rust_source: Compile Rust code and call from R

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Compile Rust code and call from R

Description

rust_source() compiles and loads a single Rust file for use in R. rust_function() compiles and loads a single Rust function for use in R. extendr_options() is a helper function to make it easier to pass additional options when sourcing Rust code. It also proivdes defaults for each option and does additional type checking.

Usage

rust_source(
  file = NULL,
  code = NULL,
  env = parent.frame(),
  echo = FALSE,
  quiet = FALSE,
  opts = NULL,
  ...
)

rust_function(
  code,
  extendr_fn_options = NULL,
  env = parent.frame(),
  echo = FALSE,
  quiet = FALSE,
  opts = NULL,
  ...
)

extendr_options(
  cache_build = TRUE,
  dependencies = NULL,
  extendr_deps = NULL,
  features = NULL,
  generate_module_macro = TRUE,
  module_name = "rextendr",
  patch.crates_io = getOption("rextendr.patch.crates_io"),
  profile = c("dev", "release", "perf"),
  toolchain = getOption("rextendr.toolchain"),
  use_dev_extendr = FALSE,
  use_extendr_api = TRUE,
  use_rtools = TRUE
)

## S3 method for class 'extendr_opts'
print(x, ...)

Arguments

file	character scalar, input rust file to source.
code	character scalar, input rust code to be used instead of file.
env	environment, the R environment in which the wrapping functions will be defined. Default is parent.frame().
echo	logical scalar, whether to print standard output and errors of cargo commands to the console. Default is FALSE.
quiet	logical scalar, whether to print cli errors and warnings. Default is FALSE.
opts	extendr_opts list, set using extendr_options(). Default is NULL.
...	user supplied extendr options to be injected into the extendr_opts list (for backwards compatibility).
extendr_fn_options	A list of extendr function options that are inserted into the ⁠#[extendr(...)]⁠ attribute
cache_build	logical scalar, whether builds should be cached between calls to rust_source().
dependencies	character vector, dependencies to be added to Cargo.toml.
extendr_deps	named list, versions of ⁠extendr-*⁠ crates. Defaults to rextendr.extendr_deps option (list(`extendr-api` = "*")) if use_dev_extendr is not TRUE, otherwise, uses rextendr.extendr_dev_deps option (list(`extendr-api` = list(git = "https://github.com/extendr/extendr")).
features	character vector, extendr-api features that should be enabled. Supported values are "ndarray", "faer", "either", "num-complex", "serde", and "graphics". Unknown features will produce a warning if quiet is not TRUE.
generate_module_macro	logical scalar, whether the Rust module macro should be automatically generated from the code. Default is TRUE. Ignored for Rust source provided via file. The macro generation is done with make_module_macro() and it may fail in complex cases. If something doesn't work, try calling make_module_macro() on your code to see whether the generated macro code has issues.
module_name	character scalar, name of the module defined in the Rust source via ⁠extendr_module!⁠. Default is "rextendr". If generate_module_macro is FALSE or if file is specified, should match exactly the name of the module defined in the source.
patch.crates_io	character vector, patch statements for crates.io to be added to Cargo.toml.
profile	character scalar, Rust profile. Can be either "dev", "release" or "perf". The default, "dev", compiles faster but produces slower code.
toolchain	character scalar, Rust toolchain. The default, NULL, compiles with the system default toolchain. Accepts valid Rust toolchain qualifiers, such as "nightly", or (on Windows) "stable-msvc".
use_dev_extendr	logical scalar, whether to use development version of extendr. Has no effect if extendr_deps are set.
use_extendr_api	logical scalar, whether ⁠use extendr_api::prelude::*;⁠ should be added at the top of the Rust source provided via code. Default is TRUE. Ignored for Rust source provided via file.
use_rtools	logical scalar, whether to append the path to Rtools to the PATH variable on Windows using the RTOOLS4X_HOME environment variable (if it is set). The appended path depends on the process architecture. Does nothing on other platforms.
x	an extendr_opts list

Value

For rust_source() and rust_function(), the result from dyn.load(), which is an object of class DLLInfo. See getLoadedDLLs() for more details. For extendr_options(), an extendr_opts list.

Examples

## Not run: 
# creating a single rust function
rust_function("fn add(a:f64, b:f64) -> f64 { a + b }")
add(2.5, 4.7)

# creating multiple rust functions at once
code <- r"(
#[extendr]
fn hello() -> &'static str {
    "Hello, world!"
}

#[extendr]
fn test( a: &str, b: i64) {
    rprintln!("Data sent to Rust: {}, {}", a, b);
}
)"

rust_source(code = code)
hello()
test("a string", 42)

# use case with an external dependency: a function that converts
# markdown text to html, using the `pulldown_cmark` crate.
code <- r"(
  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
  }
)"

rust_source(
  code = code,
  opts = extendr_options(
    dependencies = list(`pulldown-cmark` = "0.8")
  )
)

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)

# see default options
extendr_options()

## End(Not run)

rextendr documentation built on April 18, 2026, 5:07 p.m.