API¶

Package `frigid`¶

Data structures which are completely immutable after creation. This behavior is useful for configuration objects, value objects, and other scenarios requiring collections with strong immutability guarantees.

Dictionary: A dict-like structure that becomes completely immutable after creation. Includes a ValidatorDictionary variant, which validates entries during creation.
Namespace: Similar to types.SimpleNamespace but completely immutable after creation.
Class: Metaclass for producing classes with immutable class attributes. Has variants which are compatible with abc.ABCMeta and typing.Protocol.
Module: A module type that enforces complete attribute immutability.
reclassify_modules: Convenience function for making modules in a package immutable.
Object: Base class for objects with immutable attributes.
immutable: Decorator for causing classes to produce immutable instances.
one: Convenience function for producing single-element tuples.

Module `frigid.dictionaries`¶

Immutable dictionaries.

Dictionaries which cannot be modified after creation.

Note

While types.MappingProxyType also provides a read-only view of a dictionary, it has important differences from Dictionary:

A MappingProxyType is a view over a mutable dictionary, so its contents can still change if the underlying dictionary is modified.
Dictionary owns its data and guarantees that it will never change.
Dictionary provides set operations (union, intersection) that maintain immutability guarantees.

Use MappingProxyType when you want to expose a read-only view of a dictionary that might need to change. Use Dictionary when you want to ensure that the data can never change, such as for configuration objects or other cases requiring strong immutability guarantees.

AbstractDictionary: Base class defining the immutable dictionary interface. Implementations must provide __getitem__, __iter__, and __len__.
Dictionary: Standard implementation of an immutable dictionary. Supports all usual dict read operations but prevents any modifications.
ValidatorDictionary: Validates entries before addition using a supplied predicate function.

>>> from frigid import Dictionary
>>> d = Dictionary( x = 1, y = 2 )
>>> d[ 'z' ] = 3  # Attempt to add entry
Traceback (most recent call last):
    ...
frigid.exceptions.EntryImmutabilityError: Cannot assign or delete entry for 'z'.
>>> d[ 'x' ] = 4  # Attempt modification
Traceback (most recent call last):
    ...
frigid.exceptions.EntryImmutabilityError: Cannot assign or delete entry for 'x'.
>>> del d[ 'y' ]  # Attempt removal
Traceback (most recent call last):
    ...
frigid.exceptions.EntryImmutabilityError: Cannot assign or delete entry for 'y'.

class frigid.dictionaries.AbstractDictionary¶

Bases: Mapping[H, V]

Abstract base class for immutable dictionaries.

An immutable dictionary prevents modification or removal of entries after creation. This provides a clean interface for dictionaries that should never change.

Implementations must provide __getitem__, __iter__, __len__.

get(k[, d]) → D[k] if k in D, else d. d defaults to None.¶

items() → a set-like object providing a view on D's items¶

keys() → a set-like object providing a view on D's keys¶

values() → an object providing a view on D's values¶

class frigid.dictionaries.Dictionary(*iterables: Annotated[Mapping[H, V] | Iterable[tuple[H, V]], Doc('Zero or more iterables from which to initialize dictionary data. Each iterable must be dictionary or sequence of key-value pairs. Duplicate keys will result in an error.')], **entries: Annotated[V, Doc('Zero or more keyword arguments from which to initialize dictionary data.')])¶

Bases: Object, _DictionaryOperations[H, V]

Immutable dictionary.

Prevents addition, alteration, or removal of dictionary entries after creation.

copy() → Self¶: Provides fresh copy of dictionary.

get(key: H, default: V | AbsentSingleton = absence.absent) → Annotated[V, Doc('Value of entry, if it exists. Else, supplied default value or ``None``.')]¶: Retrieves entry associated with key, if it exists.

items() → ItemsView[H, V]¶: Provides iterable view over dictionary items.

keys() → KeysView[H]¶: Provides iterable view over dictionary keys.

values() → ValuesView[V]¶: Provides iterable view over dictionary values.

with_data(*iterables: Annotated[Mapping[H, V] | Iterable[tuple[H, V]], Doc('Zero or more iterables from which to initialize dictionary data. Each iterable must be dictionary or sequence of key-value pairs. Duplicate keys will result in an error.')], **entries: Annotated[V, Doc('Zero or more keyword arguments from which to initialize dictionary data.')]) → Self¶: Creates new dictionary with same behavior but different data.

class frigid.dictionaries.ValidatorDictionary(validator: Annotated[Callable[[H, V], bool], Doc('Callable which validates entries before addition to dictionary.')], /, *iterables: Annotated[Mapping[H, V] | Iterable[tuple[H, V]], Doc('Zero or more iterables from which to initialize dictionary data. Each iterable must be dictionary or sequence of key-value pairs. Duplicate keys will result in an error.')], **entries: Annotated[V, Doc('Zero or more keyword arguments from which to initialize dictionary data.')])¶

Bases: Dictionary[H, V]

Immutable dictionary with validation of entries on initialization.

Prevents addition, alteration, or removal of dictionary entries after creation.

When an attempt to create a dictionary with entries, each entry is validated against supplied criteria. If validation fails for any entry, then the dictionary creation is rejected.

copy() → Self¶: Provides fresh copy of dictionary.

get(key: H, default: V | AbsentSingleton = absence.absent) → Annotated[V, Doc('Value of entry, if it exists. Else, supplied default value or ``None``.')]¶: Retrieves entry associated with key, if it exists.

items() → ItemsView[H, V]¶: Provides iterable view over dictionary items.

keys() → KeysView[H]¶: Provides iterable view over dictionary keys.

values() → ValuesView[V]¶: Provides iterable view over dictionary values.

with_data(*iterables: Annotated[Mapping[H, V] | Iterable[tuple[H, V]], Doc('Zero or more iterables from which to initialize dictionary data. Each iterable must be dictionary or sequence of key-value pairs. Duplicate keys will result in an error.')], **entries: Annotated[V, Doc('Zero or more keyword arguments from which to initialize dictionary data.')]) → Self¶: Creates new dictionary with same behavior but different data.

Module `frigid.namespaces`¶

Immutable namespaces.

Provides a namespace type with immutable attributes. Similar to types.SimpleNamespace, but attributes cannot be modified or deleted after initialization.

The namespace implementation is modeled after types.SimpleNamespace but adds immutability. Like types.SimpleNamespace, it provides a simple __repr__ which lists all attributes.

>>> from frigid import Namespace
>>> ns = Namespace( x = 1, y = 2 )
>>> ns.z = 3  # Attempt to add attribute
Traceback (most recent call last):
    ...
frigid.exceptions.AttributeImmutabilityError: Cannot assign or delete attribute 'z'.
>>> ns.x = 4  # Attempt modification
Traceback (most recent call last):
    ...
frigid.exceptions.AttributeImmutabilityError: Cannot assign or delete attribute 'x'.
>>> ns
frigid.namespaces.Namespace( x = 1, y = 2 )

class frigid.namespaces.Namespace(*iterables: Annotated[Mapping[H, V] | Iterable[tuple[H, V]], Doc('Zero or more iterables from which to initialize dictionary data. Each iterable must be dictionary or sequence of key-value pairs. Duplicate keys will result in an error.')], **attributes: Annotated[V, Doc('Zero or more keyword arguments from which to initialize dictionary data.')])¶

Bases: Object

Immutable namespaces.

A namespace is an object, whose attributes can be determined from iterables and keyword arguments, at initialization time. The string representation of the namespace object reflects its current instance attributes. Modeled after types.SimpleNamespace.

Prevents assignment or deletion of instance attributes after instance creation.

Module `frigid.modules`¶

Immutable modules.

Provides a module type that enforces complete attribute immutability. This helps ensure that module-level constants remain constant and that module interfaces remain stable during runtime.

The module implementation is derived from types.ModuleType and adds immutability. This makes it particularly useful for:

Ensuring constants remain constant
Preventing modification of module interfaces

Also provides a convenience function:

reclassify_modules: Converts existing modules to immutable modules.

class frigid.modules.Module(name, doc=None)¶

Bases: ModuleType

Immutable modules.

Derived from types.ModuleType, this class is suitable for use as a Python module class.

Prevents assignment or deletion of module attributes after module creation.

This behavior helps ensure that module-level constants remain constant and that module interfaces remain stable during runtime.

frigid.modules.reclassify_modules(attributes: Annotated[Mapping[str, Any] | ModuleType | str, Doc('Module, module name, or dictionary of object attributes.')], recursive: Annotated[bool, Doc('Recursively reclassify package modules?')] = False) → None¶

Reclassifies modules to be immutable.

Can operate on individual modules or entire package hierarchies.

Notes¶

Only converts modules within the same package to prevent unintended modifications to external modules.
When used with a dictionary, converts any module objects found as values if they belong to the same package.
Has no effect on already-immutable modules.

Module `frigid.classes`¶

Immutable classes.

Provides metaclasses for creating classes with immutable attributes. Once a class is initialized, new attributes may not be assigned to it and its existing attributes cannot be reassigned or deleted.

The implementation includes:

Class: Standard metaclass for immutable classes; derived from type.
ABCFactory: Metaclass for abstract base classes; derived from abc.ABCMeta.
ProtocolClass: Metaclass for protocol classes; derived from typing.Protocol.

Additionally, metaclasses for dataclasses are provided as a convenience.

>>> from frigid import Class
>>> class Example( metaclass = Class ):
...     x = 1
>>> Example.y = 2  # Attempt assignment
Traceback (most recent call last):
    ...
frigid.exceptions.AttributeImmutabilityError: Cannot assign or delete attribute 'y'.
>>> Example.x = 3  # Attempt reassignment
Traceback (most recent call last):
    ...
frigid.exceptions.AttributeImmutabilityError: Cannot assign or delete attribute 'x'.

class frigid.classes.ABCFactory(name: str, bases: tuple[type, ...], namespace: dict[str, Any], *, decorators: Iterable[Callable[[type], type]] = (), docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = (), **args: Any)¶

Bases: ABCMeta

Immutable abstract base class factory.

Derived from type, this is a metaclass. A metaclass is a class factory class. I.e., it is a class that produces other classes as its instances.

Prevents assignment or deletion of class attributes after class creation.

mro()¶: Return a type’s method resolution order.

register(subclass)¶

Returns the subclass, to allow usage as a class decorator.

class frigid.classes.Class(name: str, bases: tuple[type, ...], namespace: dict[str, Any], *, decorators: Iterable[Callable[[type], type]] = (), docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = (), **args: Any)¶

Bases: type

Immutable class factory.

Derived from type, this is a metaclass. A metaclass is a class factory class. I.e., it is a class that produces other classes as its instances.

Prevents assignment or deletion of class attributes after class creation.

mro()¶: Return a type’s method resolution order.

frigid.classes.ClassDecorators¶: alias of Iterable[Callable[[type], type]]

class frigid.classes.CompleteDataclass(name: str, bases: tuple[type, ...], namespace: dict[str, Any], *, decorators: Iterable[Callable[[type], type]] = (), docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = (), **args: Any)¶

Bases: Class

Immutable dataclass factory.

Dataclasses from this factory produce immutable instances.

Derived from type, this is a metaclass. A metaclass is a class factory class. I.e., it is a class that produces other classes as its instances.

Prevents assignment or deletion of class attributes after class creation.

mro()¶: Return a type’s method resolution order.

class frigid.classes.CompleteProtocolDataclass(name: str, bases: tuple[type, ...], namespace: dict[str, Any], *, decorators: Iterable[Callable[[type], type]] = (), docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = (), **args: Any)¶

Bases: ProtocolClass

Immutable protocol dataclass factory.

Dataclasses from this factory produce immutable instances.

Derived from type, this is a metaclass. A metaclass is a class factory class. I.e., it is a class that produces other classes as its instances.

Prevents assignment or deletion of class attributes after class creation.

mro()¶: Return a type’s method resolution order.

register(subclass)¶

Returns the subclass, to allow usage as a class decorator.

class frigid.classes.Dataclass(name: str, bases: tuple[type, ...], namespace: dict[str, Any], *, decorators: Iterable[Callable[[type], type]] = (), docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = (), **args: Any)¶

Bases: Class

Immutable dataclass factory.

Derived from type, this is a metaclass. A metaclass is a class factory class. I.e., it is a class that produces other classes as its instances.

Prevents assignment or deletion of class attributes after class creation.

mro()¶: Return a type’s method resolution order.

class frigid.classes.ProtocolClass(name: str, bases: tuple[type, ...], namespace: dict[str, Any], *, decorators: Iterable[Callable[[type], type]] = (), docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = (), **args: Any)¶

Bases: _ProtocolMeta

Immutable protocol class factory.

Derived from type, this is a metaclass. A metaclass is a class factory class. I.e., it is a class that produces other classes as its instances.

Prevents assignment or deletion of class attributes after class creation.

mro()¶: Return a type’s method resolution order.

register(subclass)¶

Returns the subclass, to allow usage as a class decorator.

class frigid.classes.ProtocolDataclass(name: str, bases: tuple[type, ...], namespace: dict[str, Any], *, decorators: Iterable[Callable[[type], type]] = (), docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = (), **args: Any)¶

Bases: ProtocolClass

Immutable protocol dataclass factory.

Derived from type, this is a metaclass. A metaclass is a class factory class. I.e., it is a class that produces other classes as its instances.

Prevents assignment or deletion of class attributes after class creation.

mro()¶: Return a type’s method resolution order.

register(subclass)¶

Returns the subclass, to allow usage as a class decorator.

Module `frigid.objects`¶

Immutable objects.

Provides a base class and decorator for creating objects with immutable attributes. Once an object is initialized, its attributes cannot be modified or deleted.

>>> from frigid import Object
>>> class Point( Object ):
...     def __init__( self, x, y ):
...         self.x = x
...         self.y = y
...         super( ).__init__( )
...
>>> obj = Point( 1, 2 )  # Initialize with attributes
>>> obj.z = 3  # Attempt to add attribute
Traceback (most recent call last):
...
frigid.exceptions.AttributeImmutabilityError: Cannot assign or delete attribute 'z'.
>>> obj.x = 4  # Attempt modification
Traceback (most recent call last):
...
frigid.exceptions.AttributeImmutabilityError: Cannot assign or delete attribute 'x'.

The immutable decorator can be used to make any class immutable:

>>> from frigid import immutable
>>> @immutable
... class Config:
...     def __init__( self, verbose = False ):
...         self.verbose  = verbose
...
>>> config = Config( verbose = True )
>>> config.verbose = False  # Attempt to modify attribute
Traceback (most recent call last):
    ...
frigid.exceptions.AttributeImmutabilityError: ...

class frigid.objects.Object(*posargs: Any, **nomargs: Any)¶

Bases: object

Immutable objects.

Prevents assignment or deletion of instance attributes after instance creation.

frigid.objects.immutable(class_: type[C] | AbsentSingleton = absence.absent, *, docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = ()) → type[C] | Callable[[type[C]], type[C]]¶

Decorator which makes class immutable after initialization.

Cannot be applied to classes which define their own __setattr__ or __delattr__ methods.

This decorator can be used in different ways:

Simple decorator:

>>> @immutable
... class Config:
...     pass

With parameters:

>>> @immutable( mutables = ( 'version', ) )
... class Config:
...     pass

Module `frigid.sequences`¶

Immutable sequences.

frigid.sequences.one(value: _V) → tuple[_V, ...]¶

Produces single-item tuple from value.

Provides a more explicit and readable alternative to the comma-syntax for creating single-item tuples. While Python allows ( x, ) for creating single-item tuples, using one( x ) can be clearer, especially in certain contexts:

List comprehensions and generator expressions
Situations where formatter behavior with trailing commas is undesired

Module `frigid.installers`¶

Convenience to expose certain package features as Python builtins.

frigid.installers.install(single_name: Annotated[str | None, Doc('Name to use for single function in builtins. ``None`` to skip.')] = 'one') → None¶: Installs 1-element tuple constructor into builtins.

Module `frigid.exceptions`¶

Family of exceptions for package API.

Provides a hierarchy of exceptions that are raised when immutability is violated. The hierarchy is designed to allow both specific and general exception handling.

exception frigid.exceptions.AttributeImmutabilityError(name: str)¶

Bases: Omnierror, AttributeError, TypeError

Attempt to modify immutable attribute.

with_traceback()¶: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args¶

name¶: attribute name

obj¶: object

exception frigid.exceptions.DecoratorCompatibilityError(class_name: str, method_name: str)¶

Bases: Omnierror, TypeError

Attempt to apply decorator to incompatible class.

with_traceback()¶: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args¶

exception frigid.exceptions.EntryImmutabilityError(key: Hashable)¶

Bases: Omnierror, TypeError

Attempt to modify immutable dictionary entry.

with_traceback()¶: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args¶

exception frigid.exceptions.EntryValidityError(indicator: Hashable, value: Any)¶

Bases: Omnierror, ValueError

Attempt to add invalid entry to dictionary.

with_traceback()¶: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args¶

exception frigid.exceptions.Omnierror¶

Bases: Omniexception, Exception

Base for error exceptions raised by package API.

with_traceback()¶: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args¶

exception frigid.exceptions.Omniexception¶

Bases: ImmutableObject, BaseException

Base for all exceptions raised by package API.

with_traceback()¶: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args¶

Module `frigid.qaliases`¶

Qualified aliases to immutable data structures.

Provides aliases prefixed with “Immutable” for all core classes. These are useful for avoiding namespace collisions when importing from the package, particularly with common names like “Dictionary” or “Namespace”.

For example, instead of:

>>> from frigid import Dictionary
>>> # Possible conflict with other Dictionary classes

you could use:

>>> from frigid.qaliases import ImmutableDictionary
>>> # Clearly indicates the source and behavior

frigid.qaliases.AbstractImmutableDictionary: alias of AbstractDictionary

frigid.qaliases.ImmutableABCFactory: alias of ABCFactory

frigid.qaliases.ImmutableClass: alias of Class

frigid.qaliases.ImmutableCompleteDataclass: alias of CompleteDataclass

frigid.qaliases.ImmutableCompleteProtocolDataclass: alias of CompleteProtocolDataclass

frigid.qaliases.ImmutableDataclass: alias of Dataclass

frigid.qaliases.ImmutableDictionary: alias of Dictionary

frigid.qaliases.ImmutableModule: alias of Module

frigid.qaliases.ImmutableNamespace: alias of Namespace

frigid.qaliases.ImmutableObject: alias of Object

frigid.qaliases.ImmutableProtocolClass: alias of ProtocolClass

frigid.qaliases.ImmutableProtocolDataclass: alias of ProtocolDataclass

frigid.qaliases.ImmutableValidatorDictionary: alias of ValidatorDictionary

frigid.qaliases.immutable(class_: type[C] | AbsentSingleton = absence.absent, *, docstring: str | None | AbsentSingleton = absence.absent, mutables: Collection[str] = ()) → type[C] | Callable[[type[C]], type[C]]

Decorator which makes class immutable after initialization.

Cannot be applied to classes which define their own __setattr__ or __delattr__ methods.

This decorator can be used in different ways:

Simple decorator:

>>> @immutable
... class Config:
...     pass

With parameters:

>>> @immutable( mutables = ( 'version', ) )
... class Config:
...     pass

frigid.qaliases.reclassify_modules_as_immutable(attributes: Annotated[Mapping[str, Any] | ModuleType | str, Doc('Module, module name, or dictionary of object attributes.')], recursive: Annotated[bool, Doc('Recursively reclassify package modules?')] = False) → None

Reclassifies modules to be immutable.

Can operate on individual modules or entire package hierarchies.

Notes¶

Only converts modules within the same package to prevent unintended modifications to external modules.
When used with a dictionary, converts any module objects found as values if they belong to the same package.
Has no effect on already-immutable modules.

API¶

Package frigid¶

Module frigid.dictionaries¶

Module frigid.namespaces¶

Module frigid.modules¶

Notes¶

Module frigid.classes¶

Module frigid.objects¶

Module frigid.sequences¶

Module frigid.installers¶

Module frigid.exceptions¶

Module frigid.qaliases¶

Notes¶

Package `frigid`¶

Module `frigid.dictionaries`¶

Module `frigid.namespaces`¶

Module `frigid.modules`¶

Module `frigid.classes`¶

Module `frigid.objects`¶

Module `frigid.sequences`¶

Module `frigid.installers`¶

Module `frigid.exceptions`¶

Module `frigid.qaliases`¶