (usually four ````).

````qmd
---
title: "Reproducible Quarto Document"
format: html
engine: knitr
---

This is a reproducible Quarto document using `format: html`.
It is written in Markdown and contains embedded R code.
When you run the code, it will produce a plot.

```{r}
plot(cars)
```

![A placeholder image](https://placehold.co/600x400.png)

The end.
````

[venpopov]

---
title: "Reproducible Quarto Document"
format: html
engine: knitr
---

$$
i = 1,…,5 \ \text{ (Task #)}
$$

[cderv]

I have an equation that was rendered just fine within visual editing mode of Rstudio:
(...)
But when I rendered the html, it was not:

I think this comes from the fact that RStudio IDE may still use Mathjax 2.7 while Quarto HTML uses Mathjax 3 by default.

Try this document

---
title: "Reproducible Quarto Document"
format: html
html-math-method: 
  method: mathjax
  url: "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-AMS-MML_HTMLorMML"
---

$$
i = 1,…,5 \ \text{ (Task #)}
$$

This should show the equation correctly in the HTML

I think this is related upstream to

• Consider updating Mathjax to version 3 or 4 rstudio/rstudio#8715
• Update to latest release of MathJax 2.7 rstudio/rstudio#11535

Maybe you can open one specific to visual editor if none there already.

I spend half an hour trying to solve until I decided to try rendering it to pdf and I got this error message:

Using # in math without escaping in LaTeX is not valid. So this is why you get the error.

Hope it helps understand

[venpopov]

Thanks for the explanation, it does help. My suggestion is to somehow raise an error like it happens when I tried rendering a pdf, so that the user knows what is the problem.