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Variable

chanfig.Variable

Bases: Generic[V]

Mutable wrapper for immutable objects.

Parameters:

Name Type Description Default

value

Any

The value to wrap.

 Null

type

type | None

Desired type of the value.

 None

choices

list | None

Possible values of the value.

 None

validator

Callable | None

Callable that validates the value.

 None

required

bool

Whether the value is required.

 False

help

str | None

Help message of the value.

 None

Raises:

Type Description
RuntimeError

If required is True and value is Null.
TypeError

If type is specified and value is not an instance of type.
ValueError

| If choices is specified and value is not in choices. If validator is specified and validator returns False.

Attributes:

Name Type Description
value Any

The wrapped value.
dtype type

The type of the wrapped value.
Notes

Variable by default wrap the instance type to type of the wrapped object. Therefore, isinstance(Variable(1), int) will return True.

To temporarily disable this behaviour, you can call context manager with Variable.unwrapped().

To permanently disable this behaviour, you can call Variable.unwrap().

Examples:

Python Console Session
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>>> v = Variable(1)
>>> n = v
>>> v, n
(1, 1)
>>> v += 1
>>> v, n
(2, 2)
>>> v.value = 3
>>> v, n
(3, 3)
>>> n.set(4)
>>> v, n
(4, 4)
>>> n = 5
>>> v, n
(4, 5)
>>> f'{v} < {n}'
'4 < 5'
>>> isinstance(v, int)
True
>>> type(v)
<class 'chanfig.variable.Variable'>
>>> v.dtype
<class 'int'>
>>> with v.unwrapped():
...    isinstance(v, int)
False
>>> v = Variable('hello')
>>> f'{v}, world!'
'hello, world!'
>>> v += ', world!'
>>> v
'hello, world!'
>>> "hello" in v
True
Source code in chanfig/variable.py
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class Variable(Generic[V]):  # pylint: disable=R0902
    r"""
    Mutable wrapper for immutable objects.

    Args:
        value: The value to wrap.
        type: Desired type of the value.
        choices: Possible values of the value.
        validator: `Callable` that validates the value.
        required: Whether the value is required.
        help: Help message of the value.

    Raises:
        RuntimeError: If `required` is `True` and `value` is `Null`.
        TypeError: If `type` is specified and `value` is not an instance of `type`.
        ValueError: |
            If `choices` is specified and `value` is not in `choices`.
            If `validator` is specified and `validator` returns `False`.

    Attributes:
        value: The wrapped value.
        dtype: The type of the wrapped value.

    Notes:
        `Variable` by default wrap the instance type to type of the wrapped object.
        Therefore, `isinstance(Variable(1), int)` will return `True`.

        To temporarily disable this behaviour, you can call context manager `with Variable.unwrapped()`.

        To permanently disable this behaviour, you can call `Variable.unwrap()`.

    Examples:
        >>> v = Variable(1)
        >>> n = v
        >>> v, n
        (1, 1)
        >>> v += 1
        >>> v, n
        (2, 2)
        >>> v.value = 3
        >>> v, n
        (3, 3)
        >>> n.set(4)
        >>> v, n
        (4, 4)
        >>> n = 5
        >>> v, n
        (4, 5)
        >>> f'{v} < {n}'
        '4 < 5'
        >>> isinstance(v, int)
        True
        >>> type(v)
        <class 'chanfig.variable.Variable'>
        >>> v.dtype
        <class 'int'>
        >>> with v.unwrapped():
        ...    isinstance(v, int)
        False
        >>> v = Variable('hello')
        >>> f'{v}, world!'
        'hello, world!'
        >>> v += ', world!'
        >>> v
        'hello, world!'
        >>> "hello" in v
        True
    """

    wrap_type: bool = True
    _storage: List[Any]
    _type: Optional[type] = None
    _choices: Optional[list] = None
    _validator: Optional[Callable] = None
    _required: bool = False
    _help: Optional[str] = None

    def __init__(  # pylint: disable=R0913
        self,
        value: Any = Null,
        type: type | None = None,  # pylint: disable=W0622
        choices: list | None = None,
        validator: Callable | None = None,
        required: bool = False,
        help: str | None = None,  # pylint: disable=W0622
    ) -> None:
        self._storage = [value]
        self._type = type
        self._choices = choices
        self._validator = validator
        self._required = required
        self._help = help

    @property  # type: ignore[misc]
    def __class__(self) -> type:
        return self.value.__class__ if self.wrap_type else type(self)

    @property
    def value(self) -> Any:
        r"""
        Fetch the object wrapped in `Variable`.
        """

        return self._storage[0]

    @value.setter
    def value(self, value) -> None:
        r"""
        Assign value to the object wrapped in `Variable`.
        """

        self.validate(value)
        self._storage[0] = self._get_value(value)

    @property
    def dtype(self) -> type:
        r"""
        Data type of the object wrapped in `Variable`.

        Examples:
            >>> id = Variable(1016)
            >>> type(id)
            <class 'chanfig.variable.Variable'>
            >>> id.dtype
            <class 'int'>
            >>> issubclass(id.dtype, int)
            True
        """

        return self.value.__class__

    @property
    def storage(self) -> list[Any]:
        r"""
        Storage of `Variable`.
        """

        return self._storage

    @property
    def type(self) -> type | None:
        return self._type

    @property
    def choices(self) -> list | None:
        return self._choices

    @property
    def validator(self) -> Callable | None:
        return self._validator

    @property
    def required(self) -> bool:
        return self._required

    @property
    def help(self) -> str:
        return self._help or ""

    def validate(self, *args) -> None:
        r"""
        Validate if the value is valid.
        """

        if len(args) == 0:
            value = self.value
        elif len(args) == 1:
            value = args[0]
        else:
            raise ValueError("Too many arguments.")
        if self._required and value is Null:
            raise RuntimeError("Value is required.")
        if self._type is not None and not isinstance(value, self._type):
            raise TypeError(f"Value {value} is not of type {self._type}.")
        if self._choices is not None and value not in self._choices:
            raise ValueError(f"Value {value} is not in choices {self._choices}.")
        if self._validator is not None and not self._validator(value):
            raise ValueError(f"Value {value} is not valid.")

    def get(self) -> Any:
        r"""
        Fetch the object wrapped in `Variable`.
        """

        return self.value

    def set(self, value) -> None:
        r"""
        Assign value to the object wrapped in `Variable`.

        `Variable.set` is extremely useful when you want to change the value without changing the reference.

        In `FlatDict.set`, all assignments of `Variable` calls `Variable.set` Internally.
        """

        self.value = value

    def __get__(self, obj, objtype=None):
        return self

    def __set__(self, obj, value):
        self.value = value

    def to(self, cls: Callable) -> Any:  # pylint: disable=C0103
        r"""
        Convert the object wrapped in `Variable` to target `cls`.

        Args:
            cls: The type to convert to.

        Examples:
            >>> id = Variable(1016)
            >>> id.to(float)
            1016.0
            >>> id.to(str)
            '1016.0'
        """

        self.value = cls(self.value)
        return self

    def int(self) -> int:
        r"""
        Convert the object wrapped in `Variable` to python `int`.

        Examples:
            >>> id = Variable(1016.0)
            >>> id.int()
            1016
        """

        return self.to(int)

    def float(self) -> float:
        r"""
        Convert the object wrapped in `Variable` to python `float`.

        Examples:
            >>> id = Variable(1016)
            >>> id.float()
            1016.0
        """

        return self.to(float)

    def str(self) -> str:
        r"""
        Convert the object wrapped in `Variable` to python `float`.

        Examples:
            >>> id = Variable(1016)
            >>> id.str()
            '1016'
        """

        return self.to(str)

    def wrap(self) -> None:
        r"""
        Wrap the type of `Variable`.

        Examples:
            >>> id = Variable(1016)
            >>> id.unwrap()
            >>> isinstance(id, int)
            False
            >>> id.wrap()
            >>> isinstance(id, int)
            True
        """

        self.wrap_type = True

    def unwrap(self) -> None:
        r"""
        Unwrap the type of `Variable`.

        Examples:
            >>> id = Variable(1016)
            >>> id.unwrap()
            >>> isinstance(id, int)
            False
        """

        self.wrap_type = False

    @contextmanager
    def unwrapped(self):
        r"""
        Context manager which temporarily unwrap the `Variable`.

        Examples:
            >>> id = Variable(1016)
            >>> isinstance(id, int)
            True
            >>> with id.unwrapped():
            ...    isinstance(id, int)
            False
        """

        wrap_type = self.wrap_type
        self.wrap_type = False
        try:
            yield self
        finally:
            self.wrap_type = wrap_type

    @staticmethod
    def _get_value(obj) -> Any:
        if isinstance(obj, Variable):
            return obj.value
        return obj

    def __getattr__(self, attr) -> Any:
        return getattr(self.value, attr)

    def __lt__(self, other) -> bool:
        return self.value < self._get_value(other)

    def __le__(self, other) -> bool:
        return self.value <= self._get_value(other)

    def __eq__(self, other) -> bool:
        return self.value == self._get_value(other)

    def __ne__(self, other) -> bool:
        return self.value != self._get_value(other)

    def __ge__(self, other) -> bool:
        return self.value >= self._get_value(other)

    def __gt__(self, other) -> bool:
        return self.value > self._get_value(other)

    # def __index__(self):
    #     return self.value.__index__()

    def __invert__(self):
        return ~self.value

    def __abs__(self):
        return abs(self.value)

    def __add__(self, other):
        return Variable(self.value + self._get_value(other))

    def __radd__(self, other):
        return Variable(self._get_value(other) + self.value)

    def __iadd__(self, other):
        self.value += self._get_value(other)
        return self

    def __and__(self, other):
        return Variable(self.value & self._get_value(other))

    def __rand__(self, other):
        return Variable(self._get_value(other) & self.value)

    def __iand__(self, other):
        self.value &= self._get_value(other)
        return self

    def __floordiv__(self, other):
        return Variable(self.value // self._get_value(other))

    def __rfloordiv__(self, other):
        return Variable(self._get_value(other) // self.value)

    def __ifloordiv__(self, other):
        self.value //= self._get_value(other)
        return self

    def __mod__(self, other):
        return Variable(self.value % self._get_value(other))

    def __rmod__(self, other):
        return Variable(self._get_value(other) % self.value)

    def __imod__(self, other):
        self.value %= self._get_value(other)
        return self

    def __mul__(self, other):
        return Variable(self.value * self._get_value(other))

    def __rmul__(self, other):
        return Variable(self._get_value(other) * self.value)

    def __imul__(self, other):
        self.value *= self._get_value(other)
        return self

    def __matmul__(self, other):
        return Variable(self.value @ self._get_value(other))

    def __rmatmul__(self, other):
        return Variable(self._get_value(other) @ self.value)

    def __imatmul__(self, other):
        self.value @= self._get_value(other)
        return self

    def __pow__(self, other):
        return Variable(self.value ** self._get_value(other))

    def __rpow__(self, other):
        return Variable(self._get_value(other) ** self.value)

    def __ipow__(self, other):
        self.value **= self._get_value(other)
        return self

    def __truediv__(self, other):
        return Variable(self.value / self._get_value(other))

    def __rtruediv__(self, other):
        return Variable(self._get_value(other) / self.value)

    def __itruediv__(self, other):
        self.value /= self._get_value(other)
        return self

    def __sub__(self, other):
        return Variable(self.value - self._get_value(other))

    def __rsub__(self, other):
        return Variable(self._get_value(other) - self.value)

    def __isub__(self, other):
        self.value -= self._get_value(other)
        return self

    def __copy__(self):
        return Variable(self.value)

    def __deepcopy__(self, memo: Mapping | None = None):
        return Variable(copy(self.value))

    def __format__(self, format_spec):
        return self.value if isinstance(self, str) else format(self.value, format_spec)

    def __iter__(self):
        return iter(self.value)

    def __next__(self):
        return next(self.value)

    def __hash__(self):
        return hash(self.value)

    def __repr__(self):
        return repr(self.value)

    def __str__(self):
        return self.value if isinstance(self, str) else str(self.value)

    def __json__(self):
        return self.value

    def __contains__(self, name):
        return name in self.value

value property writable

Python
value: Any

Fetch the object wrapped in Variable.

dtype property

Python
dtype: type

Data type of the object wrapped in Variable.

Examples:

Python Console Session
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>>> id = Variable(1016)
>>> type(id)
<class 'chanfig.variable.Variable'>
>>> id.dtype
<class 'int'>
>>> issubclass(id.dtype, int)
True

storage property

Python
storage: list[Any]

Storage of Variable.

validate

Python
validate(*args) -> None

Validate if the value is valid.

Source code in chanfig/variable.py
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def validate(self, *args) -> None:
    r"""
    Validate if the value is valid.
    """

    if len(args) == 0:
        value = self.value
    elif len(args) == 1:
        value = args[0]
    else:
        raise ValueError("Too many arguments.")
    if self._required and value is Null:
        raise RuntimeError("Value is required.")
    if self._type is not None and not isinstance(value, self._type):
        raise TypeError(f"Value {value} is not of type {self._type}.")
    if self._choices is not None and value not in self._choices:
        raise ValueError(f"Value {value} is not in choices {self._choices}.")
    if self._validator is not None and not self._validator(value):
        raise ValueError(f"Value {value} is not valid.")

get

Python
get() -> Any

Fetch the object wrapped in Variable.

Source code in chanfig/variable.py
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def get(self) -> Any:
    r"""
    Fetch the object wrapped in `Variable`.
    """

    return self.value

set

Python
set(value) -> None

Assign value to the object wrapped in Variable.

Variable.set is extremely useful when you want to change the value without changing the reference.

In FlatDict.set, all assignments of Variable calls Variable.set Internally.

Source code in chanfig/variable.py
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def set(self, value) -> None:
    r"""
    Assign value to the object wrapped in `Variable`.

    `Variable.set` is extremely useful when you want to change the value without changing the reference.

    In `FlatDict.set`, all assignments of `Variable` calls `Variable.set` Internally.
    """

    self.value = value

to

Python
to(cls: Callable) -> Any

Convert the object wrapped in Variable to target cls.

Parameters:

Name Type Description Default

cls

Callable

The type to convert to.

 required

Examples:

Python Console Session
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>>> id = Variable(1016)
>>> id.to(float)
1016.0
>>> id.to(str)
'1016.0'
Source code in chanfig/variable.py
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def to(self, cls: Callable) -> Any:  # pylint: disable=C0103
    r"""
    Convert the object wrapped in `Variable` to target `cls`.

    Args:
        cls: The type to convert to.

    Examples:
        >>> id = Variable(1016)
        >>> id.to(float)
        1016.0
        >>> id.to(str)
        '1016.0'
    """

    self.value = cls(self.value)
    return self

int

Python
int() -> int

Convert the object wrapped in Variable to python int.

Examples:

Python Console Session
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>>> id = Variable(1016.0)
>>> id.int()
1016
Source code in chanfig/variable.py
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def int(self) -> int:
    r"""
    Convert the object wrapped in `Variable` to python `int`.

    Examples:
        >>> id = Variable(1016.0)
        >>> id.int()
        1016
    """

    return self.to(int)

float

Python
float() -> float

Convert the object wrapped in Variable to python float.

Examples:

Python Console Session
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>>> id = Variable(1016)
>>> id.float()
1016.0
Source code in chanfig/variable.py
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def float(self) -> float:
    r"""
    Convert the object wrapped in `Variable` to python `float`.

    Examples:
        >>> id = Variable(1016)
        >>> id.float()
        1016.0
    """

    return self.to(float)

str

Python
str() -> str

Convert the object wrapped in Variable to python float.

Examples:

Python Console Session
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>>> id = Variable(1016)
>>> id.str()
'1016'
Source code in chanfig/variable.py
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def str(self) -> str:
    r"""
    Convert the object wrapped in `Variable` to python `float`.

    Examples:
        >>> id = Variable(1016)
        >>> id.str()
        '1016'
    """

    return self.to(str)

wrap

Python
wrap() -> None

Wrap the type of Variable.

Examples:

Python Console Session
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>>> id = Variable(1016)
>>> id.unwrap()
>>> isinstance(id, int)
False
>>> id.wrap()
>>> isinstance(id, int)
True
Source code in chanfig/variable.py
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def wrap(self) -> None:
    r"""
    Wrap the type of `Variable`.

    Examples:
        >>> id = Variable(1016)
        >>> id.unwrap()
        >>> isinstance(id, int)
        False
        >>> id.wrap()
        >>> isinstance(id, int)
        True
    """

    self.wrap_type = True

unwrap

Python
unwrap() -> None

Unwrap the type of Variable.

Examples:

Python Console Session
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>>> id = Variable(1016)
>>> id.unwrap()
>>> isinstance(id, int)
False
Source code in chanfig/variable.py
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def unwrap(self) -> None:
    r"""
    Unwrap the type of `Variable`.

    Examples:
        >>> id = Variable(1016)
        >>> id.unwrap()
        >>> isinstance(id, int)
        False
    """

    self.wrap_type = False

unwrapped

Python
unwrapped()

Context manager which temporarily unwrap the Variable.

Examples:

Python Console Session
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>>> id = Variable(1016)
>>> isinstance(id, int)
True
>>> with id.unwrapped():
...    isinstance(id, int)
False
Source code in chanfig/variable.py
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@contextmanager
def unwrapped(self):
    r"""
    Context manager which temporarily unwrap the `Variable`.

    Examples:
        >>> id = Variable(1016)
        >>> isinstance(id, int)
        True
        >>> with id.unwrapped():
        ...    isinstance(id, int)
        False
    """

    wrap_type = self.wrap_type
    self.wrap_type = False
    try:
        yield self
    finally:
        self.wrap_type = wrap_type