RustPython

A Python-3 (CPython >= 3.5.0) Interpreter written in Rust 🐍 😱 🤘.

Usage

To test RustPython, do the following:

$ git clone https://github.com/RustPython/RustPython
$ cd RustPython
$ cargo run demo.py
Hello, RustPython!

Or use the interactive shell:

$ cargo run
Welcome to rustpython
>>>>> 2+2
4

Goals

• Full Python-3 environment entirely in Rust (not CPython bindings)
• A clean implementation without compatibility hacks

Documentation

Currently the project is in an early phase, and so is the documentation.

You can read the online documentation for the latest code on master.

You can also generate documentation locally by running:

$ cargo doc # Including documentation for all dependencies
$ cargo doc --no-deps --all # Excluding all dependencies

Documentation HTML files can then be found in the target/doc directory.

Code organization

• parser/src: python lexing, parsing and ast
• vm/src: python virtual machine
  • builtins.rs: Builtin functions
  • compile.rs: the python compiler from ast to bytecode
  • obj: python builtin types
• src: using the other subcrates to bring rustpython to life.
• docs: documentation (work in progress)
• py_code_object: CPython bytecode to rustpython bytecode convertor (work in progress)
• wasm: Binary crate and resources for WebAssembly build
• tests: integration test snippets

Contributing

To start contributing, there are a lot of things that need to be done.

Most tasks are listed in the issue tracker. Check issues labeled with good first issue if you wish to start coding.

Another approach is to checkout the sourcecode: builtin functions and object methods are often the simplest and easiest way to contribute.

You can also simply run cargo run tests/snippets/whats_left_to_implement.py to assist in finding any unimplemented method.

Testing

To test rustpython, there is a collection of python snippets located in the tests/snippets directory. To run those tests do the following:

$ cd tests
$ pipenv shell
$ pytest -v

There also are some unittests, you can run those will cargo:

$ cargo test --all

Using another standard library

As of now the standard library is under construction.

You can play around with other standard libraries for python. For example, the ouroboros library.

To do this, follow this method:

$ cd ~/GIT
$ git clone [email protected]:pybee/ouroboros.git
$ export PYTHONPATH=~/GIT/ouroboros/ouroboros
$ cd RustPython
$ cargo run -- -c 'import statistics'

Compiling to WebAssembly

At this stage RustPython only has preliminary support for web assembly. The instructions here are intended for developers or those wishing to run a toy example.

Setup

To get started, install wasm-bindgen and wasm-pack. You will also need to have npm installed.

Build

Move into the wasm directory. This contains a custom library crate optimized for wasm build of RustPython.

cd wasm

From here run the build. This can take several minutes depending on the machine.

wasm-pack build

Upon successful build, cd in the the /pkg directory and run:

npm link

Now move back out into the /app directory. The files here have been adapted from wasm-pack-template.

Finally, run:

npm install
npm link rustpython_wasm

and you will be able to run the files with:

node_modules/.bin/webpack-dev-server

Open a browser console and see the output of rustpython_wasm. To verify this, modify the line in app/index.js

rp.run_code("print('Hello Python!')\n");

To the following:

rp.run_code("assert(False)\n");

and you should observe: Execution failed in your console output, indicating that the execution of RustPython has failed.

Code style

The code style used is the default rustfmt codestyle. Please format your code accordingly.

Community

Chat with us on gitter.

Credit

The initial work was based on windelbouwman/rspython and shinglyu/RustPython

Links

These are some useful links to related projects:

• https://github.com/ProgVal/pythonvm-rust
• https://github.com/shinglyu/RustPython
• https://github.com/windelbouwman/rspython