RsPython

**ATTENTION: project superseeded by: ** https://github.com/RustPython/RustPython

Rust implementation of the python language 🐍 😱 🤘.

ATTENTION: project in prototyping phase!

Introduction

This package aims to implement the python 3 language in rust. Current implementations of the python3 language are:

• CPython3 (reference implementation in C)
• PyPy3 (python implemented in python)
• IronPython3 (python implementation in .NET)
• MicroPython (python implementation in C for microcontrollers)
• RsPython (you are reading the readme now)

Use cases for RsPython:

• Compile RsPython to webassembly and run python3 scripts in the browser
• Port python to Redox-os.
• Provide an alternative implementation next to CPython
• Combine rust with python in a more natural way

Usage

$ git clone https://github.com/windelbouwman/rspython
$ cd rspython
$ cat demos/simple.py
print('a=', 2 - 22)
$ cargo run demos/simple.py
a= -20
$ python demos/simple.py
a= -20

To get a whole lot of logging, use:

$ RUST_LOG=trace ./target/debug/rspython demos/simple.py

Planning

• Phase 1: Minimal demo with built in print function and integer variables
• Phase 2: Add function definitions
• Phase 3: Add class definitions

Design

The design follows that of CPython. The code is first parsed into an AST (abstract syntax tree). Then it is compiled into bytecode. This bytecode is then executed by a virtual machine. The virtual machine has access to several built-in python types such as int, tuple, list, set, dict and iter.

Parsing

A handwritten lexer is combined with a LALRPOP generated parser. To deal with indentation, the lexer inserts INDENT and DEDENT tokens at the appropriate points.

Compilation

The AST is transformed in bytecode. The available bytecode operations are loosely based upon the ones in CPython

Ideas / notes

• Instead of compiling to bytecode, the abstract syntax tree can be compiled into rust code and compiled with the language runtime objects. This would give a speedup?
• A compatible bytecode would be beneficial in order to be able to exchange bytecode files between CPython / micropython.