lilVali

A small Python 3.12 validation experiment for playing with PEP 695.

Supports most basic typing constructs including Generics. Also supports dataclasses and classes with annotated __init__ methods.

Install

pip install lilvali

Usage

from lilvali import validate, validator
from lilvali.errors import *

Simple examples

@validate
def add[T: (int, float)](x: int, y: T) -> int | float:
    return x + y


def main():
    print(f"{add(1, 2)=}")
    print(f"{add(1, 2.0)=}")

    try:
        print(f"{add(1.0, 2)=}")
    except ValidationError as e:
        print(f"{e=}")
    else:
        raise RuntimeError("Expected ValidationError")


if __name__ == "__main__":
    main()

@validate
@dataclass
class SomeClass:
    x: int
    y: str = field(default="hello")

    @validator
    def _x(value):
        if value is None or value < 0:
            raise ValidationError

    @validator
    def _y(value) -> bool:
        return value == "hello"


@validate
class NotADC:
    def __init__(self, x: int, y: str):
        self.x = x
        self.y = y

    @validator
    def _x(value):
        if value is None or value < 0:
            raise ValidationError

    @validator
    def _y(value) -> bool:
        return value == "hello"

See the demo folder as well.

Tests

$ ./test.sh
Running tests with coverage
.........................
----------------------------------------------------------------------
Ran 25 tests in 0.006s

OK
Name                           Stmts   Miss  Cover   Missing
------------------------------------------------------------
lilvali/__init__.py                2      0   100%
lilvali/binding.py               167      0   100%
lilvali/errors.py                  6      0   100%
lilvali/validate.py               80      0   100%
tests/test_tiny_validate.py      195      0   100%
tests/test_validate_types.py     124      0   100%
------------------------------------------------------------
TOTAL                            574      0   100%

TODO