Usage

When creating an Option with labrea, specify the expected type using either of the following syntaxes:

from labrea import Option

X = Option("X", type=int)
Y = Option[int]("Y")

Either literal types or type hints can be used, such as List[int] or Union[str, List[str]].

To enable type validation, simply import labrea_type_validation and call the enable function:

import labrea_type_validation

X({"X": "1"})  # No error

labrea_type_validation.enable()

X({"X": "1"})
# ...
# TypeError: Expected type <class 'int'> but got <class 'str'> ('1')
#
# The above exception was the direct cause of the following exception:
#
# Traceback (most recent call last):
# ...
# labrea.exceptions.EvaluationError: Originating in Option('X') | Error during evaluation

Type validation can also be used in a with statement as a context manager using enabled.

with labrea_type_validation.enabled():
    X({"X": "1"})
# ...
# TypeError: Expected type <class 'int'> but got <class 'str'> ('1')
#
# The above exception was the direct cause of the following exception:
#
# Traceback (most recent call last):
# ...
# labrea.exceptions.EvaluationError: Originating in Option('X') | Error during evaluation

Alternatively, the LABREA_TYPE_VALIDATION_ENABLED environment variable can be set to TRUE.

Multithreaded Applications

Type validation is based on the labrea.runtime module. For this reason, type validation is enabled for the current thread and any threads spawned from it. If you are using a multithreaded application, ensure that type validation is enabled in the main thread before spawning any new threads.