sain 0.0.2

Standard Rust core types implementations for Python.

sain

A pure Python package that implements standard Rust core types for Python.

Install

You'll need Python 3.8 or higher.

Still not on PyPI

$ pip install git+https://github.com/nxtlo/sain

Example

import sain

#[cfg_attr(target_os = unix)]
@sain.cfg_attr(target_os="unix")
def run_when_unix() -> None:
    import uvloop
    uvloop.install()

# If this returns True, get_token will run, otherwise returns.
if sain.cfg(requires_modules=("dotenv", ...), python_version=(3, 9, 6)):
    # Stright up replace typing.Optional[str]
    def get_token() -> sain.Option[str]:
        import dotenv
        return sain.Some(dotenv.get_key(".env", "SECRET_TOKEN"))

# Raises RuntimeError("No token found.") if T is None.
token: int = get_token().expect("No token found.")

# Unwrap the value, Returning DEFAULT_TOKEN if it was None.
env_or_default: str = get_token().unwrap_or("DEFAULT_TOKEN")

# type hint is fine.
as_none: sain.Option[str] = sain.Some(None)
assert as_none.is_none()

Defaults

A protocol that types can implement which have a default value.

import sain

class DefaultCache(sain.Default[dict[str, int]]):
    # One staticmethod must be implemented and must return the same type.
    @staticmethod
    def default() -> dict[str, int]:
        return {}

Iter

Turns normal iterables into Iter type.

import sain

f = sain.Iter([1,2,3])
# or f = sain.into_iter([1,2,3])
assert 1 in f

for item in f.take_while(lambda i: i > 1):
    print(item)

Why

i like Rust coding style :p

Notes

Since Rust is a compiled language, Whatever predict returns False will not compile.

But there's no such thing as this in Python, So RuntimeError will be raised and whatever was predicated will not run.