Result

The Result class indicates the success/failure of validation.

from exacting import Result

# Success
Result.Ok("some value")

# Error
Result.Err(
    "You bad",
    "literally"
)

Is OK?

This checks if the validation result is OK.

if some_result.is_ok():
    ... # good!
else:
    ... # bad!

Raising

Result can help you raise a ValidationError if errors are present.

some_result.raise_for_err()

Unwrapping

You can get the data that got through the validation by unwrapping, or the error messages.

ok = Result.Ok(-123)
print(ok.unwrap())  # -123

err = Result.Err("be be nos")
print(err.unwrap_err())  # deque(['be be nos'])

Trace

You can trace errors down using the trace() function, making previous errors appear indented.

base_err = Result.Err("Gustavo Fring")

(
    base_err
        .trace("Woah, there's a gustavo down here")
        .trace("Breaking bad!")
        .raise_for_err()
)

ValidationError: Breaking bad!

ValidationError: 
Breaking bad!
  • Woah, there's a gustavo down here
    • Gustavo Fring

Trace below

Make other errors appear indented below your message.

error1 = Result.Err("ooga", "booga")
error2 = Result.trace_below(
    "Check these out:",
    *error1.unwrap_err()
)

error2.raise_for_err()

ValidationError: Check these out:

ValidationError: 
Check these out:
  • ooga
  • booga