Rapidus

A toy JavaScript engine (now aiming for ES5)

Features

• Small
• Partly support for Tracing-JIT compiling
• Simple REPL

Building from Source

Building on Linux

1. Install Rust

Run the command below and follow the onscreen instructions.

curl https://sh.rustup.rs -sSf | sh

2. Use Rust Nightly

rustup override set nightly

3. Install dependencies

• LLVM 6.0
• (Other packages as necessary...)

# e.g. Ubuntu or Debian
apt-get install llvm-6.0

4. Test

cargo test

• If the compilation failed because of LLVM-related errors, the following command may help.

ln -sf /usr/bin/llvm-config-6.0 /usr/bin/llvm-config

5. Build

cargo run --release

6. Run

cargo run --release example/XXX.js

Building on other platforms

I don't know.

• tips: If you are using macOS, you cannot use llvm installed with brew. You should use macports or docker instead. Now it works!

Use DLLs written in Rust

THIS FEATURE IS EXPERIMENTAL

1. Make a cargo project in the directory rapidus' directory is located

$ cargo new hello --lib
$ ls
rapidus hello

2. Edit Cargo.toml

$ cd hello
$ <YOUR EDITOR> Cargo.toml

# Add the followings to Cargo.toml

[dependencies]
rapidus = { path = "../rapidus" }
# other dependencies if you want...

[lib]
name = "hello"
crate_type = ["cdylib"] # try 'dylib' if it doesn't work.

3. Edit src/lib.rs

$ <YOUR EDITOR> src/lib.rs

// src/lib.rs

#[macro_use]
extern crate rapidus;
use rapidus::{
   gc,
   vm::{callobj::CallObject, error::RuntimeError, value::*, vm::VM},
};

#[no_mangle]
fn initialize(vm: &mut VM, _: &Vec<Value>, _: &CallObject) -> Result<(), RuntimeError> {
    // make_object!() is useful
    let module_exports = make_object!(
        greet:   Value::default_builtin_function(greet),
        message: Value::string("hello".to_string())
    );

    vm.set_return_value(module_exports); // We have to return module.exports

    Ok(())
}

#[no_mangle]
fn greet(vm: &mut VM, _: &Vec<Value>, _: &CallObject) -> Result<(), RuntimeError> {
    println!("Hello World from Rust DLL!");

    vm.set_return_value(Value::undefined()); // Remember to return a value you want

    Ok(())
}

4. Let's build

$ cargo build # --release as necessary

5. Copy the generated DLL to rapidus' directory

$ cp ./target/debug/libhello.(so|dll|dylib) ../rapidus
$ cd ../rapidus
$ ls
libhello.(so|dll|dylib) etc...

6. You're ready to use it from rapidus. Let's try from REPL.

$ cargo run
> var mod = require('hello')
> mod.greet()
Hello World from Rust DLL!
> mod.message
'hello'

7. Now everything can be possible from Rust!

Use Dockerfile

• Docker image: uint256/rapidus

$ docker build -t rapidus:0.1.1 .
$ docker run -it rapidus:0.1.1