56269f704a
* Align LOAD_FAST_BORROW analysis with CPython chain shape Three changes that bring optimize_load_fast_borrow closer to CPython's optimize_load_fast in flowgraph.c: * ir.rs: split mark_cold into the CPython-style two passes. Phase 1 propagates "warm" from the entry block, phase 2 propagates "cold" from except_handler blocks. Blocks reached by neither phase keep cold=false and stay in their original b_next position, matching CPython's handling of empty placeholders left by remove_unreachable (e.g. the inner_end of a nested try/except whose incoming jumps were re-routed by optimize_cfg). * ir.rs: in optimize_load_fast_borrow, push the fall-through successor only when the current block has a last instruction (is_some_and). Empty blocks now terminate fall-through propagation, matching the `term != NULL` check in optimize_load_fast. * compile.rs: add switch_to_new_or_reuse_empty() helper and use it in compile_while. The helper reuses the current block when it is empty and unlinked, mirroring USE_LABEL absorption in cfg_builder_maybe_start_new_block. This stops a stray empty block from appearing between e.g. a try/except end_block and the following while loop header. Four codegen tests that depended on the previous fall-through-through- empty behavior are marked #[ignore] with TODO comments. Also includes a handful of dictionary entries in .cspell.dict picked up during the work. * Interleave const fold passes per-block to match CPython Mirror CPython's optimize_basic_block() (flowgraph.c) by walking each block once in instruction order and trying tuple, list, set, unary, and binop folding at each position before advancing. This replaces the previous global-pass sequence where every fold_unary_constants pattern in the whole CFG was registered before any tuple constant, leaving negated literals like `-1` at co_consts positions earlier than CPython produces (e.g. snippets.py: -1 at idx 280 vs CPython idx 726). Changes: - Extract `fold_unary_constant_at` and `fold_binop_constant_at` per- position helpers from the existing global passes; the global passes now call the helpers in a loop. - Add `fold_constants_per_block` that walks each block to a fixed point, trying all five folds at each instruction position. - Call the new walker before the legacy global passes in optimize_finalize so co_consts insertion order matches CPython's. Measured on the full Lib tree: differing files 270 → 269; the only newly matching file is `test/test_ast/snippets.py`, the case raised in youknowone/RustPython#28. * Inline small fast-return blocks only through unconditional jumps `inline_small_fast_return_blocks` previously appended the target `LOAD_FAST(_BORROW)/RETURN_VALUE` block's instructions onto any predecessor whose fall-through eventually reached it, in addition to the unconditional-jump case CPython handles in `inline_small_or_no_lineno_blocks` (flowgraph.c:1210). CPython only inlines through unconditional jumps, leaving fall-through predecessors to reach the shared return block via the natural CFG layout. The extra fall-through branch duplicated the return tail (e.g. `if/elif/return` emitted two adjacent `LOAD_FAST_BORROW x; RETURN_VALUE` sequences). Remove the fall-through inlining branch and keep only the unconditional-jump path. Measured on the full Lib tree: differing files 270 → 239 (-31), no new regressions. Files newly matching include copy.py, argparse.py, dataclasses.py, logging/__init__.py, pathlib/__init__.py, etc. * Allow scope-exit/jump-back reorder within a shared except handler `reorder_conditional_scope_exit_and_jump_back_blocks` previously skipped any reorder where the conditional, scope-exit, or jump-back block had an `except_handler` attached, even when all three shared the same handler. CPython reorders these regardless of try/except context, as long as the blocks stay within the same protected region. The over- conservative guard left patterns like `try: for: if cond: return` with the loop body's scope-exit ahead of the backedge, while CPython places the backedge first and inverts the conditional. Replace the `block_is_protected` triple-check with a single `mismatched_protection` test: skip only when the three blocks do not share the same `except_handler`. Same-handler reorders preserve the protected range because every instruction's `except_handler` field stays attached as `.next` pointers shift. Measured on the full Lib tree: differing files 239 → 237; no new regressions. * Skip jump-over-cleanup reorder when target restarts an exception scope reorder_jump_over_exception_cleanup_blocks was swapping a small scope-exit target with a preceding cold cleanup chain even when the target block began a fresh try (SETUP_FINALLY/SETUP_CLEANUP/SETUP_WITH). The swap moved the next try's setup ahead of the prior handler's cleanup_end/next_handler/cleanup_block, making the cleanup_body's JUMP_FORWARD fall through directly to the cleanup_end and get elided as redundant. The bytecode then lacked the JUMP_FORWARD that skips the cleanup blocks and matched the prior handler's borrow tail incorrectly. Skip the reorder when the target block contains any block-push pseudo op so a new try's setup stays in source order. Re-enables the four named/typed except-cleanup borrow tests that were marked #[ignore] in commit 7481459ea. * fix if block_idx == BlockIdx::NULL
RustPython
A Python-3 (CPython >= 3.14.0) Interpreter written in Rust 🐍 😱 🤘.
Usage
Check out our online demo running on WebAssembly.
RustPython requires Rust latest stable version (e.g 1.67.1 at February 7th 2023). If you don't currently have Rust installed on your system you can do so by following the instructions at rustup.rs.
To check the version of Rust you're currently running, use rustc --version. If you wish to update,
rustup update stable will update your Rust installation to the most recent stable release.
To build RustPython locally, first, clone the source code:
git clone https://github.com/RustPython/RustPython
RustPython uses symlinks to manage python libraries in Lib/. If on windows, running the following helps:
git config core.symlinks true
Then you can change into the RustPython directory and run the demo (Note: --release is
needed to prevent stack overflow on Windows):
$ cd RustPython
$ cargo run --release demo_closures.py
Hello, RustPython!
Or use the interactive shell:
$ cargo run --release
Welcome to rustpython
>>>>> 2+2
4
NOTE: For windows users, please set RUSTPYTHONPATH environment variable as Lib path in project directory.
(e.g. When RustPython directory is C:\RustPython, set RUSTPYTHONPATH as C:\RustPython\Lib)
You can also install and run RustPython with the following:
$ cargo install --git https://github.com/RustPython/RustPython rustpython
$ rustpython
Welcome to the magnificent Rust Python interpreter
>>>>>
venv
Because RustPython currently doesn't provide a well-packaged installation, using venv helps to use pip easier.
$ rustpython -m venv <your_env_name>
$ . <your_env_name>/bin/activate
$ python # now `python` is the alias of the RustPython for the new env
PIP
If you'd like to make https requests, you can enable the ssl feature, which
also lets you install the pip package manager. Note that on Windows, you may
need to install OpenSSL, or you can enable the ssl-vendor feature instead,
which compiles OpenSSL for you but requires a C compiler, perl, and make.
OpenSSL version 3 is expected and tested in CI. Older versions may not work.
Once you've installed rustpython with SSL support, you can install pip by running:
cargo install --git https://github.com/RustPython/RustPython
rustpython --install-pip
You can also install RustPython through the conda package manager, though
this isn't officially supported and may be out of date:
conda install rustpython -c conda-forge
rustpython
SSL provider
For HTTPS requests, ssl-rustls feature is enabled by default. You can replace it with ssl-openssl feature if your environment requires OpenSSL.
Note that to use OpenSSL on Windows, you may need to install OpenSSL, or you can enable the ssl-vendor feature instead,
which compiles OpenSSL for you but requires a C compiler, perl, and make.
OpenSSL version 3 is expected and tested in CI. Older versions may not work.
WASI
You can compile RustPython to a standalone WebAssembly WASI module so it can run anywhere.
Build
cargo build --target wasm32-wasip1 --no-default-features --features freeze-stdlib,stdlib --release
Run by wasmer
wasmer run --dir `pwd` -- target/wasm32-wasip1/release/rustpython.wasm `pwd`/extra_tests/snippets/stdlib_random.py
Run by wapm
$ wapm install rustpython
$ wapm run rustpython
>>>>> 2+2
4
Building the WASI file
You can build the WebAssembly WASI file with:
cargo build --release --target wasm32-wasip1 --features="freeze-stdlib"
Note: we use the
freeze-stdlibto include the standard library inside the binary. You also have to run oncerustup target add wasm32-wasip1.
JIT (Just in time) compiler
RustPython has a very experimental JIT compiler that compile python functions into native code.
Building
By default the JIT compiler isn't enabled, it's enabled with the jit cargo feature.
cargo run --features jit
This requires autoconf, automake, libtool, and clang to be installed.
Using
To compile a function, call __jit__() on it.
def foo():
a = 5
return 10 + a
foo.__jit__() # this will compile foo to native code and subsequent calls will execute that native code
assert foo() == 15
Embedding RustPython into your Rust Applications
Interested in exposing Python scripting in an application written in Rust,
perhaps to allow quickly tweaking logic where Rust's compile times would be inhibitive?
Then examples/hello_embed.rs and examples/mini_repl.rs may be of some assistance.
Disclaimer
RustPython is in development, and while the interpreter certainly can be used in interesting use cases like running Python in WASM and embedding into a Rust project, do note that RustPython is not totally production-ready.
Contribution is more than welcome! See our contribution section for more information on this.
Conference videos
Checkout those talks on conferences:
Use cases
Although RustPython is a fairly young project, a few people have used it to make cool projects:
- GreptimeDB: an open-source, cloud-native, distributed time-series database. Using RustPython for embedded scripting.
- pyckitup: a game engine written in rust.
- Robot Rumble: an arena-based AI competition platform
- Ruff: an extremely fast Python linter, written in Rust
Goals
- Full Python-3 environment entirely in Rust (not CPython bindings)
- A clean implementation without compatibility hacks
Documentation
Currently along with other areas of the project, documentation is still in an early phase.
You can read the online documentation for the latest release, or the user guide.
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 or you can append --open to the previous commands to
have the documentation open automatically on your default browser.
For a high level overview of the components, see the architecture document.
Contributing
Contributions are more than welcome, and in many cases we are happy to guide contributors through PRs or on Discord. Please refer to the development guide as well for tips on developments.
With that in mind, please note this project is maintained by volunteers, some of the best ways to get started are below:
Most tasks are listed in the issue tracker. Check issues labeled with good first issue if you wish to start coding.
To enhance CPython compatibility, try to increase unittest coverage by checking this article: How to contribute to RustPython by CPython unittest
Another approach is to checkout the source code: builtin functions and object methods are often the simplest and easiest way to contribute.
You can also simply run python -I scripts/whats_left.py to assist in finding any unimplemented
method.
Compiling to WebAssembly
Community
Chat with us on Discord.
Code of conduct
Our code of conduct can be found here.
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
License
This project is licensed under the MIT license. Please see the LICENSE file for more details.
The project logo is licensed under the CC-BY-4.0 license. Please see the LICENSE-logo file for more details.