chumicro-compat-experimental 0.3.0

Cross-runtime compatibility polyfills for CircuitPython, MicroPython, and CPython — functools.partial and more.

chumicro-compat

Stdlib polyfills for the bits CircuitPython and MicroPython skipped.

Import from chumicro_compat instead of the stdlib and your code works everywhere. CPython gets the real C implementation (zero overhead); CircuitPython and MicroPython get a lightweight pure-Python version of the same public API.

Part of the ChuMicro family — small, focused Python libraries for microcontrollers and laptops. Browse all libraries.

Install

# CircuitPython (after `circup bundle-add ChuMicro/ChuMicro-Bundle`)
circup install chumicro-compat

# MicroPython
mpremote mip install github:ChuMicro/ChuMicro-Bundle/chumicro_compat

# CPython
pip install chumicro-compat

For bundle setup, pre-compiled .mpy bundles, the experimental channel, and details on PyPI naming, see the chumicro INSTALL guide.

Quick example

from chumicro_compat.functools import partial

def set_led(pin: int, brightness: int) -> None:
    """Set an LED pin to a brightness level."""
    print(f"pin {pin} → {brightness}%")

# Freeze the pin, vary the brightness later.
set_status_led = partial(set_led, 13)
set_status_led(50)   # pin 13 → 50%
set_status_led(100)  # pin 13 → 100%

What's included

functools

Symbol	Description
partial(func, *args, **keywords)	Freeze positional and keyword arguments to a callable
partial.func	The original wrapped callable
partial.args	Frozen positional arguments (tuple)
partial.keywords	Frozen keyword arguments (dict)

Platform support

Runtime	What happens
CPython	Uses the built-in functools.partial directly — zero overhead
MicroPython	Lightweight pure-Python replacement
CircuitPython	Lightweight pure-Python replacement

The public API (.func, .args, .keywords, __call__, __repr__) is identical across all runtimes.

Where this fits

Leaf — no upstream ChuMicro deps. Used directly by any library or app that wants stdlib features (functools.partial, …) missing from CircuitPython / MicroPython.

Examples

Example	What it shows
partial_basic.py	Freeze one argument to a function
partial_keyword_override.py	Freeze keyword args, override at call time
partial_callback.py	Wire a callback with frozen context (embedded pattern)

Contributing

Working on chumicro-compat itself? Clone the mono-repo if you haven't already — the rest of the workflow assumes you're inside that workspace.

pip install -e .[test]
pytest tests/                  # host-side tests
pytest functional_tests/       # on-device tests (needs a board registered in devices.yml)

Register a board before running functional tests: chumicro-workspace add-device <id> --address <port>.

Docs

📖 Stable docs · Experimental docs

Find this library

• PyPI: chumicro-compat
• Bundle: ChuMicro-Bundle (CircuitPython & MicroPython)
• Experimental bundle: ChuMicro-Bundle-Experimental
• Source: libraries/compat

License

MIT