crashbytes-result

A practical Result type for Python — Ok, Err, and pattern matching.

Install

pip install crashbytes-result

Usage

from crashbytes_result import Ok, Err, Result, safe

def divide(a: float, b: float) -> Result[float, str]:
    if b == 0:
        return Err("division by zero")
    return Ok(a / b)

result = divide(10, 3)
match result:
    case Ok(value):
        print(f"Result: {value}")
    case Err(error):
        print(f"Error: {error}")

# Or use .match()
msg = result.match(
    ok=lambda v: f"Got {v:.2f}",
    err=lambda e: f"Failed: {e}",
)

# @safe decorator
@safe
def parse_int(s: str) -> int:
    return int(s)

parse_int("42")   # Ok(42)
parse_int("abc")  # Err(ValueError(...))

API

Method	Ok	Err
.unwrap()	Returns value	Raises UnwrapError
.unwrap_or(default)	Returns value	Returns default
.unwrap_err()	Raises UnwrapError	Returns error
.map(fn)	Ok(fn(value))	self
.map_err(fn)	self	Err(fn(error))
.bind(fn)	fn(value)	self
.match(ok, err)	ok(value)	err(error)
.is_ok	True	False
.is_err	False	True

License

MIT