Engine options for Quarto

[jleclai2]

Description

I have a question about the engine options for Quarto. When I create a new quarto document, the options for engine are 'knitr', 'jupyter', and 'none'. I understand that if I'm using R I should use knitr, and jupyter when using python, but what is the none option for? Thank you!

[mcanouil]

When you don't want code cell to be evaluated at all, i.e., no engine is started at all.

[jleclai2]

Thanks for your help. Sorry, can you please clarify? When I make a dummy .qmd file, and select engine = none, and add an R code chunk with the expression 1+1, it is evaluated and presents 2. Can you please explain? Thanks!

[mcanouil]

See @cderv's comment, I did not realise it was not a valid option.

By the way, I looked at the codebase and julia is not suggested as well as markdown.

• https://github.com/quarto-dev/quarto-cli/blob/7a0131d23e5525629de83959cd2d585f28603a92/src/resources/editor/tools/yaml/web-worker.js#L13877-L13889

---
title: "Quarto Playground"
format: html
engine: markdown
---

```{r}
1 + 1
```

Won't have code cell executed.

[cderv]

Where do you see this none exactly ?

Here is our doc about engine binding if you want to know how it works
https://quarto.org/docs/computations/execution-options.html#engine-binding

[jleclai2]

Thanks for your help -

File -> New Quarto Document -> Engine (options in drop down menu include Knitr, Jupyter, and None).

When would we select "none"? I am still able to get R code to execute when I select engine = none setting up my qmd file.

[mcanouil]

File -> New Quarto Document -> Engine (options in drop down menu include Knitr, Jupyter, and None).

Where is that? Rstudio, VSCode, Positron? I am assuming the first, but not entirely sure.
The editor interface is independent of Quarto CLI. The integration is done by the editor (RStudio, etc.)

[jleclai2]

Sorry I should've clarified, RStudio!

[cderv]

In Rstudio IDE context, (None) means do not set anything in the YAML header. Then the default Engine binding behavior from Quarto applies. Which is described in the link I shared above.

When I make a dummy .qmd file, and select engine = none, and add an R code chunk with the expression 1+1, it is evaluated and presents 2. Can you please explain?

Reading this part of the doc should anwser your question. If you have a R cells in a document, then quarto automatically bind to the knitr engine if nothing else is specified.

[mcanouil]

So "None" is for "don't set an engine" while the other values are for "set the engine to XXX".
A bit confusing in my opinion.

[jleclai2]

Got it thank you both!

[cderv]

So "None" is for "don't set an engine" while the other values are for "set the engine to XXX".
A bit confusing in my opinion.

Feel free to give feedback to IDE team and suggest another name for it: https://github.com/rstudio/rstudio