Emacs Module in Rust

User Guide | Examples

This provides a high-level binding to emacs-module, Emacs's support for dynamic modules.

Code for a minimal module looks like this:

use emacs::{defun, Env, Result, Value};

emacs::plugin_is_GPL_compatible!();

#[emacs::module(name = "greeting")]
fn init(_: &Env) -> Result<()> { Ok(()) }

#[defun]
fn say_hello(env: &Env, name: String) -> Result<Value<'_>> {
    env.message(&format!("Hello, {}!", name))
}

(require 'greeting)
(greeting-say-hello "Emacs")

Live Reloading

Emacs does not support unloading modules. Live reloading thus requires a custom module loader. rs-module is one such loader (which itself is a module that must be loaded by Emacs's normal loading mechanism). See load.sh.

Note: This doesn't work on macOS 10.13+ (High Sierra and up). See Rust's issue #28794.

Sample Modules

• test-module.
• emacs-rs-examples.
• magit-libgit2 is an experimental attempt to speed up magit using libgit2.

Development

• Building:

  cargo build --all
  

• Testing:

  bin/test.sh
  

• Continuous testing (requires cargo-watch):

  cargo watch -x 'build --all' -s bin/test.sh