In rextendr: Call Rust Code from R using the 'extendr' Crate

knitr::opts_chunk$set(
  message = FALSE,
  collapse = TRUE,
  comment = "#>"
)

Basic use example:

library(rextendr)

# create a Rust function
rust_function("fn add(a:f64, b:f64) -> f64 { a + b }")

# call it from R
add(2.5, 4.7)

The package also enables a new chunk type for knitr, extendr, which compiles and evaluates Rust code. For example, a code chunk such as this one:

`r ''````{extendr}
rprintln!("Hello from Rust!");

let x = 5;
let y = 7;
let z = x*y;

z
```

would create the following output in the knitted document:

rprintln!("Hello from Rust!");

let x = 5;
let y = 7;
let z = x*y;

z

Define variable _x:

```{extendr chunk_x, eval = FALSE} let _x = 1;

Define variable `_y`:

```{extendr chunk_y, eval = FALSE}
let _y = 2;

Print:

```{extendr out, preamble = c("chunk_x", "chunk_y")} rprintln!("x = {}, y = {}", _x, _y);

```{extendrsrc engine.opts = list(dependencies = list(`pulldown-cmark` = "0.8"))}
use pulldown_cmark::{Parser, Options, html};

#[extendr]
fn md_to_html(input: &str) -> String {
    let mut options = Options::empty();
    options.insert(Options::ENABLE_TABLES);
    let parser = Parser::new_ext(input, options);
    let mut output = String::new();
    html::push_html(&mut output, parser);
    output
}

md_text <- "# The story of the fox
The quick brown fox **jumps over** the lazy dog.
The quick *brown fox* jumps over the lazy dog."

md_to_html(md_text)