mxutils.CheckType

mxutils.CheckType(item: Any, t: Optional[Union[Type, tuple]] = None, label: str | None = None) → Any

Checks item for being of type t.

When the check fails, an error is being raised. If not, item is being passed through. The function can automatically discover the symbol of item when it is defined in the local or global scope of the function call.

Parameters

• item (typing.Any) – The item to be type checked.

• t (typing.Type | tuple[typing.Type] | None (, optional)) – The type or types item is allowed to be. Passing None will only assert that item is not None. Defaults to None.

• label (str | None (, optional)) – The label with which to refer to item in exceptions. Passing None will result in an attempt to infer the symbol. Symbol discovery only works for values in the local or global scope. Defaults to None.

Raises

• TypeError – When item is failing the type test.

• RuntimeError – When accessing a stack trace or reading an executed file failed on a symbol discovery attempt.

Returns

The value of item when the check succeeded.

Return type

typing.Any

Example

import c4d
import math

from mxutils import CheckType

MY_INT: int = 42

class Foo:
    SOME_INT: int = 42

    def __init__(self, x: int) -> None:
        # Asserts that `x` is not `None`.
        CheckType(x)

        # Asserts that `x` is not `None` and assigns its values to `self._x`.
        self._x: object = CheckType(x)

        # Asserts that `MY_INT` is of type `int` or `float` and assigns its int value to `self._y`.
        self._y: int = int(CheckType(MY_INT, (int, float)))


        # Symbols which are neither in the global nor local scope are not automatically
        # discoverable and error messages for such values will refer to the value with
        # 'unknown symbol'.

        # `Foo.SOME_INT` and `math.pi` are not part of the local or global scope. When error
        # messages should not refer to a generic 'Unknown Symbol', one must pass in a label.

        # CheckType(Foo.SOME_INT, bool)
        # TypeError: Expected value of type <class 'bool'> for 'Unknown Symbol'. Received: <class 'int'>

        CheckType(math.pi, int, 'math.pi')
        # TypeError: Expected value of type <class 'int'> for 'math.pi'. Received: <class 'float'>

        # `x`, `y`, and `MY_INT` are in the global/local scope and automatically discovered.
        y: float = 1.0

        CheckType(x, float) 
        # TypeError: Expected value of type <class 'float'> for 'x'. Received: <class 'int'>

        CheckType(y, int)
        # TypeError: Expected value of type <class 'int'> for 'y'. Received: <class 'float'>

        CheckType(MY_INT, bool)
        # TypeError: Expected value of type <class 'bool'> for 'MY_INT'. Received: <class 'int'>