How to access variable from Julia chunk in R

[DominiqueMakowski]

Imagine I have these two chunks:

x = 3

x

How can I access the variables in the Julia workspace? I know the JuliaCall package allows for some inter-operability, but here I don't want to execute a Julia command in R, rather access a variable already created in the Julia workspace. Thanks!

Note: Markdown doesn't render but the first chunk is defined as ```{julia} ... and the second as ```{r} ...

[mcanouil]

See #3792 and mostly #3701 and #4303

[mcanouil]

Closing as a duplicate and in favour of #3701 or #4303

[DominiqueMakowski]

Thanks @mcanouil Unfortunately the proposed solutions don't seem to work:

If I do:

```{julia}
x = 3
```

```{r}
JuliaCall::julia_eval("x")
```

it throws:

Error: Error happens in Julia.
UndefVarError: `x` not defined
Stacktrace:
 [1] top-level scope
   @ :0
 [2] eval
   @ .\boot.jl:370 [inlined]
 [3] eval_string(x::String)
   @ Main.JuliaCall C:\Users\domma\AppData\Local\R\win-library\4.2\JuliaCall\julia\setup.jl:203
 [4] docall(call1::Ptr{Nothing})
   @ Main.JuliaCall C:\Users\domma\AppData\Local\R\win-library\4.2\JuliaCall\julia\setup.jl:176

[mcanouil]

There is no obvious reason for why it's not working in VSCode.
It's CLI, so the IDE does not matter.

Could you share a small "working" (reproducible) example to work with, i.e., a complete Quarto document or a Git repository? Thanks.
Also could you share the results of quarto check?

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
---

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)
```

The end.
````

[DominiqueMakowski]

Interesting, here's a minimal quarto doc:

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

```{julia}
x = 3
```

```{r}
JuliaCall::julia_eval("x")
```

• From RStudio
  • Rendering works ✅
  • Running the chunks from within in the console without rendering works ✅
• From VScode
  • Rendering works ✅

• Running chunks doesn't 🔴

Note that executing the code (CTRL + Enter) runs it in a Julia terminal (1.) and the object then shows in the Julia environment (2.). And running R code happens in the R terminal. Not sure if that's important

[mcanouil]

Yes, because when you run code cells, you are not using kernel/engine.
The extension guess to what terminal the code should be sent.

RStudio is focussed on R, thus everything runs through it.
VSCode is language agnostic, thus Julia goes to Julia, R to R, etc.

In conclusion, everything works as expected.

[DominiqueMakowski]

That's good to know, but is there a way to make it work in VScode? For instance by setting it up in a way that sends Julia code to the R console... assuming that would work

[mcanouil]

Change your keyboard shortcuts to execute the command you want.