pyderive

pyderive provides derive macros for Python spacial methods and a class attributes for PyO3.

// Enable `multiple-pymethods` feature of PyO3
use pyo3::prelude::*;
use pyderive::*;

// Place #[derive(PyNew, ...)] before #[pyclass]
#[derive(PyNew, PyMatchArgs, PyRepr, PyEq)]
#[pyclass(get_all)]
#[derive(PartialEq, Hash)]
struct MyClass {
    string: String,
    integer: i64,
    option: Option<String>
}

from rust_module import MyClass

# Derives __new__()
m = MyClass("a", 1, None)

# Derives __match_args__ (supports Pattern Matching by positional arguments)
match m:
    case MyClass(a, b, c):
        assert a == "a"
        assert b == 1
        assert c is None
    case _:
        raise AssertionError

# Derives __repr__(), calls Python repr() recursively
assert str(m) == "MyClass(string='a', integer=1, option=None)"
assert repr(m) == "MyClass(string='a', integer=1, option=None)"

# Derives __eq__() that depends on PartialEq trait
assert m == MyClass("a", 1, None)

This provides deriving following special methods and attributes;

Derive Macro	Python Method/Attribute
PyNew	__new__()
PyMatchArgs	__match_args__
PyRepr	__repr__()
PyStr	__str__()
PyEq	__eq__() and __ne__()
PyOrd	__lt__(), __le__(), __gt__() and __ge__()
PyRichCmp	==, !=, >, >=, < and <= by __richcmp__()
PyIter	__iter__()
PyReversed	__reversed__()
PyLen	__len__()
PyDataclassFields	__dataclass_fields__
PyNumeric	Numeric op methods (__add__() etc.)
PyBitwise	Bitwise op methods (__and__() etc.)

The field attributes #[pyderive(..)] is used to customize the implementation, like dataclasses.field() of Python.

Module pyderive::ops and pyderive::convert provides derive macros that implement individual method that enumerating numeric type (__add__() etc.) and called by builtin functions (__int__() etc.).

It requires to enable multiple-pymethods feature of PyO3 because this may produce multiple #[pymethods].

It experimentally provides the derive macors implement methods that the namedtuple() generates

Derive Macro	Python Method/Attribute
PyNamedTupleAsdict	_asdict()
PyNamedTupleFieldDefaults	_field_defaults
PyNamedTupleFields	_fields
PyNamedTupleMake	_make()
PyNamedTupleReplace	_replace()

Feature

PyRepr and PyStr

The methods implemented by PyRepr and PyStr are recursively calls repr() or str() like a Python dataclass.

PyEq and PyOrd

The implementation of PyEq and PyOrd does not use __richcmp__().

License

MIT or Apache-2.0