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RacketScript

RacketScript is an experimental lightweight Racket to JavaScript (ECMAScript 6) compiler. RacketScript aims to leverage both JavaScript and Racket's ecosystem, and make interoperability between them clean and smooth.

RacketScript takes in Racket source files, uses Racket's macro expander to produce Fully Expanded Programs, and then compile these fully expanded programs to JavaScript. RacketScript currently supports only a subset of Racket.

Try RacketScript

You can try RacketScript in your browser at RacketScript Playground.

Disclaimer

RacketScript is work-in-progress and is not mature and stable. Several Racket features and libraries are not yet implemented (eg. number pyramid, contracts, proper tail calls, continuations). There are also quite a few missing primitive functions. That said, we encourage experimentation, user feedback, discussions, bug reports and pull requests.

Installation

Following system packages are required:

Racket 6.12 or higher
NodeJS (14.0 or higher) and NPM
Make

Quick Install

RacketScript can be installed using the Racket package manager raco:

raco pkg install racketscript

See Basic Usage to get started.

Install from Github

# Clone RacketScript
git clone git@github.com:racketscript/racketscript.git`
cd racketscript

# Build and install
make setup

If you do not wish to pollute your root NPM directory, you can set a custom global location by changing your npmrc (eg. echo "prefix = $HOME/.npm-packages" >> ~/.npmrc. Then add /prefix/path/above/bin to your PATH.

Basic Usage

RacketScript compiler is named racks.

racks -h # show help

To compile a Racket source file:

# Installs all NPM dependencies and compile file.rkt
racks /path/to/file.rkt

The above command will create a output build directory named js-build, copy RacketScript runtime, copy other support files, install NPM dependencies, compile file.rkt and its dependencies.

The compiled JavaScript modules typically goto one of following three folders:

"modules": The normal Racket files.
"collects": Racket collects source files.
"links": Other third party packages.
"dist": Contains sources compiled to ES6 or bundled JavaScript ready for distribution.

Here are few other examples that would come in handy:

# To skip `npm install` step. Useful when building
# for second time.
racks -n /path/to/module-name.rkt

# Run the assembled JavaScript module.
node js-build/modules/module-name.rkt.js

# Use `-b` to format the assembled JavaScript code use `-b`. Assumes
# `js-beautify` is available in `$PATH`.
racks -b /path/to/module-name.rkt

# Override default output directory
racks -d /path/to/output/dir /path/to/module-name.rkt

# Print JavaScript output to stdout
racks --js --js-beautify /path/to/module-name.rkt

By default tail call optimization is turned off. To enable translation of self recursive tail calls to loop, pass --enable-self-tail flag.

racks --enable-self-tail /path/to/source.rkt

Browser

Most browsers can load RacketScript modules directly without any external dependencies <script type="module" src="path/to/module.rkt.js"></script>.

Module Bundler (Webpack)

For deployment, you may want to bundle all generated modules into single JavaScript file. RacketScript can generate some boiler-plate for using Webpack/Babel, however we recommend you to use your own configuration.

# Use `--target` or `-t` flag.
racks --target webpack /path/to/source.rkt

# Call webpack to bundle in `js-build` directory. Will produce
# single JavaScript bundle in `js-build/dist` directory.
npx webpack